March 2018
Sunday Monday Tuesday Wednesday Thursday Friday Saturday

1

1. 1:30 pm, ISB Bldg. 734 Conf. Rm. 201 (upstairs)

Hosted by: Igor Zaliznyak

We study the temperature dependence of the electrical resistivity in a system composed of critical spin chains interacting with three dimensional conduction electrons and driven to criticality via an external magnetic field. The relevant experimental system is Yb2Pt2Pb, a metal where itinerant electrons coexist with localized moments of Yb-ions which can be described in terms of effective S = 1/2 spins with dominantly one-dimensional exchange interaction. The spin subsystem becomes critical in a relatively weak magnetic field, where it behaves like a Luttinger liquid. We theoretically examine a Kondo lattice with different effective space dimensionalities of the two interacting sub-systems. We characterize the corresponding non-Fermi liquid behavior due to the "local criticality" from the spins by calculating the electronic relaxation rate and the dc resistivity and establish its quasi linear temperature dependence.

2

1. 12:15 pm, Building 510, Room 2-160

Hosted by: Christoph Lehner

2. 2 pm, Small Seminar Room, Bldg. 510

Hosted by: Chun Shen

It has long been known that sub-nucleonic fluctuations of the energy density in the initial stages of heavy ion collisions play an important role in generating the observed distributions of particles and their flow. These energy density fluctuations are dominated by the radiation of small-x gluons which are populated to classically large occupation numbers in the wave functions of ultra-relativistic heavy ions. While these soft gluons dominate the initial conditions for the energy density, it is quark production which determines the initial conditions of other conserved charges, like flavor and baryon number. With the recent development of state-of-the art hydrodynamics codes tailored to the Beam Energy Scan which can propagate these conserved charges into the final state, it is timely and important to calculate the initial conditions of these conserved charges from first principles in QCD. In this talk, I will present new results for the spatial correlations among quarks and antiquarks produced at mid-rapidity by pair production from small-x gluons. This single-pair production mechanism, which has been studied for some time in momentum space, is the leading contribution to these correlations in coordinate space for dilute-dense collisions. As one moves from the dilute-dense regime toward the dense-dense regime, correlations due to double pair production become more important, and these correlations persist over larger length scales than the single-pair production mechanism. Over nonperturbative length scales, only the correlations from the overlap geometry remain. I will present explicit results for quark-antiquark correlations due to single pair production, and I will outline some preliminary results for the various double-pair production mechanisms. The ultimate goal of this work will be to construct a code which can initialize these conserved charges over all length scales in heavy-ion collisions.

3

1. 8:30 am, Stony Brook University

The Girl Power in STEM: Press for Progress! symposium at Stony Brook University (SBU) on March 3, co-sponsored by Brookhaven Women in Science (BWIS), will celebrate the accomplishment of women in the Science, Technology, Engineering, and Math (STEM) fields. Lecturers and panelists, including many from Brookhaven Lab, will discuss the impact of women in STEM careers, on the work environment, and on the economy, and how society can improve women's participation in STEM fields. The event marks International Women's Day, proclaimed by the United Nations (UN) as a day to champion women's rights. This year the UN celebrates taking action to promote equal opportunities at all levels and to help forge a more gender inclusive world.

4

1. No events scheduled

5

1. No events scheduled

6

1. 11 am, Small Seminar Room, Bldg. 510

Hosted by: Jia Jiangyong

Upcoming beam energy scan (BES) phase II will explore the QCD phase diagram with an unprecedented precision and would potentially discover the QCD critical point. I will discuss recent theoretical developments aim at maximizing the discovery potential of BESII from both phenomenological and formal perspectives. First, I will discuss new observables which are very sensitive to the presence of the QCD critical point and are possible due to the iTPC upgrade. In the second part, I will report recent progress on understanding and describing hydrodynamic fluctuations. Remarkably, effects of hydrodynamic fluctuations can be potentially important for precise determination of shear viscosity at top RHIC energy and would play a crucial role near the QCD critical point.

2. 2:30 pm, Large Conference Room, Bldg. 535

At the Extreme Light Lab at the Air Force Research Laboratory, Dayton, we explore light matter interaction at relativistic fields with liquid targets. Although demonstrations of up to 4 GeV1 electrons and ~100 MeV protons2 have been achieved in the past, all of these are not feasible as future accelerators, due to their slow duty cycle (usually single shot, rarely 1 Hz). There are many challenges to increasing the duty cycle, where laser technology, target technology, damage to system, target alignment, high repetition rate sub-micron plasma diagnostics provides nearly insurmountable obstacles. In this program, we developed ways to accelerate MeV x-rays, electrons3 and ions4 at kHz repetition rate with a small milli-joule class laser system, by developing a combination of suitable laser system, diagnostic system, target system and experimental data collection system capable of handling the high duty cycle. We also perform femtosecond-time resolution pump-probe imaging of the interaction, and extensive large scale relativistic laser plasma interaction simulations5 that reveal the nature of the acceleration processes. Such a system opens the door to extensive future application as a source for materials processing, radiation hardness testing, medical isotope production, time resolved proton probing on relativistic interactions, and many others.

3. 3:30 pm, Large Seminar Room, Bldg. 510

Hosted by: Andrei Nomerotski

hile non-perturbative approaches such as lattice gauge theory led to significant advances in understanding the physics of strong interactions, many problems remain out of reach for classical computation, in particular, real-time dynamics or properties of QCD at finite baryon density that are being explored in heavy-ion collision experiments. Recent advances in the technology of engineering custom interactions for ultra-cold atomic gases in optical lattices opened a possibility for quantum simulations as was envisioned by R. Feynman in the 1980s. The main idea is that the degrees of freedom of the original system are mapped onto a quantum Hamiltonian whose dynamics can be realized in a laboratory. Many condensed matter Hamiltonians, such as Bose-Hubbard model, have been recently studied in this way. Quantum simulation of gauge theories is however challenging since the gauge symmetry is not naturally present in the ultra-cold atomic systems. I will review the current status of theoretical proposals for quantum simulation of field theories and then focus on our recent work on an explicitly gauge-invariant formulation of the Abelian-Higgs model for simulation on optical lattices.

7

1. 2 pm, Small Seminar Room, Bldg. 510

Hosted by: Christopher Murphy

8

1. 3 pm, Small Seminar Room, Bldg. 510

Hosted by: Chao Zhang

The NOvA experiment is an off-axis long-baseline neutrino oscillation experiment using the NuMI $\nu_{\mu}$ beam originating at Fermilab. By examining the disappearance of muon neutrinos and the appearance of electron neutrinos between the near detector at Fermilab and the far detector in Ash River, MN, NOvA has the potential to help answer a number of fundamental questions: Are the neutrinos' masses ordered the same way as those of the charged leptons? Do leptons experience charge-parity violation? Are there underlying symmetries in the way the neutrino states mix with one another? In this talk I will present NOvA's most recent constraints on the answers to those questions utilizing muon neutrino disappearance and electron neutrino appearance. These updated results are based on a 50% increase in exposure relative to previous results as well as numerous simulation and analysis improvements.

9

1. 12:15 pm, Building 510, Room 2-160

2. 2 pm, Small Seminar Room, Bldg. 510

Hosted by: Chun Shen

The MHV action is the Yang-Mills action quantized on the light-front, where the two explicit physical gluonic degrees of freedom have been canonically transformed to a new set of fields. This transformation leads to the action with vertices being off-shell continuations of the MHV amplitudes. We show that the solution to the field transformation expressing one of the new fields in terms of the Yang-Mills field is a certain type of the Wilson line. More precisely, it is a straight infinite gauge link with a slope extending to the light-cone minus and the transverse direction. One of the consequences of that fact is that certain MHV vertices reduced partially on-shell are gauge invariant — a fact discovered before using conventional light-front perturbation theory. We also analyze the diagrammatic content of the field transformations leading to the MHV action. We found that the diagrams for the solution to the transformation (given by the Wilson line) and its inverse differ only by light-front energy denominators.

10

1. No events scheduled

11

1. No events scheduled

12

1. 3 pm, Small Seminar Room, Bldg. 510

Hosted by: Alessandro Tricoli

The LHC experiments require huge, ever-increasing volumes of data to explore the frontiers of particle physics, and the grid provides the infrastructure to meet this challenge. Today, even medium sized experiments produce petabytes of data that need to be analysed by international collaborations and the relationship between particle physicists and their data has had to evolve to keep pace. Calibrating and systematically understanding detectors requires detailed information, deep learning algorithms promise to allow us to fully exploit our experiments, and on the other hand we want to analyse our data quickly and be the first to publish. This talk will first describe how, shortly after the Higgs discovery, ATLAS realised that the way that analysis was done had to change, and will briefly illustrate what those changes entailed. Next, the NA62 experiment will be described. Recording a billion events per day, NA62 aims to measure the very rare decay of a charged kaon to a charged pion and two neutrinos. The collaboration had to quickly implement petabyte scale data processing infrastructure to perform the sub-nanosecond calibrations needed to challenge the 10% precision of the theory prediction.

13

1. No events scheduled

14

1. 2 am, CFN, Bldg. 735 - first, floor, conference room A

Hosted by: Mingzhao Liu

Solar radiation is a vast, distributed, and renewable energy source which Humanity can utilize via the photovoltaic effect. The goal of photovoltaic technology is to minimize the true costs, while maximizing the power conversion efficiency and lifetime of the cell/module. Interface-related approaches to achieving this goal are explored here, for two technologically-important classes of light absorbers: crystalline-silicon (c-Si) and metal halide perovskite (MHP). The simplest solar cell consists of a light absorber, sandwiched between two metals with dissimilar work functions. Carrier-selective contacts (CSC's), which are ubiquitous in modern solar cells, are added to improve the electrical performance. Solar cells require asymmetric carrier transport within the cell, which can be effected via electrostatic and/or effective fields, and CSC's augment the asymmetry by selectively transporting holes to one contact, and electrons to the other contact. The proper design and implementation of a CSC is crucial, as the performance, lifetime, and/or cost reduction of a solar cell can be hampered by a single interface or layer. A framework, consisting of eight core requirements, was developed from first-principles to evaluate the effectiveness of a given CSC. The framework includes some requirements which are well-recognized, such as the need for appropriate band offsets, and some requirements which are not well-recognized at the moment, such as the need for effective valence/conduction band density of states matching between the absorber and CSC. The application of the framework to multiple silicon-based and MHP-based CSC's revealed the difficulties of effectively designing and implementing a CSC. Three metal oxide/c-Si heterojunctions initially expected to yield comparable electron-selective contacts (ESC's), titanium dioxide/c-Si (TiO2/c-Si), zinc oxide/c-Si (ZnO/c-Si), and tin dioxide/c-Si (SnO2/c-Si), were instead discovered to be widely diff

15

1. 11 am, ISB Bldg. 734 Seminar Room 201 (upstairs)

Hosted by: Mark Dean

5d transition metal oxides have emerged as a novel playground for some of the most outstanding and challenging problems in condensed matter physics, such as metal-insulator transition and quantum magnetism. In particular, layered iridates hosting square lattices of IrO6 octahedra have drawn significant interests due to the electronic and magnetic analogy with high-Tc cuprates. However, materials of this kind are limited to a few Ruddlesden-Popper (RP) compounds. In this talk, I will discuss our recent work on overcoming this bottleneck by constructing such two-dimensional (2D) structures confined in superlattices grown by heteroepitaxy. By leveraging the layering control of epitaxial growth, we are not only able to develop new structural variants of layered iridates, but also unravel and exploit the intriguing spin-orbit-driven 2D magnetism beyond the cuprate physics yet invisible in the RP iridates. The results demonstrate the power of this approach in tailing the exchange interactions, enabling new magnetic controls, and providing unique insights into the emergent phenomena of 5d electrons.

2. 12:30 pm, Building 510, Room 2-160

3. 1:30 pm, ISB Bldg. 734 Conf. Rm. 201 (upstairs)

Hosted by: Robert Konik

We obtain a controlled description of a strongly correlated regime of electronic behaviour. We argue that there are two ways to characterise the electronic degree of freedom, either by the canonical fermion algebra or by the graded Lie algebra su(2|2). The first underlies the Fermi liquid description of correlated matter, and we identify a novel regime governed by the latter. We obtain the electronic spectral function within a controlled approximation, and find a splitting in two of the electronic band. The Luttinger sum rule is violated and a Mott metal-insulator transition is exhibited.

4. 3 pm, Small Seminar Room, Bldg. 510

Hosted by: Chao Zhang

Precision measurements of various asymmetries in neutron decay permit an extraction of the weak axial-vector coupling constant, gA, a fundamental quantity important for weak-interaction physics and as a benchmark for lattice QCD calculations. I will discuss a recent new result from the UCNA Experiment at Los Alamos National Laboratory for a 0.16% precision result on gA from a measurement of the 'A' asymmetry, which represents the parity-violating angular correlation between the neutron's spin and the decay electron's momentum. This long-standing effort was carried out with a superconducting solenoidal electron spectrometer at the LANL Ultracold Neutron (UCN) facility. This new result will be placed in the context of historical results for gA and recent discrepant values for the neutron lifetime obtained via different experimental techniques. I will also discuss the first-ever extraction of the Fierz interference term 'b' in free neutron decay from an analysis of the electron's spectral shape as measured in the UCNA Experiment. A non-zero 'b' term would result from beyond-Standard Model interactions, such as Scalar or Tensor physics. Although the result for 'b' from the UCNA Experiment was systematics limited, it points to the requisite significant improvements in the characterization of the detector energy response that future experiments aimed at a measurement of 'b' will need to achieve in order to probe beyond Standard Model physics at a competitive precision.

16

1. 12:15 pm, Building 510, Room 2-160

Hosted by: Christoph Lehner

2. 1:30 pm, ISB Bldg. 734 Conf. Rm. 201 (upstairs)

Hosted by: Robert Konik

In this talk we review the slave boson meanfield formulation of the fermion+boson quantum dimer model for the pseudogap phase of the high temperature superconductors. We show that in the presence of weak slowly varying external magnetic and electric fields the fermionic dimers undergo semiclassical motion in the external field. As a result in the presence of magnetic fields strong enough to destroy superconductivity the dimers undergo quantum oscillations. Indeed they satisfy Onsager quantization for their orbits and Lifshtiz-Kosevich formula for the amplitude of oscillations. We also compute the effective charges of the dimers in the presence of external magnetic fields as a function of temperature. We show that the effective magnetic charge changes sign from negative −e at low temperature to positive +e at high temperature. This leads to a change of the sign of the Hall coeÿcient as a function of temperature. We also compute the magnetoresistance as a function of the external field and temperature within a linearized Boltzmann equation approximation for the fermionic dimers. Furthermore we further show that the dimers undergo a Lifshitz transition as a function of doping with a van Hove singularity appearing at the Fermi surface near optimal doping ∼ 20%. Indeed the van Hove singularity leads to a divergence of the density of states and as such an optimum Tc. We study the interplay of nematic fluctuations and the van Hove singularity both of which occur near optimal doping. We show that the van Hove singularity modifies the critical properties of the QCP (quantum critical point) for nematic fluctuations and that the QCP may be described by Hertz Millis like theory with z = 4. This allows us to calculate the critical exponents of the nematic fluctuations and to show that the fermionic dimers have non-Fermi liquid behavior near the QCP with the self energy diverging ∼ |ω3/4| near the QCP.

3. 2 pm, Small Seminar Room, Bldg. 510

Hosted by: Andrey Tarasov

It is well known that BFKL gives anomalous dimensions of twist-2 operators of spin j in the "BFKL limit'' $g^2\righarrow 0,\omega\equiv j-1\righarrow 0,{g^2\over\omega}$ fixed. I demonstrate that such limit describes the non-local light-ray operators and present the results of calculation of two- and three-point correlation functions of these operators in this limit. The calculation is performed in ${\cal N}$=4 SYM but the result is valid in other gauge theories such as QCD.

17

1. No events scheduled

18

1. No events scheduled

19

1. No events scheduled

20

1. MAR

20

Today

11 am, Small Seminar Room, Bldg. 510

Tuesday, March 20, 2018, 11:00 am

Hosted by: Lijuan Ruan

Recent years, evidence for collective effects has been revealed in pp and pPb collisions when looking at events releasing large number of particles. The experimental observations lead to a debate of the formation of strongly coupled Quark-Gluon Plasma in those small collision systems. Azimuthal anisotropy coefficient (vn) of heavy-flavor particles, and especially the comparison to light flavor particles vn, can shed light on the strength of the coupling between heavy flavor quarks and the hypothesized hydrodynamic medium at a significantly reduces size, and impose further constrains on different interpretations related to the origin of the observed collectivity. In this talk, the most recent results of prompt D0 meson elliptic flow (v2) in high-multiplicity pPb collisions are presented over a wide transverse momentum range. The results are compared to those of strange hadrons, including Kshort, Lambda, Cascade and Omega particles.

2. MAR

20

Today

2 pm, Building 480 Conference Room

Tuesday, March 20, 2018, 2:00 pm

Hosted by: Yimei Zhu

Recent-generation TEM/STEM instruments fitted with an electron monochromator provide an energy resolution down to 0.01 eV for electron energy-loss spectroscopy (EELS) and are themselves capable of achieving a spatial resolution approaching 0.1 nm. Besides offering the possibility of vibrational-mode EELS for examining chemical bonds, these instruments could be useful for mapping the electronic properties (e.g. band gap) of insulators and semiconductors. However, basic physics imposes a spatial resolution of few nm (or tens of nm) for energy loss below 10 eV, due to delocalization of the inelastic scattering. We will discuss what might be done to improve the spatial resolution, to make low-loss EELS competitive with other techniques.

3. MAR

20

Today

3:30 pm, Large Seminar Room, Bldg. 510

Tuesday, March 20, 2018, 3:30 pm

Hosted by: Peter Petreczky

This is an introduction to how atomic nuclei and other quantum few- and many-body systems can be studied using lattice simulations. The first part of the talk explains the basic formalism called lattice effective field theory. The rest of the talk is a discussion of novel methods and the new physics insights one gains with each. The methods discussed are the adiabatic projection method for scattering and reaction calculations, pinhole algorithm for probing structure and thermodynamic properties, and eigenvector continuation for extending calculations to regions of parameter space where things otherwise break down.

21

1. MAR

21

Wednesday

2 pm, Small Seminar Room, Bldg. 510

Wednesday, March 21, 2018, 2:00 pm

Hosted by: Christopher Murphy

22

1. MAR

22

Thursday

1:30 pm, ISB Bldg. 734 Conf. Rm. 201 (upstairs)

Thursday, March 22, 2018, 1:30 pm

Hosted by: Robert Konik

Resonant inelastic x-ray scattering (RIXS) is a relatively new technique for probing low energy excitations in materials. In addition to traditional techniques, such as angle resolved photoemission, it has become an important, high precision characterization tool of strongly correlated electron materials. To calculate RIXS, and related core and valence level spectra, we solve the Bethe-Salpeter equation (BSE) based on a self-energy corrected density functional theory electronic structure. I outline our implementation of the BSE and use SrVO3 for demonstration. The sensitivity of spectral features to the self-energy approximation – whether G0W0, qpscGW, or DMFT – is highlighted. To include interactions beyond the usual BSE I introduce the cumulant expansion. Spectral functions derived from a GW self-energy are typically inadequate when the dressed Green's function is built via the Dyson equation. With the same GW self-energy, a superior Green's function and spectral function, implicitly including vertex corrections, is obtained through the cumulant expansion. I consider application of the GW-cumulant expansion to photoemission, photoabsorption, and X-ray scattering. Lastly, vibronic coupling has important impacts on these spectra. I show how to calculation the phonon contribution to photoemission, absorption and scattering with a vibronic cumulant.

2. MAR

22

Thursday

4 pm, Large Seminar Room, Bldg. 510

Thursday, March 22, 2018, 4:00 pm

Edward Sierra will provide a talk on Marie Curie, an extraordinary scientist, the first woman to win a Nobel Prize, and still the only one awarded with two Nobel Prizes. Ed's interest in the early pioneers of radioactivity was piqued by the discussions he had many years ago with the renowned Dr. Maurice Goldhaber, the prominent physicist and a former Laboratory Director at Brookhaven National Laboratory. He learned that Goldhaber was a student under Sir James Chadwick at the Cavendish Laboratory at Cambridge University and that he attended a graduate course in Berlin given by Dr. Lise Meitner. Ed's research on Meitner led to an interest in Marie Curie. Her work and life is the topic of this talk.

23

1. MAR

23

Friday

12:15 pm, Building 510, Room - 2-160

Friday, March 23, 2018, 12:15 pm

24

1. No events scheduled

25

1. No events scheduled

26

1. No events scheduled

27

1. MAR

27

Tuesday

7 pm, Napper Tandy's 60 E. Main Street Bay Shore, N

Tuesday, March 27, 2018, 7:00 pm

28

1. No events scheduled

29

1. MAR

29

Thursday

1:30 pm, ISB Bldg. 734 Conf. Rm. 201 (upstairs)

Thursday, March 29, 2018, 1:30 pm

Hosted by: Igor Zaliznyak

TBD

30

1. No events scheduled

31

1. No events scheduled

1. MAR

20

Today

Nuclear Physics Seminar

"Probing the collectivity of heavy quarks in pPb collisions with prompt D0 elliptic flow using CMS detector"

Presented by Zhenyu Chen, Rice University

11 am, Small Seminar Room, Bldg. 510

Tuesday, March 20, 2018, 11:00 am

Hosted by: Lijuan Ruan

Recent years, evidence for collective effects has been revealed in pp and pPb collisions when looking at events releasing large number of particles. The experimental observations lead to a debate of the formation of strongly coupled Quark-Gluon Plasma in those small collision systems. Azimuthal anisotropy coefficient (vn) of heavy-flavor particles, and especially the comparison to light flavor particles vn, can shed light on the strength of the coupling between heavy flavor quarks and the hypothesized hydrodynamic medium at a significantly reduces size, and impose further constrains on different interpretations related to the origin of the observed collectivity. In this talk, the most recent results of prompt D0 meson elliptic flow (v2) in high-multiplicity pPb collisions are presented over a wide transverse momentum range. The results are compared to those of strange hadrons, including Kshort, Lambda, Cascade and Omega particles.

2. MAR

20

Today

Condensed-Matter Physics & Materials Science Seminar

"Spatial Resolution of Low-Loss EELS"

Presented by R.F. Egerton, University of Alberta, Canada

2 pm, Building 480 Conference Room

Tuesday, March 20, 2018, 2:00 pm

Hosted by: Yimei Zhu

Recent-generation TEM/STEM instruments fitted with an electron monochromator provide an energy resolution down to 0.01 eV for electron energy-loss spectroscopy (EELS) and are themselves capable of achieving a spatial resolution approaching 0.1 nm. Besides offering the possibility of vibrational-mode EELS for examining chemical bonds, these instruments could be useful for mapping the electronic properties (e.g. band gap) of insulators and semiconductors. However, basic physics imposes a spatial resolution of few nm (or tens of nm) for energy loss below 10 eV, due to delocalization of the inelastic scattering. We will discuss what might be done to improve the spatial resolution, to make low-loss EELS competitive with other techniques.

3. MAR

20

Today

Physics Colloquium

"Nuclear lattice simulations"

Presented by Dean Lee, Michigan State University

3:30 pm, Large Seminar Room, Bldg. 510

Tuesday, March 20, 2018, 3:30 pm

Hosted by: Peter Petreczky

This is an introduction to how atomic nuclei and other quantum few- and many-body systems can be studied using lattice simulations. The first part of the talk explains the basic formalism called lattice effective field theory. The rest of the talk is a discussion of novel methods and the new physics insights one gains with each. The methods discussed are the adiabatic projection method for scattering and reaction calculations, pinhole algorithm for probing structure and thermodynamic properties, and eigenvector continuation for extending calculations to regions of parameter space where things otherwise break down.

4. MAR

21

Wednesday

HET Seminar

"Empirical Determination of Dark Matter Velocities"

Presented by Lina Necib, Caltech

2 pm, Small Seminar Room, Bldg. 510

Wednesday, March 21, 2018, 2:00 pm

Hosted by: Christopher Murphy

5. MAR

22

Thursday

Condensed-Matter Physics & Materials Science Seminar

"Accurate spectral calculations for testing electronic structures, low energy excitations, and vibronic interactions"

Presented by Keith Gilmore, The European Synchrotron Radiation Facility, France

1:30 pm, ISB Bldg. 734 Conf. Rm. 201 (upstairs)

Thursday, March 22, 2018, 1:30 pm

Hosted by: Robert Konik

Resonant inelastic x-ray scattering (RIXS) is a relatively new technique for probing low energy excitations in materials. In addition to traditional techniques, such as angle resolved photoemission, it has become an important, high precision characterization tool of strongly correlated electron materials. To calculate RIXS, and related core and valence level spectra, we solve the Bethe-Salpeter equation (BSE) based on a self-energy corrected density functional theory electronic structure. I outline our implementation of the BSE and use SrVO3 for demonstration. The sensitivity of spectral features to the self-energy approximation – whether G0W0, qpscGW, or DMFT – is highlighted. To include interactions beyond the usual BSE I introduce the cumulant expansion. Spectral functions derived from a GW self-energy are typically inadequate when the dressed Green's function is built via the Dyson equation. With the same GW self-energy, a superior Green's function and spectral function, implicitly including vertex corrections, is obtained through the cumulant expansion. I consider application of the GW-cumulant expansion to photoemission, photoabsorption, and X-ray scattering. Lastly, vibronic coupling has important impacts on these spectra. I show how to calculation the phonon contribution to photoemission, absorption and scattering with a vibronic cumulant.

6. MAR

23

Friday

HET Lunch Discussion /Neutrino Discovery Initative

"Boosted Dark Matter at DUNE"

Presented by Lina Necib, Caltech

12:15 pm, Building 510, Room - 2-160

Friday, March 23, 2018, 12:15 pm

7. MAR

27

Tuesday

PubSci

"PubSci: Nuclear Medicine for Personalized Cancer Treatment"

7 pm, Napper Tandy's 60 E. Main Street Bay Shore, N

Tuesday, March 27, 2018, 7:00 pm

8. MAR

29

Thursday

Condensed-Matter Physics & Materials Science Seminar

"TBD"

Presented by Andreas Weichselbaum, Brookhaven National Lab

1:30 pm, ISB Bldg. 734 Conf. Rm. 201 (upstairs)

Thursday, March 29, 2018, 1:30 pm

Hosted by: Igor Zaliznyak

TBD

9. APR

3

Tuesday

Physics Colloquium

"Eigenstate thermalization and its implications to statistical mechanics"

Presented by Anatoli Polkovnikov, Boston University

3:30 pm, Large Seminar Room, Bldg. 510

Tuesday, April 3, 2018, 3:30 pm

Hosted by: Rob Pisarski

In this talk I will overview recent developments in understanding quantum chaos through random matrix theory. I will discuss various conjectures on the nature of quantum stationary states in chaotic systems and show numerical evidence supporting them. It is the random nature of eigenstates, which ultimately leads to loss of information about initial conditions and leads to emergence of statistical mechanics in isolated systems. I will then introduce the so-called Eigenstate Thermalization Hypothesis (ETH) ansatz first proposed by J. Deutsch and M. Srednicki in 90th, which gives a unified framework for the structure of physical observable in quantum chaotic systems. I will demonstrate how the ETH ansatz naturally leads to emergence of various thermodynamic relations. At the end of the talk I will mention some open problems.

10. APR

4

Wednesday

HET Seminar

"Excluding a thin dark matter disk in the Milky Way with Gaia DR1"

Presented by Katelin Schutz, UC Berkeley

2 pm, Small Seminar Room, Bldg. 510

Wednesday, April 4, 2018, 2:00 pm

Hosted by: Christopher Murphy

If a component of the dark matter has dissipative interactions, it could collapse to form a thin dark disk in our Galaxy coincident with the baryonic disk. It has been suggested that dark disks could explain a variety of observed phenomena, including mass extinction events due to periodic comet impacts. Using the first data release from the Gaia space observatory, I will present the results of a search for a dark disk via its effect on stellar kinematics in the Milky Way. I will discuss our strong new limits that disfavor the presence of a thin dark matter disk and present updated measurements on the total matter density in the solar neighborhood.

11. APR

5

Thursday

Condensed-Matter Physics & Materials Science Seminar

"TBA"

Presented by Bin Chen, Director, Shanghai Laboratory of HPSTAR, China

1:30 pm, ISB Bldg. 734 Seminar Room 201 (upstairs)

Thursday, April 5, 2018, 1:30 pm

Hosted by: Cedomir Petrovic

12. APR

5

Thursday

Particle Physics Seminar

"Time for High Luminosity – a new Detector for ATLAS"

Presented by Joern Lange, Institut de Fisica d'Altes Energies (IFAE) Barcelona

3 pm, Small Seminar Room, Bldg. 510

Thursday, April 5, 2018, 3:00 pm

Hosted by: Alessandro Tricoli

13. APR

6

Friday

Nuclear Theory/RIKEN Seminar

"TBA"

Presented by Andreas Schmitt, University of Southampton

2 pm, Small Seminar Room, Bldg. 510

Friday, April 6, 2018, 2:00 pm

Hosted by: Chun Shen

14. APR

17

Tuesday

Physics Colloquium

"Plasma science - From laboratory-fusion to astrophysical plasmas"

Presented by Fatima Ebrahimi, Princeton Plasma Physics Laboratory and Princeton University

3:30 pm, Large Seminar Room, Bldg. 510

Tuesday, April 17, 2018, 3:30 pm

Hosted by: Rob Pisarski

Our universe is immersed in magnetized plasma, electrically conducting ionized gas. Some of the most fundamental and long-standing astrophysical problems, such as the magnetization of the universe, collimation of astrophysical jets, the accretion process and transport in astrophysical disks (surrounding e.g. black holes) and their coronas can only be explored through plasma physics. Our sun as a natural laboratory for plasma physics provides inspiring as well as challenging problems, including its dynamo cycles, heating, and the replication of its core reaction, fusion energy, on earth in a lab. There is an abundance of observational/experimental data emerging from natural phenomena of space and astrophysical plasmas, as well as laboratory plasma experiments, for plasma physicists to explore. I will review some of these topics, in particular magnetic reconnection, the rearrangement of the magnetic ?field topology of plasmas, which energizes many processes in nature and has been shown to also be critical in the nonlinear dynamics of many processes in toroidal fusion plasmas. Using global simulations, I will demonstrate the instrumental role of magnetic reconnection, which enables an innovative technique for producing current in fusion plasmas.

15. APR

18

Wednesday

Joint BNL/SBU HET seminar

"TBA"

Presented by Csaba Csaki, Cornell University

2:30 pm, YITP

Wednesday, April 18, 2018, 2:30 pm

Hosted by: Christopher Murphy

16. APR

24

Tuesday

Physics Colloquium

"Nature vs. Nurture in Complex (and Not-So-Complex) Systems"

Presented by Daniel Stein, NYU

3:30 pm, Large Seminar Room, Bldg. 510

Tuesday, April 24, 2018, 3:30 pm

Hosted by: Rob Pisarski

Understanding the dynamical behavior of many-particle systems following a deep quench is a central issue in both statistical mechanics and complex systems theory. One of the basic questions centers on the issue of predictability: given a system with a random initial state evolving through a well-defined stochastic dynamics, how much of the information contained in the state at future times depends on the initial condition (nature'') and how much on the dynamical realization (nurture'')? We discuss this question and present both old and new results for both homogeneous and random systems in low and high dimension.

17. APR

25

Wednesday

Joint BNL/SBU HET Seminar

"TBA"

Presented by Matthew Buckley, Rutgers University

2 pm, Small Seminar Room, Bldg. 510

Wednesday, April 25, 2018, 2:00 pm

Hosted by: Christopher Murphy

18. MAY

14

Monday

Condensed-Matter Physics & Materials Science Seminar

"Superconductivity and quantum paraelectric fluctuations in STO"

Presented by Alexander Balatsky, Los Alamos National Laboratory

1:30 pm, ISB Bldg. 734 Conf. Rm. 201 (upstairs)

Monday, May 14, 2018, 1:30 pm

Hosted by: Laura Classen

STO is one of the earliest examples of superconductivity in oxides. With the pioneering discovery of the superconductivity in STO interfaces the field of emergent states at interfaces has been rapidly growing. Recently we come to realize that the key to a lot of puzzles in these devices lies in the complicated states of bulk STO[1,2]. Superconducting state is STO exhibits the dome as a function of doping. STO is also a known quantum paraelectric. Historically ferroelectric quantum criticality and superconducting dome in STO were assumed to be unrelated. We propose that they are in fact closely connected. We suggest that ferroelectric quantum criticality can induce superconductivity. We will present our results on investigation of the origin of superconductivity in doped STO using a combination of density functional and strong coupling theory[3]. Our approach suggests a model in which the ferroelectric soft mode fluctuations provide the pairing interaction for superconductivity carriers. This approach adds to the range of superconducting states induced by quantum criticality beyond magnetic and valence fluctuations[3,4,5]. Based on this model we made a prediction that superconducting Tc will increase with increasing 18O isotope substitution, a scenario that is experimentally verifiable[6]. We also discuss proposal to use strain as another tool to control paraelectric fluctuations and thus control superconductivity in STO[7]. We will illustrate the ongoing debate on the nature of the pairing states in bulk STO and in related heterostructure devices: the possibility to realize composite pairing states and multiband superconductivity[8]. [1]J. Haraldsen et al., Phys. Rev. B 84, 020103(R) (2011), [2]J. Haraldsen et al., Phys. Rev. B 85, 134501 (2012), [3]J. Edge et al Phys. Rev. Lett. 115, 247002 (2015), [4] Y. Kedem et.al, Physical Review B 93 , 184507 (2016), [5] CW Rischau et al, Nature Physics, 13, 643–648 (2017) [6] A. Stucky, et.al, Sci

19. MAY

16

Wednesday

HET Seminar

"TBA"

Presented by Anastassios Vladikas, INFN Roma Tor Vergata

2 pm, Small Seminar Room, Bldg. 510

Wednesday, May 16, 2018, 2:00 pm

Hosted by: Mattia Bruno

20. MAY

23

Wednesday

HET Seminar

"TBA"

Presented by Stefan Prestel, Fermilab

2 pm, Small Seminar Room, Bldg. 510

Wednesday, May 23, 2018, 2:00 pm

Hosted by: Christopher Murphy

21. MAY

25

Friday

Nuclear Theory/RIKEN Seminar

"TBA"

Presented by Stanley Brodsky, Standford Univeristy

2 pm, Small Seminar Room, Bldg. 510

Friday, May 25, 2018, 2:00 pm

22. JUL

9

Monday

Office of Educational Programs Event

"High School Research Program Begins"

8 am, Berkner Hall Auditorium

Monday, July 9, 2018, 8:00 am

Hosted by: Aleida Perez

1. Nuclear Theory/RIKEN Seminar

"Correlators of twist-2 light-ray operators in the BFKL approximation"

Presented by Ian Balitsky

Friday, March 16, 2018, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Andrey Tarasov

It is well known that BFKL gives anomalous dimensions of twist-2 operators of spin j in the "BFKL limit'' $g^2\righarrow 0,\omega\equiv j-1\righarrow 0,{g^2\over\omega}$ fixed. I demonstrate that such limit describes the non-local light-ray operators and present the results of calculation of two- and three-point correlation functions of these operators in this limit. The calculation is performed in ${\cal N}$=4 SYM but the result is valid in other gauge theories such as QCD.

2. Condensed-Matter Physics & Materials Science Seminar

"Quantum dimer models for high temperature superconductors"

Presented by Garry Goldstein, Cambridge University, United Kingdom

Friday, March 16, 2018, 1:30 pm
ISB Bldg. 734 Conf. Rm. 201 (upstairs)

Hosted by: Robert Konik

In this talk we review the slave boson meanfield formulation of the fermion+boson quantum dimer model for the pseudogap phase of the high temperature superconductors. We show that in the presence of weak slowly varying external magnetic and electric fields the fermionic dimers undergo semiclassical motion in the external field. As a result in the presence of magnetic fields strong enough to destroy superconductivity the dimers undergo quantum oscillations. Indeed they satisfy Onsager quantization for their orbits and Lifshtiz-Kosevich formula for the amplitude of oscillations. We also compute the effective charges of the dimers in the presence of external magnetic fields as a function of temperature. We show that the effective magnetic charge changes sign from negative −e at low temperature to positive +e at high temperature. This leads to a change of the sign of the Hall coeÿcient as a function of temperature. We also compute the magnetoresistance as a function of the external field and temperature within a linearized Boltzmann equation approximation for the fermionic dimers. Furthermore we further show that the dimers undergo a Lifshitz transition as a function of doping with a van Hove singularity appearing at the Fermi surface near optimal doping ∼ 20%. Indeed the van Hove singularity leads to a divergence of the density of states and as such an optimum Tc. We study the interplay of nematic fluctuations and the van Hove singularity both of which occur near optimal doping. We show that the van Hove singularity modifies the critical properties of the QCP (quantum critical point) for nematic fluctuations and that the QCP may be described by Hertz Millis like theory with z = 4. This allows us to calculate the critical exponents of the nematic fluctuations and to show that the fermionic dimers have non-Fermi liquid behavior near the QCP with the self energy diverging ∼ |ω3/4| near the QCP.

3. HET Lunch Discussions

"Updated Global SMEFT Fit to Higgs, Diboson and Electroweak Data"

Presented by Christopher Murphy, BNL

Friday, March 16, 2018, 12:15 pm
Building 510, Room 2-160

Hosted by: Christoph Lehner

4. Particle Physics Seminar

"Precision Measurements of Asymmetries and Spectra in Neutron Decay"

Presented by Brad Plaster, University of Kentucky

Thursday, March 15, 2018, 3 pm
Small Seminar Room, Bldg. 510

Hosted by: Chao Zhang

Precision measurements of various asymmetries in neutron decay permit an extraction of the weak axial-vector coupling constant, gA, a fundamental quantity important for weak-interaction physics and as a benchmark for lattice QCD calculations. I will discuss a recent new result from the UCNA Experiment at Los Alamos National Laboratory for a 0.16% precision result on gA from a measurement of the 'A' asymmetry, which represents the parity-violating angular correlation between the neutron's spin and the decay electron's momentum. This long-standing effort was carried out with a superconducting solenoidal electron spectrometer at the LANL Ultracold Neutron (UCN) facility. This new result will be placed in the context of historical results for gA and recent discrepant values for the neutron lifetime obtained via different experimental techniques. I will also discuss the first-ever extraction of the Fierz interference term 'b' in free neutron decay from an analysis of the electron's spectral shape as measured in the UCNA Experiment. A non-zero 'b' term would result from beyond-Standard Model interactions, such as Scalar or Tensor physics. Although the result for 'b' from the UCNA Experiment was systematics limited, it points to the requisite significant improvements in the characterization of the detector energy response that future experiments aimed at a measurement of 'b' will need to achieve in order to probe beyond Standard Model physics at a competitive precision.

5. Condensed-Matter Physics & Materials Science Seminar

"Splitting of electrons and violation of the Luttinger sum rule"

Presented by Eoin Quinn, University of Amsterdam, Netherlands

Thursday, March 15, 2018, 1:30 pm
ISB Bldg. 734 Conf. Rm. 201 (upstairs)

Hosted by: Robert Konik

We obtain a controlled description of a strongly correlated regime of electronic behaviour. We argue that there are two ways to characterise the electronic degree of freedom, either by the canonical fermion algebra or by the graded Lie algebra su(2|2). The first underlies the Fermi liquid description of correlated matter, and we identify a novel regime governed by the latter. We obtain the electronic spectral function within a controlled approximation, and find a splitting in two of the electronic band. The Luttinger sum rule is violated and a Mott metal-insulator transition is exhibited.

6. RIKEN Lunch Seminar

"Hadronic light-by-light scattering in the muon g-2"

Presented by Andreas Nyffeler, University of Mainz

Thursday, March 15, 2018, 12:30 pm
Building 510, Room 2-160

7. Condensed-Matter Physics & Materials Science Seminar

"Enabling emergent spin-orbit magnetism in iridate-based heterostructures"

Presented by Jian Liu, The University of Tennessee, Knoxville

Thursday, March 15, 2018, 11 am
ISB Bldg. 734 Seminar Room 201 (upstairs)

Hosted by: Mark Dean

5d transition metal oxides have emerged as a novel playground for some of the most outstanding and challenging problems in condensed matter physics, such as metal-insulator transition and quantum magnetism. In particular, layered iridates hosting square lattices of IrO6 octahedra have drawn significant interests due to the electronic and magnetic analogy with high-Tc cuprates. However, materials of this kind are limited to a few Ruddlesden-Popper (RP) compounds. In this talk, I will discuss our recent work on overcoming this bottleneck by constructing such two-dimensional (2D) structures confined in superlattices grown by heteroepitaxy. By leveraging the layering control of epitaxial growth, we are not only able to develop new structural variants of layered iridates, but also unravel and exploit the intriguing spin-orbit-driven 2D magnetism beyond the cuprate physics yet invisible in the RP iridates. The results demonstrate the power of this approach in tailing the exchange interactions, enabling new magnetic controls, and providing unique insights into the emergent phenomena of 5d electrons.

8. Center for Functional Nanomaterials Seminar

"Metal oxide/semiconductor heterojunctions as carrier-selective contacts for photovoltaic applications"

Presented by Gabriel Man

Wednesday, March 14, 2018, 2 am
CFN, Bldg. 735 - first, floor, conference room A

Hosted by: Mingzhao Liu

Solar radiation is a vast, distributed, and renewable energy source which Humanity can utilize via the photovoltaic effect. The goal of photovoltaic technology is to minimize the true costs, while maximizing the power conversion efficiency and lifetime of the cell/module. Interface-related approaches to achieving this goal are explored here, for two technologically-important classes of light absorbers: crystalline-silicon (c-Si) and metal halide perovskite (MHP). The simplest solar cell consists of a light absorber, sandwiched between two metals with dissimilar work functions. Carrier-selective contacts (CSC's), which are ubiquitous in modern solar cells, are added to improve the electrical performance. Solar cells require asymmetric carrier transport within the cell, which can be effected via electrostatic and/or effective fields, and CSC's augment the asymmetry by selectively transporting holes to one contact, and electrons to the other contact. The proper design and implementation of a CSC is crucial, as the performance, lifetime, and/or cost reduction of a solar cell can be hampered by a single interface or layer. A framework, consisting of eight core requirements, was developed from first-principles to evaluate the effectiveness of a given CSC. The framework includes some requirements which are well-recognized, such as the need for appropriate band offsets, and some requirements which are not well-recognized at the moment, such as the need for effective valence/conduction band density of states matching between the absorber and CSC. The application of the framework to multiple silicon-based and MHP-based CSC's revealed the difficulties of effectively designing and implementing a CSC. Three metal oxide/c-Si heterojunctions initially expected to yield comparable electron-selective contacts (ESC's), titanium dioxide/c-Si (TiO2/c-Si), zinc oxide/c-Si (ZnO/c-Si), and tin dioxide/c-Si (SnO2/c-Si), were instead discovered to be widely diff

9. Particle Physics Seminar

"From first beam to particle physics discoveries with petabytes of data"

Presented by Paul Laycock, CERN

Monday, March 12, 2018, 3 pm
Small Seminar Room, Bldg. 510

Hosted by: Alessandro Tricoli

The LHC experiments require huge, ever-increasing volumes of data to explore the frontiers of particle physics, and the grid provides the infrastructure to meet this challenge. Today, even medium sized experiments produce petabytes of data that need to be analysed by international collaborations and the relationship between particle physicists and their data has had to evolve to keep pace. Calibrating and systematically understanding detectors requires detailed information, deep learning algorithms promise to allow us to fully exploit our experiments, and on the other hand we want to analyse our data quickly and be the first to publish. This talk will first describe how, shortly after the Higgs discovery, ATLAS realised that the way that analysis was done had to change, and will briefly illustrate what those changes entailed. Next, the NA62 experiment will be described. Recording a billion events per day, NA62 aims to measure the very rare decay of a charged kaon to a charged pion and two neutrinos. The collaboration had to quickly implement petabyte scale data processing infrastructure to perform the sub-nanosecond calibrations needed to challenge the 10% precision of the theory prediction.

10. Nuclear Theory/RIKEN Seminar

"Yang-Mills action on the light front: MHV amplitudes and Wilson lines"

Presented by Anna Stasto, Penn State

Friday, March 9, 2018, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Chun Shen

The MHV action is the Yang-Mills action quantized on the light-front, where the two explicit physical gluonic degrees of freedom have been canonically transformed to a new set of fields. This transformation leads to the action with vertices being off-shell continuations of the MHV amplitudes. We show that the solution to the field transformation expressing one of the new fields in terms of the Yang-Mills field is a certain type of the Wilson line. More precisely, it is a straight infinite gauge link with a slope extending to the light-cone minus and the transverse direction. One of the consequences of that fact is that certain MHV vertices reduced partially on-shell are gauge invariant — a fact discovered before using conventional light-front perturbation theory. We also analyze the diagrammatic content of the field transformations leading to the MHV action. We found that the diagrams for the solution to the transformation (given by the Wilson line) and its inverse differ only by light-front energy denominators.

11. HET Lunch Discussions

"An update on the HVP contribution to the muon g-2"

Presented by Christoph Lehner

Friday, March 9, 2018, 12:15 pm
Building 510, Room 2-160

12. Particle Physics Seminar

"New neutrino oscillation results from NOvA"

Presented by Jeremy Wolcott, Tufts University

Thursday, March 8, 2018, 3 pm
Small Seminar Room, Bldg. 510

Hosted by: Chao Zhang

The NOvA experiment is an off-axis long-baseline neutrino oscillation experiment using the NuMI $\nu_{\mu}$ beam originating at Fermilab. By examining the disappearance of muon neutrinos and the appearance of electron neutrinos between the near detector at Fermilab and the far detector in Ash River, MN, NOvA has the potential to help answer a number of fundamental questions: Are the neutrinos' masses ordered the same way as those of the charged leptons? Do leptons experience charge-parity violation? Are there underlying symmetries in the way the neutrino states mix with one another? In this talk I will present NOvA's most recent constraints on the answers to those questions utilizing muon neutrino disappearance and electron neutrino appearance. These updated results are based on a 50% increase in exposure relative to previous results as well as numerous simulation and analysis improvements.

13. HET Seminar

"Dispersion relation for hadronic light-by-light scattering"

Presented by Peter Stoffer, UC San Diego

Wednesday, March 7, 2018, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Christopher Murphy

14. Physics Colloquium

"Quantum simulation of gauge theories in optical lattices"

Presented by Alexei Bazavov, Michigan State University

Tuesday, March 6, 2018, 3:30 pm
Large Seminar Room, Bldg. 510

Hosted by: Andrei Nomerotski

hile non-perturbative approaches such as lattice gauge theory led to significant advances in understanding the physics of strong interactions, many problems remain out of reach for classical computation, in particular, real-time dynamics or properties of QCD at finite baryon density that are being explored in heavy-ion collision experiments. Recent advances in the technology of engineering custom interactions for ultra-cold atomic gases in optical lattices opened a possibility for quantum simulations as was envisioned by R. Feynman in the 1980s. The main idea is that the degrees of freedom of the original system are mapped onto a quantum Hamiltonian whose dynamics can be realized in a laboratory. Many condensed matter Hamiltonians, such as Bose-Hubbard model, have been recently studied in this way. Quantum simulation of gauge theories is however challenging since the gauge symmetry is not naturally present in the ultra-cold atomic systems. I will review the current status of theoretical proposals for quantum simulation of field theories and then focus on our recent work on an explicitly gauge-invariant formulation of the Abelian-Higgs model for simulation on optical lattices.

15. Instrumentation Division Seminar

"Table-top MeV laser particle accelerator @ kHz repetition rate"

Presented by Enam Chowdhury, Department of Physics, Ohio State University

Tuesday, March 6, 2018, 2:30 pm
Large Conference Room, Bldg. 535

At the Extreme Light Lab at the Air Force Research Laboratory, Dayton, we explore light matter interaction at relativistic fields with liquid targets. Although demonstrations of up to 4 GeV1 electrons and ~100 MeV protons2 have been achieved in the past, all of these are not feasible as future accelerators, due to their slow duty cycle (usually single shot, rarely 1 Hz). There are many challenges to increasing the duty cycle, where laser technology, target technology, damage to system, target alignment, high repetition rate sub-micron plasma diagnostics provides nearly insurmountable obstacles. In this program, we developed ways to accelerate MeV x-rays, electrons3 and ions4 at kHz repetition rate with a small milli-joule class laser system, by developing a combination of suitable laser system, diagnostic system, target system and experimental data collection system capable of handling the high duty cycle. We also perform femtosecond-time resolution pump-probe imaging of the interaction, and extensive large scale relativistic laser plasma interaction simulations5 that reveal the nature of the acceleration processes. Such a system opens the door to extensive future application as a source for materials processing, radiation hardness testing, medical isotope production, time resolved proton probing on relativistic interactions, and many others.

16. Nuclear Physics Seminar

"Looking ahead to BESII: new observables and new theoretical frameworks"

Presented by Yin Yi, MIT

Tuesday, March 6, 2018, 11 am
Small Seminar Room, Bldg. 510

Hosted by: Jia Jiangyong

Upcoming beam energy scan (BES) phase II will explore the QCD phase diagram with an unprecedented precision and would potentially discover the QCD critical point. I will discuss recent theoretical developments aim at maximizing the discovery potential of BESII from both phenomenological and formal perspectives. First, I will discuss new observables which are very sensitive to the presence of the QCD critical point and are possible due to the iTPC upgrade. In the second part, I will report recent progress on understanding and describing hydrodynamic fluctuations. Remarkably, effects of hydrodynamic fluctuations can be potentially important for precise determination of shear viscosity at top RHIC energy and would play a crucial role near the QCD critical point.

17. Nuclear Theory/RIKEN Seminar

"Quark / Antiquark Correlations in Heavy-Light Ion Collisions"

Presented by Matt Sievert, LANL

Friday, March 2, 2018, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Chun Shen

It has long been known that sub-nucleonic fluctuations of the energy density in the initial stages of heavy ion collisions play an important role in generating the observed distributions of particles and their flow. These energy density fluctuations are dominated by the radiation of small-x gluons which are populated to classically large occupation numbers in the wave functions of ultra-relativistic heavy ions. While these soft gluons dominate the initial conditions for the energy density, it is quark production which determines the initial conditions of other conserved charges, like flavor and baryon number. With the recent development of state-of-the art hydrodynamics codes tailored to the Beam Energy Scan which can propagate these conserved charges into the final state, it is timely and important to calculate the initial conditions of these conserved charges from first principles in QCD. In this talk, I will present new results for the spatial correlations among quarks and antiquarks produced at mid-rapidity by pair production from small-x gluons. This single-pair production mechanism, which has been studied for some time in momentum space, is the leading contribution to these correlations in coordinate space for dilute-dense collisions. As one moves from the dilute-dense regime toward the dense-dense regime, correlations due to double pair production become more important, and these correlations persist over larger length scales than the single-pair production mechanism. Over nonperturbative length scales, only the correlations from the overlap geometry remain. I will present explicit results for quark-antiquark correlations due to single pair production, and I will outline some preliminary results for the various double-pair production mechanisms. The ultimate goal of this work will be to construct a code which can initialize these conserved charges over all length scales in heavy-ion collisions.

18. HET Lunch Discussions

"Semileptonic decays using Oktay-Kronfeld heavy quarks on the HISQ lattice"

Presented by Yong-Chull Jang, BNL

Friday, March 2, 2018, 12:15 pm
Building 510, Room 2-160

Hosted by: Christoph Lehner

19. Condensed-Matter Physics & Materials Science Seminar

"3D non-Fermi liquid behavior from 1D critical local moments"

Presented by Laura Classen, BNL

Thursday, March 1, 2018, 1:30 pm
ISB Bldg. 734 Conf. Rm. 201 (upstairs)

Hosted by: Igor Zaliznyak

We study the temperature dependence of the electrical resistivity in a system composed of critical spin chains interacting with three dimensional conduction electrons and driven to criticality via an external magnetic field. The relevant experimental system is Yb2Pt2Pb, a metal where itinerant electrons coexist with localized moments of Yb-ions which can be described in terms of effective S = 1/2 spins with dominantly one-dimensional exchange interaction. The spin subsystem becomes critical in a relatively weak magnetic field, where it behaves like a Luttinger liquid. We theoretically examine a Kondo lattice with different effective space dimensionalities of the two interacting sub-systems. We characterize the corresponding non-Fermi liquid behavior due to the "local criticality" from the spins by calculating the electronic relaxation rate and the dc resistivity and establish its quasi linear temperature dependence.

20. Joint BNL/SBU HET Seminar

"Searching for Light Dark Matter with Dirac Materials"

Presented by Yonatan Kahn, Princeton University

Wednesday, February 28, 2018, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Christopher Murphy

Dark matter with mass below a GeV is invisible to standard WIMP searches. In this talk I will present two recent proposals for direct detection of keV-GeV mass dark matter, both utilizing Dirac materials, where low-energy electronic excitations have linear dispersion relations and obey the Dirac equation. Dark matter with mass in the MeV-GeV range can eject electrons from graphene sheets, which can act as both targets and detectors when employed in a field-effect transistor mode, allowing directional detection. Dark matter as light as a few keV can excite electrons to the conduction band of Dirac semimetals like ZrTe5, where the linear dispersion protects the in-medium mass of the mediator and provides superior reach to a light dark photon mediator compared to superconductors. I will discuss recent progress towards experimental realizations of these proposals.

21. High-Energy Physics & RIKEN Theory Seminar

"Preparing High Energy Physics Software for the Future - the Community White Paper"

Presented by Dr. Benedikt Hegner, CERN, Switzerland

Wednesday, February 28, 2018, 12 pm
Seminar Room, Bldg. 725

Hosted by: Eric Lancon

Particle physics has an ambitious and broad experimental program for the coming decades. This program requires large investments in detector hardware, either to build new facilities and experiments, or to upgrade existing ones. Similarly, it requires commensurate investment into R&D of software to acquire, manage, process, and analyses the shear amounts of data to be recorded. In planning for the High Luminosity LHC in particular, it is critical that all of the collaborating stakeholders agree on the software goals and priorities, and that their efforts complement each other. In this spirit, the High Energy Physics community has created a white paper (arXiv:1712.06982) to describe and define the R&D activities required in order to prepare for this software upgrade. This presentation describes the expected software and computing challenges, and the plans to address them that are laid out in the white paper.

22. Physics Colloquium

"The Multi-Messenger Picture of a Neutron Star Merger"

Presented by Brian Metzger, Columbia University

Tuesday, February 27, 2018, 3:30 pm
Large Seminar Room, Bldg. 510

Hosted by: Peter Petreczky

On August 17 the LIGO/Virgo gravitational wave observatories detected the first binary neutron star merger event (GW170817), a discovery followed by the most ambitious electromagnetic (EM) follow-up campaign ever conducted. A gamma-ray burst (GRB) of short duration and very low luminosity was discovered by the Fermi and INTEGRAL satellites within 2 seconds of the merger. Within 11 hours, a bright but rapidly-fading thermal optical counterpart was discovered in the galaxy NGC 4993 at a distance of only 40 Mpc. The properties of the optical transient match remarkably well predictions for kilonova emission powered by the radioactive decay of heavy nuclei synthesized in the expanding merger ejecta by the r-process. The rapid spectral evolution of the kilonova emission to near-infrared wavelengths demonstrates that a portion of the ejecta contains heavy lanthanide nuclei. Two weeks after the merger, rising non-thermal X-ray and radio emission were detected from the position of the optical transient, consistent with delayed synchrotron afterglow radiation from an initially off-axis relativistic jet with the properties consistent with those of (on-axis) cosmological short GRB. I will describe a unified scenario for the range of EM counterparts from GW170817 and their implications for the astrophysical origin of the r-process and the properties of neutron stars. I will preview the upcoming era of multi-messenger astronomy, once Advanced LIGO/Virgo reach design sensitivity and a neutron star merger is detected every few weeks.

23. HET Lunch Seminar

"Recent indications of LU...... violations: A possible shaking of HEP in the making"

Presented by Amarjit Soni, BNL

Friday, February 23, 2018, 12 pm
Building 510, Room 2-160

Hosted by: Christoph Lehner

24. RIKEN Lunch Seminar

"Drell-Yan process beyond collinear approximation"

Presented by Stebel Tomasz, BNL

Thursday, February 22, 2018, 12:30 pm
Building 510, Room 2-160

Hosted by: Yuya Tanizaki

25. Condensed-Matter Physics & Materials Science Seminar

"Topological Spin Excitations in a Highly Interconnected 3D Spin Lattice"

Presented by Yuan Li, International Center for Quantum Materials, Peking University, China

Thursday, February 22, 2018, 11 am
ISB Bldg. 734 Conf. Rm. 201 (upstairs)

Hosted by: Mark Dean

The recent discovery of topological semimetals, which possess distinct electron-band crossing with non-trivial topological characteristics, has stimulated intense research interest. By extending the notion of symmetry-protected band crossing into one of the simplest magnetic groups, namely by including the symmetry of time-reversal followed by space-inversion, we predict the existence of topological magnon-band crossing in three-dimensional (3D) collinear antiferromagnets. The crossing takes on the forms of Dirac points and nodal lines, in the presence and absence, respectively, of the conservation of the total spin along the ordered moments. In a concrete example of a Heisenberg spin model for a "spin-web" compound, we theoretically demonstrate the presence of Dirac magnons over a wide parameter range using linear spin-wave approximation, and obtain the corresponding topological surface states [1]. Inelastic neutron scattering experiments have been carried out to detect the bulk magnon-band crossing in a single-crystal sample. The highly interconnected nature of the spin lattice suppresses quantum fluctuations and facilitates our experimental observation, leading to remarkably clean experimental data and very good agreement with the linear spin-wave calculations. The predicted topological band crossing is confirmed [2]. [1] K. Li et al., PRL 119, 247202 (2017). [2] W. Yao et al., arXiv:1711.00632.

26. HET Seminar

"Analysis of a Dilaton EFT for Lattice Data"

Presented by Thomas Appelquist, Yale University

Wednesday, February 21, 2018, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Christoph Murphy

27. Particle Physics Seminar

"21-cm cosmology topics"

Presented by Dr. Francisco Villaescusa-Navarro, Center for Computational Astrophysics, Flatiron Institute

Thursday, February 15, 2018, 3 pm
Small Seminar Room, Bldg. 510

Hosted by: Chris Sheehy

28. Physics Colloquium

"The Social Life of Heavy Quarks"

Presented by Marek Karliner, Tel Aviv University

Tuesday, February 13, 2018, 3:30 pm
Large Seminar Room, Bldg. 510

Hosted by: Peter Petreczky

I will discuss recent developments regarding new types of hadrons involving heavy quarks: hadronic molecules, doubly heavy baryons, stable tetraquarks and others. I will also explain how the discovery of the doubly heavy baryon leads to quark-level analogue of nuclear fusion, with energy release per reaction an order of magnitude greater than in ordinary fusion.

29. Condensed-Matter Physics & Materials Science Seminar

"Nematic superconductivity in topological materials"

Presented by Matt Smylie, Argonne National Laboratory

Tuesday, February 13, 2018, 1:30 pm
ISB Bldg. 734 Conf. Rm. 201 (upstairs)

Hosted by: Genda Gu

In a topological superconductor, a bulk superconducting gap induces a symmetry-protected gapless superconducting surface state. This surface state can host exotic Majorana zero modes, which are expected to revolutionize computation technology through energy-efficient fault-tolerant quantum computing. In this talk, we will discuss the search for bulk topological superconductors and the discovery of nematic superconductivity in MxBi2Se3 (M=Cu,Sr,Nb), where the superconducting system spontaneously breaks rotational symmetry at Tc. The nematic superconducting state and possible origins of the rotational symmetry breaking will be explored, with many conventional causes being eliminated.

30. Computational Science Initiative Event

"Physics Informed Machine Learning"

Presented by Michael (Mischa) Chertkov, Los Alamos National Lab

Tuesday, February 13, 2018, 10:30 am
Seminar Room, Bldg. 725

Hosted by: Frank Alexander

Machine Learning (ML) capabilities are in a phase of tremendous growth, and there is great opportunity to point these tools toward physical modeling. The challenge is to incorporate domain expertise from traditional scientific discovery into next-generation ML models. We propose to develop new Physics Informed Machine Learning (PIML) algorithms that extend cutting-edge computational and algorithmic ML tools and merge them with physical knowledge in the form of constraints, symmetries, and domain expertise regarding effective degrees of freedom. This PIML methodology is illustrated on the following four enabling examples: 1. Topology and Parameter Estimation in Power Grids [based on arXiv:1710.10727] 2. Creating Turbulent Flows with Deep Learning [based on an APS/DFD2017 abstract] 3. Learning Graphical Models [Science 2018 in print; arXiv:1612.05024] 4. Renormalization of Tensor Networks (Graphical Models) [based on arXiv:1801.01649 and ICML2018 submission]

31. Joint Nuclear Theory and HET Seminar

"TeV Scale Lepton Number Violation: Neutrinoless Double Beta Decay & the LHC"

Presented by Michael Ramsey-Musolf, U. Mass. Amherst

Friday, February 9, 2018, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Christopher Murphy

32. RIKEN Lunch Seminar

"Biased nuclear gluon distribution from a reweighted JIMWLK small-x ensemble"

Presented by Adrian Dumitru, Baruch College/BNL

Thursday, February 8, 2018, 12:30 pm
Building 510, Room 2-160

Hosted by: Yuya Tanizaki

33. Nuclear Theory/RIKEN Seminar

"New nonperturbative scales and glueballs in confining gauge theories"

Presented by Mohamed Anber, Lewis & Clark College

Friday, February 2, 2018, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Chun Shen

Studying confining gauge theories on a circle can provide answers to some of the deepest questions about QCD. In this talk, I start by summarizing the main characteristics shared by the compactified theories and their four dimensional cousins. Next, I show that the glueball spectrum of the compactified theories is much richer than what have been thought before. In particular, new nonperturbative scales and glueballs emerge in the deep IR regime of the theory. I discuss the spectrum in the context of super Yang-Mills and show that the lightest glueball states fill a chiral supermultiplet with doubly nonperturbative binding energy. I end with possible implications of these findings for the four dimensional gauge theories.

34. NSLS-II Friday Lunchtime Seminar Series

"Combining high energy x-ray diffraction techniques with laser-induced fluorescence in operando catalysis"

Presented by Uta Hejral, Lund University, Sweden

Friday, February 2, 2018, 12 pm
NSLS-II Bldg. 743 Rm 156

Hosted by: M. Abeykoon, S. Chodankar, B. Ocko, T. Tanabe, J. Thieme

35. RIKEN Lunch Seminar

"The Coulomb Branch of N=4 SYM and Its Gravity dual as a New Holographic Model to QCD"

Presented by Kiminad Mamo, Stony Brook

Thursday, February 1, 2018, 12:30 pm
Building 510, Room 2-160

Hosted by: Yuya Tanizaki

36. Joint BNL / SBU Seminar

"New SM Physics and the LHC"

Presented by Yuval Grossman, Cornell University

Wednesday, January 31, 2018, 2:30 pm
Stony Brook University YITP

37. Condensed-Matter Physics & Materials Science Seminar

"Establishing Jeff =3/2 Ground State in a Lacunar Spinel GaTa4Se8"

Presented by Myung Joon Han, Korea Advanced Institute of Science and Technology (KAIST)

Wednesday, January 31, 2018, 1:30 pm
ISB Bldg. 734 Conf. Rm. 201 (upstairs)

Hosted by: Sangkook Choi

In this talk, after briefly introducing the research activities in my group, I will present our recent progress on GaTa4Se8 which is known as a 'paramagnetic Mott' insulator and exhibits superconducting transition under pressure. Its low temperature behaviors found in susceptibility and specific heat measurement have not yet been clearly understood. The important first step to study these intriguing phenomena and the relationship between them is to clarify the nature of its electronic and magnetic property. By using first-principles band structure calculation and resonant inelastic x-ray scattering technique, we show that GaTa4Se8 is a novel 'Jeff=3/2 Mott' insulator in which spin-orbit interaction plays a key role to form a gap together with electronic correlation. The excitations involving the Jeff = 1/2 molecular orbital are absent only at the Ta L2 edge, manifesting the realization of the molecular Jeff = 3/2 ground state in GaTa4Se8. Based on this finding, the possible consequences of the Jeff = 3/2 state will be discussed

38. Physics Colloquium

Presented by Jeff Peterson, Carnegie Mellon University

Tuesday, January 30, 2018, 3:30 pm
Large Seminar Room, Bldg. 510

Hosted by: Andrei Nomerotski

Fast Radio Bursts are millisecond flashes of radio emission that appear randomly across the sky. Since the first report of a burst in 2006, over 20 of these FRBs have been reported. I will review the evidence that FRB sources are at cosmological distances and therefore have inferred brightness temperatures as high as 10^35 K, twenty orders of magnitude higher than gamma ray bursts. The all-sky rate of these events is estimated to be about 5000 per day, so the new HIRAX telescope in South Africa will have the potential to detect 10 events per day. HIRAX will also localize the emission to a single galaxy, so there will be much more information on these mysterious objects in the next few years.

39. Joint Nuclear and Particle Physics Seminar

"The SNOLAB Science Programme: cutting-edge science from a deep hole in the ground"

Presented by Nigel Smith, SNOLab

Tuesday, January 30, 2018, 1:30 pm
Small Seminar Room, Bldg. 510

Hosted by: Hong Ma

SNOLAB is a deep underground research facility, hosted 2km beneath the surface of the Earth in a working mine at Creighton, near Sudbury, Ontario. Initially the site of the Sudbury Neutrino Observatory, which unambiguously demonstrated flavour-change in neutrinos created in the fusion process of the Sun, SNOLAB now hosts a multi-disciplinary programme. Why do we need to go to such great depths to probe the Universe? This work, and several of the major questions studied in contemporary astro-particle and sub-atomic physics, such as the search for the Galactic dark matter, and studies of neutrinos from supernova, require the ultra-quiet radiation environment afforded by deep underground facilities like SNOLAB. In these facilities, the cosmic-radiation induced backgrounds in the detection systems are reduced to a manageable level, with additional shielding from natural ambient radioactivity and low background construction of detector systems. This talk will provide a review of the science programme at SNOLAB outlining the main science objectives, will review the detectors used for these studies, and outline future plans for the facility.

40. Particle Physics Seminar

"A Tale of Two Higgs"

Presented by Baojia Tong, Harvard University

Thursday, January 25, 2018, 3 pm
Small Seminar Room, Bldg. 510

Hosted by: Alessandro Tricoli

An enhanced production of double Higgs bosons at the LHC would be a clear sign of beyond Standard Model physics. An ATLAS search is performed for resonant and non-resonant production, where the two Higgs bosons both decay to a pair of Bottom quarks. The analyses use up to ~13/36 fb−1 of p-p collision data collected at 13 TeV. The talk will focus on the boosted analysis, with the resolved analysis introduced as well. Other RunII double Higgs search results and future prospect will also be discussed.

41. RIKEN Lunch Seminar

"Exact results on massless 3-flavor QCD through new anomaly matching"

Presented by Yuya Tanizaki, RBRC

Thursday, January 25, 2018, 12:30 pm
Building 510, Room 2-160

Hosted by: Enrico Rinaldi

Recently, we find a new 't Hooft anomaly of massless 3-flavor QCD, and it turns out to be useful for constraining the possible chiral symmetry breaking at finite density and zero temperature. We briefly review the anomaly matching by a toy example, and show that massless 3-flavor QCD has an 't Hooft anomaly related to ''center'' and discrete axial symmetries. We also discuss its consequences on the expectation value of the special symmetry-twisting operator, which gives the phase diagram of so-called Z(3)-QCD.

42. Physics Colloquium

"Cold Atom Sensing: Gravity, Tomography, and Gyroscopes"

Presented by Steve Libby, LLNL

Tuesday, January 23, 2018, 3:30 pm
Large Seminar Room, Bldg. 510

Hosted by: Rob Pisarski

The ability to use lasers to cool atoms to micro-kelvin temperatures and to subsequently control their quantum mechanical behavior1 has led to the development of exquisitely precise 'quantum' sensors.2 Applications of these sensors include the measurement of local gravitational anomalies to unprecedented accuracy and very accurate, highly stable gyroscopes. Our LLNL - AOSense, Inc. collaboration is pursuing diverse applications of these sensors that directly exploit their extraordinary scale factor stability, low noise and bias drift characteristics. These applications include shielded threat detection in passing vehicles, emergency response, and treaty verification, all of which require rapid, passive methods to determine hidden mass configurations precisely and/or verify the masses present in containers. Such dense, localized objects can in principle be discovered and accurately measured by their effect on the local gravitational field.3 Furthermore, near field measurements of these gravitational perturbations from multiple vantage points allow for a kind of gravitational 'tomography,' leading to the real-time determination of the hidden mass distribution. Additionally, we are interested in the potential of atom interferometer Sagnac gyroscopes to do accurate 'dead reckoning' navigation without the aid of GPS.4 After reviewing the physics of atom interferometry in atomic fountain-Mach-Zehnder and Sagnac configurations, I will describe the development of a 'gravity tomography' signal analysis system for vehicle portals, including the optimal synthesis of the gravitational sensor signals with complementary radiation detection.

43. Nuclear Physics Seminar

"Probing the Quark-Gluon Plasma with Open Heavy Flavor Mesons using CMS detector"

Presented by Professor Yen-Jie Lee, MIT

Tuesday, January 23, 2018, 11 am
Small Seminar Room, Bldg. 510

Hosted by: Rongrong Ma

The measurements of heavy flavor production and collective flow could be used to extract the properties of the high-density QCD medium created in heavy-ion collisions as heavy quarks are sensitive to the transport properties of the medium and may interact with the QCD matter differently from light quarks. In particular, the comparison between the nuclear modification factors (RAA) of light- and heavy-flavor particles provides insights into the expected flavor dependence of in-medium parton energy loss. Furthermore, azimuthal anisotropy coefficient (vn) of heavy-flavor particles provide information about the degree of the thermalization of the bulk medium at low pT, and unique information about the path length dependence of heavy quark energy loss at high pT. Recently, a comprehensive heavy flavor program is established in the CMS collaboration including the detection of charm and beauty meson. Using the large statistics heavy ion data samples collected during the 2015 and 2016 LHC runs, high precision open charm and beauty measurements are performed with CMS over a wide transverse momentum range. This allows us to set an important milestone in our understanding of the interactions between heavy quarks and the medium. In this talk, the most recent results of v2 and v3 of D0 mesons in PbPb collisions at 5.02 TeV are presented and compared to the same results for charged hadrons at the same energy. Latest results on nuclear modification factor of D, non-prompt J/psi and B mesons in PbPb collisions are also presented.

44. Condensed-Matter Physics & Materials Science Seminar

"Spin-orbit coupling and electronic correlations in Hund's metals: Sr2RuO4"

Presented by Minjae Kim, École Polytechnique, France

Monday, January 22, 2018, 1:30 pm
ISB Bldg. 734 Conf. Rm. 201 (upstairs)

Hosted by: Gabi Kotliar

We investigate the interplay of spin-orbit coupling (SOC) and Hund's rule coupling driven electronic correlations in Sr2RuO4 using dynamical mean-field theory. We find that the orbital diagonal components of the dynamical electronic correlations are unaffected by the SOC, which validates the concept of a Hund's metal in the presence of SOC. In contrast, SOC itself is enhanced by approximately a factor of two by electronic correlations. We introduce the concept of an energy dependent quasiparticle SOC, which is found to be essential in accounting simultaneously for: (i) the Fermi surface (ii) the low-energy dispersion of quasiparticles and (iii) the splitting between bands at higher binding energy. Our calculations are in good agreement with available experimental data. References: [1-4] [1] C. Veenstra et al., Physical Review Letters 112, 127002 (2014) [2] M. Haverkort et al., Physical Review Letters 101, 026406 (2008) [3] J. Mravlje et al., Physical Review Letters 106, 096401 (2011) [4] M. Kim et al., arXiv preprint arXiv:1707.02462 (2017)

45. Nuclear Theory/RIKEN Seminar

"Semi-inclusive jet cross sections within SCET"

Presented by Felix Ringer, LBL

Friday, January 19, 2018, 2 pm
Small Seminar Room, Bldg. 510

We review the de nition of semi-inclusive jet functions within Soft Collinear E ective Theory (SCET) and their application to inclusive jet cross sections. We consider the fully inclusive production cross section of jets as well as several jet substructure observables in proton-proton collisions relevant for the LHC and RHIC. The corresponding semi-inclusive jet functions satisfy renormalization group (RG) equations which take the form of standard timelike DGLAP evolution equations, analogous to collinear fragmentation functions. By solving these RG equations, the resummation of potentially large single logarithms n s lnn R can be achieved. We present numerical results at NLO+NLLR accuracy and compare to the available data.

46. Particle Physics Seminar

"Search for the Higgs boson produced in association with top quarks and decaying into a b quark pair with the ATLAS detector at LHC"

Presented by Thomas Calvet, Stony Brook University

Thursday, January 18, 2018, 3 pm
Small Seminar Room, Bldg. 510

Hosted by: Alessandro Tricoli

The discovery of a particle compatible with the Standard Model (SM) Higgs boson in 2012 by the ATLAS and CMS collaborations at LHC is a milestone in particle physics. In order to assess whether or not this Higgs boson belongs to the SM, it is necessary to measure its properties, in particular its coupling to the top quark (the strongest Yukawa coupling in the SM). The associated production of a Higgs boson with a pair of top quarks, ttH gives the most favorable direct access to the top quark Yukawa coupling and is accessible for the first time in LHC Run 2. A search for the ttH production with the Higgs boson decaying into a b quark pair, ttH(bb), will be presented. It uses the 36.1 fb^-1 of data recorded by the ATLAS detector in 2015 and 2016. The main limitation to the search of ttH(bb) events is the tt+jets background and its systematic uncertainties. To achieve sufficient sensitivity, this complex analysis relies on several advanced tools to separate the leading background tt+jets from the signal, and to extract both of these processes from data (multi-variate analysis, profile likelihood fit, etc.). All these key aspects of the analysis will be discussed. The combination of the ttH(bb) channel with the other decay modes is necessary to improve the sensitivity to the ttH production mode. This combination leads to 4.2 sigma evidence of the ttH production and will be also presented.

47. RIKEN Lunch Seminar

"World-line Approach to Chiral Kinetic Theory and the Chiral Magnetic Effect"

Presented by Niklas Mueller, BNL

Thursday, January 18, 2018, 12:30 pm
Building 510, Room 1-224

Hosted by: Enrico Rinaldi

Experimental searches for messengers of CP- and P- odd phenomena at RHIC and LHC have attracted much interest and are a prime motivation for significant theoretical effort: Anomalous and topological effects receive important contributions from the pre-equilibrium phase of a collision and an interesting question of phenomenological relevance is how the chiral imbalance generated at early times persists through a fluctuating background of sphalerons in addition to other "non-anomalous" interactions with the QGP. To address this question, we construct a relativistic chiral kinetic theory using the world-line formulation of quantum field theory. We outline how Berry's phase arises in this framework, and how its effects can be clearly distinguished from those arising from the chiral anomaly. We further outline how this framework can be matched to classical statistical simulations at early times and to anomalous chiral hydrodynamics at late times.

48. Environmental & Climate Sciences Department Seminar

"Understanding the Structure and Dynamics of Long-Duration Floods using Physics Informed Bayesian Multilevel Models"

Presented by Naresh Devineni, CUNY

Thursday, January 18, 2018, 11 am
Conference Room Bldg 815E

Hosted by: Bob McGraw

Long duration floods cause substantial damage and prolonged interruptions to water resource facilities, critical infrastructure, and regional economic development. We present a novel physics-based model for inference of such floods with a deeper understanding of dynamically integrated nexus of land surface wetness, effective atmospheric blocking/circulation, and moisture transport/release mechanism. Diagnostic results indicate that the flood duration is varying in proportion to the antecedent flow condition which itself is a function of the available moisture in the air, the persistency in atmospheric pressure blocking, convergence of water vapor, and the effectiveness of divergent wind to condense the aforesaid atmospheric water vapor into liquid precipitation. A physics-based Bayesian inference model is developed that considers the complex interactions between moisture transport, synoptic-to-large-scale atmospheric blocking/circulation pattern, and the antecedent wetness condition in the basin. We explain more than 80% variations in flood duration with a high success rate on the occurrence of long duration floods. Our findings underline that the synergy between a large persistent low-pressure blocking system and a higher rate of divergent wind often triggers a long duration flood, even in the presence of moderate moisture supply in the atmosphere. This condition in turn causes an extremely long duration flood if the basin-wide surface wetness prior to the flood event was already high.

49. Condensed-Matter Physics & Materials Science Seminar

""In situ characterization of the phase behavior of metal oxides at extreme conditions""

Presented by Leighanne Gallington, Argonne National Laboratory

Wednesday, January 17, 2018, 1:30 pm
ISB Bldg. 734 Conf. Room 201 (upstairs)

Hosted by: Ian Robinson

In situ characterization of the phase behavior of materials in the lab is complicated by the difficulty of designing compatible sample environments as well as the long time scales required to acquire diffraction data with sufficient counting statistics for crystallographic analyses. The high energy x-rays available at synchrotron sources allow for penetration of most sample environments, while high flux allows for rapid acquisition of diffraction patterns, thereby allowing construction of detailed phase diagrams. Low and negative thermal expansion (NTE) materials have been studied extensively, as they can potentially be used to create composites with finely controlled thermal expansion characteristics, improved resistance to thermal shock, and a broader range of operating temperatures.1-4 While the thermal expansion behavior of the NTE materials ZrW2O8 and HfW2O8 was well-described at ambient pressures,4-6 knowledge of the effects of stress on their thermal expansion was limited.7 In situ synchrotron powder diffraction was utilized to explore the role of orientational disorder in determining both the phase behavior and the thermoelastic properties of these materials. An especially designed pressure cell allowed for simultaneous sampling of temperatures up to 513 K and pressures up to 414 MPa.8 Reversible compression-induced orientational disordering of MO4 tetrahedra occurred concomitantly with elastic softening on heating and enhanced negative thermal expansion upon compression in ZrW2O8 and HfW2O8, but only in the ordered phase.9, 10 In light of the comparatively recent nuclear disaster in Fukushima, understanding interactions and phase behavior in nuclear fuels under severe accident conditions is of paramount interest. While diffraction measurements have been performed on materials recovered from melts of corium (UO2-ZrO2), there is a lack of in situ characterization of this material at elevated temperatures. Achieving the extreme temperatures required

50. Physics Colloquium

"Nuclear nonproliferation: the role of Brookhaven, and the nuclear agreement with Iran"

Presented by Susan Pepper & Leslie Fishbone, BNL

Tuesday, January 16, 2018, 3:30 pm
Large Seminar Room, Bldg. 510

Hosted by: Rob Pisarski

51. Particle Physics Seminar

"Improved Point Source Detection in Crowded Fields using Probabilistic Cataloguing"

Presented by Stephen Portillo, Harvard University

Tuesday, January 16, 2018, 11 am
Small Seminar Room, Bldg. 510

Hosted by: Erin Sheldon

Cataloging is challenging in crowded fields because sources are extremely covariant with their neighbors and blending makes even the number of sources ambiguous. We present the first optical probabilistic stellar catalogue, cataloguing a crowded (~0.1 sources per pixel) SDSS r band image from M2. We show that our probabilistic catalogue goes more than a magnitude deeper than the DAOPHOT while having a lower false discovery rate brighter than 20th magnitude. We detail our efforts to speed up the method and extend it to galaxies, making probabilistic cataloguing applicable to the data that will be collected in the LSST era.

52. HET Lunch Discussions

"Precision physics in the LHC era"

Presented by Pier Paolo Giardino, BNL

Friday, January 12, 2018, 12:15 pm
Building 510, Room 2-160

Hosted by: Christoph Lehner

53. Condensed-Matter Physics & Materials Science Seminar

"Singular density fluctuations in the strange metal phase of Bi2Sr2CaCu2O8+x observed with momentum-resolved EELS (M-EELS)"

Presented by Peter Abbamonte, University of Illinois at Urbana Champaign

Friday, January 12, 2018, 11 am
ISB Bldg. 734, Conf. Room 201 (upstairs)

Hosted by: Peter D. Johnson

High-temperature superconductivity arises out of an anomalous normal state commonly referred to as a "bad" or "strange" metal, since it lacks the usual signatures of electron quasiparticles. In ordinary metals, such quasiparticles manifest as propagating collective modes encoded in the dynamic charge susceptibility ??(q,?), which describes the response of the system to applied fields. However, the analogous collective modes of a strange metal are currently unknown. Here, we present the first measurement of ??(q,?) for a prototypical strange metal, Bi2.1Sr1.9CaCu2O8+x (BSCCO), using momentum-resolved inelastic electron scattering (M-EELS). We discover a surprising energy- and momentum-independent continuum of fluctuations extending up to 1 eV, at odds with the dispersive plasmons expected in normal metals. This spectrum is found to be temperature-independent across the superconducting phase transition at optimal doping. Tuning the composition to overdoping, where a crossover to Fermi liquid behavior is expected, this momentum-independent continuum is found to persist, though a 0.5 eV gap-like feature now emerges at low temperature. Our results indicate that the phenomenon underlying the strange metal is a singular form a charge dynamics of a new kind, that does not fit into any known picture of quantum critical scaling.

54. Condensed-Matter Physics & Materials Science Seminar

"Bose condensation of excitons in TiSe2"

Presented by Peter Abbamonte, University of Illinois at Urbana–Champaign

Thursday, January 11, 2018, 1:30 pm
ISB Bldg. 734, Conf. Room 201 (upstairs)

Hosted by: Peter D. Johnson

Bose condensation has shaped our understanding of macroscopic quantum phenomena, having been realized in superconductors, atomic gases, and liquid helium. Excitons are bosons that have been predicted to condense into either a superfluid or an insulating electronic crystal. But definitive evidence for a thermodynamically stable exciton condensate has never been achieved. In this talk I will describe our use of momentum-resolved electron energy-loss spectroscopy (M-EELS) to study the valence plasmon in the transition metal dichalcogenide semimetal, 1T-TiSe2. Near the phase transition temperature, TC = 190 K, the plasmon energy falls to zero at nonzero momentum, indicating dynamical slowing down of plasma fluctuations and crystallization of the valence electrons into an exciton condensate. At low temperature, the plasmon evolves into an amplitude mode of this electronic crystal. Our study represents the first observation of a soft plasmon in any material, the first definitive evidence for exciton condensation in a three-dimensional solid, and the discovery of a new form of matter, "excitonium."

55. RIKEN Lunch Seminar

"Three-dimensional gauge theories using lattice regularization"

Presented by Nikhil Karthik

Thursday, January 11, 2018, 12:30 pm
Building 510, Room 2-160

Hosted by: Yuya Tanizaki

Three-dimensional gauge theories with massless fermions provide a simple yet non-perturbative setting to understand why QCD has a scale, and also provide effective descriptions of condensed matter systems. Along these lines, I will present results on infra-red scaling and scale-breaking in three-dimensional QED, QCD and large-Nc theories. I will also present some preliminary results on three-dimensional QED with one flavor of fermion regulated with and without parity anomaly.

56. Condensed-Matter Physics & Materials Science Seminar

""Photoemission studies of the electronic properties of rare-earth intermetallics and oxide interface""

Presented by Alla Chikina, Paul Scherrer Institute, Switzerland

Monday, January 8, 2018, 3 pm
ISB Bldg. 734 Seminar Room 201 (upstairs)

Hosted by: Cedomir Petrovic

Longer than 70 years solid state research has been focused on the study of materials with strong electron correlations due to their remarkable electronic and magnetic properties. In such systems, the average energy of the Coulomb interaction is greater or comparable to its kinetic energy and electrons tend to be localized. This localization is strong enough that electrons can be considered in the framework of the atomic approach. Interaction with itinerant electrons makes the interpretation of their physical properties more complicated. A typical example of a strongly-correlated system contains transition and rare earth (RE) elements. Here, I present both theoretical and experimental insight into the itinerant-localized electron interaction in rare-earth 122 silicides (RERh2Si2). The properties of RERh2Si2 change from the heavy-fermion behavior in YbRh2Si2 up to well-pronounced magnetic properties in EuRh2Si2 and GdRh2Si2. The competition between the Kondo effect and the magnetic RKKY interactions determines the properties of a large class of materials which have localized 4f magnetic moments coupled to itinerant valence electrons. The strong electron correlations, also well known in the transition metal oxides, rise up their remarkable functional and magnetic properties. It gives a route in a manipulation of electron, spin, orbital and lattice degrees of freedom for novel electronic and spintronic devices based on oxide interfaces. An important role in the electronic and magnetic properties of this interface is played by oxygen vacancies which form a dichotomic electron system where strongly correlated localized electrons in the in-gap states (IGSs) coexist with less correlated ones constituting the mobile two-dimensional electron system (2DES). On the example of the interface between LaAlO3 and SrTiO3 we consider a complex band ordering in the dichotomic LAO/STO electron system that goes beyond the conventional eg vs t2g picture.

57. Nuclear Theory Seminar

"Thermodynamics of string bits"

Presented by Sourav Raha, University of Florida

Monday, January 8, 2018, 11 am
Large Seminar Room, Bldg. 510

Hosted by: Andrey Tarasov

We study the Hagedorn transition in the singlet sector of the simplest super-string bit model in the tensionless limit. The gauge group of our model is SU(N) and this transition takes place when N is infinite. We use orthogonality of group characters in order to calculate the partition function. At the Hagedorn temperature there is a change in the distribution of parameters that maximize this partition function. We conclude by devising a field-theoretic interpretation of the this phenomenon.

58. Nuclear Theory/RIKEN Seminar

"Thermodynamics of string bits"

Presented by Sourav Raha, University of Florida

Friday, January 5, 2018, 2 pm
Small Seminar Room, Bldg. 510

We study the Hagedorn transition in the singlet sector of the simplest super-string bit model in the tensionless limit. The gauge group of our model is SU(N) and this transition takes place when N is infinite. We use orthogonality of group characters in order to calculate the partition function. At the Hagedorn temperature there is a change in the distribution of parameters that maximize this partition function. We conclude by devising a field-theoretic interpretation of the this phenomenon.

59. Condensed-Matter Physics & Materials Science Seminar

"Illuminating rationally engineered complex oxides"

Presented by Derek Meyers, BNL

Friday, January 5, 2018, 1:30 pm
ISB Bldg. 734 Conf. Rm. 201 (upstairs)

Hosted by: Mark Dean

Advances in unit cell scale synthesis have unlocked the ability to create artificial materials at the interface of complex oxides. This opens the door to the rational design of materials properties. To explore the spin, charge, and orbital character of these synthetic materials, resonant x-ray scattering techniques are utilized which unveil their long-range ordering and low energy excitations. In this talk, we will explore several recent examples of this new methodology and provide an outlook on the future of this emergent field.

60. Condensed-Matter Physics & Materials Science Seminar

"Spin fluctuations in 122 transition metal arsenides measured using inelastic neutron scattering technique"

Presented by Aashish Sapkota, Ames Laboratory

Thursday, December 21, 2017, 1:30 pm
ISB Bldg. 734 Conf. Rm. 201 (upstairs)

122 transition metal compounds with ThCr2Si2-type structure have been extensively studied because of their wide range of interesting physical properties like superconductivity, valence fluctuations, various magnetic ground states, etc. A subset (ATM2Pn2) of this class consisting of alkaline earth metals (A), 3d transition metals (TM) and pnictogen (Pn) attracted significant interest after discovery of an unconventional superconductivity in 122 iron arsenide compounds. In 122 iron arsenide superconductors, magnetism is in close proximity to the superconductivity and the spin fluctuations are considered as a key component for the pairing mechanism for superconductivity. These properties as well as the wide range of magnetic ground states, found in ATM2As2, motivated a detail studies of the magnetism in these compounds and neutron scattering technique has been extensively used for the study. In this seminar, I will discuss our results of inelastic neutron scattering measurements of the spin fluctuations in two compounds [CaCo1.86As2 and Ca(Fe1-xCox)2As2] of ATM2Pn2 class. First, I will discuss extremely extended spin fluctuations along two directions of reciprocal space in CaCo1.86As2, which shows A-type antiferromagnetic ground states. The result suggests that CaCo1.86As2 is highly-frustrated and is a unique example of highly-frustrated square-lattice system. Next, I will discuss the evolution of the spin fluctuations in Co-doped CaFe2As2 and compare it to that of Co-doped BaFe2As2. In this part, I will also discuss a peculiar suppression of the spin fluctuations with temperature observed in Ca(Fe1-xCox)2As2, x = 0.030 compound, which shows superconducting ground state.

61. Nuclear Theory/RIKEN Seminar

"Simultaneous extraction of spin-dependent parton distributions"

Presented by Nobuo Sato, Jlab/University of Connecticut

Friday, December 15, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Andrey Tarasov

In this talk, I will present a recent global QCD analysis of spin-dependent PDFs and FFs using a MC methodology by the Jefferson Angular Momentum collaboration (JAM).

62. HET Seminar

"Searching for Ultralight Particles with Black Holes and Gravitational Waves"

Presented by Masha Baryakhtar, Perimeter Inst. Theor. Phys.

Wednesday, December 13, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Christopher Murphy

The LIGO detection of gravitational waves has opened a new window on the universe. I will discuss how the process of superradiance, combined with gravitational wave measurements, makes black holes into nature's laboratories to search for new light bosons, from axions to dark photons. When a bosonic particle's Compton wavelength is comparable to the horizon size of a black hole, superradiance of these bosons into hydrogenic' bound states extracts energy and angular momentum from the black hole. The occupation number of the levels grows exponentially and the black hole spins down. One candidate for such an ultralight boson is the QCD axion with decay constant above the GUT scale. Current black hole spin measurements disfavor a factor of 30 (400) in axion (vector) mass; future measurements can provide evidence of a new boson. Particles transitioning between levels and annihilating to gravitons may produce thousands of monochromatic gravitational wave signals, and turn LIGO into a particle detector.

63. Physics Colloquium

"The "self-stirred" genome: Bulk and surface dynamics of the chromatin globule"

Presented by Alexandra Zidovska, New York University

Tuesday, December 12, 2017, 3:30 pm
Large Seminar Room, Bldg. 510

Chromatin structure and dynamics control all aspects of DNA biology yet are poorly understood. In interphase, time between two cell divisions, chromatin fills the cell nucleus in its minimally condensed polymeric state. Chromatin serves as substrate to a number of biological processes, e.g. gene expression and DNA replication, which require it to become locally restructured. These are energy-consuming processes giving rise to nonequilibrium dynamics. Chromatin dynamics has been traditionally studied by imaging of fluorescently labeled nuclear proteins and single DNA-sites, thus focusing only on a small number of tracer particles. Recently, we developed an approach, displacement correlation spectroscopy (DCS) based on time-resolved image correlation analysis, to map chromatin dynamics simultaneously across the whole nucleus in cultured human cells [1]. DCS revealed that chromatin movement was coherent across large regions (4–5μm) for several seconds. Regions of coherent motion extended beyond the boundaries of single-chromosome territories, suggesting elastic coupling of motion over length scales much larger than those of genes [1]. These largescale, coupled motions were ATP-dependent and unidirectional for several seconds. Following these observations, we developed a hydrodynamic theory of active chromatin dynamics, using the two-fluid model and describing the content of cell nucleus as a chromatin solution, which is subject to both passive thermal fluctuations and active (ATP-consuming) scalar and vector events [2]. In this work we continue in our efforts to elucidate the mechanism and function of the chromatin dynamics in interphase. We investigate the chromatin interactions with the nuclear envelope and compare the surface dynamics of the chromatin globule with its bulk dynamics [3]. Furthermore, we explore the rheology of the chromatin inside the cell nucleus using the native subnuclear structures [4]. [1] Zidovska A, Weitz DA, Mitchi

64. Particle Physics Seminar

"A Unified Program of Argon Dark Matter Searches: DarkSide-20k and The Global Argon Dark Matter Collaboration"

Presented by Cristiano Galbiati, Princeton University

Monday, December 11, 2017, 3 pm
Small Seminar Room, Bldg. 510

Hosted by: Alessandro Tricoli

: Experimenters from four different argon dark matter searches have joined their forces in the the "Global Argon Dark Matter Collaboration" to carry out a unified program for dark matter direct detection. The participants are researchers currently working on the ArDM experiment at LSC; on the DarkSide-50 experiment at LNGS; on the DEAP-3600 experiment at SNOLab; and on the MiniCLEAN experiment at SNOLab. In 2015/2016 The DarkSide-50 experiment at LNGS produced two zero-background science results, along with a comparison of the results obtained with both atmospheric and underground argon fills, demonstrating the ability of large experiments to eliminate background from betas/gammas at the tens of tonne-year exposure. The DEAP-3600 experiment at SNOLAB is the first tonne-scale experiment to achieve both stable operations and an extended physics run. DEAP-3600 has been collecting physics data with over 3 tonnes of argon since late 2016 and published its first results in 2017. Researchers from the four experiments will jointly carry out as the single next step at the scale of a few tens of tonnes the DarkSide-20k experiment. DarkSide-20k was approved in 2017 by the Italian INFN, by the host laboratory LNGS, and by the US NSF. DarkSide-20k is also officially and jointly supported by the three underground laboratories LNGS, LSC, and SNOLab. DarkSide-20k is a 20-tonne fiducial volume dual-phase TPC to be operated at LNGS with an underground argon fill, designed to collect an exposure of 100 tonne×years, completely free of neutron-induced nuclear recoil background and all electron recoil background. DarkSide-20k is set to start operating by 2021 and will have sensitivity to WIMP-nucleon spin-independent cross sections of 1.2 × 10−47 cm2 for WIMPs of 1 TeV/c2 mass, to be achieved during a 5 year run. An extended 10 year run could produce an exposure of 200 tonne×years, with sensitivity for the cross-section of 7.4 × 10&min

65. Special HET Seminar

"Effective Theories and Phenomenology of Dark Mesons"

Presented by Graham Kribs, University of Oregon

Monday, December 11, 2017, 1:30 pm
Building 510, Room 2-160

Hosted by: Hooman Davoudiasl

66. HET Lunch Discussions

"A precise determination of the QCD coupling by the ALPHA Collaboration"

Presented by Mattia Bruno, BNL

Friday, December 8, 2017, 12:15 pm
Building 510, Room 2-160

Hosted by: Christoph Lehner

67. Particle Physics Seminar

"Machine Learning Analysis of Ising Worms"

Presented by Sam Foreman, University of Iowa

Thursday, December 7, 2017, 3 pm
Small Seminar Room, Bldg. 510

Hosted by: Chao Zhang

Motivated by recent results demonstrating the applicability of machine learning techniques to quantum spin systems, we explore an application of the worm algorithm to the two dimensional Ising model. We begin by presenting the high temperature expansion of the Ising model, which is used to generate equilibrium configurations of "worms" represented as two¬dimensional greyscale images. From these configurations, we are then able to calculate physical quantities of interest. In particular, we are able to identify the logarithmic divergence of the specific heat at the critical temperature. We then propose a complementary approach using machine learning techniques (in particular, principal component analysis, (PCA)) which also successfully identifies the divergent behavior near criticality. Finally, we investigate the behavior of the previously mentioned concepts under a renormalization group coarse¬graining procedure, and present ideas for future research.

68. RIKEN Lunch Seminar

"Pushing the boundaries of relativistic fluid dynamics"

Presented by Jorge Noronha

Thursday, December 7, 2017, 12:30 pm
Building 510, Room 2-160

Hosted by: Enrico Rinaldi

For nearly a century, dissipative effects have been included in fluid dynamics using gradients of macroscopic quantities such as the temperature and fluid velocity. Recently, results from heavy ion collision experiments and explicit model calculations have pushed the boundaries of relativistic fluid dynamics towards the far-from-equilibrium regime. In this talk I will present calculations of the large order behavior of the gradient expansion, both in kinetic theory and in holography, which have demonstrated that this series has zero radius of convergence. I will discuss the role played by novel non-equilibrium attractor solutions in determining the emergence of fluid dynamic behavior in many-body systems under extreme conditions.

69. Condensed-Matter Physics & Materials Science Seminar

"Examples of translational research using thermoelectric oxides"

Presented by Ryoji Funahashi, National Institute of Advanced Industrial Science & Technology, Japan

Wednesday, December 6, 2017, 3 pm
Conference Room, Building 480

Hosted by: Qiang Li

We have been relishing a lot of affluence thanks to energy. Fossil energy provides us fun to drive, warmth to escape from cold, brightness of illumination, etc. However consumption of the fossil fuel produces CO2. The amount of CO2 emission will increase with increasing consumption of fossil energy, gas, oil, and coal year by year. The average of total utilizing efficiency of the primary energy is as low as 30 %, with 70 % exhausted to the air as waste heat. It is clear that improved efficiencies of energy conversion systems could have a significant impact on energy consumption and carbon dioxide emission rate. Where a large sum of heat is localized, mechanical conversion systems can be used to generate electricity. However, most sources of waste heat are widely dispersed. Although technologies of storage and transport of such the dilute heat energy have been developed, most waste heat can't be used effectively. Electricity is a convenient form of energy that is easily transported, redirected, and stored, thus there are a number of advantages to the conversion of waste heat emitted from our living and industrial activities to electricity. Thermoelectric conversion is paid attention as the strongest candidate to generate electricity from dilute waste heat. Oxide materials are considered to be promising ones because of their durability against high temperature, low cost for producing etc. The misfit CoO2 compounds show high thermoelectric efficiency at high temperature in air. Thermoelectric modules using p-type Ca3Co4O9, one of the CoO2 compounds and n-type CaMnO3 have been produced [1, 2]. The maximum power density against area of the substrate of the module reaches 4.3 kW/m2 at 973 K of the heat source temperature [3]. Portable power generation units composed of an oxide thermoelectric module. Water circulation and batteries for air cooling are unnecessary for thermoelectric conversion. The units can generate 2-5 W using heat energy with temperature of 300-8

70. Physics Colloquium

"Thinking inside the box - hadron resonances in QCD"

Presented by Jozef Dudek, JLab

Tuesday, December 5, 2017, 3:30 pm
Large Seminar Room, Bldg. 510

Hosted by: Rob Pisarski

I will describe how we can make use of the finite box in which lattice QCD calculations are performed to learn something about hadron scattering amplitudes from first principles. These amplitudes contain information about the resonance structure of QCD and hence the spectrum of excited mesons and baryons. I'll present the results of recent calculations in which the lightest scalar, vector and tensor mesons have been studied.

71. Nuclear Theory/RIKEN seminar

"Medium modification of jet and jet-induced medium excitation"

Presented by Shanshan Cao, Wayne State University

Friday, December 1, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Chun Shen

A coupled linear Boltzmann transport and hydrodynamics model (CoLBT-hydro) is developed for concurrent simulation of jet propagation and hydrodynamic evolution in high-energy nuclear collisions. Diverse microscopic scattering processes (elastic and inelastic) are incorporated for parton showers, and both massive and massless partons are calculated on the same footing. Energy deposition from jets into nuclear matter is treated as source term of hydrodynamic evolution. Within this CoLBT-hydro model, nuclear modification of heavy and light flavor hadrons are simultaneously described. Evidence of jet-induced medium excitation is explored with photon-triggered jets, where significant enhancement of soft hadron production is found due to energy deposition from jets.

72. HET Lunch Discussions

"Double Higgs Production in the Complex Singlet Extended Standard Model"

Presented by Matt Sullivan, University of Kansas

Friday, December 1, 2017, 12:15 pm
Orange Room

Hosted by: Christoph Lehner

73. HET Seminar

"Do Electroweak Corrections Violate Factorization?"

Presented by Ira Rothstein, Carnegie Mellon U

Wednesday, November 29, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Eder Izaguirre

74. Particle Physics Seminar

"The strong CP-problem and axion dark matter searches"

Presented by Yannis Semertzidis, KAIST and IBS

Monday, November 27, 2017, 3 pm
Small Seminar Room, Bldg. 510

Hosted by: Chao Zhang

The strong CP-problem, i.e. why is the neutron EDM experimental limit is at least ten orders of magnitude lower than expected from the theory of QCD is one of the mysteries in physics today. Peccei and Quinn came up with a solution to the strong CP-problem at the expense of requiring an extra pseudo-scalar particle, the axion. It turns out, the axion at a certain mass range is also an ideal dark matter candidate and it can be detected via its conversion to microwave photons in the presence of a strong magnetic field. IBS/CAPP in South Korea, the center for axion and precision physics research of the institute for basic science, was established to elucidate the strong CP-problem and in particular the axion dark matter mystery. I'm going to give an overview of the history of axion dark matter searches, the present status and the plans for answering whether or not axions are a significant part of the dark matter in our galaxy.

75. Physics Colloquium

"Numerical Relativity in the Multimessenger Era"

Presented by Manuela Campanelli, Rochester Institute of Technology

Tuesday, November 21, 2017, 3:30 pm
Large Seminar Room, Bldg. 510

Hosted by: Peter Petreczky

The recent discovery of gravitational waves by Advanced LIGO ushered in a new kind of astronomy, one potentially integrating its findings with those obtained from electromagnetic and/or neutrino observations. Multi-messenger astronomy promises to revolutionize our understanding of the universe by providing dramatically contrasting views of the same objects. To understand this unprecedented wealth of observational evidence, computer intensive theoretical calculations of the Einstein field equations, coupled with the equations of magneto-hydrodynamics, are required in order to link data with underlying physics. In this talk, I will provide a review on the recent progress in this exciting field of computational astrophysics. With Advanced LIGO now fully operational and the detection of additional gravitational wave events imminent, we expect that there will be a surge in the number of researchers interested in performing simulations of compact binary mergers.

76. Nuclear Theory/RIKEN Seminar

"Higher-order corrections to jet quenching"

Presented by Yacine Mehtar-Tani, University of Washington

Friday, November 17, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Chun Shen

The phenomenon of jet quenching in ultra-relativistic heavy ion collisions reveals to effect of substantial finial state interactions which cause QCD jets to lose energy to the quark-gluon plasma (QGP), mainly by induced gluon radiation. In standard analytic approaches to energy loss, jets are approximated by single partons and thus higher-order effects in the strong coupling constant are neglected. This may prove insufficient to reliably extract QGP properties at high pT, where a significant jet suppression was recently reported by the ATLAS collaboration in PbPb collisions at the LHC. In this work we explore higher-order corrections to the inclusive jet spectrum which may be sizable owing to the fact that the probability for a highly virtual parton to split in the medium increases with the jet pT. As the effective number of jet constituents increases, jets are expected to lose more energy than a single color charge. This translates into large logarithmic enhancements of higher-orders in the perturbative series, that need to be resummed. As a result we obtain a Sudakov-like suppression factor which we investigate in the leading logarithmic approximation. We note, however, that the phase space for higher-order corrections is mitigated by coherence effects that relate to the fact that, below a characteristic angular scale, the medium does not resolve the inner jet structure. In this case, the jet lose energy coherently as a single color charge, namely, the primary parton.

77. HET Lunch Discussions

"Unified Scenario for Composite Right-Handed Neutrinos and Dark Matter"

Presented by Pier Paolo Giardino

Friday, November 17, 2017, 12:15 pm
Building 510, Room 2-160

Hosted by: Christoph Lehner

78. Condensed-Matter Physics & Materials Science Seminar

"Complementary response of static spin-stripe order and superconductivity to non-magnetic impurities and pressure in cuprates"

Presented by Zurab Guguchia, Columbia University

Thursday, November 16, 2017, 1:30 pm
ISB Bldg. 734, Conference Room 201 (upstairs)

Hosted by: Emil Bozin

Cuprate high-temperature superconductors (HTSs) have complex phase diagrams with multiple competing ordered phases. Understanding to which degree charge, spin, and superconducting orders compete or coexist is paramount for elucidating the microscopic pairing mechanism in the cuprate HTSs. In this talk, i will report some novel results of muonspin rotation (μSR), neutron Scattering and magnetization experiments on non-magnetic Zn impurity and hydrostatic pressure effects on the static spin-stripe order and superconductivity in the La214 cuprates [1,2]. Namely, in La2−xBaxCu1−yZnyO4 (0.11 ≤ x ≤ 0.17) and La1.48Nd0.4Sr0.12Cu1−yZnyO4. Remarkably, it was found that in these systems the spin-stripe ordering temperature Tso decreases linearly with Zn doping y and disappears at y ≈ 4 % , demonstrating the extreme sensitivity of static spin-stripe order to impurities within a CuO2 plane. Moreover, Tso is suppressed in the same manner as the superconducting transition temperature Tc by Zn impurities. We also observed the same pressure evolution of both Tc and Tso in La2−xBaxCuO4, while there is an antagonistic pressure evolution of magnetic volume fraction and superfluid density [1,2,3]. These results indicate that static spin-stripe order and SC pairing correlations develop in a cooperative fashion in La214 cuprates. In other words, the existence of the stripe order requires intertwining with the SC pairing correlations, such as occurs in the proposed pair-density wave (PDW) state [4]. [1] Z. Guguchia et. al., Phys. Rev. B 94, 214511 (2016). [2] Z. Guguchia et. al., Phys. Rev. Lett. 119, 087002 (2017). [3] Z. Guguchia et. al., Phys. Rev. Lett. 113, 057002 (2014). [4] E. Fradkin, S.A. Kivelson, and J.M. Tranquada, Rev. Mod. Phys. 87, 457 (2015).

79. RIKEN Lunch Seminar

"QCD from gluon, quark, and meson correlators"

Presented by Mario Mitter, BNL

Thursday, November 16, 2017, 12:30 pm
Building 510, Room 2-160

Hosted by: Hiromichi Nishimura

We present non-perturbative first-principle results for quark-, gluon- and meson 1PI correlation functions of two-flavour Landau-gauge QCD in the vacuum and Yang-Mills theory at finite temperature. They are obtained by solving their Functional Renormalisation Group equations in a systematic vertex expansion, aiming at apparent convergence within a self-consistent approximation scheme. These correlation functions carry the full information about the theory and their connection to physical observables is discussed. The presented calculations represent a crucial prerequisite for quantitative first-principle studies of QCD and its phase diagram within this framework. In particular, we have computed the ghost, quark and scalar-pseudoscalar meson propagators, as well as gluon, ghost-gluon, quark-gluon, quark, quark-meson, and meson interactions and the magnetic and electric components of the gluon propagator, and the three- and four-gluon vertices. Our results stress the crucial importance of the quantitatively correct running of different vertices in the semi-perturbative regime for describing the phenomena and scales of confinement and spontaneous chiral symmetry breaking without phenomenological input. We confront our results for the correlators with lattice simulations and compare our Debye mass to hard thermal loop perturbation theory. Finally, applications to "QCD-enhanced" low-energy effective models of QCD are discussed.

80. HET Seminar

"Analysis of a Dilaton EFT for Lattice Data"

Presented by Thomas Appelquist, Yale University

Wednesday, November 15, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Mattio Bruno

81. Physics Colloquium

""The muon anomalous magnetic moment — A precision test of the standard model""

Presented by Christoph Lehner, BNL

Tuesday, November 14, 2017, 3:30 pm
Large Seminar Room, Bldg. 510

Hosted by: Robert Pisarski

The anomalous magnetic moment of the muon is one of the most precisely determined quantities in particle physics. It is currently known both experimentally and from theory to approximately 1/2 parts per million. Interestingly, there is an approximate 3—4 sigma tension between theory computation and the experimental value (BNL E821) which may hint at new physics beyond the standard model of particle physics. In this talk, I review the current status of a soon-expected improved experimental measurement (FNAL E989) and recent rapid progress in reducing the uncertainty of the standard model theory computation.

82. Nuclear Physics Seminar

"Fermilab E-906/SeaQuest: A novel nucleon structure laboratory"

Presented by Bryan Ramson, University of Michigan

Tuesday, November 14, 2017, 11 am
Small Seminar Room, Bldg. 510

Hosted by: Oleg Eyser

SeaQuest is the latest iteration in a series of Fermilab experiments designed to probe nucleon structure using the Drell-Yan process. The most recent ancestor of SeaQuest, E866/NuSea, used the Drell-Yan process to provide the most comprehensive observations of the light-quark flavor asymmetry to date, which suggested significant non-pertubative effects in the nucleon sea. Other measurements concerning cold nuclear matter, J/Psi production, and Drell-Yan angular distributions were conducted as well. SeaQuest aims to complement the flagship NuSea measurement by probing higher seaquark momenta at a lower center-of-mass energy and higher intensity. A summary of the light-quark flavor asymmetry measurement status will be reported as well as the status of various parallel analyses, one of which could have implications for the Boer-Mulders initial state TMD.

83. Center for Functional Nanomaterials Seminar

"Using Modeling and Machine Learning to Accelerate High-Throughput Experimental Materials Discovery"

Presented by Jason R. Hattrick-Simpers, National Institute of Standards and Technology

Monday, November 13, 2017, 11 am
CFN, Bldg. 735, Conference Room A, 1st Floor

Hosted by: Matthew Sfeir

Over the past 10 years there has been a resurgent interest in the development of novel metallic alloys, both as multiple principle component solid solution alloys, so-called high entropy alloys (HEA) as well as amorphous metallic glasses. Although a number of empirical rules have been proposed for the prediction of potential alloy compositions, calculating their stability and quantifying their properties of interest at operating temperatures from first principles represents a significant challenge. In fact, even high-throughput experimental studies struggle to effectively explore such large composition-processing-property parameter spaces efficiently. Here, I will discuss an approach that seeks to address the rational experimental exploration of such alloys by combining theory, experiment and data science. Our approach is to use insights from the literature, theory, and/or data mining to identify the regions of parameter space most likely to yield interesting materials. We then employ computationally guided high-throughput synthesis techniques to strategically probe composition and processing space. In situ synchrotron diffraction studies yield tens of thousands of data sets describing the evolution of the alloy phase and corrosion products. The data are evaluated using automated knowledge extraction techniques, enabling us to assess our experiments, update the models used to generate the initial lead materials, and plan the next material system to study. In this talk, I will emphasize our recent work using these techniques to investigate phase stability in metallic glasses.

84. Particle Physics - SB/BNL Joint Cosmo seminar (at BNL)

"Dark Matter Searches with CCDs and the Sensei Experiment"

Presented by Dr. Javier Tiffenberg, FNAL

Thursday, November 9, 2017, 3 pm
Small Seminar Room, Bldg. 510

Hosted by: Erin Sheldon

85. Condensed-Matter Physics & Materials Science Seminar

"Quasiparticle spectra from stochastic many-body methods"

Presented by Vojtech Vlcek, University of California, Los Angeles

Thursday, November 9, 2017, 1:30 pm
ISB Bldg. 734 Conf. Rm. 201 (upstairs)

Hosted by: Gabi Kotliar

I will present new developments and applications of stochastic approaches to electronic structure and many-body perturbation theory, which overcome the steep scaling of conventional deterministic schemes. The general principles of linear-scaling stochastic methods for TDDFT, GW and BSE will be discussed and exemplified on realistic nanoscale systems with more than 5000 valence electrons. The stochastic approaches enable mapping the evolution of optical absorption, spectral functions and quasiparticle energies and lifetimes, as well as the emergence of collective excitations, over the full range from molecules to large bulk-like 3D nanoclusters and 2D layers.

86. HET Seminar

"Tomorrow's Colloquium: Joanna Kiryluk: IceCube: Understanding the High Energy Universe with Cosmic Neutrinos"

Presented by Linda Carpenter, Ohio State University

Wednesday, November 8, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Sally Dawson

Though the Higgs has a non trivial branching fraction -8 percent, to light jets, this is a very hard channel to directly capture with the LHC. We study the Higgs boson (h ) decay to two light jets at the 14 TeV High-Luminosity-LHC (HL-LHC), where a light jet (j ) represents any nonflavor-tagged jet from the observational point of view. The decay mode Higgs to gluons is chosen as the benchmark since it is the dominant channel in the Standard Model, but the bound obtained is also applicable to the light quarks. We estimate the achievable bounds on the decay branching fractions through the associated production V h (V =W±,Z ). Events of the Higgs boson decaying into heavy (tagged) or light (untagged) jets are correlatively analyzed. We find that with 3000 fb-1 data at the HL-LHC corresponds to a reachable upper bound of a few times the SM prediction. Which can ten be turned into a bound on the Higgs couplings to gluons and light quark flavors. A consistency fit also leads to an upper bound on the Higgs to charm coupling. The estimated bound may be further strengthened by adopting multiple variable analyses or adding other production channels.

87. Updated HET Seminar

"Capturing Higgs Boson Decays to Light Jets at LHC"

Presented by Linda Carpenter, Ohio State University

Wednesday, November 8, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Christopher Murphy

Though the Higgs has a non trivial branching fraction -8 percent, to light jets, this is a very hard channel to directly capture with the LHC. We study the Higgs boson (h ) decay to two light jets at the 14 TeV High-Luminosity-LHC (HL-LHC), where a light jet (j ) represents any nonflavor-tagged jet from the observational point of view. The decay mode Higgs to gluons is chosen as the benchmark since it is the dominant channel in the Standard Model, but the bound obtained is also applicable to the light quarks. We estimate the achievable bounds on the decay branching fractions through the associated production V h (V =W±,Z ). Events of the Higgs boson decaying into heavy (tagged) or light (untagged) jets are correlatively analyzed. We find that with 3000 fb-1 data at the HL-LHC corresponds to a reachable upper bound of a few times the SM prediction. Which can ten be turned into a bound on the Higgs couplings to gluons and light quark flavors. A consistency fit also leads to an upper bound on the Higgs to charm coupling. The estimated bound may be further strengthened by adopting multiple variable analyses or adding other production channels.

88. Physics Colloquium

"Building an entanglement sharing quantum network"

Presented by Professor Eden Figueroa, Stony Brook University

Tuesday, November 7, 2017, 3:30 pm
Large Seminar Room, Bldg. 510

Hosted by: Andrei Nomerotski

In the first part of our talk we will show how to produce photonic quantum entanglement and how to store it and distribute it by optically manipulating the properties of room temperature atomic clouds. We will discuss our recent experiments in which several quantum devices are already interconnected forming an elementary quantum cryptographic network. We will also discuss our progress regarding the construction of an entanglement sharing link between Stony Brook and BNL. In the second part we will show our progress regarding the construction of an analog quantum computer capable of simulating relativistic dynamics using atoms and quantized light. We will show how our device is already capable of simulating Dirac and Jackiw-Rebbi Hamiltonians as well as the road map towards simulating Quantum Field Theory Hamiltonians.

89. Condensed-Matter Physics & Materials Science Seminar

"Proximity effects in cuprate/manganite multilayers"

Presented by Christian Bernhard, University of Fribourg, Switzerland

Monday, November 6, 2017, 1:30 pm
ISB Bldg. 734 Seminar Room 201 (upstairs)

Hosted by: Chris Homes

Recently we observed an intriguing, magnetic-filed-induced insulator-to-metal transition in YBa2Cu3O7/Pr1-xCaxMnO3 (YBCO/PCMO) multilayers [1]. In the low field regime, the response of these multilayers is highly resistive and resembles the one of granular superconductors or frustrated Josephson-networks. Notably, a coherent superconducting response can be restored with a large magnetic field. The latter also suppresses the charge/orbital order of the PCMO layers towards a ferromagnetic state. This coincidence suggests an intimate relationship between the insulator-to-superconductor transition in the YBCO layer and the suppression of the charge/orbital order in the PCMO. I will discuss the evidence, based on resonant x-ray scattering experiments, that the latter induces (or strongly enhances) a static Cu-CDW order in YBCO that is intertwined with superconductivity. [1] B.P.P. Mallett et al., Phys. Rev. B 94, 180503(R) (2016).

90. Nuclear Theory/RIKEN Seminar

Presented by Gerald Miller, University of Washington

Friday, November 3, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Chun Shen

91. HET Lunch Discussions

"Dark Parity Violation After Qweak and Future Neutrino Physics Discussion"

Presented by William J. Marciano, BNL

Friday, November 3, 2017, 12:15 pm
Building 510, Room 2-160

Hosted by: Christoph Lehner

92. Updated HET Lunch Discussions

""Dark Parity Violation After Qweak and Future Neutrino Physics Discussion" (Neutrino Discovery Initiative)"

Presented by William J. Marciano, BNL

Friday, November 3, 2017, 12:15 pm
Building 510, Room 2-160

Hosted by: Christoph Lehner

To participate via BlueJean connection, please click on the following link: https://bluejeans.com/753838707/7269 Meeting ID: 753 838 707 Participate Passcode: 7269

93. Condensed-Matter Physics & Materials Science Seminar

"Wandering amongst the Feynamn diagrams"

Presented by Nikolay Prokofiev, University of Massachusetts-Amherst

Friday, November 3, 2017, 11 am
ISB Bldg. 734 Conf. Rm. 201 (upstairs)

Hosted by: Igor Zaliznyak

Feynman diagrams are the most celebrated and powerful tool of theoretical physics usually associated with the analytic approach. I will argue that diagrammatic expansions are also an ideal numerical tool with enormous and yet to be explored potential for solving interacting many-body systems by direct simulation of Feynman diagrams (bare or skeleton) for the proper self-energies and polarization operators up to high order. Though the original series based on are propagators are sign-alternating and often divergent one can determine the answer behind them by using proper series re-summation techniques and working with skeleton diagrams, i.e. by making the entire scheme self-consistent. The bottom line is that the diagrammatic Monte Carlo approach generically solves the computational complexity for interacting fermionic systems. In terms of physical applications, I will disucss results for the Hubbard model, resonant fermi gas at unitarity, and stability of Dirac liquid against strong Coulomb interaction in graphene.

94. Particle Physics Seminar

"UCNtau: A magneto-gravitational trap measurement of the free neutron lifetime"

Presented by Robert Pattie, Los Alamos National Laboratory

Thursday, November 2, 2017, 3 pm
Small Seminar Room, Bldg. 510

Hosted by: Xin Qian

The neutron is the simplest nuclear system that can be used to probe the structure of the weak interaction and search for physics Beyond the Standard Model. Measurements of neutron ?-decay observables are sensitive to scalar and tensor interactions in the weak force which are not present in the Standard Model. The lifetime of the neutron ?n is an important parameter for Big-Bang Nucleo-synthesis models, solar fusion models, and absolute neutrino scattering cross-sections, and can be used to test the unitarity of the Cabibbo-Kobayashi-Maskawa quark mixing matrix. Presently, the two typical methods used to measure the neutron lifetime, cold neutron beam measurements and stored ultracold neutron (UCN) measurements, disagree by roughly 4?. This discrepancy motivates the need for new measurements with complementary systematic uncertainties to previous efforts. The UCN? experiment uses an asymmetric magneto-gravitational UCN trap with in situ counting of surviving neutrons to measure the neutron lifetime. Previous bottle experiments confined UCN in a material storage vessel creating a significant correction due to losses resulting from the material UCN interactions. The magnetic and gravitational confinement of the UCN minimizes losses due to material interactions. Additionally, UCN? uses a detection system that is lowered into the storage volume which avoids emptying the surviving UCN into an external detector. This minimizes any possible transport related systematics. This in situ detector also enables counting at various heights in the vessel, which provides information on the trapped UCN energy spectrum, quasi-bound orbits, and possible phase space evolution. I will present the physics motivation for precision neutron physics, a description of the UCN? experiment, the results of data collected during the 2016-2017 accelerator cycle which resulted in a value of τn=877.7±(0.7) stat (+0.3/−0.1) sys in agreement with previous material bottle

95. RIKEN Lunch Seminar

"Rotating Dirac fermion in Magnetic field in 1+2 and 1+3 dimensions"

Presented by Yizhuang Liu, Stony Brook University

Thursday, November 2, 2017, 12:30 pm
Building 510, Room 2-160

Hosted by: Hiromichi Nishimura

96. HET/RIKEN Seminar

"Calculation of the electric dipole moment with the gradient flow"

Presented by Andrea Shindler, Michigan State University

Wednesday, November 1, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Sally Dawson

97. HET Lunch Discussions

"A statistical approach to Higgs couplings in the SMEFT, 1710.02008"

Presented by Chris Murphy, BNL

Friday, October 27, 2017, 12:15 pm
Building 510, Room 2-160

Hosted by: Christoph Lehner

98. Particle Physics Seminar

"Search for dark matter at the CMS experiment"

Presented by Adish Vartak, University of California San Diego

Friday, October 27, 2017, 10 am
Small Seminar Room, Bldg. 510

Hosted by: Alessandro Tricoli

There is an extensive, on-going dark matter search program at the LHC that explores several different types of possible interactions between WIMP-like dark matter and standard model particles. The dark matter searches at the LHC are complementary, and in case of certain models, significantly more sensitive than the direct and indirect dark matter searches. In this talk I will discuss several key dark matter searches being pursued by the CMS collaboration. These cover a wide variety of final states in which dark matter particles are produced in association with one or more energetic, visible objects in the detector resulting in 'MET+X' signatures. Furthermore, I will also discuss the constraints set on dark matter interactions by certain resonance searches.

99. Particle Physics Seminar

"Observation of Coherent Elastic Neutrino-Nucleus Scattering by COHERENT"

Presented by Kate Scholberg, Duke University

Thursday, October 26, 2017, 3 pm
Small Seminar Room, Bldg. 510

Hosted by: Xin Qian

Coherent elastic neutrino-nucleus scattering (CEvNS) is a process in which a neutrino scatters off an entire nucleus at low momentum transfer, and for which the observable signature is a low-energy nuclear recoil. It represents a background for direct dark matter detection experiments, as well as a possible signal for astrophysical neutrinos. Furthermore, because the process is cleanly predicted in the Standard Model, a measurement is sensitive to beyond-the-Standard-Model physics, such as non-standard interactions of neutrinos. The process was first predicted in 1973. It was measured for the first time by the COHERENT collaboration using the high-quality source of pion-decay-at-rest neutrinos from the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory and a CsI[Na] scintillator detector. This talk will describe COHERENT's recent 6.7-sigma measurement of CEvNS, the status and plans of COHERENT's suite of detectors at the SNS, and future physics reach.

100. RIKEN Lunch Seminar

"Approach to equilibrium of quarkonium in quark-gluon plasma"

Presented by Xiaojun Yao, BNL

Thursday, October 26, 2017, 12:30 pm
Building 510, Room 2-160

Hosted by: Hiromichi Nishimura

Quarkonium can be used as a probe of quark-gluon plasma (QGP) in heavy ion collisions. The production process is complicated by several factors: plasma screening effect, in-medium dissociation and recombination, cold nuclear matter effect and feed-down contributions. In this talk, I will present a set of Boltzmann transport equations that govern the in-medium evolution of the heavy quark and quarkonium system. The dissociation and recombination rates are calculated from potential non-relativistic QCD at leading order. I will explain how the system reaches equilibrium in a QGP box and show how the system evolves under a boost invariant longitudinal expansion. I will argue that the angular distribution of quarkonium probes the stages at which recombination occurs. The presented framework will be extended in future work to include other factors influencing quarkonium production.

101. Condensed-Matter Physics & Materials Science Seminar

"Theory and Computation Guided Discovery of New Thermoelectric Materials"

Presented by Vladan Stevanovic, Colorado School of Mines & National Renewable Energy Laboratory

Wednesday, October 25, 2017, 1:30 pm
ISB Bldg. 734, Conf. Rm. 201 (upstairs)

Hosted by: Cedomir Petrovic

Progress in the widespread adoption of all solid heat-to-electricity technologies has largely been hindered by the absence of suitable thermoelectric materials. In pursuit for new thermoelectrics recent advances in large-scale deployment of first principles calculations could be useful in identifying new promising material systems. However, the need to predict electron and phonon transport properties with sufficient accuracy renders direct assessment of the thermoelectric figure of merit (zT) for large numbers of systems unfeasible. This is true even in the case of relatively simple semiconductor materials, which could be described by the computationally inexpensive single particle theories such as density functional theory (DFT). While the state-of-the-art DFT based approaches to charge carrier and heat transport of semiconductors can deliver desired accuracy, they are currently limited to relatively simple chemistries and/or case-by-case studies. In this talk I will discuss integrated theory-computation-experiment efforts in developing a robust set of material descriptors that: (1) are rooted in the Boltzmann transport theory, but do not rely on classic and largely inapplicable constant relaxation time or constant mean free path approximations, (2) are computationally tractable allowing material searches across large chemical spaces, and (3) are sufficiently accurate to provide reliable predictions. Our approach is demonstrated to correctly identify known thermoelectric materials1 and reliably suggest new and promising candidate semiconductors.2 At the end, I will review successes and failures in our quest for new thermoelectrics, and discuss dopability of semiconductors as the critical outstanding challenge in achieving high zT materials. 1. Yan, P. Gorai, B. Ortiz, S. Miller, S. A. Barnett, T. Mason, V. Stevanovic, and E. S. Toberer, "Material descriptors for thermoelectric performance", Energy Environ. Sci. 2. P. Gorai, V. Stevanovic, and E. Tobe

102. Physics Colloquium

"The Path Forward in Gravitational-wave astronomy"

Presented by Zsuzsa Marka, Columbia University

Tuesday, October 24, 2017, 3:30 pm
Large Seminar Room, Bldg. 510

Hosted by: Peter Petreczky

On August 17, 2017 the merger of two neutron stars was detected in the form of gravitational-waves by LIGO/Virgo. As a result of over a decade long preparation for multimessenger observations the event was also seen electromagnetically across the full spectrum. The history and future of the multimessenger effort using gravitational-waves will be discussed from an instrumentalist viewpoint.

103. Nuclear Physics Seminar

"To CME or not to CME? Implications of recent charge separation measurements in p(d)+Au, Au(Cu)+Au and U+U collisions for the chiral magnetic effect in heavy ion collisions"

Presented by Roy Lacey, Stony Brook University

Tuesday, October 24, 2017, 11 am
Small Seminar Room, Bldg. 510

Hosted by: Bjoern Schenke

The observation of charge separation induced by the Chiral Magnetic Effect (CME), could provide crucial insights on anomalous transport and the interplay of chiral symmetry restoration, axial anomaly, and gluonic topology in the Quark Gluon Plasma (QGP) produced in heavy ion collisions. I will discuss recent differential charge separation measurements,for p(d)+Au, Au(Cu)+Au and U+U, with a correlator specifically designed to give discernible responses to CME-driven charge separation and non-CME backgrounds. Measurements which span the beam energy range Root_s = 19.5 - 200 GeV will be presented. The d(p)+Au results are observed to be consistent with the reduced magnetic field strength and the essentially random B-field orientations expected in these collisions. In contrast, the Au(Cu)+Au and U+U measurements validate the presence of CME-driven charge separation quantified by the Fourier dipole coefficient a1. Ongoing attempts for CME-signal quantification, as well as implications for the upcoming RHIC isobar run, will be discussed as well.

104. Condensed-Matter Physics & Materials Science Seminar

"Pressure-driven collapse of Jeff=1/2 electronic state in a honeycomb iridate"

Presented by Young-June Kim, University of Toronto, Canada

Friday, October 20, 2017, 3 pm
ISB Bldg. 734 Conf. Rm. 201 (upstairs)

Hosted by: Igor Zaliznyak

Orbital and spin degrees of freedom in heavy transition metal compounds can be locked into each other due to strong spin-orbit coupling. The magnetism in this case is described by an effective total angular momentum jeff=1/2 rather than usual spin angular momentum. Furthermore, these jeff=1/2 moments residing on a honeycomb lattice can be coupled through bond-dependent Kitaev interactions. Magnetic properties of some honeycomb lattice iridates, such as Na2IrO3 and Li2IrO3 have been extensively investigated to examine whether Kitaev quantum spin liquid is realized in these compounds. However, the applicability of the jeff=1/2 local moment model in real materials have not been critically scrutinized experimentally. A combination of x-ray absorption spectroscopy, x-ray diffraction, and resonant inelastic x-ray scattering experiments on a honeycomb lattice Li2IrO3 reveals that the jeff=1/2 picture breaks down under high pressure, and electrons take on more itinerant character under this condition.

105. Nuclear Theory/RIKEN Seminar

"Quantization of three-body scattering amplitude in isobar formulation"

Presented by Maxim Mai, George Washington University

Friday, October 20, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Chun Shen

In the so-called isobar parametrization the three-particle states are populated via an interacting two-particle system (resonant or non-resonant), and a spectator. Using this parametrization, we derive the isobar-spectator interaction such that the three-body Unitarity is ensured exactly. In the first part of my talk I will show the major steps of this derivation. (arXiv:1706.06118) The second part of the talk will be dedicated to the finite-volume implementation of the framework (arXiv:1709.08222). Imaginary parts in the infinite volume, dictated by Unitarity, determine the dominant power-law finite volume effects to ensure the correct 3-body quantization condition. Furthermore, various building blocks of the 3->3 amplitude in the finite volume can become singular. However, when all contributions are summed-up, only genuine 3-body singularities remain. I will demonstrate the corresponding cancellation mechanisms explicitly for the simplified case of only one S-wave isobar.

106. Particle Physics Seminar

"Study of the Higgs properties in the H->ZZ*->4l channel with the ATLAS detector"

Presented by Gaetano Barone, Brandeis University

Thursday, October 19, 2017, 3 pm
Small Seminar Room, Bldg. 510

Hosted by: Alessandro Tricoli

Recent measurements of the Higgs boson properties in the four lepton channel for 36.1 fb-1 of proton—proton collisions at 13 TeV using the ATLAS detector will be presented. The measurements include the Higgs boson mass as well as inclusive, fiducial and differential cross sections and, constraints on Higgs boson production couplings. The results are interpreted within the Standard Model and various extensions.

107. RIKEN Lunch Seminar

"Lattice QCD and Neutrino Physics"

Presented by Aaron Meyer, HET Group

Thursday, October 19, 2017, 12:30 pm
Building 510, Room 2-160

Hosted by: Enrico Rinaldi

The nucleon axial form factor is a dominant contribution to systematic uncertainties in neutrino oscillation studies. The most commonly used model parametrization of the axial form factor has uncontrolled and underestimated systematic errors. First-principles computations from lattice QCD have the potential to control theory errors by disentangling the effects of nuclear corrections from the nucleon amplitudes. In this talk, I discuss fits to the axial form factor with deuterium bubble chamber data using the model-independent $z$ expansion parameterization. I then present preliminary results for a blinded lattice QCD calculation of the nucleon axial charge $g_A$ with physical light quark masses. This calculation is being done with the Highly Improved Staggered Quark (HISQ) action and 2+1+1 flavors of sea quarks.

108. Environmental & Climate Sciences Department Seminar

"Desert Dust, Wildfire Smoke, Volcanic Ash, Urban and Industrial Pollution – Grasping the Role Particles Play in Global Climate and Regional Air Quality"

Presented by Ralph Kahn, NASA Goddard Space Flight Center

Thursday, October 19, 2017, 11 am
Conference Room Bldg 815E

Hosted by: Steve Schwartz

Airborne particles are ubiquitous components of our atmosphere, originating from a variety of natural and anthropogenic sources, exhibiting a wide range of physical properties, and contributing in multiple ways to regional air quality as well as regional-to-global-scale climate. Most remain in the atmosphere for a week or less, but can traverse oceans or continents in that time, carrying nutrients or disease vectors in some cases. Bright aerosols reflect sunlight, and can cool the surface; light-absorbing particles can heat the atmosphere, suppressing cloud formation or mediating larger-scale circulations. In most cases, particles are required to collect water vapor as the initial step in cloud formation, so their presence (or absence) and their hygroscopic or hydrophilic properties can affect cloud occurrence, structure, and ability to precipitate. Grasping the scope and nature of aerosol environmental impacts requires understanding microphysical-to-global scale processes, operating on timescales from minutes to days or longer. Satellites are the primary source of observations on kilometer-to-global scales. Spacecraft observations are complemented by suborbital platforms: aircraft in situ measurements and surface-based instrument networks that operate on smaller spatial scales, some on shorter timescales. Numerical models play a third key role in this work — providing a synthesis of current physical understanding with the aggregate of measurements, and allowing for some predictive capability. This presentation will focus on what we can say about aerosol amount and type from space. Constraining particle "type" is at present the leading challenge for satellite aerosol remote sensing. We will review recent advances and future prospects, including the strengths and limitations of available approaches, and current work toward better integrating measurements with models to create a clearer picture of aerosol environmental impacts, globally.

109. HET Seminar

"Semileptonic decays of B_(s) mesons to light pseudoscalar mesons with lattice QCD"

Presented by Zechariah Gelzer, Iowa University

Wednesday, October 18, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Mattia Bruno

110. Particle Physics Seminar

"The R&D and Mass Production of 20"MCP-PMT for Neutrino Detection"

Presented by Dr. Sen Qian, IHEP China

Monday, October 16, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Xin Qian

Researchers at IHEP, Beijing have conceived a new concept of MCP-PMT several years ago. The small MCP (Microchannel Plate) units replace the bulky Dynode chain in the tranditional large PMTs for better photoelectron detection. After three years R&D, a number of 8 inch prototypes were produced and their performance was carefully tested at IHEP in 2013 by using the MCP-PMT evaluation system built at IHEP. The 20 inch prototypes were followed in 2014, and its' performance were improving a lot in 2015. Compensating the PMT performances with fiducially volume convert all specifications to cost, radioactivity, dark noise, TTS, the JUNO ordered 15000 pic 20-inch MCP-PMT from the NNVT in Dec.2015. In 2016, the MCP-PMT collaboration group finished to build the mass production line in Nanjing at the end of 2016, and finished the batch test system in the same place within 100 days at the beginning of 2017. From 2017 to 2019, all the 20-inch MCP-PMT will be produced and tested one by one in NNVT for JUNO. This presentation will talk about the R&D process and mass production, batch test result of the first 2K pieces of MCP-PMT prototypes for JUNO.

111. Condensed-Matter Physics & Materials Science Seminar

"Domain walls and phase boundaries - new nanoscale functional elements in complex oxides"

Presented by Jan Seidel, UNSW Sydney

Monday, October 16, 2017, 1:30 pm
Bldg. 480, Conference Room

Hosted by: Myung-Geun Han

Topological structures in functional materials, such as domain walls and skyrmions, see increased attention due to their properties that can be completely different from that of the parent bulk material [1]. I will discuss recent results on multiferroic phase boundaries, domain walls in BiFeO3 [2, 3, 4, 5, 6] using SPM, TEM and ab-initio theory, and discuss future prospects [7]. References [1] J. Seidel (ed.), Topological structures in ferroic materials: domain walls, skyrmions and vortices, ISBN: 978-3-319-25299-5, Springer, Berlin (2016) [2] P. Sharma, et al., Scientific Reports 6, 32347 (2016) [3] P. Sharma, et al., Advanced Electronic Materials 2, 1600283 (2016) [3] J. Seidel, et al., Advanced Materials 26, 4376 (2014) [4] Y. Heo, et al., Advanced Materials 26, 7568 (2014) [5] Y. Heo et al., ACS Nano, DOI: 10.1021/acsnano.6b07869 (2017) [6] P. Sharma, et al., Advanced Materials Interfaces 3, 1600033 (2016) [7] J. Seidel, Nature Nanotechnology 10, 190 (2015)

112. Nuclear Theory/RIKEN Seminar

"What can we learn from flow observables in heavy-ion collisions?"

Presented by Jacquelyn Noronha-Hostler, Rutgers University

Thursday, October 12, 2017, 12:30 pm
Building 510, Room 2-160

Hosted by: Chun Shen

The Quark Gluon Plasma (QGP), nature's first and most perfect liquid, has been successfully reproduced in heavy-ion collisions at RHIC and the LHC. The dynamics of the QGP can be well described by relativistic viscous hydrodynamics, allowing for precise comparisons to experimental data in order to extract the properties of the QGP. While a small shear viscosity is well-established, questions still remain regarding the precise initial state, the temperature dependence of viscosity, the smallest system that displays QGP-like properties, and the equation of state at large densities. In this talk, the various flow harmonic observables are analyzed to help answer these remaining questions.

113. Particle Physics Seminar

"SB/BNL Joint Cosmo Seminar (at Stony Brook)"

Presented by Chang Feng, UC Irvine

Wednesday, October 11, 2017, 1:30 pm
Stony Brook

Hosted by: Neelima Sehgal

114. HET Lunch Discussions

"Repulsion of Dark Matter and Null Direct Signals"

Presented by Hooman Davoudiasl, BNL

Friday, October 6, 2017, 12:15 pm
Building 510, Room 2-160

Hosted by: Christoph Lehner

115. HET Seminar

"Flavorful Higgs bosons"

Presented by Wolfgang Altmannshofer, Cincinnati University

Wednesday, October 4, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Sally Dawson

Measurements of Higgs production and decays have revealed that most of the mass of the weak gauge bosons is due to the 125 GeV Higgs. Similarly, we know that the Higgs is at least partially responsible for giving mass to the top and bottom quarks and the tau lepton. Much less is known about the origin of mass for the first two generations. In this talk, I will discuss a framework in which the first and second generation masses originate from a second source of electroweak symmetry breaking and outline the phenomenological implications.

116. Nuclear Physics Seminar

"The nature of flow fluctuations, from pp to A+A, and back again"

Presented by Mingliang Zhou, Stony Brook University

Tuesday, October 3, 2017, 11 am
Small Seminar Room, Bldg. 510

Hosted by: Jiangyong Jia

In recent years, there have been rapid progresses in our understanding of the event-by-event flow fluctuation, which provides direct insight into the fluctuations in the initial geometry. I will start my talk by briefly discussing the flow (collectivity) and its fluctuation in small systems pp and p+Pb, using the newly-proposed subevent cumulant method, which is able to suppress the non-flow background effectively. I will show there is significant fluctuation of elliptic flow $v_2$ in pp and non-Gaussian fluctuation of triangular flow $v_3$ in p+Pb. Moving from small to large systems, STAR collaboration recently has shown different behaviors of cumulant $c_2\{4\}$ between Au+Au and U+U in ultra-central collisions, which is believed to support the different geometry fluctuations. By presenting the newest ATLAS flow measurements in ultra-central collisions, together with detailed MC Glauber studies, I will explain why sign change of $c_2\{4\}$ is observed and its implications. In the end, I will go back to small systems and discuss the potential impact of centrality resolution on pp flow measurements.

117. Particle Physics Seminar

"Latest Results from the T2K Experiment"

Presented by Kendall Mahn, Michigan State University

Friday, September 29, 2017, 3:30 pm
Small Seminar Room, Bldg. 510

Hosted by: Xin Qian

One of the most promising investigations of beyond-the-Standard-Model physics has been the study of neutrino oscillation, that is, the conversion of neutrinos from one flavor to another as they propagate. While neutrino oscillation is studied in a wide variety of experiments, accelerator based experiments, such as T2K, use a muon neutrino or antineutrino beam as a source to look for electron (anti)neutrino appearance, muon neutrino disappearance. The source also is used to make measurements of neutrino interactions and search for exotic physics. This talk will describe a recent analysis of both neutrino and antineutrino beam data from T2K. Comparisons between neutrino and antineutrino event rates provide a tantalizing window on possible CP violation in the neutrino sector. The talk will also highlight the increasingly important role of systematic uncertainty assessment for T2K and other future measurements of CP violation with accelerator beams.

118. Nuclear Theory/RIKEN Seminar

"QCD on a small circle"

Presented by Aleksey Cherman, University of Washington

Friday, September 29, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Heikki Mantysaari

Recent developments have shown that QCD-like theories can be engineered to remain in a confined phase when compactified on an arbitrarily small circle, where their features may be studied quantitatively in a controlled fashion. I'll explain how a non-perturbative mass gap and chiral symmetry breaking, which are both historically viewed as prototypical strong coupling effects, appear from systematic weak-coupling calculations. Then I'll describe the rich spectrum of hadronic states, including glueball, meson, and baryon resonances in the calculable small-circle context.

119. Particle Physics Seminar

"Beauty and charm decays and physics beyond the Standard Model: an experimentalist perspective"

Presented by Marina Artuso, Syracuse University

Thursday, September 28, 2017, 3 pm
Small Seminar Room, Bldg. 510

Hosted by: Alessandro Tricoli

The Standard Model provides a comprehensive explanation for a vast array of data collected at different experiments. Nonetheless fundamental questions remain unanswered and the search for a more complete theory is still a coveted goal of particle physics. Recently, tensions with standard model predictions have been uncovered in several experimental observables in b-hadron decays at LHCb. I will discuss the data, possible implications, and the connection with other experimental programs such as study of kaon rare decays and neutrino mixing and CP violation

120. Condensed-Matter Physics & Materials Science Seminar

"Suppression of weak ferromagnetism in ultrathin iridates by interfacial engineering of octahedral rotations"

Presented by Yuefeng Nie, Nanjing University, China

Thursday, September 28, 2017, 1:30 pm
ISB Bldg. 734 Conf. Rm. 201 (upstairs)

Hosted by: Weiguo Yin

Layered iridates, Srn+1IrnO3n+1, have drawn great attention since they share remarkable similarities with high-Tc cuprates, including layered crystalline structure, (pseudo) spin ½ states, antiferromagnetic (AFM) Mott insulating ground state, Fermi arcs, and V shape energy gap, etc. Nonetheless, direct evidences of superconductivity such as zero resistivity and Meissner effect are still lacking up to date. The strong spin-orbit coupling and IrO6 octahedral rotations in 5d iridates result in a canted AFM ground state with weak ferromagnetic moments in each IrO2 plane. Here, we propose to suppress the weak ferromagnetism by suppressing the octahedral rotations in iridates, which may facilitate the Cooper pairing. Using a combination of reactive molecular beam epitaxy (MBE), in situ angleresolved photoemission spectroscopy (ARPES) and first principle calculations, we investigate the evolution of octahedral rotations, electronic structure and magnetic ordering in ultra-thin SrIrO3 films grown on (001) SrTiO3 substrate. Our experimental results and theoretical calculations show that octahedral rotations and weak ferromagnetic moments are fully suppressed in 1 and 2 unit cell thick SrIrO3 films through interfacial clamping effects. If time allows, I will also present our recent work on the new understanding of RHEED oscillations in the growth of oxides and the chemically specific termination control of oxide interfaces via layerby- layer mean inner potential engineering.

121. RIKEN Lunch Seminar

"Color Memory, Large Gauge Transformations, and Soft Theorems in Yang-Mills Theory"

Presented by Monica Pate, Harvard University

Thursday, September 28, 2017, 12:30 pm
Building 510, Room 2-160

Hosted by: Hiromichi Nishimura

An infinite dimensional symmetry group which governs the infrared sectors of gauge and gravity theories has been recently discovered. This symmetry can be established both from an asymptotic symmetry analysis as well as from the corresponding Ward identities which are quantum field theoretic soft theorems. Moreover, the spontaneous breaking of these symmetries induces vacuum transitions which are detectable by charged particles through the so-called memory effect. In this seminar, I will explain the precise equivalence between asymptotic symmetries, soft theorems and memory effects in the context of tree level Yang-Mills. In particular, in this context the soft gluon theorem is Ward identity of a large gauge symmetry, whose action on the vacuum can be measured from the relative color charge of colored detectors.

122. Condensed-Matter Physics & Materials Science Seminar

"Ultrafast TEM and Time-of-Flight EELS using microwave cavities"

Presented by Jom Luiten, Eindhoven University of Technology, Netherlands

Friday, September 22, 2017, 11 am
Bldg. 480, Conference Room

Hosted by: Yimei Zhu

Ultrafast Transmission Electron Microscopy (U-TEM) has become a very important tool for the study of ultrafast phenomena at (sub-)nm length scales and (sub-)ps time scales. U-TEM is usually based on the creation of ultrashort electron pulses by femtosecond laser photoemission from a flat cathode, with the result that both the beam quality and the average current are significantly less than in state-of-the-art continuous-beam TEMs. At Eindhoven University we have developed U-TEM in which ultrashort electron pulses are produced by using a 3 GHz deflecting microwave cavity in TM110 mode to sweep a high-brightnes continuous beam across a slit [1]. We have demonstrated ultrafast beam chopping with conservation of the beam quality and the sub-eV energy spread of the FEG source of an adapted 200 keV Tecnai TEM, enabling atomic resolution with sub-ps temporal resolution at 3 GHz rep rate [2] In addition we have developed a new method for doing Time-of-Flight Electron Energy Loss Spectroscopy (ToF-EELS) based on the combined use of two TM110 deflecting cavities and two TM010 (de)compression cavities. The first 'chopping' TM110 cavity produces ultrashort electron pulses which are sent through a sample. Energy loss in the sample translates into reduction of the electron velocity and thus into a later arrival time at the detector, which is measured with a synchronized second TM110 'streak' cavity. In this way an energy resolution of 12 eV at 30 keV has been demonstrated [3]. By adding a TM010 (de)compression cavity after the sample, the longitudinal phase space can be manipulated in such a way that the energy resolution is improved to 2 eV (to be published). By adding a second TM110 cavity before the sample, full control over the longitudinal phase space can be achieved. Detailed charged particle tracking simulations show that an energy resolution of 20 meV combined with a temporal resolution of 2 ps can be achieved; or, alternatively, 2

123. Particle Physics Seminar

"Evidence for the H to bb decay with the ATLAS detector"

Presented by Giacinto Piacquadio, Stony Brook University

Thursday, September 21, 2017, 4 pm
Small Seminar Room, Bldg. 510

Hosted by: Alessandro Tricoli

Most Higgs bosons are expected to decay to a pair of b-quarks, with the Standard Model predicting a branching fraction of about 58%. Probing this decay is important to furthering our understanding of the Higgs sector, but its observation at hadron colliders is complicated by overwhelming Standard Model backgrounds. In this seminar, the search for the Higgs to bb decay, looking at the associated production of the Higgs boson with a W or Z boson, is presented, based on 36 fb-1 of 13 TeV LHC Run 2 data.

124. Condensed-Matter Physics & Materials Science Seminar

"Two new applications of geometric critical phenomena for disordered electron systems"

Presented by Matthew Foster, Rice University

Thursday, September 21, 2017, 1:30 pm
ISB Bldg. 734 Conf. Rm. 201 (upstairs)

Hosted by: Robert Konik

I will discuss two very recent results relating to the properties of electrons in two spatial dimensions (2D), subject to the effects of quenched disorder (impurities) and quantum interference [Anderson (de)localization]. In both cases, the key physics is tied to classical geometric critical phenomena in 2D. I will first present numerical evidence that strongly suggests the equivalence of disordered surface states of topological superconductors and geometric percolation. Percolation is known to play a role in quantum Hall systems with magnetic fields. Our unexpected result implies that percolation applies to topological superconductor surface states in the absence of time-reversal symmetry breaking. Moreover, the usual "even-odd" effect that occurs in such a system (as identified by Pruisken in the integer quantum Hall effect and by Haldane for spin chains) is found to be absent. Second, I will discuss a "toy model" for the ergodic to many-body localized phase transition in 2D, and relate it to an effective self-interacting walk. I will present analytical results of a controlled expansion which suggest that the transition can be viewed as a "dephasing catastrophe."

125. Nuclear Theory/RIKEN Seminar

"TMD gluon distributions for dijet production and their behavior at small x"

Presented by Elena Petreska, NIKHEF

Friday, September 15, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Heikki Mantysaari

Starting from the Color Glass Condensate (CGC) cross section for dijet production in proton-nucleus collisions we derive a transverse-momentum-dependent (TMD) factorization formula for small transverse-momentum imbalance of the jets and for finite number of colors. For the eight TMD distributions appearing in the cross section we determine their operator definitions at small-x as CGC correlators of Wilson lines and we study their JIMWLK evolution. We find that at large transverse momentum the universality of TMDs gets restored. We also discuss an extension of the approach to generalized TMDs (GTMDs) that can give an insight into the angular correlations between impact parameter and dipole size in the CGC framework.

126. HET Lunch Discussions

"Precision calculation of the g-2 HVP contribution by combining lattice and R-ratio data"

Presented by Christoph Lehner, BNL

Friday, September 15, 2017, 12:15 pm
Building 510, Room 2-160

127. Particle Physics Seminar

"SB/BNL Joint Cosmo seminar (at BNL): Mapping the Cosmos with the Dark Energy Survey"

Presented by Dr. Chihway Chang, ETH Zurich

Thursday, September 14, 2017, 3 pm
Small Seminar Room, Bldg. 510

Hosted by: Erin Sheldon

The first year data from the Dark Energy Survey (DES Y1) provides the most powerful optical survey dataset to date. In this talk I will first give an overall summary of the cosmology results from the DES Y1 dataset combining galaxy clustering and weak gravitational lensing. Next, I will describe our work in generating and testing the wide-field weak lensing mass maps from the galaxy shape measurements and some exciting applications for the maps. I will end with thoughts on how weak lensing could also inform us on various topics of galaxy formation, which is essential for completing the story behind the Universe we see today.

128. RIKEN Lunch Seminar

"Thermal Fluctuations in Hydrodynamic Simulations of QGP"

Presented by Mayank Singh, McGill University

Thursday, September 14, 2017, 12:30 pm
Building 510, Room 2-160

Hosted by: Hiromichi Nishimura

Multi-particle correlations measured in heavy-ion collision experiments carry info on fluctuations present in the entire evolutionary history of the system. Initial states include geometric and quantum fluctuations and are important contributors. The thermal fluctuations during the course of QGP evolution is another conceptually important source of these fluctuations and should be studied in detail. We begin by treating thermal fluctuations as a linearized perturbation on hydrodynamic background. We present a full calculation of hadronic and photonic observables including these fluctuations. Recently we have included fluctuations in our simulations in a non-perturbative manner. Progress based on this approach will be discussed.

129. Physics Colloquium and Leona Woods Lecture

"Momentum-space structure of hadrons and nuclei at high energy"

Presented by Elena Petreska, NIKHEF

Tuesday, September 12, 2017, 3:30 pm
Large Seminar Room, Bldg. 510

Hosted by: Peter Petreczky

Transverse-momentum-dependent (TMD) distributions describe the configuration of quarks and gluons inside protons and nuclei in three-dimensional momentum space. Observables in scattering experiments can be calculated with the help of TMD factorization formulas, where the target and projectile are represented with non-perturbative TMD distributions, which are separated from the short-distance perturbative part of the collision. A complementary approach to study the momentum structure of protons and nuclei at high energy is the Color Glass Condensate which is an effective theory for the high-gluon-density region of ultra-relativistic particles. We introduce both theories and we discuss connections between them. We present phenomenological results derived from these connections.

130. NSLS-II Seminar

"On the assessment of radiation damage and high temperature effects in novel nuclear materials using the BNL accelerators and synchrotrons"

Presented by Nick Simos, Sr Scientist Emeritus, BNL

Friday, September 8, 2017, 3 pm
Large Seminar Room, Bldg. 510

Hosted by: Ron Pindak

In search for new and improved materials, composites and super-alloys capable of withstanding the anticipated extreme states associated fusion reactors; high temperature fast reactors and multi-MW particle accelerators, novel reactor steels, super-alloys and composites are continuously being explored to help meet both the challenge of the higher demand environments and the intended application. Higher fluxes and fluences of irradiating species (neutrons and/or protons), extreme temperatures and aggressively corrosive environments make up the new cocktail of operating conditions of the new array of material structures. One of the challenges in characterizing the effects that high radiation fluxes of neutrons and protons induce on these novel material structures in conjunction with high temperatures is the link between lattice induced damage and phase transformation and macroscopic physical properties which ultimately determine performance in the real environment. High energy X-rays at the BNL synchrotrons have offered a path in establishing this important connection between micro-scale effects and physical properties of novel material structures exposed to high radiation fluxes. Specifically, by integrating the unique capabilities of the BNL accelerator complex that includes, in addition to the NSLS and NSLS II, the proton accelerator and Tandem as well as those of CFN, the evolution and/or damage of materials ranging from classical structures such as graphite, beryllium and steels to novel super-alloys, such as those of Invar and "Gum" metal, and new composites have been characterized both at the two length scales. The pivotal role of high energy X-rays from NSLS to NSLS II in making the connection will be presented demonstrating the enormous potential of the NSLS II in answering fundamental questions in our path towards the next generation nuclear materials. Furthermore, first glimpses of the correlation of lattice effects or damage induced by differ

131. HET Lunch Discussions

"Towards a non-perturbative calculation of Weak Hamiltonian Wilson Coefficients"

Presented by Mattia Bruno, BNL

Friday, September 8, 2017, 12:15 pm
Building 510, Room 2-160

Hosted by: Christoph Lehner

132. NSLS-II Colloquium Series

"Experiments, Analyses, and Manipulations with Particle Beam"

Presented by Shyh-Huan Lee, Indiana University, IN

Thursday, September 7, 2017, 4 pm
Large Seminar Room, Bldg. 510

Hosted by: John Hill

Progress on particle beam physics research have provided marked improvements in beam intensity, brightness, and stability advancing frontier research in applied and fundamental science. This talk will review some beam measurements and manipulation studies being undertaken to improve beam performance in storage rings. Hopefully, these studies will be relevant to the operation and improvement of National Accelerator User Facilities.

133. Particle Physics Seminar

"Radiation damage study of a thin YAG:Ce scintillator using low-energy protons"

Presented by Dr. Vladmir Linhart, Czech Technical University in Prague

Thursday, September 7, 2017, 3 pm
Small Seminar Room, Bldg. 510

Hosted by: Xin Qian

Radiation hardness of a 50µm thin YAG:Ce scintillator in a form of dependence of a signal efficiency on 3.1MeV proton ?uence was measured and analyzed using X-ray beam. The signal efficiency is a ratio of signals given by a CCD chip after and before radiation damage. The CCD chip was placed outside the primary beam because of its protection from damage which could be caused by radiation. Using simplified assumptions, the 3.1MeV proton fluencies were recalculated to: • 150 MeV proton fluencies with intention to estimate radiation damage of this sample under conditions at proton therapy centers during medical treatment, • 150 MeV proton doses with intention to give a chance to compare radiation hardness of the studied sample with radiation hardness of other detectors used in medical physics, • 1 MeV neutron equivalent fluencies with intention to compare radiation hardness of the studied sample with properties of position sensitive silicon and diamond detectors used in nuclear and particle physics. The following results of our research were obtained. The signal efficiency of the studied sample varies slightly (±3%) up to 3.1MeV proton ?uence of c. (4 − 8) × 1014 cm−2. This limit is equivalent to 150MeV proton ?uence of (5 − 9) × 1016 cm−2, 150MeV proton dose of (350 − 600) kGy and 1MeV neutron ?uence of (1 − 2) × 1016 cm−2. Beyond the limit, the signal efficiency goes gradually down. Fifty percent decrease in the signal efficiency is reached around 3.1MeV ?uence of (1 − 2) × 1016 cm−2 which is equivalent to 150 MeV proton ?uence of around 2 × 1018 cm−2, 150MeV proton dose of around 15 MGy and 1 MeV neutron equivalent ?uence of (4 − 8) × 1017 cm−2. In contrast with position sensitive silicon and diamond radiation detectors, the studied sample has at least two order of magnitude greater radiation resistance. Therefore, YAG:Ce sci

134. Simons Center for Geometry and Physics Public Lecture

"Mysteries of the Universe and Everyday Life"

Presented by Michelangelo Mangano; Young-Kee Kim; Joe Lykken, LHC/CERN; University of Chicago; Fermilab

Tuesday, September 5, 2017, 5:30 pm
Simons Center at Stony Brook University, Della Pie

In the past few decades we have learned a great deal about the basic laws of Physics in the infinitely small – and the infinitely large – and how the two are intimately connected. New windows have expanded our understanding, and many unexpected questions have emerged. This is an exhilarating time in history. New tools, both theoretical and observational, may lead in the next decade to major advances in our understanding of the universe. As in the past, when major discoveries are made about the fundamental laws of Nature, not only is our view of the world enriched, but also our life is transformed. A good place to explore the discoveries from the past decades is in the description of symmetry, symmetry breaking and the Higgs boson in High Energy Physics: why, how and where to…. in a nutshell. These talks will present what we know and what we seek in the fundamental laws of Nature; how we go about answering basic questions in high energy experiments, how much we have learned, and how the technical developments needed to make discoveries have changed society. They will also delineate the boundaries of our knowledge and the known unknowns in fundamental high energy physics and cosmology.

135. HET Lunch Discussions

"Finite Volume in QCD+QED & g-2 HLbL"

Presented by Taku Izubuchi, BNL

Friday, September 1, 2017, 12:15 pm
Building 510, Room 2-160

Hosted by: Christoph Lehner

136. Particle Physics Seminar

"Wiener-SVD approach to data unfolding"

Presented by Dr. Hanyu Wei, BNL

Thursday, August 31, 2017, 3 pm
Small Seminar Room, Bldg. 510

Hosted by: Xin Qian

Data unfolding is a commonly used technique in the high energy physics experiments, to retrieve the distorted or transformed measurements by various detector effects. Inspired by the deconvolution technique in the digital signal processing, a new unfolding technique based on the Singular Value Decomposition (SVD) of the response matrix is developed. With the well-known Wiener filter concept, the modified SVD approach, Wiener-SVD, achieves the maximizing signal-to-noise ratio of the binned data in a transformed set of orthonormal bases where the uncertainties are bin-to-bin uncorrelated. In this talk, the mathematical principles and formulations of the newly developed Wiener-SVD unfolding will be presented. A few applications will be demonstrated. A comparison with the commonly used regularization method will also be shown. The advantages and disadvantaged of the Wiener-SVD approach will be discussed.

137. Nuclear Theory/RIKEN Seminar

"QCD corrections to high-pT hadron production in ep scattering"

Presented by Werner Vogelsang, Tuebingen University

Friday, August 25, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Heikki Mantysaari

We discuss various cross sections and spin observables in high-pT hadron production in lepton proton collisions, with special focus on the role of perturbative QCD corrections. We present phenomenological studies relevant for present fixed-target experiments and for a future EIC.

138. Particle Physics Seminar

"Precision tests with antimatter: A glimpse at the 1S – 2S transition in trapped antihydrogen"

Presented by Dr. William Bertsche, CERN

Thursday, August 24, 2017, 10 am
Small Seminar Room, Bldg. 510

Hosted by: Xin Qian

Optical spectroscopy with antihydrogen atoms remains one of the most promising routes towards testing CPT invariance and physics beyond the Standard Model in an effort to address the observed Baryon asymmetry in the Universe today. The ALPHA collaboration has made significant progress towards the first measurements of optical transitions in trapped antihydrogen atoms, and has recently published the first observation of the 1S – 2S transition in a fully antimatter atom. This work finds the transition consistent with CPT invariance at a level of approximately 2 x 10-10 [1]. This talk will review the details of this pioneering experiment and discuss the prospects of future spectroscopy studies and other fundamental measurements with the ALPHA experiment. [1] M. Ahmadi, et al (ALPHA Collaboration), "Observation of the 1S–2S transition in trapped antihydrogen" Nature 541, 506–510 (2017).

139. Condensed-Matter Physics & Materials Science Seminar

"Experiments on electron hydrodynamics with and without applied magnetic fields"

Presented by Andrew Mackenzie, Max-Planck-Institute, Germany

Wednesday, August 23, 2017, 1:30 pm
Bldg. 734, ISB Conf. Room 201 (upstairs)

Hosted by: Cedomir Petrovic

Will discuss experiments aimed at probing signatures of viscous contributions to electrical transport in ultra pure metallic systems. The hydrodynamic regime was reached in semiconductor heterostructures in the 1990s, but has only recently come into reach in naturally occurring compounds. I will focus on our group's work on layered delafossite metals, but possibly also discuss results from other groups on different material families.

140. Nuclear Theory/RIKEN Seminar

"Factorization and phenomenology for Transverse Momentum Dependent distributions"

Friday, August 18, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Heikki Mantysaari

Factorization and phenomenology for Transverse Momentum Dependent distributions Abstract: The factorization of the hadronic part of the cross sections plays a central role in our comprehension of collider physics. I will review some aspects of the factorization, like the appearence of rapidity divergences and the related subtractions and log resummation (up to higher orders in QCD perturbative expansion) in transverse momentum dependent cross sections. As an application I will describe the inclusion of the TMD formalism in an analysis of vector boson production data.

141. RIKEN Lunch Seminar

"Revisit the energy density and the gluon spectrum in the boost-invariant Glasma from a semi-analytic approach"

Presented by Ming Li

Thursday, August 17, 2017, 12:30 pm
Building 510, Room 2-160

Hosted by: Hiromichi Nishimura

In high energy heavy-ion collisions, the soft degrees of freedom at the very initial stage after the collision can be effectively represented by strong classical gluonic fields within the Color Glass Condensate framework. Understanding the space-time evolution of the system is equivalent to solving the classical Yang-Mills equations for the gluonic fields. There have been many efforts in the past two decades in numerically solving these equations. In this talk, on the contrary, I will use a semi-analytic approach that assumes the solution has the form of a power series expansion in the proper time. I will discuss the energy-momentum tensor and the gluon spectrum obtained from this approach and make comparisons with the numerical results in the literature.

142. Special Nuclear Theory Seminar

"Gluon orbital angular momentum at small-x"

Presented by Yoshitaka Hatta, YITP, Kyoto University

Wednesday, August 16, 2017, 10:30 am
Small Seminar Room, Bldg. 510

Hosted by: Raju Venugopalan

After reviewing the general aspects of the partonic orbital angular momentum in QCD (rigorous definition, connection to the Wigner distribution, etc), I focus on the gluon OAM in the small-x regime and discuss its measurability and a possible relation to the polarized gluon distribution.

143. Nuclear Theory/RIKEN Seminar

"Resummation of nonglobal logarithms in QCD"

Presented by Yoshitaka Hatta, Kyoto University

Friday, August 11, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Heikki Mantysaari

The large angle emission of soft gluons from QCD jets gives rise to the so-called nonglobal logarithms. In this talk I discuss the resummation of nonglobal logarithms at finite Nc with particular emphasis on its deep connection to the small-x logarithms in high energy scattering.

144. HET Lunch Discussions

"Hierarchion - a unified framework to address the Standard Model's hierarchies"

Presented by Gilad Perez, Weizmann Institute

Friday, August 11, 2017, 12:15 pm
Building 510, Room 2-160

Hosted by: Christoph Lehner

145. Brookhaven Lecture

"516th Brookhaven Lecture: 'From NSLS to NSLS-II and Beyond: Accelerator Physics Challenges'"

Tuesday, August 8, 2017, 4 pm
Berkner Hall Auditorium

Hosted by: Larry Carr

146. Nuclear Theory/RIKEN Seminar

"General formulae for dipole Wilson line correlators with the Color Glass Condensate"

Presented by Kenji Fukushima, University of Tokyo

Friday, August 4, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Heikki Mantysaari

I talk about general formulae to compute Wilson line correlators with the Color Glass Condensate approximated by the McLerran-Venugopalan model. Specifically, as an application, I explain about a perturbative expansion of the dipole correlators in terms of 1/N_c to derive fully analytical expressions. I finally discuss the validity of the large-N_c expansion by calculating the higher-order harmonics of the flow observables in the dipole model.

147. HET Lunch Discussions

"The Standard Model as a Lamppost"

Presented by Eder Izaguirre, BNL

Friday, August 4, 2017, 12:15 pm
Building 510, Room 2-160

Hosted by: Christoph Lehner

148. NSLS-II Friday Lunchtime Seminar Series

"From Particles to Patients: The Role of an Epoxide Hydrolase in P. Aeruginosa Virulence"

Presented by Kelli Hvorency, 2017 Julian D. Baumert. PhD. Thesis Award Winner, Dartmouth College

Friday, August 4, 2017, 12 pm
NSLS-II Bldg 743 (LOB 3), room 156

Hosted by: Ben Ocko, Shirish Chodankar, Milinda Abeykoon, Juergen Thieme and Guimei Wang

149. HET Lunch Discussions

"Possible origin(s) of flavor anomalies"

Presented by Amarjit Soni, BNL

Friday, July 28, 2017, 12:15 pm
Building 510, Room 2-160

Hosted by: Christoph Lehner

150. Particle Physics Seminar

"Latest Results from NOvA"

Presented by Louise Suter, Fermilab

Thursday, July 27, 2017, 3 pm
Small Seminar Room, Bldg. 510

Hosted by: Xin Qian

NOvA is a long-baseline neutrino experiment which utilizes two basically fully active, finely segmented, liquid scintillator detectors: a Near Detector located at Fermilab, and a Far Detector located in Ash River, MI, and situated roughly 14 mrad off Fermilab's NuMI beam. Using this narrow-band beam of mostly muon neutrinos we study the oscillation of these neutrinos over the 810 km baseline to measure the rate of electron neutrino appearing and of muon neutrinos and neutral current interactions disappearing between the two detectors. These are interpreted to give our latest measurements on the neutrino mass ordering, CP violation, the flavor content of the third neutrino mass eigenstate, and tests of the three-neutrino paradigm.

151. Computational Science Initiative Event

"The AMReX Astrophysics Suite: Simulating the Stars at the Exascale"

Presented by Michael Zingale, Associate Professor, Dept. Of Physics and Astronomy, Stony Brook University

Thursday, July 27, 2017, 1:30 pm
Seminar Room, Bldg. 725

Hosted by: Meifeng Lin

Astronomy is an observational science — we take data (primarily light) from the objects in the Universe and use this to infer how systems work. Astrophysical simulations allow us to perform virtual experiments on these systems, giving us the ability to see into stars in a way that light alone does not allow. Stellar systems can be modeled using the equations of hydrodynamics, together with nuclear reactions, self-gravity, complex equations of state, and at times, radiation (and magnetic fields). The resulting simulation codes are multiphysics and multiscale, and a variety of techniques have been developed to permit accurate and efficient simulations. We describe the adaptive mesh refinement (AMR) codes for astrophysics built upon the AMReX library: the AMReX Astrophysics Suite. We'll focus on the codes for stellar / nuclear astrophysics: Maestro and Castro. Maestro models subsonic stellar flows while Castro focuses on highly-compressible flows. They share the same microphysics (reaction networks, equations of state) and parallelization strategy. Through AMReX, we distribute boxes in our AMR hierarchy across nodes and we use OpenMP (via a logical tiling model in Castro) to spread the work on a box across cores in a node. Recently we've implemented a GPU strategy in AMReX that allows us to move the computational kernels onto GPUs to offload expensive calculations. We'll discuss the current performance of the hydrodynamics and reaction networks on GPUs and how our strategy will evolve in the future.

152. Environmental & Climate Sciences Department Seminar

"Classifying Aerosol Particles with a Centrifugal Particle Mass Analyzer (CPMA)"

Presented by Kristen Okorn, Stevens Institute of Technology (SULI Student Summer 2017)

Thursday, July 27, 2017, 11 am
Conference Room Bldg 815E

Hosted by: Ernie Lewis

Although wood stoves are a carbon-neutral renewable energy source, they are the largest source of particulate matter (PM) emissions in New York State. A Differential Mobility Analyzer (DMA), which classifies particles by their mobility diameter, has traditionally been employed to characterize such particulate emissions. However, because the black carbon (BC) particles produced by combustion that contribute to PM are fractal, their mobility diameters are not equal to their mass-equivalent diameters. In contrast to the DMA, the Centrifugal Particle Mass Analyzer (CPMA) classifies aerosol particles by their mass, using two rotating cylinders and an electric potential; when the centrifugal and electrostatic forces on a particle are equal, it passes through. The CPMA can select particles with masses ranging from 2×10 4 to 1.05×103 fg (corresponding to diameters, for particles with density 1 g cm 3, ranging from 7 to 1300 nm). It can be operated in two different ways: the "Run" classification method can be used to select for a single particle mass, and the "Step Scan" method can be used to select particles over a set range of masses. A neutralizer must be used upstream of the CPMA to create a charge distribution on particles before they enter the instrument. A DMA can optionally be used to pre-select particles of a specific mobility diameter before entering the CPMA. Downstream of the instrument, a Condensation Particle Counter (CPC) must be used in order to determine the number concentration of particles that pass through the CPMA. The basic operating principles of the CPMA are discussed, and results are presented for its characterization of polystyrene latex (PSL) particles, ammonium sulfate particles, and emissions from a wood burning stove.

153. HET Lunch Discussions

"Quasi PDFs"

Presented by Luchang Jin, BNL

Friday, July 21, 2017, 12:15 pm
Building 510, Room 2-160

Hosted by: Christoph Lehner

154. Particle Physics Seminar

"W boson mass measurement with the ATLAS experiment"

Presented by Fabrice Balli, CEA Saclay

Thursday, July 20, 2017, 3 pm
Small Seminar Room, Bldg. 510

Hosted by: Alessandro Tricoli

The W boson mass is a fundamental parameter of the Standard Model (SM) and was measured by several experiments at high energy e+e- and ppbar colliders. This parameter's measurement has the biggest impact on indirect searches for new particles or interactions, by comparing the measurement of this parameter with the prediction from the SM. It was measured recently by the ATLAS experiment at LHC, using data recorded in 2011, with a centre of mass energy of 7 TeV. I will review the thorough work that was performed in the ATLAS collaboration for this measurement and will discuss some considerations for future measurements at the LHC.

155. HET Lunch Discussions

"Long-lived light scalars and displaced vertices as probe of seesaw"

Presented by Bhupal Dev, Washington University

Friday, July 14, 2017, 12 pm
Building 510, Room 2-160

Hosted by: Amarjit Soni

In low-scale seesaw models for neutrino masses with local B −L symmetry breaking, the Higgs field breaking the B −L symmetry can leave a physical real scalar field with mass around GeV scale. In the specific case when the B − L symmetry is embedded into the left-right symmetry, low energy flavor constraints necessarily require such a light scalar to be long lived, with a distinct displaced photon signal at the LHC. We will discuss this previously unexplored region of parameter space, which opens a new window to TeV scale seesaw physics at colliders.

156. NSLS-II Friday Lunchtime Seminar Series

"Bio-cryo Electron Microscopy: The Opportunity and Plan" and "Characterizing Self-Assembled Nanoparticles Employed in Drug Delivery Systems"

Presented by Sean McSweeney and Kazuo Sakurai, NSLS-II, BNL and University of Kitakyushu

Friday, July 14, 2017, 12 pm
NSLS-II Bldg 743 (LOB 3), room 156

Hosted by: Ben Ocko, Shirish Chodankar, Milinda Abeykoon, Juergen Thieme and Guimei Wang

157. Physics Colloquium

"Anomalies in Reactor Neutrinos"

Presented by Chao Zhang, BNL

Tuesday, July 11, 2017, 3:30 pm
Large Seminar Room, Bldg. 510

Nuclear reactors are one of the most intense, pure, controllable, cost-effective and well-understood sources of neutrinos. Reactor neutrinos have played a major role in the discovery of neutrinos and neutrino oscillations. However, recently there emerged a few anomalies from reactor neutrino experiments when compared with state-of-the-art model predictions. The anomalies include a 5.5% deficit of the integrated antineutrino flux, a discrepancy in the antineutrino prompt energy spectrum around 5 MeV, and a 7.8% deficit in the 235U antineutrino flux from the new fuel evolution analysis in the Daya Bay Experiment. In this talk, those anomalies and their implications will be discussed. A new reactor neutrino experiment, PROSPECT, is aiming to resolve the anomalies by precisely measuring the 235U antineutrino spectrum at a very short baseline. The status of the PROSPECT experiment will also be reported

158. Office of Educational Programs Event

"High School Research Program Begins"

Monday, July 10, 2017, 8:30 am
Hamilton Seminar Room, Bldg. 555

159. Nuclear Theory/RIKEN Seminar

"Holographic Pomeron: Scattering, saturation, entropy and black hole."

Presented by Ismail Zahed, Stony Brook

Friday, July 7, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Heikki Mantysaari

I will discuss the general nature of the holographic Pomeron as a quantum QCD string exchange in both flat and curved AdS space for both pp and ep collisions at either large energies or small x. This description leads naturally to the concept of wee-strings and their distribution both in rapidity and transverse space. The holographic Pomeron carries intrinsic temperature and entropy, with the latter being identical to the recently reported entanglement entropy. I will show that this non-perturbative description of the Pomeron cross over to the the perturbative one, with a phase boundary dominated by string balls, i.e. long and massive strings near their intrinsic Hagedorn temperature. These string balls lead to a distribution of large multiplicity pp events that is in agreement with the one reported for pp collisions at the LHC. I will show that at low-x, the quantum string is so entangled that very weak string self-interactions can cause it to turn to a black hole. I will suggest that low-x saturation occurs when the density of wee-strings reaches the Bekenstein bound, with a proton size that freezes with increasing rapidity.

160. Nuclear Theory/RIKEN Seminar

"Probing Transverse Momentum Broadening in Heavy Ion Collisions"

Presented by Feng Yuan, LBL

Friday, June 30, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Heikki Mantysaari

In this talk, we will discuss the dijet azimuthal de-correlation in relativistic heavy ion collisions as an important probe of the transverse momentum broadening effects in heavy ion collisions. We take into account both the soft gluon radiation in vacuum associated with the Sudakov logarithms and the jet PT-broadening effects in the QCD medium. We find that the Sudakov effects are dominant at the LHC, while the medium effects can play an important role at RHIC energies. This explains why the LHC experiments have not yet observed sizable PT-broadening effects in the measurement of dijet azimuthal correlations in heavy ion collisions. Future investigations at RHIC will provide a unique opportunity to study the PT-broadening effects and help to pin down the underlying mechanism for jet energy loss in a hot and dense medium.

161. HET Seminar

"Double Gauge Boson Production in the SM Effective Field Theory"

Presented by Ian Lewis, University of Kansas

Wednesday, June 28, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Sally Dawson

162. Nuclear Physics Seminar

"Measurement of longitudinal flow correlations in 2.76 and 5.02 TeV Pb+Pb collisions with the ATLAS detector"

Presented by Peng Huo, Stony Brook University

Tuesday, June 27, 2017, 11 am
Small Seminar Room, Bldg. 510

Hosted by: Jin Huang

Longitudinal dynamics has recently become a topic of great interest in the study of ultra-relativistic heavy ion collisions. Measurement of the longitudinal fluctuations of the flow harmonic coefficients $v_n$ and event-plane angles $\Psi_n$ can provide a more complete picture of space-time evolution of the hot, dense medium formed in heavy ion collisions. Longitudinal flow decorrelations can be modeled with two contributions: magnitude fluctuations and event plane twist. However, existing observables do not separate these two effects. In this analysis, a new 4-particle correlator is used to separate the event-plane twist from magnitude fluctuations in 2.76 and 5.02 Pb+Pb collisions. Results show both effects have a linear dependence on pseudorapidity separation for $v_{2-5}$, and show a small but measurable variation with collision energy. The correlation of $\Psi_n$ of different order are also expected to have longitudinal fluctuations due to the non-linear mixing effects between lower and higher order flow harmonics. First measurement of such non-linear mode-mixing effects as a function of pseudorapidity is also presented. These result will help to constrain initial conditions along longitudinal direction and also help understand the longitudinal evolution of the fireball.

163. Condensed-Matter Physics & Materials Science Seminar

"Resonant inelastic X-ray scattering on "moderately correlated" quantum materials"

Presented by L. Andrew Wray, New York University

Thursday, June 22, 2017, 1 pm
ISB Bldg. 734 Conf. Rm. 201 (upstairs)

Hosted by: Mark Dean

The resonant inelastic X-ray scattering (RIXS) technique is best known for significant breakthroughs in the investigation of strongly correlated materials such as cuprates. However, the rapid advancement of RIXS spectrographs has made it increasingly attractive to apply the technique to a broad range of quantum materials outside of this comfort zone. This talk will review lessons learned from our recent measurements on material systems that feature a balance of correlated and itinerant physics, including VO2, the hidden order compound URu2Si2, and Prussian blue analogue battery electrodes. RIXS spectra enable the first observation of important collective modes for these systems, and provide a look into how correlated electron symmetries are melted - or persist! - in relatively itinerant and covalent environments. The data also highlight the need for improved theoretical modeling and higher photon throughput to achieve deeper insights.

164. Condensed-Matter Physics & Materials Science Seminar

"Tailoring Lattice and Charge at Complex Oxide Nanostructures and Interfaces"

Presented by Xia Hong, University of Nebraska-Lincoln

Tuesday, June 20, 2017, 11 am
Bldg. 480, Conference Room

Hosted by: Yimei Zhu

Capitalizing on the energy competition of charge itineracy with the strong electron-electron and electron-phonon couplings, nanoscale manipulation of the charge and lattice degrees of freedom in strongly correlated oxides can often lead to new functionalities that are inaccessible in the bulk form. In this talk, I will present our studies of the emerging phenomena at epitaxial correlated oxide nanostructures and hetero-interfaces that result from the nanoscale lattice and charge control. By creating nanoscale periodic depth modulation, we have achieved a 50-fold enhancement of the magnetic crystalline anisotropy in ultrathin colossal magnetoresistive (La,Sr)MnO3, which is attributed to a non-equilibrium strain distribution established in the nanostructures [1]. I will also discuss the intricate interplay between epitaxial strain and electric field effect in determining the correlated transport of the charge transfer type Mott insulator (Sm,Nd)NiO3 [2,3], and how the interfacial charge transfer between two correlated oxides can be exploited to effectively engineer the performance of ferroelectric-gated Mott transistors [4]. [1] A. Rajapitamahuni et al., PRL 116, 187201 (2016). [2] L. Zhang et al., JPCM 27, 132201 (2015). [3] L. Zhang et al., APL 107, 152906 (2015). [4] X. Chen et al., Adv. Mater, in press (2017).

165. Condensed-Matter Physics & Materials Science Seminar

"Laser-driven Pulsed Neutron Sources as a Potential Pool-side Characterization Tool for Nuclear Fuels"

Presented by Sven Vogel, Los Alamos National Laboratory

Monday, June 19, 2017, 1:30 pm
ISB Bldg. 734, Conf. Rm. 201 (upstairs)

Hosted by: Emil Bozin

The unique advantages of neutrons for characterization of nuclear fuel materials [1] are applied at the pulsed spallation neutron source at LANSCE to accelerate the development and ultimately licensing of new nuclear fuel forms. Neutrons allow to characterize the crystallography of phases consisting of heavy elements (e.g. uranium) and light elements (e.g. oxygen, nitrogen, or silicon) [2]. The penetration ability in combination with comparably large (e.g. cm sized) beam spots provide microstructural characterization of typical fuel geometries for phase composition, strains, and textures from neutron diffraction. In parallel, we are developing energy-resolved neutron imaging and tomography with which we can complement diffraction characterization. This unique approach not only allows to visualize cracks, arrangement of fuel pellets in rodlets etc., but also characterization of isotope or element densities by means of neutron absorption resonance analysis [3]. Laser-driven pulsed neutron sources [4] have the potential to provide these capabilities "pool-side", e.g. at the Advanced Test Reactor at Idaho National Laboratory. Compared to proton accelerator driven spallation sources, requiring investments exceeding $1B, the investment cost for a laser-driven neutron source would be of the order of several$10M with the potential of similar flux to that of a smaller, earlier generation spallation neutron source. Compared to electron accelerator-driven neutron sources, the flux of a laser-driven source would be at least one order of magnitude higher. Compared to reactor neutron sources, the pulse structure of the laser-driven neutron source would enable unique characterization not possible with steady-state reactor neutrons. In this presentation, we provide an overview of our recent accomplishments in fuel characterization for accident-tolerant fuel consisting of uranium nitride/uranium silicide composite fuels as well as metallic fuels.

166. Nuclear Theory/RIKEN Seminar

"Better fitting through (fictitious) chemistry"

Presented by Pasi Huovinen, Uniwersytet Wroclawski

Monday, June 19, 2017, 10 am
Small Seminar Room, Bldg. 510

Hosted by: Heikki Mantysaari

One of the puzzles we have faced at the LHC is why the thermal models apparently cannot properly fit the yield of protons. I will explore how the fit improves if we assume that nucleon-antinucleon annihilations freeze-out way later than all other number changing processes or if strange particles freeze-out before non-strange particles, and how this affects the final particle distributions in hydrodynamical calculations.

167. Nuclear Theory/RIKEN Seminar

"Exploring the phase structure and dynamics of QCD"

Presented by Jan Pawlowski, Heidelberg

Friday, June 16, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Heikki Mantysaari

The past years have seen tremendous progress in the description of Quantum Chromodynamics at vanishing and finite temperature and density with functional approaches, such as the functional renormalisation group or Dyson-Schwinger equations. Within these approaches QCD correlation functions of quarks, gluon and hadrons are computed non-perturbatively from first principles. In the talk I will discuss results for the phase structure of QCD at finite temperature and density, as well as for thermodynamical obserables such as the pressure and the trace anomaly. The approach is also applied to baryon number fluctuations. By now functional approaches also allow for a direct computation of transport coefficients in QCD. First results concern the temperature dependence of the shear viscosity over entropy ratio in Yang-Mills theory and QCD. The talk concludes with a discussion of the further prospects for our understanding of the phase structure and dynamics of QCD.

168. Particle Physics Seminar

"First Results from XENON1T"

Presented by Dr. Fei Gao, Columbia University

Thursday, June 15, 2017, 3 pm
Small Seminar Room, Bldg. 510

Hosted by: Xin Qian

Understanding the properties of dark matter particle is a fundamental problem in particle physics and cosmology. The search of dark matter particle scattering off nuclei target using ultra-low background detector is one of the most promising technology to decipher the nature of dark matter. The XENON1T experiment, which is a dual phase detector with ~2.0 tons of xenon running at the Gran Sasso Laboratory in Italy, is designed to lead the field of dark matter direct detection. Since November 2016, the XENON1T detector is continuously taking data, with a background rate of more than one order of magnitude lower than any current generation dark matter search experiment. In this talk, I will present the first dark matter search results from XENON1T. Details about the XENON1T detector as well as the data analysis techniques will also be covered.

169. Condensed-Matter Physics & Materials Science Seminar

"A model of chiral spin liquids with tunable edge states"

Presented by Christopher Mudry, Paul Scherrer Institute, Switzerland

Thursday, June 15, 2017, 1:30 pm
Bldg. 734, ISB Conference Room 201 (upstairs)

Hosted by: Alexei Tsvelik

We construct a quantum field theory in (2+1)-dimensional spacetime for strongly interacting Majorana fields that is amenable to a mean-field approximation. The mean-field phase diagram predicts the existence of two competing phases, one of which supports chiral non-Abelian topological order, while the other supports chiral Abelian topological order. The two mean-field phases are separated by a continuous phase transition. This quantum field theory captures the low-energy physics of quantum spin-1/2 localized on the sites of a lattice whose interactions are $SU(2)$ symmetric but break time-reversal symmetry. The lattice geometry can be interpreted as a one-dimensional stacking of two-leg ladders or as a bilayer of two square lattices. Both incompressible ground states can thus be thought of as chiral spin liquids in two-dimensional space supporting non-Abelian and Abelian topological order, respectively.

170. HET/RIKEN Seminars

"Searching for New Physics with Higgs Decays"

Presented by Daniel Stolarski, Carleton University

Wednesday, June 14, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Pier Paolo Giardino

171. Particle Physics Seminar

"Hadronically interacting Dark Matter, and a new mechanism for the Baryon Asymmetry, within QCD"

Presented by Professor Glennys Reynolds Farrar, NYU

Wednesday, June 14, 2017, 10 am
Small Seminar Room, Bldg. 510

Hosted by: Xin Qian

There may be a so-far-undiscovered neutral, stable particle composed of 6 quarks, denoted S, with mass m_S ~ 2 m_p. If so, the S is an excellent Dark Matter candidate. More generally, I will discuss how hadronic-strength interaction between DM and baryons can cause local DM to co-rotate with gas and stars, resulting in DM energy deposits below threshold for direct detection. DM-baryon interactions cause rotation curves to reflect baryonic density profiles, as observed in some galaxies, and can help alleviate some of the issues with CDM at small scales. An open question is whether the measured Ly-alpha power spectrum places an upper limit on the DM-baryon cross section, which is sufficiently robust and constraining to rule out the co-rotation scenario. The S-DM scenario suggests a new mechanism for producing the observed baryon asymmetry, and appears capable of naturally explaining the DM to baryon ratio.

172. Physics Colloquium

"Stable Sexaquark as Dark Matter"

Presented by Professor Glennys Reynolds Farrar, NYU

Tuesday, June 13, 2017, 3:30 pm
Small Seminar Room, Bldg. 510

Hosted by: Xin Qian

Dark Matter could be composed of an as-yet-undiscovered stable or essentially stable, neutral B=2 hadron composed of uuddss quarks. How such a particle, designated S for Sexaquark and to distinguish from the loosely bound di-Lambda called H-dibaryon, can be compatible with current knowledge is explained. The S is absolutely stable if m_S < 2 m_p+ 2 m_e. If m_S > 2 m_p+ 2 m_e but < m_p+m_e + m_Lambda, its lifetime could be longer than the age of the Universe. Experiments are proposed to discover and measure the mass of the proposed particle. To first approximation it behaves like standardl Cold Dark Matter, but some distinctive differences may help explain some puzzles about DM at galactic scales.

173. Nuclear Theory/RIKEN Seminar

"Gluon structure of hadrons and nuclei"

Presented by Phiala Shanahan, MIT

Friday, June 9, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Heikki Mantysaari

I will present the results of recent lattice QCD studies of the gluon generalised form factors of both hadrons and light nuclei. The generalised transversity gluon distributions are of particular interest since they are purely gluonic; they do not mix with quark distributions at leading twist. In light nuclei they moreover provide a clean signature of non-nucleonic degrees of freedom. The goal of these studies is to provide QCD predictions to be tested at an electron-ion collider (EIC) designed to access gluon structure quantities including transverse-momentum dependent distributions (TMDs) and gluon generalised parton distributions (GPDs).

174. RIKEN Lunch Seminar

"Anomalies and Exact Results In Massive Quantum Chromodynamics"

Presented by Zohar Komargodski, Stony Brook

Thursday, June 8, 2017, 12:30 pm
Building 510, Room 2-160

Hosted by: Hiromichi Nishimura

175. Nuclear Physics Seminar

"Anatomy of Azimuthal Angle Correlations in Large and Small Systems - Why the fuss?"

Presented by Roy Lacey, Stony Brook University

Tuesday, June 6, 2017, 11 am
Small Seminar Room, Bldg. 510

Hosted by: Oleg Eyser

Azimuthal momentum anisotropy measurements are ubiquitous at both RHIC and the LHC. However, there are pervasive misconceptions as to the mechanistic origin of this anisotropy in both small and large systems. In this talk, I will demonstrate how recent momentum anisotropy measurements, for a broad range of systems, have been leveraged to gain new mechanistic insights and to constrain the properties of the medium produced in these collisions. In particular, the role of final state effects versus initial state momentum domain effects in explanations of the measurements will be addressed.

176. Nuclear Theory/RIKEN Seminar

"Hydrodynamic Fluctuations in Heavy Ion Collisions"

Presented by Derek Teaney, Stony Brook

Friday, June 2, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Heikki Mantysaari

We develop a set of kinetic equations for hydrodynamic fluctuations which are equivalent to nonlinear hydrodynamics with noise. The hydrokinetic equations can be coupled to existing second-order hydrodynamic codes to incorporate the physics of these fluctuations. We use the hydrokinetic equations to analyze thermal fluctuations for a Bjorken expansion, evaluating the contribution of thermal noise from the earliest moments and at late times. In the Bjorken case, the solution to the kinetic equations determines the coefficient of the first fractional power of the gradient expansion $\sim 1/(\tau T)^{3/2}$ for the expanding system. Numerically, we find that the contribution to the longitudinal pressure from hydrodynamic fluctuations is larger than second-order hydrodynamics for typical medium parameters used to simulate heavy ion collisions. Subsequently we analyze the behaviour of hydrodynamic fluctuations of near the QCD critical point, and dilineate the relevance Kiblle-Zurek scaling relative to other physics. If time permits we will also describe how thermal fluctuations place a lower bound on the bulk viscosity of QCD. References: Y.~Akamatsu, A.~Mazeliauskas and D.~Teaney, A kinetic regime of hydrodynamic fluctuations and long time tails for a Bjorken expansion,'' [arXiv:1606.07742 [nucl-th]]. Y.~Akamatsu, D. Teaney, F. Yan, Y. Yin, `Transitting the critical point,'' in progress.

177. Environmental & Climate Sciences Department Seminar

"Cloud radiative fraction: Determination by high resolution photography from the surface looking upward"

Presented by Stephen E. Schwartz, Environmental & Climate Sciences Department

Thursday, June 1, 2017, 11 am
Conference Room Bldg 815E

Clouds greatly affect short- and longwave radiation transfer in the atmosphere and consequently climate. Hence it is essential that the amount and radiative influences of clouds be accurately represented in climate models. The conventional measure of the amount of cloud in a grid cell is cloud fraction, CF, the fraction of the surface area covered by cloud. CF is a commonly reported meteorological quantity, with a long record of surface observations, greatly augmented in the past several decades by satellite observations. Global cloud fraction determined from satellite measurements has systematically increased with time, a consequence not of secular increase in cloud fraction but of an increase with time in the sensitivity of active and passive satellite instruments. Such a situation raises the question of whether CF can be defined and how well it can be measured. Commercially available digital cameras provide an unprecedented opportunity for detailed study of cloud structure from the surface, looking upward. Key attributes of such cameras include large number of pixels, (e.g., 3456 x 4608; 16 M pixel) yielding rich detail of spatial structure, high spatial resolution, and high dynamic range (16 bit in each of three color channels at visible wavelengths). In the work reported here two cameras were pointed vertically, typically with field of view FOV 21 × 29 mrad and 120 × 160 mrad, respectively, denoted here narrow field of view, NFOV, and wide field of view WFOV, corresponding, for cloud base at 1 km, to 21 × 29 m (NFOV) and 120 × 160 m (WFOV). For perspective, the FOV for the NFOV camera is 2 × 3 sun diameters and for the WFOV camera 11 × 15 sun diameters. Nominal angular dimension of a single pixel is 6 μrad for the NFOV camera and 34 μrad for the WFOV camera, corresponding, again for cloud height 1 km, to 6 mm and 34 mm, respectively. Such single-pixel resolution is some 3 to 5 orders of magnitude finer than that avai

178. Particle Physics Seminar

"Higgs boson properties: what we learn from run II of LHC"

Presented by Andrei Gritsan, Johns Hopkins University

Thursday, May 25, 2017, 3 pm
Small Seminar Room, Bldg. 510

Hosted by: Alessandro Tricoli

During the second run in 2015-2016, LHC delivered the number of proton-proton collisions far beyond expectation and at higher energy than in run I. We will review the very first results on the H boson properties based on the full dataset collected by CMS by now. We will go through the four main topics: H boson couplings to gauge bosons, couplings to fermions, self-couplings, and search for an extended Higgs sector. Prospects of some of these measurements through the end of run III and phase II of LHC will be discussed.

179. RIKEN Lunch Seminar

"Mixed Anomaly and Global Consistency"

Presented by Yuya Tanizaki, RBRC

Thursday, May 25, 2017, 12:30 pm
Building 510, Room 2-160

Hosted by: Hiromichi Nishimura

Symmetry and topology are powerful tools to study strongly interacting dynamics. In this talk, we will see that mixed 't Hooft anomaly and global consistency strongly constrains the possible low-energy dynamics in a simple quantum mechanical example. I will briefly explain the same idea is useful to study the phase diagram of bifundamental gauge theories at finite theta angles.

180. HET/RIKEN Seminar

"Cosmology in Mirror Twin Higgs and Neutrinos"

Presented by Patrick Fox, Fermilab

Wednesday, May 24, 2017, 2 pm
Small Seminar Room, Bldg. 510

181. Nuclear Physics Seminar

"Searching for collectivity and testing the limits of hydrodynamics: results from the 2016 d+Au beam energy scan"

Presented by Ron Belmont, University of Colorado Boulder

Tuesday, May 23, 2017, 11 am
Small Seminar Room, Bldg. 510

Hosted by: Jin Huang

The standard picture of heavy ion collisions is that large systems (collisions of large nuclei like Au+Au and Pb+Pb) create a quark-gluon plasma that exhibits collective behavior indicative of nearly inviscid hydrodynamical evolution. Recently, data from small systems (collisions of a small projectile and a large target like d+Au and p+Pb) have been found to exhibit strikingly similar evidence for collective behavior. To further elucidate these results, RHIC delivered in 2016 a beam energy scan of d+Au collisions at 4 different energies: 200, 62.4, 39, and 19.6 GeV. In this talk we present a wide array of results from the Run16 d+Au BES and discuss the implications for collective behavior and the limits of applicability for hydrodynamics.

182. Particle Physics Seminar

"Tiny Bubbles in the Mine: New Results from the PICO-60 Dark Matter Detector"

Presented by Dr. Eric Dahl, North Western

Friday, May 19, 2017, 10 am
Small Seminar Room, Bldg. 510

Hosted by: Xin Qian

The PICO Collaboration builds bubble chambers for the direct detection of WIMP dark matter. These devices are unique among direct detection experiments both in the WIMP models they can probe and the backgrounds they face. The PICO collaboration has set consecutive world-leading direct-detection limits on the spin-dependent WIMP-proton cross section, most recently with a zero-background 1.2 ton-day exposure with a C3F8 target in the PICO-60 detector at SNOLAB. This result is significant not just because it reaches new WIMP parameter space, but also because it demonstrates our ability to eliminate the anomalous bubble nucleation background that limited past bubble chamber WIMP searches, opening the door for experiments at the ton scale and beyond. I will describe this new result from PICO, our immediate plans for new detectors at SNOLAB, and the broader role bubble chambers will play in the future of dark matter detection, including the new scintillating bubble chamber technology developed by my group at Northwestern.

183. RIKEN Lunch Seminar

"Probing quantum entanglement at the Electron Ion Collider"

Presented by Dima Kharzeev, BNL and Stony Brook University

Thursday, May 18, 2017, 12:30 pm
Building 510, Room 2-160

Hosted by: Hiromichi Nishimura

184. HET/RIKEN Seminars

"Collider and Cosmological Signatures of a Strong Electroweak Phase Transition"

Presented by Jonathan Kozaczuk, UMass Amherst

Wednesday, May 17, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Pier Paolo Giardino

185. Physics Colloquium

"Direct Detection of sub-GeV Dark Matter"

Presented by Rouven Essig, Stony Brook University

Tuesday, May 16, 2017, 3:30 pm
Large Seminar Room, Bldg. 510

Hosted by: Andrei Nomerotski

Dark matter makes up 85% of the matter in our Universe, but we have yet to learn its identity. A broad array of search strategies are needed to probe for non-gravitational interactions between dark matter and ordinary matter. While most searches focus on Weakly Interacting Massive Particles (WIMPs) with masses between 1 GeV and 1 TeV, it is imperative to also consider other motivated dark matter candidates. In this talk, I will discuss dark matter with MeV-to-GeV masses, which is a theoretically and phenomenologically appealing possibility and presents a new frontier in the search for dark matter. I will highlight novel dark matter direct-detection strategies that can probe this under-explored mass range. I will describe how XENON10 data already probes dark matter with masses as low as a few MeV, and discuss improvements expected from new experiments using semiconductors or scintillators. This includes SENSEI, a new ultra-low-threshold silicon CCD detector, which is poised to probe vast new regions of parameter space in the next few years. I will also present a few simple benchmark models of MeV-to-GeV dark matter, and contrast direct-detection probes with searches at colliders and fixed-target experiments.

186. Condensed-Matter Physics & Materials Science Seminar

"Thin-Film Alchemy: Using Epitaxial Engineering to Unleash the Hidden Properties of Oxides"

Presented by Darrell G. Schlom, Cornell University

Monday, May 15, 2017, 1:30 pm
Bldg. 734, ISB Conference Room 201 (upstairs)

Hosted by: Ivan Bozovic

Guided by theory, unparalleled properties—those of hidden ground states—are being unleashed by exploiting large strains in concert with the ability to precisely control dimensionality and stabilize metastable phases in epitaxial oxide heterostructures. For example, materials that are not ferroelectric or ferromagnetic in their unstrained state can be transmuted into materials that are both at the same time. Similarly, new tunable dielectrics with unparalleled performance have been created as well as a new single-phase multiferroic material where ferroelectricity and strong magnetic ordering are coupled near room-temperature. These are just three examples of the unparalleled properties—those of hidden ground states—being unleashed in epitaxial oxide heterostructures utilizing thin film alchemy

187. NSLS-II Friday Lunchtime Seminar Series

"Status of SSRF and the Shanghai X-FEL Projects, and Efforts in Single Particle Imaging and Whole Cell Imaging with X-FELs"

Presented by Thomas Earnest, Shanghai Synchrotron Radiation Facility

Friday, May 12, 2017, 12 pm
NSLS-II Bldg 743 (LOB 3), room 156

Hosted by: Ben Ocko and Shirish Chodankar

188. RIKEN Lunch Seminar

"The nucleon axial charge from Lattice QCD"

Presented by Enrico Rinaldi, RBRC

Thursday, May 11, 2017, 12:30 pm
Building 510, Room 2-160

Hosted by: Hiromichi Nishimura

189. Nuclear Theory/RIKEN Seminar

"Probing nucleon substructure with Bayesian parameter estimation"

Presented by Scott Moreland, Duke

Friday, May 5, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Heikki Mantysaari

Multi-particle correlations observed in small collision systems at top LHC energies exhibit signatures which are similar to those observed in large collision systems and generally attributed to the formation of a deconfined quark-gluon plasma (QGP). This suggests that even proton-proton and proton-lead collisions may produce small droplets of QGP which translate spatial inhomogeneities into final-state momentum anisotropies. A primary challenge in testing hydrodynamic descriptions of small collision systems is in modeling the initial stages of the collision. In this talk, I discuss recent efforts to apply Bayesian methodology to parametric descriptions of initial state physics. I show that such methods can be extended to smaller length scales which include partonic degrees of freedom and glean information regarding the fluctuating nature of the proton.

190. HET Lunch Discussions

"Standard Model EFT and Extended Scalar Sectors"

Presented by Chris Murphy, BNL

Friday, May 5, 2017, 12:15 pm
Building 510, Room 2-160

Hosted by: Christoph Lehner

191. Computational Science Initiative Event

"Frontiers for High Performance Computing in Cancer Research"

Presented by Dr. Eric A. Stahlberg, Frederick Nat Lab for Cancer Research

Friday, May 5, 2017, 10 am
Seminar Room, Bldg. 725

Hosted by: Frank Alexander

Anticipated advances in high-performance computing are enabling exciting new areas of computational and data oriented cancer research. These frontiers are being explored in a unique collaboration between the US Department of Energy and the National Cancer Institute in the Joint Design of Advanced Computing Solutions for Cancer. While the three-year collaboration is still in its first year, the collaboration is providing tremendous insight into the promise and challenges of employing extreme scale computing to advance research in the challenging and complex problem of cancer. Challenged with the aim of providing predictive insight in areas such as tumor response to treatments, molecular level interactions, and even clinical outcomes, the collaborative effort advances the frontiers of cancer research and computing in both numerically-intensive and data-intensive applications, while providing insights into opportunities for the high-performance computing community overall.

192. Particle Physics Seminar

"New MEG Results and Prospects for Improved Searches for Muon and Electron Number Violation in the Charged Sector"

Presented by William Molzon, University of California, Irvine

Thursday, May 4, 2017, 3 pm
Small Seminar Room, Bldg. 510

Hosted by: Xin Qian

Searches for muon and electron number violation in the charged sector continue to be a sensitive probe of non Standard Model physics. I will give results of the full data-set of the MEG collaboration's search for muons decaying to electron plus photon and describe improvements to the MEG muon beam and apparatus that will improve sensitivity by a factor of ten in the next few years. I will also briefly review other experiments in the planning and early construction phases that are expected to improve sensitivity in related processes in the coming 5-10 years.

193. Condensed-Matter Physics & Materials Science Seminar

"Transient Dynamics of Strongly Correlated Electrons After Sudden Excitations"

Presented by Marco Schiro, Institut de Physique Theorique (IPhT), CEA, Saclay, France

Thursday, May 4, 2017, 1:30 pm
Bldg. 734, ISB Conference Room 201 (upstairs)

Hosted by: Robert Konik

The development of pump-probe spectroscopies with femtosecond time resolution, which allows to track the dynamics of electronic degrees of freedom in solids under optical excitations, opens up a new window to understand strongly correlated materials and offers the intriguing possibility of controlling their properties with light, on ultra-fast time scales. Triggered by these advances, the interest around time dependent phenomena in quantum many body systems has recently substantially grown. In this talk will review recent progress in understanding transient dynamics of electrons in correlated metals, Mott Insulators and superconductors. I will show that quite generically these systems display very sharp dynamical transitions as a function of the external perturbation, in correspondence of which the lattice response and the sensitivity to density inhomogeneities can be greatly enhanced.

194. RIKEN Lunch Seminar

"Lattice study of gauge theory with multiple fermion representations"

Presented by Ethan Neil, University of Colorado, Boulder and RBRC

Thursday, May 4, 2017, 12:30 pm
Building 510, Room 2-160

Hosted by: Enrico Rinaldi

"There is long-standing theoretical interest in the behavior of a strongly-coupled gauge theory in the presence of multiple fermions charged under different representations of the gauge group. In addition to the question of whether generation of dynamically separated scales will occur, such theories appear commonly in UV realizations of composite Higgs models with partially composite top quarks. I will present a first lattice study of SU(4) gauge theory with fermions in each of the two lowest-lying representations, discussing the finite-temperature phase structure and low-lying spectrum. Connections to BSM physics through a particular composite Higgs model will also be made."

195. Joint YITP/HET Seminar

"Evidence for a ~17 MeV Particle in Rare Beryllium-8 Decays?"

Presented by Tim Tait, UCI

Wednesday, May 3, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Amarjit Soni

196. Nuclear Theory/RIKEN Seminar

"Analyticity in Spin and Causality in Conformal Theories"

Presented by Simon Caron-Huot, McGill

Friday, April 28, 2017, 2 pm
Large Seminar Room, Bldg. 510

Hosted by: Heikki Mantysaari

The conformal bootstrap aims to calculate scaling dimensions and correlation functions in various theories, starting from general principles such as unitarity and crossing symmetry. I will explain that local operators are not independent of each other but organize into analytic functions of spin, and I will present a formula, extending a classic one due to Froissart and Gribov in the early days of Regge theory, which quantifies the consequences of this fact. Applications will include a new way to solve crossing symmetry at large spin, as well as new bounds encoding bulk locality in theories with a gravity dual. Based on 1703.00278.

197. Condensed-Matter Physics & Materials Science Seminar

"Spin-liquids in novel triangular and kagome rare-earth magnets"

Presented by Martin Mourigal, Georgia Tech

Friday, April 28, 2017, 1:30 pm
Bldg. 734, ISB Conference Room 201 (upstairs)

Hosted by: Igor Zaliznyak

Insulating magnets combining the effects of geometrical frustration with strong spin-orbit coupling offer a prime route to realize correlated quantum states with exotic ground-states and excitations. Spin-space anisotropy and bond-directional magnetic exchange interactions are naturally present in rare-earth oxides. One of the most celebrated consequence is the existence of classical and quantum "spin-ice" physics in rare-earth pyrochlores, materials in which magnetic ions occupy a three-dimensional network of corner-sharing tetrahedra. In this talk, I will present the discovery of distinct flavors of exotic magnetic matter in families of rare-earth oxides with two-dimensional kagome [1] and triangular [2] geometries. This experimental work relies on recent advances in materials synthesis and combines thermodynamic characterization with state-of-the-art neutron scattering experiments to unravel the classical or quantum nature of these newly discovered quasi-two-dimensional spin-liquids. [1] Emergent order in the kagome Ising magnet Dy3Mg2Sb3O14, J. A. M. Paddison, H. S. Ong, J. O. Hamp, P. Mukherjee, X. Bai, M. G. Tucker, N. P. Butch, C. Castelnovo, M. Mourigal, and S. E. Dutton, Nature Communications 7, 13842 (2016). [2] Continuous excitations of the triangular-lattice quantum spin liquid YbMgGaO4, J. A. M. Paddison, M. Daum, Z. L. Dun, G. Ehlers, Y. Liu, M. B. Stone, H. D. Zhou, and M. Mourigal, Nature Physics AOP (2016).

198. Condensed-Matter Physics & Materials Science Seminar

"Magnetometry Study of Underdoped Cuprate YBa2Cu3O6.55"

Presented by Fan Yu, University of Michigan

Friday, April 28, 2017, 11 am
Bldg. 734, ISB. Conf. Rm. 168

Hosted by: Qiang Li

This talk would be focused on my study of the phase diagram of underdoped cuprate YBa2Cu3O6.55 using torque magnetometry as well as my exploration of extending magnetometry method into even higher magnetic fields (>45T) using pulsed magnet. The complex phase diagrams of cuprates are sometimes referred to as "competing orders", where a large variety of ordering tendencies are known to (co-)exist. Our experiment managed to reveal an anomaly on the magnetic susceptibility, which we believe was related to charge density wave transition. Particularly interesting is that this anomaly is observed in the strong diamagnetic regime where vortex liquid exists. We believe this should be considered as a direct experimental evidence for the picture of "competing orders". To further our understanding of the quantum vortex liquid, experiments at mK temperatures and at magnetic field exceeding 40 Tesla are necessary. During my PhD study, considerable amount of time was devoted to developing a reliable magnetometry method utilizing the pulsed magnet at NHMFL, Los Alamos. I would like to present my trail-and-error as well as the proposition of "time-delayed probe design", which should be able to bypass the inherent noise of a pulsed environment.

199. Particle Physics Seminar

"CP violation in neutrino oscillations and impact of new physics"

Presented by Dr. Poonam Mehta

Friday, April 28, 2017, 10 am
Small Seminar Room, Bldg. 510

Hosted by: Xin Qian

The study of CP violation addresses fundamental questions such as - are the laws of physics the same for matter and anti-matter. CP is a discrete symmetry of nature given by a product of two quantities : charge conjugation (C) and parity (P). Detecting leptonic CP violation is one of the most challenging goals in particle physics today. An attractive possibility to measure CP phase is via long baseline accelerator experiments such as Deep Underground Neutrino Experiment (DUNE). In this talk, we will show that clean extraction of CP violating phase becomes a formidable task in presence of new physics and one needs to devise ways to distinguish between standard paradigm and the new physics scenarios.

200. Particle Physics Seminar

"Searching for Optical Counterparts to Gravitational Wave Events in the Dark Energy Survey"

Presented by Jim Annis, Fermilab

Thursday, April 27, 2017, 3 pm
Small Seminar Room, Bldg. 510

Hosted by: Erin Sheldon

201. YITP/HET Joint Seminar

"TBA"

Presented by John Donoghue, U. Mass Amherst

Wednesday, April 26, 2017, 3 pm
YITP Seminar Room, Stony Brook University

202. Physics Colloquium

"Current Status of Neutrinoless Double Beta Decay Research"

Presented by Bob McKeown, Jefferson Lab

Tuesday, April 25, 2017, 3:30 pm
Large Seminar Room, Bldg. 510

Hosted by: Andrei Nomerotski

The observation of neutrinoless double beta decay would establish that neutrinos are Majorana fermions and would represent a discovery of profound importance: that lepton number is not conserved. There is currently a worldwide effort to search for neutrinoless double beta decay, using a variety of candidate isotopes and detector technologies. A subcommittee of the Nuclear Science Advisory Committee (NSAC) recently surveyed the field and the associated research and development needs. Based on the information provided to this subcommittee, I will present an overview of the present activity in this field and the prospects for the future.

203. Nuclear Theory/RIKEN Seminar

"Forward particle production in pA: implementing the NLO hybrid formalism"

Presented by Tuomas Lappi, University of Jyväskylä

Friday, April 21, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Heikki Mantysaari

Single inclusive particle production cross sections in high energy hadron collisions at forward rapidity are an important benchmark process for the CGC picture of small x QCD. The process can be calculated in the "hybrid formalism", where a collinear large-x quark or gluon scatters off the dense color field of the target. Recent calculations at next-to-leading order in perturbation theory have not led to a stable physical result for the single inclusive cross section at high transverse momenta. The problem with these NLO calculations lies in the subtraction procedure for the soft "rapidity" divergence which must be absorbed into BK renormalization group evolution of the target. This talk discusses recent work to understand and resolve the problems with the subtraction procedure. In particular, we have recently implemented numerically the quark channel production cross section using a new rapidity factorization procedure proposed by Iancu et al. For a fixed coupling one does indeed obtain a physically meaningful cross section which is positive and reduces in a controlled way to previous leading order calculations. However, it is not yet clear how to generalize this to running coupling in a way that is fully consistent with previous leading order calculations in coordinate space.

204. HET Lunch Discussions

Presented by Bill Marciano, BNL

Friday, April 21, 2017, 12:15 pm
Building 510, Room 2-160

Hosted by: Christoph Lehner

205. Particle Physics Seminar

"Searching for Our Milky Way's Dark Companions"

Presented by Alex Drlica- Wagner, Fermilab

Thursday, April 20, 2017, 3 pm
Small Seminar Room, Bldg. 510

Hosted by: Erin Sheldon

Our Milky Way galaxy is surrounded by a multitude of dwarf satellite galaxies. They are some of the oldest, least luminous, most metal poor, and most dark-matter-dominated objects known. These extreme objects provide a unique opportunity for testing the standard models of cosmology and galaxy formation. In addition, the relative proximity and large dark matter content of dwarf galaxies make them excellent systems for probing the fundamental properties of dark matter. Over the past two years, the unprecedented sensitivity of the Dark Energy Camera has allowed us to nearly double the known population of Milky Way satellites. These discoveries help address the "missing satellites problem" and can be used to test the particle nature of dark matter. However, they also raise new questions concerning the role of the Magellanic Clouds in the formation of the Milky Way's satellite population. I will summarize recent results, outstanding questions, and upcoming advances in the study of the Milky Way's dark companions.

206. Condensed-Matter Physics & Materials Science Seminar

"Unpaired Spins in Superconductors: From Assassin to Enabler"

Presented by Jeffrey Lynn, NIST Center for Neutron Research, National Institute of Standards and Technology

Thursday, April 20, 2017, 1:30 pm
Bldg. 734, ISB Conference Room 201 (upstairs)

Hosted by: Igor Zaliznyak

The magnetic properties of superconductors have a rich and interesting history, and we will briefly review some highlights. Early work showed that even tiny concentrations of magnetic impurities destroyed the superconducting pairing through the exchange-driven spin depairing mechanism, prohibiting any possibility of magnetic order coexisting with superconductivity. The first exceptions to this rule were provided by the cubic rare-earth substituted CeRu2 alloys, followed by the ternary Chevrel-phase superconductors (e.g. HoMo6S8) and related compounds, where long range magnetic order coexists or competes with superconductivity. The very low magnetic ordering temperatures (~1 K) suggested that dipolar rather than exchange interactions dominate, thus (it was thought) allowing the coexistence. These materials also provided the first examples of the competition between ferromagnetism and superconductivity. In the newer borocarbide class of magnetic superconductors (e.g. ErNi2B2C), however, it became clear that the magnetic order is in fact exchange driven. The borocarbides also provided the first example of the spontaneous formation of flux quanta (vortices). For the cuprate and iron-based superconductors (formerly known as "high Tc") we now have come full circle, as the spins are not only tolerated but are intimately tied to the superconductivity. The "parent" cuprate systems are Mott-Hubbard antiferromagnetic insulators with very strong magnetic interactions that are two-dimensional in nature. These strong exchange interactions survive into the superconducting state, yielding highly correlated electrons that participate directly in the superconducting pairing. The "parent" materials of the new iron-based high TC superconductors are also antiferromagnets with very energetic spin excitations, and in the superconducting regime they form a "magnetic resonance" that is directly tied to the superconducting order parameter, ju

207. Particle Physics SB/BNL Joint Cosmo seminar

"TBD"

Presented by Kyle Story, Stanford

Wednesday, April 19, 2017, 3 pm
Stony Brook University

208. Condensed-Matter Physics & Materials Science Seminar

"Listening to the hydrodynamic noise of Dirac fluid in graphene"

Presented by Kin Chung Fong, Raytheon BBN Technologies and Harvard University

Tuesday, April 18, 2017, 1:30 pm
Bldg. 734, ISB Conference Room 201 (upstairs)

Hosted by: Qiang Li

Interactions between the Dirac fermions in graphene can lead to new collective behavior described by hydrodynamics. By listening to the Johnson noise of the electrons, we are able to probe simultaneously the thermal and electrical transport of the Dirac fluid and observe how it departs from Fermi liquid physics. At high temperature near the neutrality point, we find a strong enhancement of the thermal conductivity and breakdown of Wiedemann-Franz law in graphene. This is attributed to the non-degenerate electrons and holes forming a strongly coupled Dirac fluid. At lower temperatures beyond the hydrodynamic behavior, the Dirac fermions are in extreme thermal isolation with minute specific heat that can be exploited for ultra-sensitive photon detection. We will present our latest experimental result towards observing single microwave photons and explore its role in scaling up the superconducting qubit systems. Our model suggests the graphene-based Josephson junction single photon detector can have a high-speed, negligible dark count, and high intrinsic quantum efficiency for applications in quantum information science and technologies. Ref: Science 351, 1058 (2016)

209. Nuclear Physics Seminar

"Search for the Chiral Magnetic Effect at RHIC : challenges and opportunities"

Presented by Prithwish Tribedy, BNL

Tuesday, April 18, 2017, 11 am
Small Seminar Room, Bldg. 510

Hosted by: Jia Jiangyong

In this talk I will discuss about the ongoing and future efforts at RHIC towards the search for the Chiral Magnetic Effect (CME). I will focus on the recent STAR measurements of the charge separation across the reaction plane, a predicted signal of the Chiral Magnetic Effect. Although charge separation has been observed, it has been argued that the measured separation in A+A collisions can be explained by elliptic flow related backgrounds. I will discuss on the challenges in disentangling such background contributions from the signals of CME. I will also discuss on implications of the recent measurements of charge separation in p+A collisions towards the search for CME.

210. Nuclear Theory/RIKEN Seminar

"Effect of magnetic field on flow fluctuations in"

Presented by Ajit M. Srivvastava

Friday, April 14, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Heikki Mantysaari

Very strong magnetic fields can arise in non-central heavy-ion collisions at ultrarelativistic energies, which may not decay quickly in a conducting plasma. We carry out magnetohydrodynamics simulations to study the effects of this magnetic field on the evolution of the plasma and on resulting flow fluctuations. Our results show that magnetic field leads to enhancement in elliptic flow, while flow fluctuations lead to reorganization of magnetic flux resulting in a transient increase in the local magnetic field. We also show generation of vorticity arising from nontrivial dependence of magnetosonic waves on pressure gradients and magnetic field direction. Magnetic field from collision of deformed nuclei shows very nontrivial features and can lead to qualitatively new effects on plasma evolutions. We discuss possibility of dynamo effect in the presence of vortices if any exotic high baryon density QCD phases are achieved in heavy-ion collisions.

211. HET Lunch Discussions

"Electroweak Wilson Coefficients from Lattice QCD"

Presented by Mattia Bruno, BNL

Friday, April 14, 2017, 12:15 pm
Building 510, Room 2-160

Hosted by: Christoph Lehner

212. Particle Physics Seminar

"Natural Seesaw in Warped/Composite Higgs framework and its LHC Signals"

Presented by Kaustubh Agashe, University of Maryland

Thursday, April 13, 2017, 3 pm
Small Seminar Room, Bldg. 510

Hosted by: Christoph Lehner

I will show how a natural seesaw model for SM neutrino mass arises within the general framework of a warped extra dimension (dual to composite Higgs in 4D). It starts out as an attempt at implementing the high-scale seesaw mechanism. I will first carefully determine what the underlying dynamical picture really is. Motivated by this physical understanding, LHC signals of TeV-mass SM singlet neutrinos within a specific model for the electroweak gauge sector will be discussed. Some of these channels are similar to those studied in 4D left-right (LR) symmetric models, but nonetheless the two can be distinguished. While other signals are more characteristic of the 5D/composite framework, i.e., are absent in 4D LR models.

213. Condensed-Matter Physics & Materials Science Seminar

"Electronic Squeezing of Pumped Phonons: Negative $U$ and Transient Superconductivity"

Presented by Dante Kennes, Columbia University

Thursday, April 13, 2017, 1:30 pm
Bldg. 734, ISB Conference Room 201 (upstairs)

Hosted by: Neil Robinson

Advances in light sources and time resolved spectroscopy have made it possible to excite specific atomic vibrations in solids and to observe the resulting changes in electronic properties but the mechanism by which phonon excitation causes qualitative changes in electronic properties has remained unclear. Here we show that the dominant symmetry-allowed coupling between electron density and dipole active modes implies an electron density-dependent squeezing of the phonon state which provides an attractive contribution to the electron-electron interaction, independent of the sign of the bare electron-phonon coupling and with a magnitude proportional to the degree of laser-induced phonon excitation. Reasonable excitation amplitudes lead to non-negligible attractive interactions that may cause significant transient changes in electronic properties including superconductivity. The mechanism is generically applicable to a wide range of systems, offering a promising route to manipulating and controlling electronic phase behavior in novel materials.

214. Nuclear Physics Seminar

"Systematic study of hadron production in highly asymmetric collisions at PHENIX"

Presented by Norbert Novitzky, Stony Brook University

Tuesday, April 11, 2017, 11 am
Small Seminar Room, Bldg. 510

Hosted by: Jin Huang

The observation of long range correlations in highly asymmetric systems as in p+Pb and d+Au collisions suggests the creation of a medium with collective behavior. Single particle production has proven to be a valuable tool to probe the quark-gluon plasma formed in heavy ion collisions as it is sensitive to energy loss, modifications of the nuclear wavefunction. It is an open question whether the apparent medium in small-on-large collisions and the QGP in large-on-large collisions is indeed the same, as is the role of the dynamics of the projectile (nucleon) wavefunction. In order to address these questions with a systematic study of highly asymmetric collisions, the RHIC collider provided beams for p+Al, p+Au, d+Au and 3He+Au collisions. The hadron production as a function of transverse momentum (pT) and rapidity can provide us very useful information about the evolution of the initial state and medium formation with system size. We will present the neutral pion and charged hadron measurements at forward, mid- and backward rapidities and discuss the implications of the results.

215. Nuclear Theory/RIKEN Seminar

"Anisotropic dissipative fluid dynamics - foundations & applications in heavy-ion physics"

Presented by Professor Dirk Rischke, Johann Wolfgang Goethe-Universität

Friday, April 7, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Heikki Mantysaari

In collisions of heavy ions at ultrarelativistic energies, a system of hot and dense strongly interacting matter is created. This matter exhibits a surprisingly strong degree of collectivity, implying a short mean free path of its constituents and, consequently, a small shear viscosity-to-entropy density ratio. This allows to describe the evolution of the system using relativistic dissipative fluid dynamics. Dissipative fluid dynamics can be understood as an expansion around local thermodynamical equilibrium, corresponding to the ideal-fluid limit where dissipative corrections are absent. A short mean free path means that this expansion is well defined and converges sufficiently rapidly. Nevertheless, in the initial stage of a heavy-ion collision, space-time gradients of the fluid-dynamical fields (energy-momentum and net-charge densities) are so large that dissipative corrections to the ideal-fluid limit can become sizable. In this situation, novel approaches to relativistic dissipative fluid dynamics are called for. One such approach is anisotropic dissipative fluid dynamics, which is based on an expansion around an anisotropic non-equilibrium state (instead of local thermodynamical equilibrium, as in conventional dissipative fluid dynamics). In this talk, I present a derivation of the equations of motion of anisotropic dissipative fluid dynamics from the Boltzmann equation, using the method of moments. I also discuss how to resolve an ambiguity to close the system of equations of motion in the case when there are no corrections to the anisotropic state which constitutes the basis of the moment expansion.

216. HET Lunch Discussions

"Fuzzy Dark Matter from Infrared Confinement"

Presented by Hooman Davoudiasl, BNL

Friday, April 7, 2017, 12:15 pm
Building 510, Room 2-160

Hosted by: Christoph Lehner

217. Instrumentation Division Seminar

"Next Generation Readout Electronics: Highly Integrated, High Performance and Low Cost Data Acquisition for Future Instrumentation Needs"

Presented by Isar Mostafanezhad, Nalu Scientific, LLC

Thursday, April 6, 2017, 2:30 pm
Large Conference Room, Bldg. 535

In this presentation, we discuss recent progress in high channel count data acquisition systems for large experiments. In recent years Nalu Scientific has established a new model for integration of readout electronics with detectors for HEP/NP applications. The most recent work has been involvement in the commissioning of the Belle II Time of Propagation Klong and Muon subdetectors at KEK in Japan. These innovations resulted in modern, modular, compact and high performance readout systems. Nalu Scientific, under multiple SBIR awards, has been working to commercialize these technologies to become available as off-the-shelf products for future experiments. We will cover: 1. Summary of Belle II TOP PID and KLM subdetectors 2. High performance, highly integrated, low cost readout 3. Current efforts in high resolution/ high performance timing 4. Specialized compact readout electronics for SiPMs

218. A Special HET/RIKEN Lunch Seminar

"The Road to Nuclear Physics from Standard Model"

Presented by Zohreh Davoudi, MIT

Thursday, April 6, 2017, 12:30 pm
Building 510, Room 2-160

Hosted by: Hiromichi Nishimura

At the core of nuclear physics is to understand complex phenomena occurring in the hottest and densest known environments in nature, and to unravel the mystery of the dark sector and other new physics possibilities. Nuclear physicists are expected to predict, with certainty, the reaction rates relevant to star evolutions and nuclear energy research, and to obtain the "standard" effects in nuclei to reveal information about the "non-standard" sector. To achieve such certainty, the field has gradually started to eliminate its reliance on the phenomenological models and has entered an era where the underlying interactions are "effectively" based on the Standard Model of particle physics, in particular Quantum Chromodynamics (QCD). The few-nucleon systems can now emerge directly from the constituent quark and gluon degrees of freedom and with only QCD interactions in play, using the numerical method of lattice QCD. Few-body observable, such as few-nucleon interactions and scattering amplitudes, as well transition amplitudes and reaction rates, have been the focus of this vastly growing field, as once obtained from QCD, and matched to effective field theories, can advance and improve the nuclear many-body calculations of exceedingly complex systems. This talk is a brief introduction to this program and its goals, with a great focus on the progress in few-body observables from QCD.

219. HET Seminar

"Hints of New Physics in Semi-leptonic B-meson Decays"

Presented by Diptimoy Ghosh, Weizman

Wednesday, April 5, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Amarjit Soni

In recent years, a number of interesting signals of potential new physics in semi-leptonic B-meson decays have been reported both by the B-factories as well as the LHCb. In this talk, I will discuss these observations with a particular emphasis on the observable $R_{D^*}$, the ratio of the branching fraction of $\bar{B} \to D^* \tau \bar{\nu}_\tau$ to that of $\bar{B} \to D^* \ell \bar{\nu}_\ell (\ell = \mu, e )$, which shows a 3.3 sigma deviation from the Standard Model prediction. I will present an effective field theory analysis of these potential new physics signals and discuss possible ways to distinguish the various operators.

220. Nuclear Physics Seminar

"New insights to the search for the anomalous chiral effects using small colliding system at the LHC"

Presented by Zhoudunming Tu, Rice University

Tuesday, April 4, 2017, 11 am
Small Seminar Room, Bldg. 510

Hosted by: Jiangyong Jia

In relativistic heavy ion collisions, anomalous chiral effects have been predicted to occur in presence of a strong magnetic field induced by the spectator protons, e.g., the chiral magnetic effect (CME) and chiral magnetic wave (CMW). In the past decade, measurements of CME and CMW have been attempted from RHIC to the LHC energies, where significant signals were found to be in line with expectations of the chiral effects. However, soon after the initial excitement, various sources of background effects were identified and proposed to qualitatively describe the data. The origin of the backgrounds has been extensively studied, but still remains inconclusive to date. Recently, novel collective phenomenon has been found in high-multiplicity pA collisions, similar to those in AA collisions. Due to the weak correlation between the magnetic field direction and the event plane, the high-multiplicity pPb data are expected to have much suppressed CME and CMW signal, comparing to that in PbPb collisions, and thus provide an ideal testing ground to observables related to the anomalous chiral effects. In this talk, I will present new measurements related to the CME and CMW from CMS in pPb and PbPb collisions at the LHC, and discuss their implications to the search for the anomalous chiral effects including an outlook for future studies.

221. Instrumentation Division Seminar

"Ultrafast imaging technology: from visible light to high-energy X-ray photons"

Presented by Zhehui Wang, LANL

Friday, March 31, 2017, 2:30 pm
Large Conference Room, Bldg. 535

We are now in the era of ultrafast imaging, which is the ability to observe transient events with a time duration no longer than 100 ps (one billionth of the time for eye blinking). Innovative methods have demonstrated photography at the mind-bending speed of one trillion frames per second. Several recent advances make ultrafast imaging possible: ultrashort lasers and X-rays for illumination, abilities to harvest ultrafast responses in materials for efficient photon and electron detection, innovative ways to store and process data. It will be shown that ultrafast imaging technology is a natural fit to mesoscopic science. Meanwhile, ultrafast imaging technology also permits photography of macroscopic objects around the corner or hidden away from the direct line of sight. One recent LANL interest in ultrafast high-energy X-ray imaging is driven by MaRIE. Some material challenges will be highlighted towards a GHz frame-rate burst mode camera for photons at above 30 keV energies.

222. HET Lunch Discussions

"A local factorization of the fermion determinant in lattice gauge theories"

Presented by Leonardo Giusti, CERN

Friday, March 31, 2017, 12:15 pm
Building 510, Room 2-160

Hosted by: Christoph Lehner

223. Particle Physics Seminar

"neutrinoless double beta decay and nuclear structure theory"

Presented by Professor Petr Vogel, Caltech

Friday, March 31, 2017, 11 am
Small Seminar Room, Bldg. 510

Hosted by: Xin Qian

Search for the neutrinoless double beta decay is one of the main goals of nuclear physics community worldwide. If observed, it would be an example of "physics beyond the Standard Model", showing that the lepton number is not a conserved quantity and that neutrinos are massive Majorana fermions. After introducing the subject and its particle physics consequences I will concentrate on the issue of evaluation of the nuclear matrix elements. Despite decades of effort and hundreds of publications, different approaches give results that differ by roughly a factor of three, and it is difficult to decide which of them is the most realistic. I will describe the strengths and weaknesses of the nuclear models used. In addition, I will discuss the problem of "quenching", i.e. of reduction of the matrix elements of weak axial current in complex nuclei, that potentially affects the neutrinoless double beta decay matrix element values signiffcantly

224. Particle Physics Seminar

"Evaluation of reactor neutrino flux: issues and uncertainties"

Presented by Professor Petr Vogel, Caltech

Thursday, March 30, 2017, 3 pm
Small Seminar Room, Bldg. 510

Hosted by: Xin Qian

Evaluation of the reactor antineutrino flux and spectrum is an essential ingredient of their application in the neutrino oscillation studies. Two anomalies, i.e. discrepancies between the observed and expected count rates, are widely discussed at the present time. The total rate is about 6% lower than the expectation at all distances > 10 m from the reactor. And there is a shoulder (often referred to as "bump") at neutrino energies 5-7 MeV, not predicted in the calculated spectrum. I review the ways the flux and spectrum is evaluated. I argue that far reaching conclusions based on these anomalies should await a thorough understanding of the uncertainties of the spectrum, and point out possible standard physics sources of the anomalies.

225. Condensed-Matter Physics & Materials Science Seminar

"Explore Mesoscopic Physics in Strongly Correlated Electron Materials with IR near-field microscopy and spectroscopy"

Presented by Mengkun Liu, Stony Brook University

Thursday, March 30, 2017, 1:30 pm
ISB Bldg. 734, Conf. Rm. 201 (upstairs)

Hosted by: Cedomir Petrovic

In strongly correlated electron materials, the delicate interplay between spin, charge, and lattice degrees of freedom often leads to extremely rich phase diagrams exhibiting intrinsic phase inhomogeneities. The key to understanding such complexities usually lies in the characterization and control of these materials at fundamental energy, time and length scales. I will use this opportunity to report the recent advances in the IR and THz near-field microscopy and spectroscopy, and explain how they can be used to probe electronic/structural phase transitions with unprecedented spatial and temporal resolutions. Specifically, with scanning near-field infrared microscopy we resolved the insulator to metal phase transitions in 3d (VO2), 4d (Ca2RuO4) and 4f (SmS) materials with ~10 nm resolution over a broad spectral range. The results set the stage for future spectroscopic investigations to access the fundamental properties of complex materials.

226. RIKEN Lunch Seminar

"The hadronic light-by-light contribution to muon g-2 from lattice QCD"

Presented by Luchang Jin, BNL

Thursday, March 30, 2017, 12:30 pm
Building 510, Room 2-160

Hosted by: Enrico Rinaldi

The current measurement of muonic g-2 disagrees with the theoretical calculation by about 3 standard deviations. Hadronic vacuum polarization (HVP) and hadronic light by light (HLbL) are the two types of processes that contribute most to the theoretical uncertainty. The current value for HLbL is still given by models. We report our latest lattice calculation of hadronic light-by-light contribution to muon g-2 using our recent developed moment method. The connected diagrams and the leading disconnected diagrams are included. The calculation is performed on a 48^3 × 96 lattice with physical pion mass and 5.5 fm box size. We expect sizable finite volume and finite lattice spacing corrections to the results of these calculations which will be estimated in calculations to be carried out over the next 1-2 years.

227. Particle Physics Seminar

"Is there evidence for cosmic acceleration?"

Presented by Subir Sarkar, Oxford University

Thursday, March 30, 2017, 11 am
Small Seminar Room, Bldg. 510

Hosted by: Xin Qian

The 'standard' model of cosmology is founded on the basis that the expansion rate of the universe is accelerating at present – as was inferred from the Hubble disgram of Type la supernovae. There exists now a much bigger database of supernovae so we can perform rigorous statistical tests to check whether these 'standardisable candles' indeed indicate cosmic acceleration. Taking account of the empirical procedure by which corrections are made to their absolute magnitudes to allow for the varying shape of the light curve and extinction by dust, we find that the data are still consistent with a constant rate of expansion. The implications of this will be discussed.

228. Physics Colloquium

"Physics in the complex domain"

Presented by Carl Bender, Washington University

Tuesday, March 28, 2017, 3:30 pm
Large Seminar Room, Bldg. 510

Hosted by: Robert Pisarski

The theory of complex variables is extremely useful because it helps to explain the mathematical behavior of functions of a real variable. Complex variable theory also provides insight into the nature of physical theories. For example, it provides a simple and beautiful picture of quantization and it explains the underlying reason for the divergence of perturbation theory. By using complex-variable methods one can generalize conventional Hermitian quantum theories into the complex domain. The result is a new class of parity-time-symmetric (PT-symmetric) theories whose remarkable physical properties have been studied and verified in many recent laboratory experiments.

229. Condensed-Matter Physics & Materials Science Seminar

"Thermalization and light cones in a model with weak integrability breaking"

Presented by Stefan Groha, University of Oxford, United Kingdom

Tuesday, March 28, 2017, 11 am
Bldg. 734, ISB Conference Room 201 (upstairs)

Hosted by: Neil Robinson

We employ equation of motion techniques to study the non-equilibrium dynamics in a lattice model of weakly interacting spinless fermions. Our model provides a simple setting for analyzing the effects of weak integrability breaking perturbations on the time evolution after a quantum quench. We establish the accuracy of the method by comparing results at short and intermediate times to time-dependent density matrix renormalization group computations. For sufficiently weak integrability-breaking interactions we always observe prethermalization plateaux, where local observables relax to non-thermal values at intermediate time scales. At later times a crossover towards thermal behaviour sets in. We determine the associated time scale, which depends on the initial state, the band structure of the non-interacting theory, and the strength of the integrability breaking perturbation. Our method allows us to analyze in some detail the spreading of correlations and in particular the structure of the associated light cones in our model. We find that the interior and exterior of the light cone are separated by an intermediate region, the temporal width of which appears to scale with a universal power-law t 1/3.

230. Nuclear Physics Seminar

"Beam energy and system dependence of anisotropic flow measurements from STAR"

Presented by Niseem Magdy, Stony Brook University

Tuesday, March 28, 2017, 11 am
Small Seminar Room, Bldg. 510

Hosted by: Jin Huang

Recent STAR measurements of azimuthal anisotropy have focused on the use of two- and multi-particle correlations as probes for model constraints for the temperature dependence of the specific shear viscosity $\eta/s$ and the initial-state structure of the collision zone. We will discuss and summarize recent two- and multi-particle correlations measurements of $v_n$ $(n > 1)$ , dipolar flow $v^{even}_1$, and $\langle cos(n \varphi_{1} + m \varphi_{2} - (n+m) \varphi_{3}) \rangle$, as a function of centrality, transverse momentum ($p_T$), and pseudorapidity ($\eta$) for $Au+Au$ at ($\sqrt{s_{NN}} = 7 - 200$~GeV;{em BES-I}), $U+U$ at ($\sqrt{s_{NN}} = 193$ GeV) and $Cu+Au$ , $Cu+Cu$ ,$d+Au$ ,$p+Au$ at ($\sqrt{s_{NN}} = 200$ GeV).

231. Condensed-Matter Physics & Materials Science Seminar

"Resonant Inelastic X-ray Scattering and X-ray Emission Spectroscopy of Iron Pnictide Superconductors"

Presented by Jonathan Pelliciari, Paul Scherrer Institute, Switzerland

Monday, March 27, 2017, 10 am
ISB Bldg. 734, Conf. Rm. 201 (upstairs)

Hosted by: Mark Dean

I will describe Resonant Inelastic X-Ray Scattering (RIXS) experiments performed at the Swiss Light Source focusing on the detection of high-energy spin fluctuations on iron pnictides. I will show that RIXS has been successfully used to extract the spin excitation spectrum on NaFeAs, BaFe2As2, EuFe2As2 and SmFeAsO, parent compounds [1-3]. We investigated electron-doped NaFe1-xCoxAs observing the persistence of broad dispersive magnetic excitations in optimal and overdoped samples [1]. The energy of such modes is unaffected by doping and the magnetic weight per iron atom of magnons / paramagnons remains constant, demonstrating the impurity role of Co doping. The persistence of magnetic spectral weight is also caught by theoretical calculations. In the second part of the talk, I will present a combined Fe-L3 RIXS and Fe-Kβ X-rays emission spectroscopy (XES) study of isovalently doped BaFe2(As1-xPx)2 spanning a large portion of the phase diagram. RIXS measurements find the persistence of broad dispersive magnetic excitations for all doping levels. Remarkably, the energy of such modes is strongly hardened by doping differently from the cases of electron- and hole-doped BaFe2As2 [5]. On the other hand, XES experiments show a gradual quenching of the local magnetic moment, which is intriguing if compared to the behavior of spin correlations. We link the unconventional evolution of magnetism to the shift from 2- to 3-dimensional electronic structure of the system, hand in hand with the warping of the Fermi surface. Combined together these findings help to shed light on the real degree of electronic correlations in Fe pnictides. References [1] J. Pelliciari et al., Phys. Rev. B, 93, 134515 (2016); [2] J. Pelliciari et al., Appl. Phys. Lett. 109, 122601 (2016); [3] J. Pelliciari et al., "Local and collective magnetism of EuFe2As2" accepted in Phys. Rev. B (2017); [4] K. J. Zhou et al, Nat. Comm., 4, 1470 (2013)

232. Nuclear Theory/RIKEN Seminar

"A solitonic approach to neutron stars: The (BPS) Skyrme model"

Presented by Carlos Naya, Durham

Friday, March 24, 2017, 2 pm
Small Seminar Room, Bldg. 510

Hosted by: Heikki Mantysaari

The Skyrme model is a low energy effective field theory of strong interactions where nuclei and baryons appear as collective excitations of pionic degrees of freedom. Proposed by Tony Skyrme in the sixties, his ideas received further support when it was discovered that in the limit of the large number of colours of QCD, an effective theory of mesons arises. In the last years, there has been a revival of Skyrme's ideas and new related models, some of them with BPS bounds (topological lower energy bounds), have been proposed. It is the aim of this talk to focus on the one known as BPS Skyrme model. After a brief introduction to this BPS limit we study its application to neutron stars where we will find that high maximal masses are supported. In addition, the BPS Skyrme model allow us to perform both mean-field and exact calculations and a comparison between both approaches will be presented.

233. Condensed-Matter Physics & Materials Science Seminar

"Shining a light on high-Tc superconductivity"

Presented by Peter Johnson, BNL

Friday, March 24, 2017, 1:30 pm
Bldg. 734, ISB Conference Room 201 (upstairs)

Hosted by: Igor Zaliznyak

TBD

234. HET Lunch Discussions

"Baryogenesis and Dark Matter in the exo-Higgs scenario"

Presented by Pier Paolo Giardino, BNL

Friday, March 24, 2017, 12:15 pm
Building 510, Room 2-160

Hosted by: Christoph Lehner

235. Particle Physics Seminar

"Neutrino Interactions with Nuclei and Long-Baseline Experiments"

Presented by Professor Ulrich Mosel, Giessen University

Friday, March 24, 2017, 10 am
Small Seminar Room, Bldg. 510

Hosted by: Xin Qian

The extraction of neutrino mixing parameters and the CP-violating phase requires knowledge of the neutrino energy. This energy must be reconstructed from the final state of a neutrino-nucleus reaction since all long-baseline experiments use nuclear targets. This reconstruction requires detailed knowledge of the neutrino reactions with bound nucleons and of the final state interactions of hadrons with the nuclear environment. Quantum-kinetic transport theory can be used to build an event generator for this reconstruction that takes basic nuclear properties, such as binding, into account. Some examples are discussed that show the effects of nuclear interactions on observables in long-baseline experiments.

236. Condensed-Matter Physics & Materials Science Seminar

"Nematic quantum paramagnet and possible application to FeSe"

Presented by Fa Wang, International Center for Quantum Materials Peking University, China

Thursday, March 23, 2017, 11 am
Bldg. 734, ISB Conference Room 201 (upstairs)

Hosted by: Weiguo Yin

The nematic phases in iron pnictides are in close proximity to the stripe antiferromagnetic order, suggesting that magnetism is the driving force for the spontaneous 4-fold crystal rotation symmetry breaking. In contrast, bulk FeSe shows a nematic phase below 90K at ambient pressure, but has no magnetic long range order down to very low temperature. This prompts suggestions that the nematicity in FeSe is driven by some other mechanism. We argue that magnetic correlation can still drive nematic order in the absence of magnetic long-range order. By field theoretical considerations and exact diagonalization results on finite size lattices, we conclude that the paramagnetic phase in frustrated spin-1 J_1-J_2 model on square lattice is likely a "nematic quantum paramagnet", which breaks only the crystal 4-fold rotation symmetry. The prototype wavefunctions of such quantum ground states are horizontal(vertical) aligned spin-1 AKLT chains. We suggest that the local spins in FeSe may form this phase due to strong frustration. One unique consequence of this proposal is that the nematic paramagnetic phase will be close to both stripe and Neel antiferromagnetic order, and will thus host low but finite energy spin fluctuations at both ordering wavevectors. Reference: Fa Wang, S. A. Kivelson, and Dung-Hai Lee, Nat. Phys. 11, 959 (2015)

237. Particle Physics Seminar

"Heavy bosons: a probe into the unknown"

Presented by Viviana Cavaliere, University of Illinois Champaign/Urbana

Wednesday, March 22, 2017, 11 am
Small Seminar Room, Bldg. 510

Hosted by: Michael Begel

The large amount of high-energy proton-proton collision data at the LHC provides an unprecedented opportunity to search for new physics beyond the Standard Model at the TeV scale. The 2012 discovery of a 125 GeV Higgs boson opened a new door to understanding the universe, providing an exciting new tool to use in these searches, given it is now produced about once per second at the current collision rate. The talk will review recent ATLAS searches for physics beyond the Standard Model, focusing on the central role of processes with heavy bosons, including the Higgs, and the corresponding new possible signatures that range from spectacular new resonances to subtle changes in kinematic distributions.

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