1. HET Lunch Discussion

   "Update on Double Higgs Production"

   Presented by Sally Dawson, BNL

   Friday, May 17, 2019, 12:15 pm
   Building 510, Room 2-160

   Hosted by: Peter Denton
2. NSLS-II Friday Lunchtime Seminar

   "MAXPD: Multi-Anvil X-ray Powder Diffraction — COMPRES Partner User Program for High Pressure Studies at 28-ID-2-D"

   Presented by Matthew L. Whitaker, Stony Brook University

   Friday, May 17, 2019, 12 pm
   NSLS-II Bldg. 743 Room 156

   Hosted by: Ignace Jarrige

   MAXPD is the downstream endstation of XPD, an insertion device beamline at Sector 28 (28-ID-2-D) of NSLS-II. The MAXPD endstation and General User Program are sponsored by the COnsortium for Materials Properties Research in Earth Sciences (COMPRES). MAXPD has an 1100-ton hydraulic press installed, which is equipped with a unique DT-25 pressure module that can be swapped out for a more standard D-DIA module as desired. MAXPD makes use of the world-class monochromatic beam available at XPD (usually ~67 keV), with which we collect both angular dispersive X-ray diffraction data and X-radiographic imaging. The first General User experiments took place in March 2018. Final Science Commissioning beamtime took place in August of last year, and the full General User program for MAXPD began in the 2018-3 cycle. In this seminar, I will give an overview of the science drivers behind the development of the endstation, some of its unique capabilities, some representative results from recent experiments conducted over the last two cycles at MAXPD, and where we are looking to go as we look to the future.
3. NT/RIKEN Seminar

   "The non-equilibrium attractor: Beyond hydrodynamics"

   Presented by Michael Strickland, Kent State University

   Friday, May 10, 2019, 2 pm
   Building 510, CFNS Seminar Room 2-38

   Hosted by: Niklas Mueller
4. HET Seminar - CANCELLED

   Presented by Nirmal Raj, Triumf

   Friday, May 10, 2019, 12:15 pm
   Building 510, Room 2-160

   Hosted by: Gopolang Mohlabeng
5. RIKEN Lunch Seminar

   "Electric dipole moments in the era of the LHC"

   Presented by Jordy de Vries, University of Massachusetts Amherst, Riken BNL

   Thursday, May 9, 2019, 12 pm
   Building 510, Room 2-160

   Hosted by: Yuta Kikuchi

   The search for an understanding of fundamental particle physics that goes beyond the Standard Model (SM) has grown into a worldwide titanic effort. Low-energy precision experiments are complementary to collider searches and, in certain cases, can even probe higher energy scales directly. However, the interpretation of a potential signal, or lack thereof, is complicated because of the non-perturbative nature of low-energy QCD. I will use the search for electric dipole moments (EDMs), which aims to discover beyond-the-SM CP violation, as an example to illustrate these difficulties and how they can be overcome by combining (chiral) effective field theory and lattice QCD. I discuss how EDM experiments involving complex systems like nucleons, nuclei, atoms, and molecules constrain possible CP-violating interactions involving the Higgs boson, how these constraints match up to direct LHC searches, and the relevance of and strategies for the improvement of the hadronic and nuclear theory.
6. Environmental & Climate Sciences Department Seminar

   "High-throughput field phenotyping of photosynthetic capacity using hyperspectral imaging"

   Presented by Katherine Meacham, Univ. of Illinois

   Thursday, May 9, 2019, 11 am
   Large Conference Room, Bldg. 490

   Hosted by: Angie Burnett

   Improved photosynthetic rates have been shown to increase crop biomass, making improved photosynthesis a focus for driving future grain yield increases. Improving the photosynthetic pathway offers opportunity to meet food demand, but requires high throughput measurement techniques to detect photosynthetic variation in natural accessions and transgenically improved plants. Gas exchange measurements are the most widely used method of measuring photosynthesis in field trials but this process is laborious and slow, and requires further modeling to estimate meaningful parameters and to upscale to the plot or canopy level. In field trials of tobacco with modifications made to the photosynthetic pathway, we infer key photosynthetic parameters from imaging spectroscopy using a partial least squares regression technique. We used two hyperspectral cameras with resolution 2.1nm in the visible range and 4.9nm in the NIR. Ground-truth measurements from leaf-level photosynthetic gas exchange, full-range (400-2500nm) hyperspectral reflectance and extracted pigments support the model. The results from a range of wild-type cultivars and from genetically modified germplasm offer a high-throughput screening tool for crop trials aimed at identifying increased photosynthetic capacity.
7. Physics Colloquium

   "Mu*STAR Accelerator-Driven Subcritical Molten-Salt All-Purpose non-Nuclear Reactor"

   Presented by Rolland Johnson, Muons Inc.

   Tuesday, May 7, 2019, 3:30 pm
   Large Seminar Room, Bldg. 510

   Hosted by: George Redlinger

   The Mu*STAR BHAG[1] is: To make superconducting RF accelerators so powerful and efficient that they make enough neutrons to produce nuclear energy for electricity or for process heat at less cost than from wind, solar, or natural gas, without weapons proliferation legacies of enrichment and chemical reprocessing, by burning unwanted nuclear materials. The arguments are presented to support that such a goal is possible in the near future. [1] BHAG: Big Hairy Audacious Goal, from "Built to Last: Successful Habits of Visionary Companies" by Jim Collins and Jerry Porras (2004)
8. NT/RIKEN Seminar

   "Relativistic Hydrodynamic Fluctuations"

   Presented by Gokce Basar, UiC

   Friday, May 3, 2019, 2 pm
   Small Seminar Room, Bldg. 510

   Hosted by: Niklas Mueller

   We present a general systematic formalism for describing dynamics of fluctuations in an arbitrary relativistic hydrodynamic flow, including their feedback (known as long-time hydrodynamic tails) in a deterministic way. The fluctuations are described by two-point equal-time correlation functions. We introduce a definition of equal time in a situation where the local rest frame is determined by the local flow velocity, and a method of taking derivatives and Wigner transforms of such equal-time correlation functions, which we call confluent. The Wigner functions satisfy evolution equations that describes the relaxation of the out-of-equilibrium modes. We find that the equations for confluent Wigner functions nontrivially match with the kinetic equation for phonons propagating on an arbitrary background, including relativistic inertial and Coriolis forces due to acceleration and vorticity of the flow. We also describe the procedure of renormalization of short-distance singularities which eliminates cutoff dependence, allowing efficient numerical implementation of these equations.
9. HET Lunch Discussion

   "Ultra-Light Boson Dark Matter and Event Horizon Telescope Observations of M87"

   Presented by Hooman Davoudiasl

   Friday, May 3, 2019, 12:15 pm
   Building 510, Room 2-160

   Hosted by: Aaron Meyer
10. Special Particle Physics Seminar

    "Observation of CP violation in charm decays"

    Presented by Angelo Di Canto, BNL

    Friday, May 3, 2019, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: Chao Zhang

    The existence of CP violation in the decays of strange and beauty mesons is well established experimentally by numerous measurements. By contrast, CP violation in the decays of charm particles has so far escaped observation. This seminar reports on the first observation of CP violation in charm decays thought the measurement of the difference between the time-integrated CP asymmetries in D0 -> K- K+ and D0 -> pi- pi+ decays. The measurement has been performed using the full data set of proton-proton collisions collected by LHCb in 2011-2018, which corresponds to an integrated luminosity of 9fb-1. In addition, a brief overview of recent measurements of mixing and mixing-induced CP violation in charm mesons at LHCb is also presented.
11. Particle Physics Seminar

    "Dark Matter Searches with the ATLAS Detector at the LHC"

    Presented by Arely Cortes Gonzalez, CERN

    Thursday, May 2, 2019, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Michael Begel

    The presence of a non-baryonic dark matter component in the Universe is inferred from the observation of its gravitational interaction. If dark matter interacts weakly with the Standard Model it would be produced at the LHC, escaping the detector and leaving a large missing transverse momentum as their signature. The ATLAS detector has developed a broad and systematic search program for dark matter production in LHC proton-proton collisions. The results of these searches on the 13 TeV data, their interpretation, and the possible evolution of the search program will be presented.
12. RIKEN Lunch Seminar

    "The Chiral Qubit: quantum computing with chiral anomaly"

    Presented by Dmitri Kharzeev, Stony Brook University and BNL

    Thursday, May 2, 2019, 12 pm
    Building 510, Room 2-160

    Hosted by: Yuta Kikuchi

    The quantum chiral anomaly enables a nearly dissipationless current in the presence of chirality imbalance and magnetic field – this is the Chiral Magnetic Effect (CME), observed recently in Dirac and Weyl semimetals. We propose to utilize the CME for the design of qubits potentially capable of operating at THz frequency, room temperature, and the coherence time to gate time ratio of about 10^4 . The proposed "Chiral Qubit" is a micron-scale ring made of a Weyl or Dirac semimetal, with the |0> and |1> quantum states corresponding to the symmetric and antisymmetric superpositions of quantum states describing chiral fermions circulating along the ring clockwise and counter-clockwise. A fractional magnetic flux through the ring induces a quantum superposition of the |0> and |1> quantum states. The entanglement of qubits can be implemented through the near-field THz frequency electromagnetic fields.
13. HET Seminar

    "Unification and Precision Measurements"

    Presented by James Wells, University of Michigan

    Wednesday, May 1, 2019, 2:30 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Sally Dawson
14. Nuclear Physics Seminar

    "Reviewing the AGS Heavy Ion Program and Looking Forward to the Fixed-Target Program at STAR"

    Presented by Prof. Daniel Cebra, UC Davis

    Tuesday, April 30, 2019, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: Rongrong Ma

    In the 1980's and 90's the AGS initiated a heavy-ion beam program with both silicon and gold beams. A suite of dedicated experiments established the systematics for production of light charged particles, strangeness, light nuclei, and anti-particles, as well as systematics for flow and femtoscopy. Those experiments established the design of the RHIC detectors and trained the personnel who would become leaders in the RHIC program. Recently, there has been renewed interest in the energy region covered by the AGS heavy-ion program. New facilities are being built Germany and Russia and proposed in Japan and China. And a conclusion of the first beam energy scan at RHIC was that it would be necessary to revisit the AGS energy range by installing a fixed-target within the STAR experiment. This talk will review key results from the AGS heavy-ion program, and those to results from the STAR fixed-target test runs, and outline the proposed physics program.
15. Particle Physics Seminar

    ""Measure what is measurable and make measurable what is not so - Uncover new physics with bosons at the LHC and upgrades of the CMS detector to maximize the discovery potential""

    Presented by Mia Liu, FNAL

    Monday, April 29, 2019, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: Alessandro Tricoli

    The Standard Model describes the building blocks of matter and their interactions. It has been tested extensively with experimental data and found to be incredibly successful in describing nature. Discovering the Higgs boson in 2012 at the LHC completed the picture of the SM. The LHC is at the forefront of directly searching for new physics which is Beyond-Standard-Model (BSM), and I will discuss searches for supersymmetric partners of the electroweak bosons, as well as measurement of an extremely rare process with three WWW bosons as stringent tests of the SM. I will also discuss the instrumentation which enables such studies. The discussion includes the recently completed CMS Phase-1 pixel upgrade, as well as the R&D studies towards solving the future trigger and computing challenges using innovative machine learning approaches in future high energy experiments.
16. Particle Physics Seminar

    "Searching for Higgs Pair Production at the LHC"

    Presented by Elizabeth Brost, Northern Illinois University

    Thursday, April 25, 2019, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Alessandro Tricoli

    Since the discovery of the Higgs boson in 2012, the particle physics community at the Large Hadron Collider (LHC) has been hard at work studying its properties, and comparing them to the predictions of the Standard Model (SM), including the couplings of the Higgs boson to itself and to other particles. The Higgs self-coupling can be measured directly in the Higgs pair production process, and will provide insight into the nature of electroweak symmetry breaking. In the SM, the di-Higgs cross section in proton-proton collisions is very small. However, a wide range of beyond-the-SM models predict enhancements to the di-Higgs production rate, which motivates searching for di-Higgs production even now, when the SM cross section is too small to measure in the current LHC dataset. Looking forward, the LHC Run 3 and HL-LHC will bring a new set of challenges, including more proton-proton collisions per bunch crossing. Extracting rare physics signatures from this busier environment will be difficult for the current ATLAS trigger system. In this talk, I will present current and future ATLAS searches for hh production using a variety of final states, and discuss the use of future track triggers in upgrades to the ATLAS trigger system.
17. RIKEN Lunch Seminar

    "Partons from the Path-Integral Formalism of the Hadronic Tensor"

    Presented by Keh-Fei Liu, University of Kentucky

    Thursday, April 25, 2019, 12 pm
    Building 510, Room 2-160

    Hosted by: Yuta Kikuchi
18. NT/RIKEN Seminar

    "Parton distributions in Euclidean space"

    Presented by Anatoly Radyushkin, ODU/JLab

    Friday, April 19, 2019, 2 pm
    Building 510, CFNS Room 2-38

    Hosted by: Niklas Mueller

    To extract parton distributions from the lattice simulations, one needs to consider matrix elements M(z,p) of bilocal correlators of parton fields [generically written as φ(0)φ(z)] at spacelike separations z=(0,0,0,z_3). A transition to PDFs may be proceeded by taking a Fourier transform either with respect to z_3 for fixed p_3 (which gives X. Ji's quasi-PDFs), or with respect to the Lorentz-invariant variable ν=-(zp) for fixed values of another Lorentz invariant z^2 [which results in pseudo-PDFs].These functions are interesting on their own, and I will discuss, in the continuum case, their general properties, the connection between the two types of functions, and their relation with the usual light-cone PDFs. I will outline the algorithm of extracting the PDFs through the use of the so-called "reduced Ioffe-time distributions",and illustrate this pseudo-PDF-oriented approach on the example of exploratory lattice simulations performed by Orginos et al.
19. Particle Physics Seminar

    "Dissecting the Higgs boson with ATLAS and leptons"

    Presented by Quentin Buat, CERN

    Thursday, April 18, 2019, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Alessandro Tricoli

    Using data taken during the first years of the LHC Run2, ATLAS has firmly established the coupling of the Higgs boson to the tau lepton, thus directly confirming the existence of leptonic Yukawa interactions. In this talk, I will present the cross-section measurements performed by ATLAS in the di-tau final state with a partial Run2 dataset and discuss the prospects of the analysis with the full Run2 dataset and beyond. I will also discuss the status of the search for the muonic Yukawa interaction.
20. Condensed-Matter Physics & Materials Science Seminar

    ""Superconductivity and magnetism at ferroelectric critical point""

    Presented by Alexander Balatsky, UConn Nordita

    Thursday, April 18, 2019, 1:30 pm
    ISB Bldg. 734 Conf. Rm. 201 (upstairs)

    Hosted by: Ilya Drozdov

    It is well established that multiple entangled orders emerge in quantum materials at criticality: eg superconducting states develop in the vicinity of magnetic phases. I will make the case that similar phenomena occur in quantum paraelectrics. Recent observations of strain and O18 isotope substitution in doped STO support the view of the key role critical ferroelectric fluctuations play in producing superconductivity. Looking beyond superconductivity, I will illustrate how quantum ferroelectric fluctuations can induce magnetic fluctuations due to recently proposed phenomenon of dynamic multiferroicity.
21. Environmental & Climate Sciences Department Seminar

    "Using High-Resolution Observations to Improve a Low-Resolution Global Climate Model"

    Presented by Greg Elsaesser, NASA GISS

    Thursday, April 18, 2019, 11 am
    Large Conference Room, Bldg. 490

    Hosted by: Mike Jensen

    This talk will begin with an overview of recent development in the representation of deep convection in the NASA Goddard Institute for Space Studies (GISS) General Circulation Model (GCM). Global satellite remote sensing products are important references for continual GCM development and evaluation, but such products often provide data at coarse temporal and/or spatial resolutions, thus making it difficult to conceptualize and evaluate "process representations" in a GCM. I will discuss the various approaches I am taking to average global satellite retrievals in new ways, coincident with efforts to use new DOE/ARM observations, to derive composite high-resolution evolutions of deep convection and the nearby environment. These depictions will not only inform future development, but they are also crucial for ensuring that recent improved mean-state representations are not the result of errors cancelling at the process level.
22. HET Seminar

    "Cores in Dwarf Galaxies from Fermi Repulsion"

    Presented by James Unwin, University of Illinois, Chicago

    Wednesday, April 17, 2019, 2:30 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Sally Dawson
23. Nuclear Physics Seminar

    "Recent Results from COMPASS"

    Presented by Ana-Sofia Nunes, BNL

    Tuesday, April 16, 2019, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: Oleg Eyser

    COMPASS is a fixed target experiment at the CERN SPS that has been collecting data since 2002 and was already approved to run in 2021. It uses unique beams of naturally polarized muons and unpolarized hadrons of 160, 190 or 200 GeV impinging on polarized and unpolarized proton, isoscalar or heavy targets to study fundamental aspects of QCD, as the structure of nucleons, hadron spectroscopy and the pion polarizability. The collected data allow measurements on the spin structure of nucleons, not only in the collinear approximation but also on nucleon tomography, either via deeply virtual Compton scattering (DVCS) and deeply virtual meson production (DVMP) which give access to generalized parton distributions (GPDs), or via semi-inclusive deep inelastic scattering (SIDIS) and polarized Drell-Yan (DY) which give access to transverse-momentum dependent parton distribution functions (TMDs). Moreover, hadron multiplicities extracted from semi-inclusive deep inelastic scattering data can be used as input for the computation of fragmentation functions (FFs) in QCD fits. A selection of the latest published and preliminary results of COMPASS in the scope of the study of the structure of nucleons and the hadronization of quarks will be presented.
24. Condensed Matter Physics and Materials Science - The Myron Strongin Seminar

    "Disappearance of Superconductivity Due to Vanishing Coupling in the Overdoped High-Temperature Cuprate Superconductors"

    Presented by Tonica Valla, BNL

    Monday, April 15, 2019, 1:30 pm
    ISB Bldg. 734, Conf. Rm. 201 (upstairs)

    Hosted by: Weiguo Yin and Jing Tao

    In high-temperature cuprate superconductors, superconductivity is accompanied by a "plethora of orders", and phenomena that may compete, or cooperate with superconductivity, but which certainly complicate our understanding of origins of superconductivity in these materials. While prominent in the underdoped regime, these orders are known to significantly weaken or completely vanish with overdoping. Here, we approach the superconducting phase from the more conventional highly overdoped side. We present angle-resolved photoemission spectroscopy (ARPES) studies of Bi2Sr2CaCu2O8+d (Bi2212) single crystals cleaved and annealed in ozone to increase the doping all the way to the metallic, non-superconducting phase. We show that the mass renormalization in the antinodal region of the Fermi surface, associated with the structure in the quasiparticle self-energy, that possibly reflects the pairing interaction, monotonically weakens with increasing doping and completely disappears precisely where superconductivity disappears. This is the direct evidence that in the overdoped regime, superconductivity is determined by the coupling strength. A strong doping dependence and an abrupt disappearance above the transition temperature (Tc) eliminate the conventional phononic mechanism of the observed mass renormalization and identify the onset of spin-fluctuations as its likely origin.
25. Physics Colloquium

    "Future Circular Collider"

    Presented by Michael Benedikt, CERN

    Friday, April 12, 2019, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: George Redlinger & Maria Chamizo Llatas

    The global Future Circular Collider Study, launched in 2014 by CERN as host institute, has published its conceptual design report by the end of 2018, as input to the update of the European Strategy for Particle Physics. Today, a staged Future Circular Collider (FCC), consisting of a luminosity-frontier highest-energy electron-positron collider (FCC-ee) followed by an energy-frontier hadron collider (FCC-hh), promises the most far-reaching physics program for the post-LHC era. FCC-ee is a precision instrument to study the Z, W, Higgs and top particles, and o?ers unprecedented sensitivity to signs of new physics. Most of the FCC-ee infrastructure can later be reused for the subsequent hadron collider, FCC-hh. The FCC-hh provides proton-proton collisions at a centre-of-mass energy of 100 TeV and can directly produce new particles with masses of up to several tens of TeV. This collider will also measure the Higgs self-coupling and explore the dynamics of electroweak symmetry breaking. Heavy-ion collisions and ep collisions (FCC-eh) further contribute to the breadth of the overall FCC program. The integrated FCC infrastructure will serve the particle physics community through the end of the 21st century. This presentation will summarize the conceptual designs of FCC-ee and FCC-hh, covering the machine concepts, the R&D for key technologies, infrastructure planning, initial considerations for the experiments, and a possible implementation schedule.
26. NT / RIKEN Seminar

    "A Complex Path Around the Sign Problem"

    Presented by Paolo Bedaque, U Maryland

    Friday, April 12, 2019, 2 pm
    Building 510, CFNS Seminar Room 2-38

    Hosted by: Niklas Mueller

    The famous "sign problem" is the main roadblock in the path to a Monte Carlo solution of QCD at finite densities and the study of real time dynamics. We review a recent developed approach to this problem based on deforming the domain of integration of the oath integral into complex field space. After discussing the math involved in the complex analysis of multidimensional spaces we will talk about the advantages/disadvantages of using Lefschetz thimbles, "learnifolds" and "optimized manifolds" as the alternative integration manifold as well as the algorithms that go with them. Several examples of lower dimensional field theories will be presented.
27. HET Lunch Seminar

    "Highlights from EW Moriond 2019"

    Presented by Amarjit Soni, BNL

    Friday, April 12, 2019, 12 pm
    Building 510, Room 2-160

    Hosted by: Aaron Meyer
28. Particle Physics Seminar

    "Neutrino Interaction Modeling and Tuning"

    Presented by Libo Jiang, University of Pittsburgh

    Thursday, April 11, 2019, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Mary Bishai

    GENIE is a well-knows event generator provides the simulation of neutrino interactions, and performs a highly-developed global analysis of neutrino scattering. It handles all neutrinos and targets, and all processes relevant from MeV to PeV energy scales. I am going to present the modelling of neutrino interactions and results of tuning against experimental data.
29. Condensed-Matter Physics & Materials Science Seminar

    "Tailoring electronic and thermal properties of bulk Cu26T2(Ge,Sn)6S32 colusite through defects engineering and functionalization of the conductive network"

    Presented by Emmanuel Guilmeau, CRISMAT Laboratory, Caen, France

    Thursday, April 11, 2019, 1:30 pm
    Bldg. 734, ISB Conference Room 201 (upstairs)

    Hosted by: Qiang Li

    A complete study of the structure and thermoelectric properties of colusite Cu26T2(Ge,Sn)6S32 (T = V, Cr, Mo, W) is presented. A brief introduction provides a state-of-theart/survey of thermoelectric sulfides, with a special focus on the structural features and transport properties relationship in Cu-based sulfides. In the first part of this presentation, we highlight the key role of the densification process on the formation of short-to-medium range structural defects in Cu26V2Sn6S32 [1]. A simple and powerful way to adjust carrier concentration combined with enhanced phonon scattering through point defects and disordered regions is described. By combining experiments with band structure and phonons calculations, we elucidate, for the first time, the underlying mechanisms at the origin of the intrinsically low thermal conductivity in colusite samples as well as the effect of S vacancies and antisite defects on the carrier concentration. In the second part, we demonstrate the spectacular role of the substitution of V5+ by hexavalent T6+ cations (Cr, Mo and W) on the electronic properties, leading to high power factors [2]. In particular, Cu26Cr2Ge6S32 shows a value of 1.53 mW m-1 K-2 at RT that reaches a maximum value of 1.94 mW m-1 K-2 at 700 K. The rationale is based on the concept of conductive "Cu-S" network, which in colusites corresponds to the more symmetric parent sphalerite structure. The interactions within the mixed octahedral-tetrahedral [TS4]Cu6 complexes are shown to be responsible for the outstanding electronic transport properties. [1] C. Bourgès et al., J. Amer. Chem. Soc. 140 (2018) 2186 [2] V. Pavan Kumar et al., Adv. Energy Mater. 9 (2019) 1803249
30. Environmental & Climate Sciences Department Seminar

    "Simulating Mixed-Phase Clouds at High Latitudes: Model Evaluation, Improvement, and Interactions with Aerosol"

    Presented by Xiahong Liu, Univ. Wyoming

    Thursday, April 11, 2019, 11 am
    Large Conference Room, Bldg. 490

    Hosted by: Damao Zhang

    Mixed-phase clouds are frequently observed in the Arctic and Antarctic and over the Southern Ocean, and have important impacts on the surface energy budget and regional climate. Global climate models (GCMs), an important tool for studying the climate change still have large biases in simulating the mixed-phase cloud properties, including supercooled liquid amount and liquid and ice phase partitioning. In this talk, I will present our recent works on mixed-phase clouds: (1) improving the representations of subgrid mixing and partitioning between cloud liquid and ice in mixed-phase clouds in the DOE's Energy Exascale Earth System Model (E3SM). Model simulations are evaluated against observation data obtained in the DOE Atmospheric Radiation Measurement (ARM) Program's field campaigns and long-term ground-based multi-sensor measurements; and (2) investigating the effects of aerosols, including dust and sea spray aerosol, on mixed-phase clouds. We found that dust, as ice nucleating particles (INPs), induces a global net warming via its indirect effect on mixed-phase clouds with a predominant warming in the NH midlatitudes and a cooling in the Arctic. INP sources of sea spray aerosol vary with time and geographic location with the maximum contribution in the marine boundary layer over the Southern Ocean, where dust has a limited influence. Modeled INP concentrations are compared with observations from different campaigns (e.g., MARCUS, SOCRATES, CAPRICORN).
31. Condensed-Matter Physics & Materials Science Seminar

    "Importance of electron interactions in understanding the photo-electron spectroscopy and the Weyl character of MoTe2"

    Presented by Niraj Aryal, Florida State University

    Thursday, April 11, 2019, 11 am
    ISB Bldg. 734 Conference Room 201 (upstairs)

    Hosted by: Weiguo Yin

    Weyl semimetals are crystalline materials that host pairs of chiral Weyl Fermions (WFs) as low energy excitations. Such WFs act as sources and sinks of Berry curvature and can contribute to many exotic transport properties. Recently, inversion symmetry broken transition metal dichalcogenide materials like MoTe2 and WTe2 have been predicted to host type-II WFs by DFT calculations and ARPES experiments. However, quantum oscillation experiments (QOE) disagree with the DFT calculations thus raising doubt about the existence of Weyl physics in these materials [1]. In order to address this discrepancy, we studied the role of electron interactions in Td-MoTe2 by employing DFT where the onsite Coulomb repulsion (Hubbard U) for the Mo 4d states is included within the DFT+U scheme. We found that in addition to explaining the QOE, inclusion of electron interaction is needed to explain the light-polarization dependence measured by ARPES [2]. We also found that while the number of Weyl points (WPs) and their position in the Brillouin Zone change as a function of U, a pair of such WPs very close to the Fermi level survive the inclusion of these important corrections. Our calculations suggest that the Fermi surface of Td-MoTe2 is in the vicinity of a correlations-induced Lifshitz transition which can be probed experimentally. If time allows, I will also present briefly our study of the interface between topological insulator and non-topological materials which are important for band engineering and studying emergent fundamental phenomena. References [1] D. Rhodes, R. Schonemann, N. Aryal, Q.R. Zhou et al., Bulk Fermi surface of the Weyl type-II semimetallic candidate ?-MoTe2, Phys. Rev. B 96, 165134 (2017). [2] N. Aryal and E. Manousakis, Importance of electron correlations in understanding the photo-electron spectroscopy and the Weyl character of MoTe2, Phys. Rev. B 99, 035123 (2019).
32. Particle Physics Seminar

    "The Search for the dark vector boson"

    Presented by Diallo Boye, BNL

    Wednesday, April 10, 2019, 4 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Alessandro Tricolli

    Hidden sector or dark sector states appear in many extensions to the Standard Model, to provide a particle candidate for dark matter in universe or to explain astrophysical observations such the as positron excess observed in the cosmic radiation flux. A hidden or dark sector can be introduced with an additional U(1)d dark gauge symmetry. The discovery of the Higgs boson during Run 1 of the Large Hadron Collider opens a new and rich experimental program based on the Higgs Portal. This discovery route uses couplings to the dark sector at the Higgs level, which were not experimentally accessible before. These searches use the possible exotic decays: H -> Z Zd -> 4l and H -> Zd Zd -> 4l. Here Zd is a dark vector boson. We have experience of this search from the Run 1 period of the LHC using the ATLAS detector at CERN. These results showed (tantalizingly) two signal events where none were expected, so that in the strict criteria of High Energy Physics, the result was not yet statistically significant. The Run 1 analysis for 8 TeV collision energy is further developed in Run 2 with 13 TeV collision energy, to expand the search area, take advantage of higher statistics, a higher Higgs production cross section, and substantially better performance of the ATLAS detector. The analysis is extended to search for heavier scalars decaying to dark vector bosons.
33. CFN Special Colloquium

    "Discovering novel materials, and novel physics, with first-principles"

    Presented by Nicola Marzari, École Polytechnique Fédérale de Lausanne (EPFL)

    Wednesday, April 10, 2019, 3:30 pm
    CFN, Bldg 735, 2nd Floor Seminar Room

    Hosted by: Mark Hybertsen

    First-principles simulations are one of the greatest accelerators in the world of science and technology. To provide some context, one could mention that 30,000 papers on density-functional theory are published every year; that 12 of these are in the top-100 most-cited papers in the entire history of science, engineering, and medicine; or that the doubling in capacity every 14 months has been the underwriter of computational science for the past 30 years. I'll highlight some of my own scientific, structural, and policy perspectives on this, taking as a case study the discovery of novel two-dimensional materials and of their properties and applications. I'll then argue how the need to calculate materials properties often forces a critical evaluation of some stalwarts of condensed-matter physics: in this case, learning that phonons are just a high-temperature approximation for heat carriers, or discovering that the Boltzmann transport equation can be generalized to describe simultaneously the propagation and interference of phonon wavepackets, thus unifying the description of thermal transport in crystals and glasses. Bio: Nicola Marzari holds the chair of Theory and Simulation of Materials at the École Polytechnique Fédérale de Lausanne, where he is also the director of the Swiss National Centre for Competence in Research MARVEL, on Computational Design and Discovery of Novel Materials (2014-26). Previous tenured appointment include the Toyota Chair for Materials Engineering at the Massachusetts Institute of Technology and the first Statutory (University) Chair of Materials Modelling at the University of Oxford, where he was also the director of the Materials Modelling Laboratory. He is the current chairman of the Psi-k Charity and Board of Trustees, and holder of an Excellence Chair at the University of Bremen.
34. BWIS Sponsored Event

    "How Beauty Leads Physics Astray"

    Presented by Sabine Hossenfelder, Frankfurt Institute for Advanced Studies, Germany

    Tuesday, April 9, 2019, 5 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Vivian Stojanoff

    To develop fundamentally new laws of nature, theoretical physicists often rely on arguments from beauty. Simplicity and naturalness in particular have been strongly influential guides in the foundations of physics ever since the development of the standard model of particle physics. In this lecture I argue that arguments from beauty have led the field into a dead end and discuss what can be done about it.
35. Physics Colloquium

    "Do Women Get Fewer Citations Than Men?"

    Presented by Sabine Hossenfelder, Frankfurt Institute for Advanced Studies, Germany

    Tuesday, April 9, 2019, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Berndt Mueller

    I will talk about the results of a citation analysis on publication data from the arXiv and inspire in which we explored gender differences. I will further explain how we can use bibliometric analysis to improve the efficiency of knowledge discovery.
36. Condensed-Matter Physics & Materials Science Seminar

    ""Charge and lattice entanglement in quantum materials observed by TEM: Tb2Cu0.83Pd0.17O4 and Cu2S""

    Presented by Wei Wang, Institute of Physics, Chinese Academy of Sciences, Beijing

    Tuesday, April 9, 2019, 3 pm
    Bldg. 480, Conference Room

    Hosted by: Jing Tao

    Plenty of physical properties in strongly electron correlated system are thought to arise from intricate interplay among charge, spin, orbital and lattice. Understanding the structural origin of these functionalities, such as superconductivity, multiferroics, etc, has attracted tremendous attention for decades. Using electron diffraction technique in TEM, we recently studied the modulated structure in Tb2Cu0.83Pd0.17O4 compound and phase transition in Cu2S. After a brief introduction of TEM techniques that I have employed for the study, I will report observations of electron-beam-induced smectic-nematic phase transitions in Tb2Cu0.83Pd0.17O4. Electron diffraction and HAADF-STEM images indicate a superlattice structure with Cu/Pd displacements perpendicular to the Cu-O plane on Cu sites. In addition, the superlattice modulation undergoes a reversible smectic-nematic phase transition under the electron beam illumination. Our in situ TEM results imply that the modulated structure root in a charge ordering at Cu sites. Then I will switch to an on-going study of the Cu2S at high temperature. Previous reports show that the crystal structural of Cu2S can be manipulated by electron beam illumination, suggesting a strong coupling between charge and lattice. To explore the structural phase transition and to have a better understanding of superionic behavior in this material, we focus on diffuse scattering in the electron diffraction patterns obtained at high temperatures, which results from short range ordering of Cu atoms. Electron diffraction tomographyic data were collected in order to reconstruct the real-space structure for Cu atoms. Preliminary results will be shown followed by a discussion with early-stage interpretations.
37. High Energy Theory Seminar

    "Dark Matter — or What?"

    Presented by Sabine Hossenfelder, Frankfurt Institute for Advanced Studies, Germany

    Tuesday, April 9, 2019, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: Berndt Mueller

    In this talk I will explain (a) what observations speak for the hypothesis of dark matter, (b) what observations speak for the hypothesis of modified gravity, and (c) why it is a mistake to insist that either hypothesis on its own must explain all the available data. The right explanation, I will argue, is instead a suitable combination of dark matter and modified gravity, which can be realized by the idea that dark matter has a super fluid phase.
38. NT / RIKEN seminar

    "The Color Glass Condensate density matrix: Lindblad evolution, entanglement entropy and Wigner functional"

    Presented by Alex Kovner, U Connecticut

    Friday, April 5, 2019, 2 pm
    Building 510, CFNS Seminar Room 2-38

    Hosted by: Niklas Mueller

    We introduce the notion of the Color Glass Condensate (CGC) density matrix ρ̂ . This generalizes the concept of probability density for the distribution of the color charges in the hadronic wave function and is consistent with understanding the CGC as an effective theory after integration of part of the hadronic degrees of freedom. We derive the evolution equations for the density matrix and show that it has the celebrated Kossakowsky-Lindblad form describing the non-unitary evolution of the density matrix of an open system. Additionally, we consider the dilute limit and demonstrate that, at large rapidity, the entanglement entropy of the density matrix grows linearly with rapidity according to dSe/dy=γ, where γ is the leading BFKL eigenvalue. We also discuss the evolution of ρ̂ in the saturated regime and relate it to the Levin-Tuchin law and find that the entropy again grows linearly with rapidity, but at a slower rate. Finally we introduce the Wigner functional derived from this density matrix and discuss how it can be used to determine the distribution of color currents, which may be instrumental in understanding dynamical features of QCD at high energy.
39. HET Lunch Discussion

    "Quantum Simulation of Gauge Theories"

    Presented by Taku Izubuchi, BNL HET

    Friday, April 5, 2019, 12:15 pm
    Building 510, Room 2-160

    Hosted by: Aaron Meyer
40. Physics Colloquium

    "Views and news on chiral transport"

    Presented by Karl Landsteiner

    Thursday, April 4, 2019, 4 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Niklas Mueller

    I present an effective action approach to chiral transport. Chiral Magnetic and Chiral Vortical Effect are treated in exact parallel and result in the known dependence on chemical potential and temperature. The approach sheds light on some of the more obscure features of chiral transport such as covariant and consistent anomalies and a seeming mismatch of the derivative expansion. As a related application I will comment on the thermal Hall effect on 2D topological insulators. Then I discuss a new example of chiral transport: anomalous Hall viscosity at the quantum critical point of the Weyl-semimetal/insulator transition. Results from a holographic model will be compared to a weak coupling quantum field theory analysis.
41. Particle Physics Seminar

    "Flavour physics with dynamical chiral fermions"

    Presented by Peter Boyle, University of Edinburgh

    Thursday, April 4, 2019, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Hooman Davoudiasl

    I discuss recent simulations with dynamical chiral fermions. In particular I focus on neutral kaon mixing amplitudes in and beyond the standard model, calculated for the first time with physical quark masses. A puzzle in the non-perturbative renormalisation of the BSM operators is resolved. The prospects for extension of this calculation to B-meson mixing amplitudes is discussed, and initial results for the standard model B mixing amplitudes presented. Prospects for future calculations over the next five years are considered.
42. Physics Colloquium

    "Prospects on nucleon tomography"

    Presented by Herve Moutard, Université Paris-Saclay

    Wednesday, April 3, 2019, 3 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Salvatore Fazio

    Much attention has been devoted in recent years to the three-dimensional quark and gluon structure of the nucleon. In particular the concept of Generalized Parton Distributions promises an understanding of the generation of the charge, spin, and energy-momentum structure of the nucleon by its fundamental constituents. Forthcoming measurements with unprecedented accuracy at Jefferson Lab and at a future electron-ion collider will presumably challenge our quantitative description of the three-dimensional structure of hadrons. To fully exploit these future experimental data, new tools and models are currently being developed. After a brief reminder of what make Generalized Parton Distributions a unique tool to understand the nucleon structure, we will discuss the constraints provided by the existing measurements and review recent theoretical developments. We will explain why these developments naturally fit in a versatile software framework, named PARTONS, dedicated to the phenomenology and theory of GPDs.
43. HET Seminar

    "Lattice QCD Inputs For Neutrino-Nucleon Scattering"

    Presented by Raza Sufian, Jefferson Lab

    Wednesday, April 3, 2019, 2:30 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Aaron Meyer

    We present lattice QCD calculation of nucleon axial and electromagnetic (up, down, strange and charm) form factors and discuss their impact on the understanding of neutrino-nucleon scattering. In a phenomenological study, using a combination of lattice QCD calculation of the strange-quark form factors, and MiniBooNE experimental neutrino scattering differential cross-section data in a limited kinematic regime, we obtain a precise determination of the weak axial form factor and of the corresponding neutral current weak-axial charge. We further show how a direct lattice QCD determination of neutral current weak-axial charge enable us to predict the BNL E734 data for the neutrino neutral current scattering differential cross section to high precision. We discuss how a direct lattice QCD calculation of neutrino-nucleon scattering cross sections can help to isolate nuclear effects in the neutrino-nucleus scattering.
44. Condensed-Matter Physics & Materials Science Seminar

    "Topological semimetals predicted from first-principles and theoretical approaches"

    Presented by Jiawei Ruan, School of Physics, Nanjing University, China

    Monday, April 1, 2019, 11 am
    Building 734, Seminar Room 201

    Hosted by: Weiguo Yin

    Weyl semimetals are new states of matter which feature novel Fermi arcs and exotic transport phenomena. Based on first-principles calculations, we report that the HgTe-class materials [1] as well as four chalcopyrites [2] are ideal Weyl semimetals, having largely separated Weyl points and uncovered Fermi arcs that are amenable to experimental detections. We also construct a minimal effective model to capture the low-energy physics of this class of Weyl semimetals. Our discovery is a major step toward a perfect playground of intriguing Weyl semimetals and potential applications for low-power and high-speed electronics. Besides the ideal Weyl semimetals, I will talk about Non-Hermitian nodal-line semimetals with an anomalous bulk-boundary correspondence [3]. I will also present recent results of saddle surface in topological materials and a new method to construct a simplified tight-binding model based on group theory analysis. [1] JR et al., Nature communications 7, 11136 (2016). [2] JR et al., PRL 116, 226801 (2016). [3] H. Wang, JR, and H. Zhang, PRB 99, 075130 (2019).
45. NT/RIKEN Seminar

    "Toward a unified description of both low and high ptparticle production in high energy collisions"

    Presented by Jamal Jalilian-Marian, Baruch College, City University of New York

    Friday, March 29, 2019, 2 pm
    Building 510, CFNS Seminar Room 2-38

    Hosted by: Niklas Mueller

    Inclusive particle production at high p_t is successfully described by perturbative QCD using collinear factorization formalism with DGLAP evolution of the parton distribution functions. This formalism breaks down at small Bjorken x (high energy) due to high gluon density (gluon saturation) effects. The Color Glass Condensate (CGC) formalism is an effective action approach to particle production at small Bjorken x (low p_t) which includes gluon saturation. The CGC formalism nevertheless breaks down at intermediate/large Bjorken x, corresponding to the high p_t kinematic region in high energy collisions. Here we describe the first steps taken towards the derivation of a new formalism, with the ultimate goal of having a unified formalism for particle production at both low and high p_t in high energy hadronic/heavy ion collisions.
46. HET Lunch Discussion

    "Discussion on arXiv 1307.5458: Implication of neutrino backgrounds on the reach of next generation dark matter direct detection experiments"

    Presented by Dr Gopolang Mohlabeng, Brookhaven National Laboratory

    Friday, March 29, 2019, 12:15 pm
    Building 510, Room 2-160

    Hosted by: Peter Denton
47. High Energy / Nuclear Theory / RIKEN Seminars

    "Lattice Workshop for US -Japan Intensity Frontier Incubation (1/1)"

    Wednesday, March 27, 2019, 9 am
    TBD

    Hosted by: Sally Dawson
48. Physics Colloquium

    "Quantum Information Science Landscape, Vision, and NIST"

    Presented by Carl Williams, NIST

    Tuesday, March 26, 2019, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Andrei Nomerotski

    The first part of the colloquium will provide an overview of United States government's interest in quantum information science from the National Strategic Overview for Quantum Information Science that established the policy objectives for this administration to the National Quantum Initiative Act that formalizes parts of this strategy for key civilian science agencies. This portion of the talk will conclude with placing the United States strategy in the global context and describe how the United States plans to establish the foundation for the quantum 2.0 economy. The second part of the colloquium will begin with a high-level overview of NIST, of NIST's interest in Quantum Information Science, before talking briefly about some interesting highlights from NIST laboratories. Moving from the highlights, the talk will explore ongoing and future metrological applications followed by some hypothetical conjectures of future technological applications with a focus on how quantum information science and its technology may impact fundamental physics from exploring potential time variation of fundamental constants to future probes of dark matter and gravitational waves.
49. High Energy / Nuclear Theory / RIKEN Seminars

    "Lattice Workshop for US -Japan Intensity Frontier Incubation (1/1)"

    Tuesday, March 26, 2019, 9 am
    TBD

    Hosted by: Sally Dawson
50. Particle Physics Seminar

    "Deep learning at the edge of discovery at the LHC"

    Presented by Javier Duarte, FNAL

    Monday, March 25, 2019, 2:30 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Alessandro Tricoli

    The discovery of the Higgs boson at the Large Hadron Collider in 2012 opened a new sector for exploration in the standard model of particle physics. Recent developments, including the use of deep learning to identify a complex but common decay of the Higgs boson to bottom quarks, have expanded our ability to study the production of Higgs bosons with very large momenta. By studying these Higgs bosons and measuring their momentum spectrum, we may be able to discover new physics at very high energy scales inaccessible directly at the LHC. I will explain these searches and the direction that deep learning is taking in particle physics, especially how it's changing the way we think about the trigger, event reconstruction, and our computing paradigm.
51. High Energy / Nuclear Theory / RIKEN Seminars

    "Lattice Workshop for US -Japan Intensity Frontier Incubation (1/1)"

    Monday, March 25, 2019, 9 am
    TBD

    Hosted by: Sally Dawson
52. CANCELED - NT/RIKEN Seminar

    "TBA"

    Presented by Alex Kovner, University of Connecticut

    Friday, March 22, 2019, 2 pm
    Building 510, Room 2-38

    Hosted by: Niklas Mueller
53. HET Lunch Discussion

    "Quantum-assisted optical interferometry"

    Presented by Paul Stankus, Oak Ridge National Laboratory

    Friday, March 22, 2019, 12:15 pm
    Building 510, Room 2-160
54. Particle Physics Seminar

    "Installation and preliminary results from ProtoDUNE Single Phase experiment at CERN"

    Presented by Maura Spanu, BNL

    Thursday, March 21, 2019, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Chao Zhang

    DUNE is a leading-edge, international experiment for neutrino science and proton decay. Its ambitious physics program requires a careful prototyping of the engineering solutions envisaged for the scale-up of the LArTPC technology, as well as a careful control of the systematics through the acquisition of a deep knowledge of the detector response and performances. ProtoDUNE is an extensive prototype program (ProtoDUNE) development at the European Research Center (CERN) Neutrino Platform facility with the aim to answer to all the open questions about DUNE design. The Single Phase prototype (ProtoDUNE SP) has been assembled in the EHN1 extension at CERN between 2016 and 2018 and it successfully took its first beam data from a dedicated SPS tertiary line from September to November 2018.
55. HET Seminar

    "Probing the Higgs Yukawa coupling to the top quark at the LHC via single top+Higgs production"

    Presented by Ya-Juan Zheng, University of Kansas

    Wednesday, March 20, 2019, 2:30 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Gopolang Mohlabeng
56. Physics Colloquium

    "Development of LArTPC for Neutrino Physics"

    Presented by Xin Qian, BNL

    Tuesday, March 19, 2019, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Andrei Nomerotski

    Liquid Argon Time Projection Chamber (LArTPC), with its mm-scale position resolution and the full-active-volume imaging-aided calorimetry, is an excellent device to detect accelerator neutrinos at GeV energy range. This technology may hold the key to search for new CP violation in the lepton sector, to determine the neutrino mass hierarchy, to search for baryon number violation, and to search for sterile neutrino(s). In this talk, I will review the existing achievements and current status of the detector development.
57. Nuclear Physics Seminar

    "Modified Structure of Protons and Neutrons in Correlated Pairs"

    Presented by Dr. Barak Schmookler, Center for Frontiers in Nuclear Science, Stony Brook University

    Tuesday, March 19, 2019, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: Jin Huang

    It has been known for several decades that the inelastic structure of the nucleon is modified by the presence of the nuclear medium. This modification is called the EMC effect. However, there is still no consensus as to the underlying QCD-based quark-gluon dynamics driving the effect. One approach to describe the EMC effect is to slightly modify the structure of all the nucleons in the nucleus. Recent evidence, however, suggests that the EMC effect may arise due to two-nucleon Short Range Correlations (SRC), which are pairs of nucleons close together in the nucleus. If this is true, it implies that nucleons are largely unmodified most of the time, but have their structure significantly modified when they temporarily fluctuate into SRC pairs. In this presentation, I will discuss the experimental evidence linking the EMC effect to two-nucleon SRCs. I will then describe a new data-driven phenomenological model of the EMC effect based on neutron-proton SRC pairs, and I will show that this model can consistently describe the effect across nuclei.
58. NT/RIKEN Seminar

    "Baryons as Quantum Hall Droplets"

    Presented by Zohar Komargodski, Simons Center, Stony Brook

    Friday, March 15, 2019, 2 pm
    Building 510, CFNS Room 2-38

    Hosted by: Niklas Mueller

    We revisit the problem of baryons in the large N limit of Quantum Chromodynamics. A special case in which the theory of Skyrmions is inapplicable is one-flavor QCD, where there are no light pions to construct the baryon from. More generally, the description of baryons made out of predominantly one flavor within the Skyrmion model is unsatisfactory. We propose a model for such baryons, where the baryons are interpreted as quantum Hall droplets. An important element in our construction is an extended, 2+1 dimensional, meta-stable configuration of the η′ particle. Baryon number is identified with a magnetic symmetry on the 2+1 dimensional sheet. If the sheet has a boundary, there are finite energy chiral excitations which carry baryon number. These chiral excitations are analogous to the electron in the fractional quantum Hall effect. Studying the chiral vertex operators we are able to determine the spin, isospin, and certain excitations of the droplet. In addition, balancing the tension of the droplet against the energy stored at the boundary we estimate the size and mass of the baryons. The mass, size, spin, isospin, and excitations that we find agree with phenomenological expectations.
59. HET Lunch Discussion

    "TBA"

    Presented by William Marciano, BNL

    Friday, March 15, 2019, 12:15 pm
    Building 510, Room 2-160
60. Joint Nuclear/High Energy Physics Seminar

    "Precision measurements of fundamental interactions with (anti)neutrinos"

    Presented by Professor Roberto Petti, University of South Carolina

    Tuesday, March 12, 2019, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: Milind Diwan
61. Condensed-Matter Physics & Materials Science Seminar

    "Neutron scattering study of strongly correlated systems"

    Presented by Yao Shen, Fudan University, China

    Monday, March 11, 2019, 1:30 pm
    ISB Bldg. 734, Conf. Rm. 201 (upstairs)

    Hosted by: Mark Dean

    In strongly correlated systems, interactions between various microscopic degrees of freedom with similar energy scales can induce strong competition and frustration, leading to exotic phenomena. Here we use neutron scattering technique to study several strongly correlated systems to show how the competition and interplay between these degrees of freedom can induce different phases and properties. 1) In the pressure-induced superconductor CrAs, the competition between various magnetic interactions lead to a noncollinear helimagnetic order. In addition, CrAs exhibits a spin reorientation at a critical pressure (Pc ~ 0.6 GPa), which is accompanied by a lattice anomaly and coincides with the emergence of bulk superconductivity, indicating the strong interplay between magnetic, structural and electronic degrees of freedom. 2) FeSe, the structurally simplest iron-based superconductor, shows nematic order at 90 K, but no magnetic order in the parent phase. Our neutron scattering experiments reveal both stripe and Neel spin fluctuations that are coupled to the nematicity. The competition between these two phases suppress the magnetic order and drive the system into a nematic quantum disordered paramagnet. Similar phenomenon is observed in YFe2Ge2, in which the magnetic order is suppressed by the competition between stripe type AFM phase and in-plane FM phase. 3) In the heavily electron-doped FeSe based superconductor Li0.8Fe0.2ODFeSe (Tc=41 K), a twisted dispersion of spin excitations is observed which may be caused by the competition between itinerant and local electrons, analogous to the hole-doped cuprates which host remarkably high Tc as well. 4) In the two-dimensional triangular lattice antiferromagnet YbMgGaO4, due to the strong spin-orbit coupling and crystalline electric field (CEF), the low-lying crystal field ground state is a Kramers doublet. The geometric frustration is enhanced by the anisotropic interactions and a quantum sp
62. HET Lunch Discussions@BNL

    "B->D* Semileptonic Decays Form Factors and CKM Matrix Element Vcb"

    Presented by Yong-Chull Jang, BNL

    Friday, March 8, 2019, 12:15 pm
    Building 510, Room 2-160

    Hosted by: Peter Denton
63. PubSci

    "PubSci: Big Bang Physics and the Building Blocks of Matter"

    Thursday, March 7, 2019, 7 pm
    The Snapper Inn 500 Shore Dr, Oakdale, NY 11769
64. Particle Physics Seminar

    "The PROSPECT Antineutrino Detector and Early Physics Results"

    Presented by Xianyi Zhang, Illinois Institute of Technology

    Thursday, March 7, 2019, 1:30 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Elizabeth Worcester

    PROSPECT, Precision Reactor Oscillation and SPECTrum, is a short baseline reactor antineutrino experiment. The PROSPECT antineutrino detector is an optically segmented liquid scintillator detector deployed ~7 m from a highly enriched U-235 reactor. This detector was designed to investigate discrepancies in the reactor antineutrino flux and spectrum by model-independently probing the eV-scale sterile neutrino oscillation from nuclear fission reactor, as well as precisely measuring the U-235 antineutrino spectrum. The particle multi-segment scattering in PROSPECT detector brought a typical challenge in characterizing the scintillator nonlinearity. This talk details the energy scale study for PROSPECT with data-MC comparison of detector calibrations. The detector construction, commissioning, and its early physics measurements are also presented.
65. HET Seminar

    "Breaking Mirror Hypercharge in Twin Higgs Models"

    Presented by Brian Batell

    Wednesday, March 6, 2019, 2:30 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Sally Dawson
66. Particle Physics Seminar

    "Neutrino cross sections"

    Presented by Callum Wilkinson, University of Bern

    Tuesday, March 5, 2019, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Elizabeth Worcester

    Current and planned neutrino oscillation experiments operate in the 0.1-10 GeV energy regime and use a variety of nuclear targets. At these energies, the neutrino cross section is not well understood: a variety of interaction processes are possible and nuclear effects play a significant role. This talk will give an overview of the state of neutrino cross sections, and explore their relationship with neutrino oscillation experiments.
67. Particle Physics Seminar

    "Measurement of LAr purity using Cosmic Muons"

    Presented by Monica Nunes, IFGW/UNICAMP, Brazil

    Monday, March 4, 2019, 3 pm
    3-209B, Bldg. 510

    Hosted by: Mary Bishai

    LArIAT is an experiment based on a LArTPC aiming to study relevant cross sections of charged particles with argon as well as the development of the related instrumentation. Charged particle crossing the detector excite and ionize the argon atoms and the electrons generated by the ionization are drifted in an electric field towards the anodic wire planes of the TPC. With electronegative impurities in the liquid argon, the amount of charge collected by the wires is going to be smaller and affect the quality of the results obtained in the experiment. Cosmic muons that cross the TPC between beam spills is a valuable tool for measuring the liquid argon purity inside the detector. With the electron lifetime obtained with the purity analysis based on cosmics, is possible to correct data used for all other studies based on charge collection of the LArTPC. In this seminar, I'll present the method and the results obtained in the LArIAT experiment. I'll also present other tasks that I performed on LArIAT during my PhD research.
68. HET Lunch Discussion

    "Dark matter beams at neutrino facilities"

    Presented by Claudia Frugiuele, CERN

    Friday, March 1, 2019, 12:15 pm
    Building 510, Room 2-160

    Hosted by: Peter Denton
69. Joint NT/RIKEN/CFNS Seminar

    "Measuring color memory in a color glass condensate"

    Presented by Ana-Maria Raclariu, Harvard University

    Thursday, February 28, 2019, 4 pm
    Building 510, Room 2-38 CFNS Seminar Room

    Hosted by: Niklas Mueller
70. Particle Physics Seminar

    "Status and physics potential of the JUNO experiment"

    Presented by Zeyuan Yu, Institute of High Energy Physics, China

    Thursday, February 28, 2019, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Chao Zhang

    The Jiangmen Underground Neutrino Observatory (JUNO) is a 20 kton multi-purpose liquid scintillator detector with an unprecedented energy resolution of 3% at 1 MeV being built in a dedicated underground laboratory in China and expected to start data taking in 2021. The main physics goal of the experiment is the determination of the neutrino mass ordering with a significance of 3-4 sigma within six years of running using electron anti-neutrinos coming from two nuclear power plants at a baseline of about 53 km. Beyond this fundamental question, JUNO will also have a very rich physics program including the precise measurement at a sub-percent level of the solar neutrino oscillation parameters, the detection of low-energy neutrinos coming from galactic core-collapse supernova, diffuse supernova background, the Sun, the Earth (geo-neutrinos) but also proton decay searches. This talk will give an overview on the JUNO physics potential and the current status of the project.
71. HET Seminar

    "Probing New Physics with Neutrino Scattering"

    Presented by Ian Shoemaker, Virginia Tech

    Wednesday, February 27, 2019, 2:30 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Gopolang Mohlabeng

    Current experimental sensitivities allow for neutrino scattering to be probed over a range of energy scales. In this talk, I'll discuss phenomenological probes of new physics using neutrino scattering at zero, GeV, and EeV momentum transfer. At zero momentum transfer, the forward coherent scattering of neutrinos on background particles provides novel sensitivity to Dark Matter. At MeV-GeV energies, the solar/atmospheric fluxes allow for the production of heavy sterile neutrinos at IceCube and direct detection experiments, resulting in distinctive signatures. Lastly, I'll discuss sterile neutrino scattering in the Earth as a possible explanation of the anomalous EeV events reported by ANITA.
72. Physics Colloquium

    "Precision measurement of neutrinos at Hyper-Kamiokande"

    Presented by Akira Konaka, TRIUMF

    Tuesday, February 26, 2019, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: George Redlinger

    Hyper-Kamiokande (HyperK) is a water Cherenkov neutrino detector whose construction in Japan was recently approved. The fiducial mass is 187kton, eight times larger than the Super-Kamiokande detector. The upgraded J-PARC accelerator located 295km away will provide high intensity neutrino and anti-neutrino beams tuned at the oscillation maximum. In this talk, I will describe the challenges of the systematic uncertainties in future neutrino oscillation experiments and how HyperK plans to address them. In addition to the observation of CP violation, Hyper-Kamiokande will explore directions that may become the main research topic in the future if something new is discovered: Precision neutrino oscillations to test the unitarity of the lepton flavour mixing, neutrino astronomy, such as supernova neutrinos and searches for astrophysical point sources of neutrinos, and searches for phenomena beyond the standard model, such as dark matter and nucleon decays.
73. Condensed-Matter Physics & Materials Science Seminar

    "Unconventional superconductivity and complex tensor order in half-Heusler superconductors"

    Presented by Igor Boettcher, University of Maryland

    Tuesday, February 26, 2019, 1:30 pm
    ISB Bldg. 734, Conf. Rm. 201 (upstairs)

    Hosted by: Laura Classen

    A revolutionary new direction in the field of superconductivity emerged recently with the synthesis of superconductors with strong inherent spin-orbit coupling such as the half-Heusler alloys. Due to band inversion, the low-energy degrees of freedom are electrons at a three-dimensional quadratic band touching point with an effective spin 3/2, which allows for higher-spin Cooper pairing and potentially topological superconductivity. I will illuminate some possibilities for unconventional superconductivity in this system, in particular a novel superconducting quantum critical point and the transition into a phase with complex tensor order, which is a superconducting state captured by a complex second-rank tensor valued order parameter describing Cooper pairs having spin 2. Here the interplay of both tensorial and complex nature results in a rich and intriguing phenomenology. I will highlight how optical response measurements can shed light on the phase structure of individual compounds.
74. NT / RIKEN Seminar

    "Quantum Chaos, Wormholes and the Sachdev-Ye-Kitaev Model"

    Presented by Jacobus Verbaarschot, Stony Brook University

    Friday, February 22, 2019, 2 pm
    2-38 CFNS Seminar Room

    Hosted by: Niklas Mueller

    The Sachdev-Ye-Kitaev (SYK) model has a long history in nuclear physics where its precursor was introduced as a model for the two-body nuclear interaction to describe the spectra of complex nuclei. Most notably, its level density is given by the Bethe formula and its level correlations are consistent with chaotic motion of the nucleons. Recently, this model received a great of attention as a solvable model for the quantum states of a black hole, exactly because of these properties. In this lecture we introduce the SYK model from a nuclear physics perspective and discuss its chaotic nature and its relation with black hole physics. We end with a summary of recent work on two SYK models coupled by a spin-spin interaction as a model for wormholes.
75. Particle Physics Seminar

    "Probing New Physics and the Nature of the Higgs Boson at ATLAS"

    Presented by Lailin Xu, University of Michigan

    Thursday, February 21, 2019, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Alessandro Tricoli

    The long-sought Higgs boson discovered at the LHC completes the Standard Model of the particle physics. During the last six years, substantial achievements have been made to probe the nature of the Higgs boson. Participle physics is however at an impasse: deep mysteries of the Electroweak symmetry breaking remain unanswered, and long-awaited new physics phenomena beyond the SM have not shown up yet. In this talk, I start with a brief overview on the current profile of measurements of the Higgs boson properties and couplings. I then present Higgs measurements in the four-lepton channel, and how we use the Higgs boson as a portal in the quest for new physics. In the end, I discuss the prospect of the Higgs measurements including the Higgs self-coupling at future colliders.
76. Physics Colloquium

    "Physics education research in higher education: What can we learn from the top cited papers in the Physical Review?"

    Presented by Charles Henderson, Western Michigan University

    Tuesday, February 19, 2019, 3:30 pm
    Large Seminar Room, Bldg. 510

    The journal Physical Review Physics Education Research was started in 2005 as the archival research journal for the field of Physics Education Research (PER). In this talk I will identify some important findings from the field of PER based on highly cited articles from the journal. For example, there is strong evidence that in typical physics courses many students do not learn the core concepts of the discipline; student beliefs about physics become less expert like; and there is a significant gender gap, with men outperforming women. Many PER-based instructional strategies can improve student knowledge and some instructional strategies can improve student beliefs. However, implementation of these strategies is low because the field often uses ineffective dissemination strategies.
77. HET Lunch Discussion

    "Opportunities in Reactor Neutrino Physics"

    Presented by Chao Zhang, BNL

    Friday, February 15, 2019, 12:15 pm
    Building 510, Room 2-160
78. Condensed-Matter Physics & Materials Science Seminar

    ": Electronic structure of d-metal systems as revealed by ab initio modeling of resonant inelastic X-ray scattering"

    Presented by Lei Xu, Leibniz Institute for Solid State and Materials Research Dresden, Germany

    Friday, February 15, 2019, 11 am
    ISB Bldg. 734 Conference Room 201 (upstairs)

    Hosted by: Weiguo Yin

    I will present our work on the theoretical investigation of the electronic structure, magnetic interactions and resonant inelastic X-ray scattering (RIXS) in 3d or 4d-5d transition metal (TM) compounds by using wave-function-based many-body quantum chemistry (QC) methods. My presentation contains two parts. In the first part, I will discuss the magnetic properties of 4d and 5d TM ions with a formally degenerate t12g electron configuration in the double-perovskite (DP) materials Ba2YMoO6, Ba2LiOsO6 and Ba2NaOsO6. Our analysis indicates that the sizable magnetic moments and g-factors found experimentally are due to both strong TM d – ligand p hybridization and dynamic Jahn-Teller effects. Our results also point out that cation charge imbalance in the DP structure allows a fine tuning of the gap between the t2g and eg levels. In another example of t12g electron configuration, spin-Peierls (SP) TiPO4 compound, we assign excitation peaks of experimental RIXS spectra and find that the d1 ground state is composed of an admixture of dz2 and dxz orbital character. In the second part, I will discuss a computational scheme for computing intensities as measured in X-ray absorption and RIXS experiments. We take into account the readjustment of the charge distribution in the 'vicinity' of an excited electron for the modeling of RIXS. The computed L3-edge RIXS spectra for Cu2+ 3d9 ions in KCuF3 and for Ni2+ 3d8 ions in La2NiO4 reproduce trends found experimentally for the incoming-photon incident-angle and polarization dependence.
79. Particle Physics Seminar

    "Measuring CCQE-like Cross Sections in MINERvA: when statistics meet precision"

    Presented by Mateus F. Carneiro, Oregon State University

    Thursday, February 14, 2019, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Elizabeth Worcester

    MINERvA is a detector build to measure neutrino-nucleus cross sections. As we move towards more precise measurements, cross sections are of extreme importance to the future of neutrino physics. This talk will walk through all the steps necessary to simulate, select signal and measure a CCQE cross section while we test different nuclear models. New preliminary MINERvA results using the new configuration of the NuMI beam will be presented.
80. RIKEN Lunch Seminar

    "Chiral Photocurrents and Terahertz Emission in Dirac and Weyl Materials"

    Presented by Mr. Sahal Kaushik, Stony Brook University

    Thursday, February 14, 2019, 12 pm
    Building 510, Room 2-160

    Hosted by: Yuta Kikuchi

    Recently, chiral photocurrents have been observed in Weyl materials. We propose a new mechanism for photocurrents in Dirac materials in the presence of magnetic fields, that does not depend on any asymmetries of the crystal. This Chiral Magnetic Photocurrent would be an independent probe of the chiral anomaly. We also also discuss an observation of terahertz emission in the Weyl material TaAs with tunable ellipticity, due to chiral photocurrents induced by an ultrafast near infrared laser.
81. Condensed-Matter Physics & Materials Science Seminar

    "Resonant inelastic X-ray scattering (RIXS) as a probe of exciton-phonon coupling"

    Presented by Andrey Geondzhian, European Synchrotron Radiation Facility (ESRF), France (UTC+1)

    Thursday, February 14, 2019, 9:30 am
    ISB Bldg. 734 Conference Room 201 (upstairs)

    Hosted by: Weiguo Yin

    Phonons contribute to resonant inelastic X-ray scattering (RIXS) as a consequence of the coupling between electronic and lattice degrees of freedom. Unlike other techniques that are sensitive to electron-phonon interactions, RIXS can give access to momentum dependent coupling constants. This Information is highly desirable in the context of understanding anisotropic conventional and unconventional superconductivity. In my talk, I will consider the phonon contribution to RIXS from the theoretical point of view. In contrast to previous studies, we emphasize the role of the core-hole lattice coupling. Our model, with parameters obtained from first principles, shows that even in the case of a deep core-hole, RIXS probes exciton-phonon coupling rather than a direct electron-phonon coupling. Further, to address the needs of predictive approach and overcome limitations of the model studies we developed a Green's function formalism to capture electron-phonon contributions to RIXS and other core-level spectroscopies (X-ray photoemission spectroscopy (XPS), X-ray absorption spectroscopy (XAS)). Our approach is based on the cumulant expansion of the Green's function combined with many-body theory calculated vibrational coupling constants. In the case of the XAS and RIXS, we use a two-particle exciton Green's function, which accounts implicitly for particle-hole interference effects that have previously proved difficult. Finally, to demonstrate the methodology, we successfully applied our formalism to small molecules, for which unambiguous experimental data exist.
82. Condensed-Matter Physics & Materials Science Seminar

    "Phase transition in functional materials and structural dynamics as studied by UTEM"

    Presented by Ming Zhang, Institute of Physics, Chinese Academy of Sciences

    Tuesday, February 12, 2019, 10 am
    ISB Bldg. 734 Conference Room 201 (upstairs)

    Hosted by: Jing Tao

    My presentation contains 3 parts. First, I will briefly introduce the pump-probe technique and Ultrafast Transmission Electron Microscopy (UTEM). Then I will demonstrate our development project of the UTEM, including the modifications of the configuration, the establishment of optical system, the generation of photoelectrons, and specific cases are discussed to show the capability of our UTEM. At last, I will highlight the application of UTEM via two examples: (1) The photoinduced martensitic (MT) transition and reverse transition in a shape memory alloy Mn50Ni40Sn10 have been examined by UTEM, and imaging and diffraction observations clearly show a variety of structural dynamic features at picosecond time scales; (2) The Lorentz UTEM for direct imaging photoinduced ultrafast magnetization dynamics, revealing remarkable features of magnetic transient states after a femtosecond pulsed laser excitation, and three successive dynamical processes involving four distinct magnetic states are evidently observed in MnNiGa crystals.
83. NT / RIKEN Seminar

    "Realizing relativistic dynamics with slow light polaritons at room temperature"

    Presented by Eden Figueroa, Stony Brook University

    Friday, February 8, 2019, 2 pm
    CFNS Seminar Room

    Hosted by: Niklas Mueller

    Experimental verification of relativistic field theory models requires accelerator experiments. A possible pathway that could help understanding the dynamics of such models for bosons or fermions is the use of quantum technology in the form of quantum analog simulators. In this talk we will explore the possibility of generating nonlinear Dirac-type Hamiltonians using coherent superpositions of photons and spin wave excitations of atoms. Our realization uses a driven slow-light setup, where photons mimic the Dirac fields and different dynamics can be implemented and tuned by adjusting optical parameters. We will show our progress tin building a quantum simulator of the Jackiw-Rebbi model using highly-interacting photons strongly coupled to a room temperature atomic ensemble. We have identified suitable conditions in which the input photons dispersion relations can be tuned to a spinor of light configuration, mimicking the Dirac regime and providing a framework to create tunable interactions and varying mass terms. Lastly, we will show our vision to scale these ideas to multiple interacting fermions.
84. HET Lunch Discussion

    "Precision Electroweak Measurements at the LHC"

    Presented by Sally Dawson

    Friday, February 8, 2019, 12:15 pm
    Building 510, Room 2-160

    Hosted by: Peter Denton
85. RIKEN Lunch Seminar

    "Modification of the nucleon-nucleon potential and nuclear correlations due to the QCD critical point"

    Presented by Juan M. Torres-Rincon, Stony Brook University

    Thursday, February 7, 2019, 12 pm
    Building 510, Room 2-160

    Hosted by: Enrico Rinaldi

    The scalar-isoscalar mode of QCD becomes lighter/nearly massless close to the chiral transition/second-order critical point. This mode is the main responsible for the attractive part of the nucleon-nucleon potential at distances of 1-2 fm. Therefore, a long-range strong attraction among nucleons is predicted to develop close to the QCD critical point. Using the Walecka-Serot model for the NN potential we study the effects of the critical mode in a system of nucleons and mesons using a Molecular Dynamics+Langevin equations for the freeze-out conditions of heavy-ion collisions. Beyond mean field, we observe strong nucleon correlations leading to baryon clustering. We propose that light-nuclei formation, together with an enhancement of cumulants of the proton distribution can signal the presence of the QCD critical point.
86. Condensed-Matter Physics & Materials Science Seminar

    "Stimulation of quantum phases by time-dependent perturbations"

    Presented by Victor Galitski, University of Maryland

    Thursday, February 7, 2019, 11 am
    ISB Bldg. 734, Conf. Room 201 (upstairs)

    Hosted by: Mark Dean

    I will review our theory work on dynamic stimulation of various quantum phases. A key idea here is that the equilibrium distribution is rarely optimal for occurrence of a given quantum state and dynamic perturbations can be used to "deform" an electron population in a favorable way in order to enhance quantum coherence. To illustrate this idea, I will show how both Cooper pairing and phase coherence can be dynamically enhanced in both conventional superconductors and bosonic superlfuids. Then, I will discuss dynamic enhancement of high-temperature superconductivity in the cuprates, as it reported in experiments by the Andrea Cavalleri group in Hamburg. It will be shown that an optical pump can suppress charge order and simultaneously enhance superconductivity, due to the inherent competition between the two. In the second part of my talk, I will generalize these ideas to quantum cavities, where the light-matter coupling can be strongly enhanced. In particular, I will discuss the hybridization of cavity photons with collective modes in interacting two-dimensional materials, including the formation of Higgs polaritons and the closest analogue to excitons in a superconductor - Bardasis-Schrieffer modes - hybridized with light.
87. Condensed-Matter Physics & Materials Science Seminar

    "Novel Electrochemistry for Fuel Cell Reactions: Efficient Synthesis and New Characterization Methods"

    Presented by Zhixiu Liang

    Wednesday, February 6, 2019, 4:30 pm
    Bldg. 480 Conference Room

    Hosted by: Jing Tao

    The ever increasing consumption of fossil fuels for transportation causes climate change causing a growing concern about their future availability and further adverse environmental effects. To address this issue, the concept of CO2 neutral fuels-based energy cycle was brought out. The key reactions in that concept are electrochemical methanol oxidation (MOR), ethanol oxidation reaction (EOR), and CO2 reduction reaction (CO2RR). These all are elctrocatalysis research challenges being slow even at the best catalyst that hamper application of fuel cells, and bring environmental benefits. My research made these improvements of catalysts for the key reactions. In-situ electrochemical infrared reflective absorbance spectrum (EC-IRRAS) reveals that at lower temperature, such reaction is not complete and generates more formate; at elevated temperature, such reaction is complete to carbonate. Ethanol is one of the ideal fuels for fuel cells, but requires highly improved catalysts. Au@PtIr/C catalyst was synthesized with a surfactant-free wet-chemistry approach. Transmission electron microscope (TEM) characterization confirms the monolayer/sub-monolayer Pt-Ir shell, gold core structure. The catalyst has a very high mass activity of 58 A/mg at peak current. In situ EC-IRRAS reveals that C-C bond is cleaved upon contact with the catalyst surface leading to ethanol complete oxidation to CO2. Related researches on methodologies, included in situ TEM to help obtaining catalysts improvements, give morphologic, structural and spectroscopic information at wide range from hundreds of microns to sub-nanometer coupled with various detectors. Microelectromechanical System (MEMS) based chips technology enables TEM observation in operando, with liquid-flow-cell chips and electrochemistry chips designed and fabricated. Ag@Au hollow cubes synthesis via galvanic replacement of Au on Ag cubes was investigated with in situ TEM. The results demonstrate abnormal react
88. HET Seminar

    "Searching for flavour symmetries: old data new tricks"

    Presented by Jessica Turner, Fermilab

    Wednesday, February 6, 2019, 2:30 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Gopolang Mohlabeng

    The observed pattern of mixing in the neutrino sector may be explained by the presence of a non-Abelian, discrete flavour symmetry broken into residual subgroups at low energies. These flavour models require the presence of Standard Model singlet scalars, namely flavons, which decay to charged leptons in a flavour-conserving or violating manner. In this talk, I will present the constraints on the model parameters of an A4 leptonic flavour model using a synergy of g-2, charged lepton flavour conversion and collider data. The most powerful constraints derive from the MEG collaboration's result and the reinterpretation of an 8 TeV ATLAS search for anomalous productions of multi-leptonic final states.
89. Nuclear Physics Seminar

    "Probing the Sea Quark Polarization at RHIC/STAR"

    Presented by Jinlong Zhang, Stony Brook University

    Tuesday, February 5, 2019, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: Oleg Eyser

    Polarized proton-proton collision experiments at RHIC have provided unique opportunities to study the spin structure of the nucleon. One of the primary motivations of RHIC spin program is to probe sea quark spin-flavor structure via W-boson production in proton-proton collisions at a center of mass energy of 500 GeV. Measurements of the longitudinal single-spin asymmetry, A_L, of W-bosons with the STAR detector have provided significant constraints on the polarized parton distribution functions and especially the first experimental indication of a flavor asymmetry of polarized sea. In this seminar, I will present the analyses and latest results from STAR, as well as their impact on our knowledge of the sea quark helicity distributions.
90. HET Lunch Discussion

    "Multiparticle States in Lattice QCD and Prospects for Neutrino Physics"

    Presented by Aaron Meyer, BNL

    Friday, February 1, 2019, 12:15 pm
    Building 510, Room 2-160

    Hosted by: Peter Denton
91. RIKEN Lunch Seminar

    "Sorting out jet quenching in heavy-ion collisions"

    Presented by Jasmine Brewer, Massachusetts Institute of Technology

    Thursday, January 31, 2019, 12 pm
    Building 510, Room 2-160

    Hosted by: Enrico Rinaldi

    We introduce a new "quantile'' analysis strategy to study the modification of jets as they traverse through a droplet of quark-gluon plasma. To date, most jet modification studies have been based on comparing the jet properties measured in heavy-ion collisions to a proton-proton baseline at the same reconstructed jet transverse momentum pT. It is well known, however, that the quenching of jets from their interaction with the medium leads to a migration of jets from higher to lower pT, making it challenging to directly infer the degree and mechanism of jet energy loss. Our proposed quantile matching procedure is inspired by (but not reliant on) the approximate monotonicity of energy loss in the jet pT. In this strategy, jets in heavy-ion collisions ordered by pT are viewed as modified versions of the same number of highest-energy jets in proton-proton collisions. Despite non-monotonic fluctuations in the energy loss, we use an event generator to validate the strong correlation between the pT of the parton that initiates a heavy-ion jet and the pT of the vacuum jet which corresponds to it via the quantile procedure. We demonstrate that this strategy both provides a complementary way to study jet modification and mitigates the effect of pT migration in heavy-ion collisions.
92. Environmental & Climate Sciences Department Seminar

    "What can we learn from cloudy convection in a box? Laboratory meets LES with cloud microphysics"

    Presented by Raymond Shaw, MTU

    Thursday, January 31, 2019, 11 am
    Conference Room Bldg 815E

    Hosted by: Fan Yang

    Inspired by early convection-tank experiments (e.g., Deardorff and Willis) and diffusion-chamber experiments, we have developed a cloud chamber that operates on the principle of isobaric mixing within turbulent Rayleigh-Bénard convection. The "Pi cloud chamber" has a height of 1 m and diameter of 2 m. An attractive aspect of this approach is the ability to make direct comparison to large eddy simulation with detailed cloud microphysics, with well characterized boundary conditions, and statistical stationarity of both turbulence and cloud properties. Highlights of what we have learned are: cloud microphysical and optical properties are representative of those observed in stratocumulus; aerosol number concentration plays a critical role in cloud droplet size dispersion, i.e., dispersion indirect effect; aerosol-cloud interactions can lead to a condition conducive to accelerated cloud collapse; realistic and persistent mixed-phase cloud conditions can be sustained; LES is able to capture the essential features of the turbulent convection and warm-phase cloud microphysical conditions. It is worth considering what more could be learned with a larger-scale cloudy-convection chamber. Turbulence Reynolds numbers and Lagrangian-correlation times would be scaled up, therefore allowing more enhanced role of fluctuations in the condensation-growth process. Larger vertical extent (of order 10 m) would approach typical collision mean free paths, thereby allowing for direct observation of the transition from condensation- to coalescence-growth. In combination with cloudy LES, this would be an opportunity for microphysical model validation, and for synergistic learning from model-measurement comparison under controlled experimental conditions.
93. HET Seminar

    "Matrix Elements for Neutrinoless Double Beta Decay from Lattice QCD"

    Presented by David Murphy, MIT

    Wednesday, January 30, 2019, 2:30 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Aaron Meyer

    While neutrino oscillation experiments have demonstrated that neutrinos have small, nonzero masses, much remains unknown about their properties and decay modes. One potential decay mode —- neutrinoless double beta decay ($0 \nu \beta \beta$) —- is a particularly interesting target of experimental searches, since its observation would imply both the violation of lepton number conservation in nature as well as the existence of at least one Majorana neutrino, in addition to giving further constraints on the neutrino masses and mixing angles. Relating experimental constraints on $0 \nu \beta \beta$ decay rates to the neutrino masses, however, requires theoretical input in the form of non-perturbative nuclear matrix elements which remain difficult to calculate reliably. In this talk we will discuss progress towards first-principles calculations of relevant nuclear matrix elements using lattice QCD and effective field theory techniques, assuming neutrinoless double beta decay mediated by a light Majorana neutrino.
94. Condensed-Matter Physics & Materials Science Seminar

    "Strongly-correlated systems: Controllable field-theoretical approach"

    Presented by Igor Tupitsyn, University of Massachusetts Amherst

    Tuesday, January 29, 2019, 1:30 pm
    ISB Bldg. 734, Conf. Rm. 201 (upstairs)

    Hosted by: Alexei Tsvelik

    Accurate account for interactions in theoretical models for strongly correlated many-body systems is the key for understanding real materials and one of the major technical challenges of modern physics. To accept this challenge, new and more effective methods, capable of dealing with interacting systems/models in an approximation-free manner, are required. One of such methods is the field-theoretical Diagrammatic Monte Carlo technique (DiagMC). While a conventional Quantum Monte Carlo samples the configuration space of a given model Hamiltonian, the DiagMC samples the configuration space of the model-specific Feynman diagrams and obtains final results with controlled accuracy by accounting for all the relevant diagrammatic orders. In contrast to conventional QMC, it does not suffer from the fermionic sign problem and can be applied to any system with arbitrary dispersion relation and shape of the interaction potential (both doped and undoped). In the first part of my talk I will introduce the technique, based on its bold-line (skeleton) implementation, and benchmark it against known results for the problem of semimetal-insulator transition in suspended graphene. In the second part I will briefly demonstrate its applications to various strongly-correlated systems/problems (stability of the 2d Dirac liquid state against strong long-range Coulomb interaction; interacting Chern insulators; phonons in metals; 1d chain of hydrogen atoms; uniform electron gas (jellium model), optical conductivity, etc).
95. Nuclear Physics Seminar

    "Measurements and Calculations of $\hat{q}L$ via transverse momentum broadening in RHIC collisions using di-hadron correlations"

    Presented by Michael Tannenbaum, BNL

    Tuesday, January 29, 2019, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: Jin Huang

    The renewed interest in analyzing RHIC data on di-hadron correlations as probes of final state transverse broadening as shown at Quark Matter 2018 by Miklos Gyulassy citing theoretical calculations compared to experimental measurements which didn't look right on Miklos' figure led me to take a closer look at this issue using published PHENIX data . The measured values of $\hat{q}L$ show the interesting effect of being consistent with zero for values of the associated particle transverse momentum pTa >3 GeV/c. This is shown to be related to the well-known effect of the variable IAA, the ratio of the Au+Au to p+p pTa distributions for a given trigger pTt.
96. Office of Educational Programs Event

    "High School Science Bowl"

    Saturday, January 26, 2019, 8 am
    Berkner Hall Auditorium

    Hosted by: Amanda Horn
97. Nuclear Theory / RIKEN Seminar

    "Effective field theory of hydrodynamics"

    Presented by Paolo Glorioso, Kadanoff Center for Theoretical Physics and Enrico Fermi Institute, University of Chicago

    Friday, January 25, 2019, 2 pm
    CFNS Seminar Room 2-38

    Hosted by: Niklas Mueller

    I will give an overview of our work on developing an effective field theory of dissipative hydrodynamics. The formulation is based on the Schwinger-Keldysh formalism, which provides a functional approach that naturally includes dissipation and fluctuations. Hydrodynamics is implemented by introducing suitable degrees of freedom and symmetries. I will then discuss two important by-products. First, the second law of thermodynamics, which in the traditional approach is imposed at phenomenological level, is here obtained from a basic symmetry principle together with constraints from unitarity. Second, I will show consistency with unitarity and causality of the hydrodynamic path-integral at all loops, which leads to the first systematic framework to compute hydrodynamic fluctuations.
98. HET Lunch Discussion

    "Hubble Parameter Tension"

    Presented by Anze Slosar, BNL

    Friday, January 25, 2019, 12:15 pm
    Building 510, Room 2-160

    Hosted by: Peter Denton
99. RIKEN Lunch Seminar

    "Quarkonium production in heavy ion collisions: open quantum system, effective field theory and transport equations"

    Presented by Xiaojun Yao, Duke University

    Thursday, January 24, 2019, 12 pm
    Building 510, Room 1-224

    Hosted by: Yuta Kikuchi

    In this talk, I will present a connection between two approaches of studying quarkonium dynamics inside quark-gluon plasma: the open quantum system formalism and the transport equation. I will discuss insights from the perspective of quantum information. I will show that under the weak coupling and Markovian approximations, the Lindblad equation turns to a Boltzmann transport equation after a Wigner transform is applied to the system density matrix. I will demonstrate how the separation of physical scales justifies the approximations, by using effective field theory of QCD. Finally, I will show some phenomenological results based on the derived transport equation.
100. Instrumentation Division Seminar

     "A Roadmap for the Best PMTs and SiPM in Physics Research"

     Presented by Razmik Mirzoyan, Max Planck Institute for Physics, Germany

     Wednesday, January 23, 2019, 2:30 pm
     Large Conference Room, Bldg. 535

     Photomultiplier Tubes (PMT) are the most wide spread detectors for measuring fast and faint light signals. In cooperation with the companies Hamamatsu Photonics K.K. (Japan) and Electron Tubes Enterprises Ltd. (England) we pursued an improvement program for the PMTs for the Cherenkov Telescope Array (CTA) project. CTA is the next major Imaging Atmospheric Cherenkov Telescopes (IACT) array for ground-based very high energy gamma-ray astrophysics. A total of ∼100 telescopes of sizes of 23m, 12m and 4m in diameter will be built in northern and southern hemispheres. The manufacturers succeeded producing 1.5′ PMTs of enhanced peak quantum efficiency of ∼38-42 % and after pulsing below 0.02% (threshold ≥ 4 photoelectrons). The novel 1.5′ PMTs have the world-wide best parameters. It is interesting to compare the performance of PMTs with the current generation of SiPMs. In the imaging camera of the MAGIC IACT, consisting of 1039 PMTs, since many months we are operating composite clusters of SiPMs from the three well-known manufacturers. A critical comparison of these two types of sensors will be presented. Prospects for further significant improvements of PMTs and SiPMs will be discussed, also in the frame of the supported by the EU SENSE Roadmap for the best fast light sensors.
101. Condensed-Matter Physics & Materials Science Seminar

     "Recent Progress in Non-perturbative methods for QFTs"

     Presented by Lorenzo Vitale, Boston University

     Wednesday, January 23, 2019, 1:30 pm
     ISB Bldg. 734 Conf. Rm. 201 (upstairs)

     Hosted by: Alexei Tsvelik

     Quantum field theories (QFT) are notoriously hard to solve in the strongly coupled regime, and few tools are available in space dimension larger than one. In this talk I discuss recent progress and ideas in characterizing certain QFTs in dimension d >= 1, based on the Hamiltonian Truncation and S-matrix bootstrap techniques. Some of the applications I will mention are Landau-Ginzburg theories and the Chern-Simons-matter theories.
102. Particle Physics Seminar

     "Exploring the HEP frontier with the Cosmic Microwave Background and 21cm cosmology"

     Presented by Laura Newburgh, Yale University

     Friday, January 18, 2019, 3 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Anze Slosar

     Current cosmological measurements have left us with deep questions about our Universe: What caused the expansion of the Universe at the earliest times? How many standard model particles are there? What is the underlying nature of Dark Energy and dark matter? New experiments like CMB-StageIV, Simons Observatory, and CHIME are poised to address these questions through measurements of the polarized Cosmic Microwave Background and 3-dimensional maps of structure. In this talk, I will describe efforts in the community to deploy enormous experiments that are capable of turning CMB measurements into probes of high energy particle physics. I will also discuss how we can broaden the potential science returns by including 21 cm measurements of large scale structure as a new means to probe Dark Energy with experiments like CHIME and HIRAX.
103. Nuclear Theory / RIKEN Seminar

     "Chiral Vortical Effect For An Arbitrary Spin"

     Presented by Andrey Sadofyev, Los Alamos National Lab

     Friday, January 18, 2019, 2 pm
     CFNS Seminar Room 2-38

     Hosted by: Niklas Mueller

     Chiral effects attracted significant attention in the literature. Recently, a generalization of chiral vortical effect (CVE) to systems of photons was suggested. In this talk I will discuss the relation of this new transport to the topological phase of photons and show that, in general, CVE can take place in rotating systems of massless particles with any spin.
104. Instrumentation Division Seminar

     "Timing circuits for high-energy physics applications"

     Presented by Jeffrey Prinzie, KU Leuven University, Belgium

     Friday, January 18, 2019, 11 am
     Large Conference Room, Bldg. 535

     In the era of complex systems on chip (SoCs), clock and timing generation is required in nearly any application. These timing generators supply clock signals to digital modules, act as heartbeats for serial communication links or provide picosecond accurate reference information to time-interval sensors. Phase Locked Loops are the main building block that provide clock signals. However, in the high-energy physics community, ionizing radiation effects degrade these circuits significantly and produce soft-errors which can disturb an entire system. In this seminar, the application of these timing blocks in the high-energy physics are discussed together with the mitigation techniques for ionizing radiation.
105. RIKEN Lunch Seminar

     "Proton decay matrix elements on lattice"

     Presented by Mr. Jun-sik Yoo, Stony Brook University

     Thursday, January 17, 2019, 12 pm
     Building 510, Room 2-160

     Hosted by: Enrico Rinaldi

     Proton decay is one of possible signatures of baryon number violation, which has to exist to explain the baryon asymmetry and the existence of nuclear matter. Proton decay is one of natural implications of the Grand Unification Theory. After integrating out the high energy degrees of freedom, the baryon number violation operator that mediates proton decay can be found as the composite operator of standard model fields. We discuss the hadronic matrix elements of this BV operator made of three quarks and a lepton. We will start from the current experimental bound of proton lifetime. We present preliminary results of matrix element calculation done with the 2+1 dynamical flavor domain wall fermions at the physical point. We will discuss the proton decay channels that no matrix element has been calculated on the lattice.
106. Condensed-Matter Physics & Materials Science Seminar

     "Effect of ion irradiation on the mechanical behavior and microstructural evolution of nanoscale metallic alloys"

     Presented by Gowtham Sriram Jawaharram, University of Illinois at Urbana - Champaign

     Wednesday, January 16, 2019, 11 am
     ISB Bldg. 734 Conference Room 201 (upstairs)

     Hosted by: Jing Tao

     Nanostructured alloys are considered as potential candidates for next generation (Generation IV) nuclear reactors because the high densities of interfacial defect sinks present in these materials. The effect of irradiation on the mechanical behavior of such alloys has received limited attention, likely resulting from the experimental challenges associated with performing such experiments. The first part of the talk will report on our recent efforts to perform high temperature irradiation induced creep (IIC) measurements in focused ion beam fabricated FCC alloys (single crystalline Ag nanopillars and nanocrystalline high entropy alloys (HEA) microbeams) by combining in-situ TEM based small-scale mechanical testing with ion irradiation and in-situ laser heating using the in-situ ion irradiation transmission electron microscope (I3TEM) at Sandia National Laboratories. The effect of pillar size, grain size, and temperature on the observed creep mechanism will be discussed. The second part of the talk will focus on the microstructural evolution of model highly immiscible CuW alloys during thermal annealing and high temperature irradiation characterized using high angle annular dark field (HAADF) imaging. The results will be discussed from the context of evolution and spatial distribution of W precipitates and its effect on hardness as a function of irradiation dose and temperature.
107. Physics Colloquium

     "Liquid Argon Detectors and Readout Electronics: From R&D to Physics Discovery"

     Presented by Hucheng Chen, BNL

     Tuesday, January 15, 2019, 3:30 pm
     Large Seminar Room, Bldg. 510

     Hosted by: Andrei Nomerotski

     BNL has a long history of R&D in noble liquid based detectors, from the invention of the first liquid argon (LAr) calorimeter in 1974, to the construction of large liquid argon time projection chambers (LAr TPC) leading to Deep Underground Neutrino Experiment (DUNE) by 2026, in a time span over half a century. Readout electronics has always been an integral part of the detector, in both ATLAS LAr Calorimeter where high precision has played an essential role in the 2012 Higgs discovery, and in LAr TPC based neutrino detectors where cryogenic electronics proved to be an enabling technology. The development of noble liquid based detectors and readout electronics systems at BNL will be presented, focused on integrated detector-readout design, as motivated by our physics interests and experiment requirements, in energy frontier LHC experiments, and in intensity frontier short baseline and long baseline neutrino experiments. As both experiments present challenges in data acquisition, the FELIX based DAQ system for high-bandwidth detector readout developed at BNL, also being adopted in various particle physics experiments worldwide, will be discussed as well.
108. Particle Physics Seminar

     "Cross section measurements and new physics searches with WZ vector boson scattering events at CMS"

     Presented by Kenneth Long, University of Wisconsin - Madison

     Thursday, January 10, 2019, 3 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Alessandro Tricolli

     As the standard model (SM) Higgs boson looks increasingly like its SM expectation, expanded tests of the electroweak (EW) sector of the SM are a focal point of the long-term LHC program. Production of massive vector bosons via vector boson scattering provides a direct probe of the self-interactions of the massive vector bosons, which are intimately connected to the Higgs-Englert-Brout mechanism of EW symmetry breaking. A search for vector boson scattering of W and Z bosons has recently been performed by the CMS experiment using data collected in 2016. I will present this search as well as WZ cross section measurements, which are less dependent on theoretical inputs. This process is also sensitive to New Physics in the EW sector. I will present interpretations of these results in terms of explicit models predicting additional charged Higgs bosons and in the generalized framework of dimension-8 effective field theory.
109. RIKEN Lunch Seminar

     "A novel background subtraction method for jet studies in heavy ion collisions"

     Presented by Alba Soto Ontoso, BNL

     Thursday, January 10, 2019, 12 pm
     Building 510, Room 2-160

     Hosted by: Yuta Kikuchi
110. Condensed-Matter Physics & Materials Science Seminar

     "Exact Solution and Semiclassical Analysis of BCS-BEC Crossover in One Dimension"

     Presented by Tianhao Ren, Columbia University

     Monday, January 7, 2019, 1:30 pm
     ISB Bldg. 734 Conf. Rm. 201 (upstairs)

     Hosted by: Alexei Tsvelik

     In this talk, I will introduce a new type of model for two-component systems in one dimension subject to exact solutions by Bethe ansatz. It describes the BCS-BEC crossover in one dimension and its integrability is obtained by fine-tuning the model parameters. The new model has rich many-body physics, where the Fermi momentum for the ground state distribution is constrained to be smaller than a certain value and the zero temperature phase diagram with an external field has a critical field strength for polarization. Also the low energy excitation spectra of the new model present robust features that can be related to solitons at BCS-BEC crossover in one dimension, as shown by the semiclassical analysis.
111. Particle Physics Seminar

     "DM-Ice17 and COSINE-100 NaI(Tl) Dark Mater Experiment: Testing DAMA's Claim for a Dark Matter Discovery"

     Presented by Jay Hyun Jo, Yale University

     Thursday, January 3, 2019, 3 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Chao Zhang

     Astrophysical observations give overwhelming evidence for the existence of dark matter, yet we do not know what it is. For over 20 years, the DAMA collaboration has asserted that they observe a dark matter-induced annual modulation signal but their observation has yet to be confirmed by an independent measurement. DM-Ice17 is a prototype experiment consisting of 17 kg of NaI(Tl) detectors to test the DAMA's claimed detection of the dark matter annual modulation, which has been continuously operating at the South Pole since 2011. COSINE-100 is a joint experiment between DM-Ice and KIMS collaboration, situated at the Yangyang Underground Laboratory in South Korea. COSINE-100 consists of eight low background NaI(Tl) crystals with a total mass of 106 kg and 2000 liters of liquid scintillator as an active veto, and the physics run of the experiment began in September 2016. The recent results from DM-Ice17 and COSINE-100, including the status of the field, will be presented.
112. Instrumentation Division Seminar

     "Data Acquisition Systems for High-Speed and High-Dynamic Range Pixel Array Detectors"

     Presented by Prafull Purohit, Cornell University

     Friday, December 28, 2018, 10:30 am
     Large Conference Room, Bldg. 535

     Pixel array detectors (PADs) have seen significant increase in performance and operational complexity in recent years due to advances in microelectronics technology and photon science needs. These advances in detector technology put equal complexity and performance requirements on the data acquisition and control systems for successful operation. A Field Programmable Gate Array (FPGA) with its high-speed processing and reconfiguration capabilities can be utilized to meet current requirements and future needs. In this talk, I will present some of the recent work done at Cornell University on FPGA-based data acquisition systems for high-speed, high dynamic range detectors as well as detectors for time resolved experiments.
113. Particle Physics Seminar (Leona Woods Distinguished Postdoctoral Lectureship Award)

     "Measurement of top quark pair production in association with a Higgs or gauge boson at the LHC with the ATLAS detector"

     Presented by María Moreno Llácer, CERN

     Thursday, December 20, 2018, 3 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Alessandro Tricoli

     The top quark is unique among the known quarks since it decays before it has an opportunity to form hadronic bound states. This makes measurements of its properties particularly interesting as one can access directly the properties of a bare quark. Given its large mass (the heaviest fundamental particle), the top quark may play a special role in the electroweak symmetry breaking mechanism and therefore, new physics related to this might be found first in top quark precision measurements. Possible new physics signals would cause deviations of the top quark couplings from the Standard Model (SM) prediction. It couples to the SM fields through its gauge and Yukawa interactions. The high statistics top quark sample at the LHC has allowed to access the associated production of a top quark pair with a boson: tt+photon, tt+W, tt+Z and tt+H. The latest measurements carried out by the ATLAS detector for these physics processes will be presented, highlighting the main challenges.
114. Physics Colloquium (Leona Woods Distinguished Postdoctoral Lectureship Award)

     "On top of the top: challenging the Standard Model with precise measurements of top quark properties"

     Presented by María Moreno Llácer, CERN

     Tuesday, December 18, 2018, 3:30 pm
     Large Seminar Room, Bldg. 510

     Hosted by: Andrei Nomerotski

     The understanding of the Electro-Weak Symmetry Breaking mechanism and the origin of the mass of fundamental particles is one of the most important questions in particle physics today. The top quark is unique among the known quarks since it is the heaviest fundamental particle in the Standard Model. Its large mass makes the top quark very different from all other particles, with a Yukawa coupling to the Higgs boson close to unity. For these reasons, the top quark and the Higgs boson play very special roles in the SM and in many extensions thereof. An accurate knowledge of their properties can bring key information on fundamental interactions at the electroweak breaking scale and beyond. The Large Hadron Collider is providing an enormous dataset of proton-proton collisions at the highest energies ever achieved in a laboratory. With the unprecedentedly large sample of top quarks, a new frontier has opened, the flavour physics of the top quark, allowing to study whether the Higgs field is the unique source of the top quark's mass and whether there are unexpected interactions between the top quark and the Higgs boson. The answers to these questions will shed light on what may lie beyond the Standard Model and can even have cosmological implications.
115. Condensed-Matter Physics & Materials Science Seminar

     "Uncovering the interactions behind quantum phenomena"

     Presented by Keith Taddei, Oak Ridge National Laboratory

     Tuesday, December 18, 2018, 11 am
     ISB Bldg. 734, Conf. Rm. 201 (upstairs)

     Hosted by: Ian Robinson/Mark Dean

     Quantum computing, spintronics and plasmonics are nascent fields with potential to radically change our technological landscape. Fundamental to advancing these technologies is a mastery of quantum materials such as superconductors, quantum-spin-liquids and multiferroics. Ideally, we would know exactly what interactions give rise to these phenomena and design materials suitable for applications however, such an understanding as of yet eludes us. Instead we are stuck digging around in the phase space of known quantum materials slowly uncovering pertinent details to their design, filling in pieces of our incomplete picture. In this presentation, I will discuss recent bits I have found in my use of neutron scattering to study quantum materials. Starting with a novel new family of quasi-one-dimensional (Q1D) superconductors (A1,2TM3As3 with A = alkali metal and TM = Cr, Mo) I will present findings of short-range structural order and a proximate magnetic instability which, due the radically different structure, allow for new insights to the pertinence to such orders to superconductivity. Importantly, in these materials the two orders break different symmetries and so their interactions with the superconducting order can be studied independently. Next, I will discuss an interesting yet neglected family of frustrated magnetic materials – the rare-earth pyrogermanates (REPG). We find the Er2Ge2O7 REPG to exhibit 'local-Ising' type magnetism in direct analogy to the spin-ice pyrochlores suggesting effects of local anisotropies and dipole interactions. Finally, I will present ongoing work investigating spin-driven polarization effects in the magnetically and structurally straightforward multiferroic BiCoO3. These results demonstrate the essential role of neutron and x-ray scattering techniques in studying these complex materials and the fruitful opportunities these systems present to advance our understanding of quantum materials.
116. Physics Colloquium

     "The Science of the Sudbury Neutrino Observatory (SNO) and SNOLAB"

     Presented by Art McDonald, Queens University

     Monday, December 17, 2018, 3:30 pm
     Large Seminar Room, Bldg. 510

     Hosted by: David Asner

     A description of the science associated with the Sudbury Neutrino Observatory, performed with substantial contributions from BNL scientists, and its relation to other neutrino measurements will be given, along with a discussion of the new set of experiments that are at various stages of development or operation at SNOLAB. These experiments will perform measurements of neutrino properties and seek direct detection of Weakly-Interacting Massive Particles (WIMPS) as Dark Matter candidates. Specific examples will include SNO+ (with BNL participation), in which the central element of the SNO detector will now be liquid scintillator with Te dissolved for neutrino-less double beta decay and DEAP-3600 using liquid argon for single phase direct Dark Matter detection. Future directions for Dark Matter detection with liquid argon will also be discussed.
117. NT/RIKEN Seminar

     "Lattice QCD Input for Fundamental Symmetry Tests"

     Presented by Micheal Wagman, MIT

     Friday, December 14, 2018, 2 pm
     Building 510, Room 2-38

     Hosted by: Niklas Mueller

     Experimental detection of fundamental symmetry violation would provide a clear signal for new physics, but theoretical predictions that can be compared with data are needed in order to interpret experimental results as measurements or constraints of beyond the Standard Model physics parameters. For low-energy experiments involving protons, neutrons, and nuclei, reliable theoretical predictions must include the strong interactions of QCD that confine quarks and gluons. I will discuss experimental searches for neutron-antineutron oscillations that test beyond the Standard Model theories of matter-antimatter asymmetry with low-scale baryon-number violation. Lattice QCD can be used to calculate the neutron-antineutron transition rate using a complete basis of six-quark operators describing neutron-antineutron oscillations in effective field theory, and I will present the first lattice QCD results for neutron-antineutron oscillations using physical quark mass simulations and fully quantified uncertainties. Other experiments searching for neutrinoless double-beta decay and dark matter direct detection use large nuclear targets that are more difficult to simulate in lattice QCD because of an exponentially difficult sign(al-to-noise) problem. I will briefly describe the state-of-the-art for lattice QCD calculations of axial, scalar, and tensor matrix elements relevant to new physics searches with nuclei and outline my ongoing efforts to improve signal-to-noise problems using phase unwrapping.
118. HET Lunch Discussion

     "Review of the Physics of the Near Detector at DUNE Workshop"

     Presented by Peter Denton, BNL

     Friday, December 14, 2018, 12:15 pm
     Building 510, Room 2-160

     Hosted by: Christoph Lehner
119. Condensed-Matter Physics & Materials Science Seminar

     "Discussion of opportunities related to Quantum Information initiative"

     Presented by Alexei Tsvelik, BNL

     Friday, December 7, 2018, 3 pm
     ISB Bldg. 734, Conf. Rm. 201 (upstairs)

     Alexei Tsvelik will be sharing his thoughts on how we can answer to the DOE initiative on Quantum Information
120. HET Lunch Discussion

     "The Neutron Lifetime Puzzle Solution"

     Presented by Bill Marciano, BNL

     Friday, December 7, 2018, 12:15 pm
     Building 510, Room 2-160

     Hosted by: Christoph Lehner
121. NSLS-II Friday Lunchtime Seminar

     "Magnetic skyrmions at room temperature - statics, dynamics, and high resolution imaging"

     Presented by Dr. Felix Buttner, Dept of Mat Sci & Eng , MIT

     Friday, December 7, 2018, 12 pm
     NSLS-II Bldg 743 Room 156

     Hosted by: Ignace Jarrige

     Magnetic skyrmions are the smallest non-trivial entities in magnetism with great potential for data storage applications. These chiral and topological quasi-particles furthermore exhibit fascinating static and dynamical properties that render them the ideal candidates to study new physics in high spin-orbit coupling materials. In this talk, I will first give a general introduction to the field of skyrmionics and the fundamental properties of skyrmions that derive from their energetics. I will then discuss various ways of creating and stabilizing room-temperature skyrmions experimentally, as well as how we can move them and observe their topological dynamics via high resolution time-resolved x-ray imaging. I will conclude with perspectives of future research in this field and related areas.
122. Particle Physics Seminar

     "The Global Electroweak Fit in the light of the new results from the LHC"

     Presented by Matthias Schott, University of Mainz

     Thursday, December 6, 2018, 3 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Alessandro Tricoli

     With the high integrated luminosities recorded at the LHC and the very good understanding of the LHC detectors, it is possible to measure electroweak observables to the highest precision. In this talk, I review the measurement of the W boson mass as well as the measurement of the electroweak mixing angle with the ATLAS detector, both achieving highest precision after several years of intense effort. Special focus is drawn on a discussion of the modeling uncertainties as well as the physics potential of the latest low-mu runs, recorded at in 2017 and 2018. The results will be interpreted in terms of the overall consistency of the Standard Modell by the global electroweak fit, performed by the Gfitter Collaboration.
123. RIKEN Lunch Seminar

     "On QCD and its Phase Diagram from a Functional RG Perspective"

     Presented by Mario Mitter, BNL

     Thursday, December 6, 2018, 12 pm
     Building 510, Room 2-160

     Hosted by: Yuta Kikuchi
124. Condensed-Matter Physics & Materials Science Seminar

     "Laser induces dynamics in complex oxides with visible/NIR and X-ray probe (Note: This will be a skype presentation)"

     Presented by Sergii Parchenko, Swiss Light Source, Paul Scherrer Institute, Switzerland

     Tuesday, December 4, 2018, 11 am
     ISB Bldg. 734, Conf. Rm. 201 (upstairs)

     Hosted by: Ian Robinson/Mark Dean

     **********Note: This will be a Skype Presentation************ recent achievements in generation of ultrashort and intense light pulses allow observation of the physical process on the ultrafast regime. exploring fundamental physical processes on the time scales of interactions, responsible for them, is the key for future understanding of the physical principles and implementation then to the technological application. with this talk, i'm going to present the study of laser induced dynamics in complex oxides with focus on several physical objects: magnetic exchange interaction, insulator to metal transition and magneto-electric coupling. it will be discussed how the study of laser induced changes with different probing methods could help to understand the microscopic mechanisms of physical processes on the ultrafast time scale.
125. Condensed-Matter Physics & Materials Science Seminar

     "First-principles description of correlated materials with strong spin-orbit coupling: the analytic continuation and branching ratio calculation"

     Presented by Jae-Hoon Sim, Department of Physics, KAIST, Korea, Republic of (South)

     Monday, December 3, 2018, 1:30 pm
     ISB Bldg. 734 Conf. Rm. 201 (upstairs)

     Hosted by: Sangkook Choi

     The DFT+DMFT combined with the continuous-time quantum Monte Carlo (CT-QMC) impurity solver is one of the successful approaches to describe correlated electron materials. However, analytic continuation of the QMC data written in the imaginary frequency to the real axis is a difficult numeric problem mainly due to the ill-conditioned kernel matrix. While the maximum entropy method is one of the most suitable choices to gain information from the noisy input data, its applications to the materials with strong spin-orbit coupling are limited by the non-negative condition of the output spectral function. In the first part of this talk, I will discuss the newly developed methods for analytic continuation problem, the so-called maximum quantum entropy method (MQEM) [1]. It is the extension of the conventional method, introducing quantum relative entropy as a regularization function. The application of the MQEM for a prototype j_eff=1/2 Mott insulator, Sr2IrO4, shows that it provides a reasonable band structure without introducing a material specific base set. I will also introduce the application of machine learning technique to the same problem [2]. In the second part, a simple technique to branching ratio from the first-principles calculation will be discussed [3]. The calculated ?L·S? and branching ratio of the different 5d iridates, namely Sr2IrO4, Sr2MgIrO6, Sr2ScIrO6, and Sr2TiIrO6 are in good agreement with recent experimental data. Its reliability and applicability also be carefully examined in the recent study. [1] J.-H. Sim and M. J. Han, Phys. Rev. B 98, 205102 (2018). [2] H. Yoon, J.-H. Sim, and M. J. Han, Phys. Rev. B (in press). [3] J.-H. Sim, H. Yoon, S. H. Park, and M. J. Han, Phys. Rev. B 94, 115149 (2016).
126. Condensed-Matter Physics & Materials Science Seminar

     "Localized-to-itinerant crossovers in Kondo materials"

     Presented by Daniel Mazzone, Brookhaven National Laboratory, NSLS-II

     Monday, December 3, 2018, 11 am
     ISB Bldg. Conf. Room 201 (upstairs)

     Hosted by: Ian Robinson/Mark Dean

     While charge carriers in crystalline structures can be located close to the nuclei or establish a delocalized character, they often epitomize strong fluctuations at intermediate regimes where emergent quantum phases show an intricate coupling among various degrees of freedom. Kondo materials are particularly interesting model systems to investigate strongly correlated phenomena, because they often possess small energy scales that are highly susceptible to macroscopic constraints. I will present recent neutron and X-ray scattering results on the series Nd1-xCexCoIn5 and Sm1-xYxS, where the ground state properties were tuned either via chemical substitution or magnetic field. We find that Nd substitution in CeCoIn5 affects the magnetic coupling parameters, triggering a change in the magnetic symmetry that is offset from the emergence of coherent heavy bands and unconventional superconductivity. Intriguingly, another magneto-superconducting phase with altered coupling is observed in Nd0.05Ce0.95CoIn5 at large magnetic fields. Sm1-xYxS features a transition towards an intermediate valence state under yttrium doping. Our results unravel a Kondo-triggered Lifshitz-transition in the mixed-valence state, which dives an unusually strong charge localization at low temperatures.
127. Nuclear Theory / RIKEN Seminar

     "Novel probes of small-x QCD"

     Presented by Juan Rojo, VU University

     Friday, November 30, 2018, 2 pm
     CFNS Seminar Room 2-38

     Hosted by: Niklas Mueller

     The small Bjorken-x regime of QCD is of great interest since a variety of different phenomena are known or expected to emerge, from BFKL small-x effects and non-linear and saturation dynamics to shadowing corrections in heavy nuclei. In this talk we present recent developments in our understanding of perturbative and non-perturbative QCD at small-x: the evidence for BFKL dynamics in the HERA structure function data, the precision determination of collinear PDFs from charm production at LHCb, and the first results on neural-network based fits of nuclear PDFs. We also highlight the remarkable connection between small-x QCD and high-energy astrophysics, in particular for the theoretical predictions of signal and background event rates at neutrino telescopes such as IceCube and KM3NET
128. HET Lunch Discussion

     "Galactic Dark Matter as the Source for Neutrino Masses"

     Presented by Dr. Gopolang Mohlabeng, BNL

     Friday, November 30, 2018, 12:15 pm
     Building 510, Room 2-160

     Hosted by: Christoph Lehner
129. Particle Physics Seminar

     "The structure of the proton in the LHC precision era"

     Presented by Juan Rojo, Vrije Universiteit Amsterdam and Nikhef

     Thursday, November 29, 2018, 3 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Alessandro Tricoli

     The determination of the partonic structure of the proton is a central component of the precision phenomenology program at the Large Hadron Collider (LHC). This internal structure of nucleons is quantified in the collinear QCD factorization framework by the Parton Distribution Functions (PDFs), which encode the probability of finding quarks and gluons inside the proton carrying a given amount of its momentum. PDFs cannot currently be computed from first principles, and therefore they need to be determined from experimental data from a variety of hard-scattering cross-sections in lepton-proton and proton-proton collisions. This program, known as the global QCD analysis, involves combining the most PDF-sensitive data and the highest precision QCD and electroweak calculations available within a statistically robust fitting methodology. In this talk I review our current understanding of the quark and gluon structure of the proton, which emphasis for the implications for precision LHC phenomenology and searches for new physics, but also exploring other aspects of the nucleon structure such as their impact on high-energy neutrino telescopes, the connection with lattice QCD calculations, and the onset of novel small-x dynamics beyond the collinear framework. Finally, I highlight the prospects for improving our understanding of the quark/gluon structure of the nucleon at the high-luminosity LHC era.
130. HET Seminar

     "FASER: ForwArd Search ExpeRiment at the LHC"

     Presented by Felix Kling, Arizona State University

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

     New physics has traditionally been expected in the high-pT region at high-energy collider experiments. If new particles are light and weakly-coupled, however, this focus may be completely misguided: light particles are typically highly concentrated within a few mrad of the beam line, allowing sensitive searches with small detectors, and even extremely weakly-coupled particles may be produced in large numbers there. We have propose a new experiment, ForwArd Search ExpeRiment, or FASER, which will be placed downstream of the ATLAS interaction point in the unused service tunnel TI12 and operated concurrently there. FASER will complement the LHC's existing physics program and extend its discovery potential to a host of new particles, such as dark photons and axion-like particles. In this talk, I will describe FASER's location and discovery potential, the detector's layout and components, as well as the experiment's timeline.
131. Physics Colloquium

     "Studying Quantum Matter on Near-Term Quantum Computers"

     Presented by Brian Swingle, University of Maryland and Institute of Advanced Study

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

     Hosted by: Rob Pisarski

     From the point of view of fundamental physics, one of the greatest promises of quantum information science is a new set of quantum computational tools for addressing previously intractable problems. However, at present we find ourselves in an age of embodied quantum information, where the substrate carrying the information cannot yet be abstracted away and effects of noise cannot be neglected. Nevertheless, I will argue that such noisy, intermediate size quantum devices may be useful for addressing open problems in quantum many-body physics, and potentially quantum field theory. Using two case studies, I will show how quantum information is informing our understanding of quantum matter and how near-term quantum computers might realistically help.
132. Nuclear Theory / RIKEN

     "Casimir effect in Yang-Mills theory"

     Presented by Dimitra Karabali, Lehman College CUNY

     Friday, November 16, 2018, 2 pm
     CFNS Seminar Room 2-38

     Hosted by: Niklas Mueller

     We consider the Casimir effect in a gauge-invariant Hamiltonian formulation of nonabelian gauge theories in $(2+1)$ dimensions. We compare our analytical results with recent lattice simulations.
133. HET Lunch Discussion

     "Lattice and new physics"

     Presented by Amarjit Soni, BNL

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

     Hosted by: Christoph Lehner
134. PubSci

     "PubSci: Big Bang Physics and the Building Blocks of Matter"

     Thursday, November 15, 2018, 7 pm
     The Snapper Inn 500 Shore Dr, Oakdale, NY 11769
135. RIKEN Lunch Seminar

     "Exclusive $\rho$ meson production in $eA$ collisions: collinear factorization and the CGC"

     Presented by Renaud Boussarie, BNL

     Thursday, November 15, 2018, 12 pm
     Building 510, Room 2-160

     Hosted by: Yuta Kikuchi

     We will focus on the theoretical description of exclusive ρ meson production in eA collisions, using a hybrid factorization scheme which involves Balitsky's shockwave description of the Color Glass Condensate in the t channel, and Distribution Amplitudes (DAs) in the s channel. We will first give a quick introduction to the shockwave framework and to collinear factorization up to twist 3 for DAs, then we will apply these framweworks to the production of a longitudinal meson at NLO accuracy, and to the production of a transverse meson at twist 3 accuracy. We will insist on the experimental applications, and on several theoretical questions raised by our results: the dilute BFKL limit at NLO for diffraction, and collinear factorization breaking at twist 3.
136. Environmental & Climate Sciences Department Seminar

     "Global models for atmospheric new particle formation from the CERN CLOUD experiment"

     Presented by Hamish Gordon, Leeds

     Thursday, November 15, 2018, 11 am
     Conference Room Bldg 815E

     Hosted by: Laura Fierce

     In this seminar I will introduce the CERN CLOUD chamber experiment studying atmospheric new particle formation. I will then focus on work we have done to parameterize new particle formation and growth rates for atmospheric models. I will discuss the implementation of the parameterizations into the models, and the implications of the results from these models for estimated cloud condensation nuclei concentrations and indirect aerosol radiative forcing. The uncertainties in modelling new particle formation remain large, and I will outline how we are moving forward to try to reduce them.
137. HET Seminar

     "Parton Distribution Functions in Lattice QCD"

     Presented by Konstantinos Orginos, College of William and Mary

     Wednesday, November 14, 2018, 2:30 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Aaron Meyer

     Computing the x-dependence of parton distribution functions (PDFs) from first principles had been a challenge for many years. Recent theoretical developments have paved the way to perform this computations for the first time using lattice QCD. In this talk I am reviewing these developments. In particular, I will introduce the concepts of quasi-PDFs and pseudo PDFs and discuss their properties. Finally, I will present results from recent calculations and discuss the prospects for the future.
138. Physics Colloquium

     "From nuts to soup: Recent advances in QCD in the Regge limit and the approach to thermalization in heavy-ion collisions"

     Presented by Raju Venugopalan, BNL

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

     Hosted by: Rob Pisarski

     Twenty five years to date, Larry McLerran and the speaker proposed that the Regge limit of QCD could be described by a many-body classical effective field theory now known as the Color Glass Condensate (CGC). Our radical conjecture was prompted by the phenomenon of gluon saturation, whereby many-body gluodynamics leads to the emergence of a semi-hard scale that screens color in the infrared. In the first part of this talk, we will review developments since in the CGC effective theory, and emphasize a paradigm shift in what constitutes fundamental degrees of freedom in the Regge limit. We shall also outline a color memory effect in the CGC which bears an exact analogy to the gravitational memory effect that could be discovered by LIGO in the near future. This correspondence in turn prompts one to speculate that asymptotic so-called BMS-like symmetries of gravity may also apply in QCD's Regge limit, leading to novel insight into how pions form "soft hair" on glue. In the second part of the talk, we discuss how the CGC provides an ab initio picture of thermalization and hydrodynamics in ultrarelativistic heavy-ion collisions. We focus on the discovery of a pre-thermal turbulent attractor, its topological properties, and a remarkable universality between this attractor and cold atomic gases prepared with the same boundary conditions.
139. Nuclear Theory / RIKEN Seminar

     "Towards laboratory detection of superfluid phases of QCD"

     Presented by Ajit Srivastava, Institute of Physics, Bhubaneswar

     Friday, November 9, 2018, 2 pm
     CFNS Seminar Room 2-38

     Hosted by: Niklas Mueller

     Exotic phases of QCD exhibiting strong correlations exist at very high baryon density and relatively low temperatures. Examples of such phases range from nucleon superfluid phases expected to occur in the interior of neutron stars, to possible color superconducting phases, which may occur in the core of a neutron stars. Some of these phases may also occur in relativistic heavy ion collisions in the high baryon density regime, e.g. at RHIC (BES), FAIR, and NICA. We discuss the possibilities of detecting them in heavy ion collisions focusing on the universal aspects of associated phase transitions.
140. Particle Physics Seminar

     "Managing scientific data at the exascale with Rucio"

     Presented by Martin Barisits, CERN

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

     Hosted by: Paul Laycock, Eric Lancon

     Rucio is an open source software framework that provides scientific collaborations the functionality to organise, manage, and access their volumes of data. The data can be spread across heterogeneous data centres at widely distributed locations. Rucio has been originally developed to meet the requirements of the high-energy physics experiment ATLAS, and is continuously extended to support the LHC upgrades and more diverse scientific communities. Next to ATLAS, the Xenon1t dark matter search and AMS cosmic ray experiment are also using Rucio in production. The CMS experiment will deploy Rucio by 2019 and operate at a similar scale as ATLAS. Additionally several other experiments such as Belle-2 (B mesons), SKA (radio astronomy), LIGO (gravitational waves), DUNE and IceCube (both neutrino) are currently evaluating Rucio for adoption. This talk will discuss the exascale challenges these scientific experiments face and how Rucio will help to address them. Specifically the possibilities for uncomplicated deployment, easy integration in existing data workflows and the benefit of using the automated services provided by Rucio, will be shown. Also the transition of Rucio from a single-experiment system to an open community project, developed by scientists from multiple experiments, will be presented as well.
141. Condensed-Matter Physics & Materials Science Seminar

     "Dirac fermions and critical phenomena: exponents and emergent symmetries"

     Presented by Michael Scherer, University of Cologne, Germany

     Thursday, November 8, 2018, 1:30 pm
     ISB Bldg. 734 Conf. Rm. 201 (upstairs)

     Hosted by: Laura Classen

     Dirac fermions appear as quasi-particle excitations in various condensed-matter systems for example in graphene or as surface states of topological insulators. Close to a quantum phase transition they exhibit a series of exotic properties, e.g., emergent symmetries, fluctuation-induced critical points, the appearance of two length scales and a hierarchy of mass gaps. I discuss mechanisms that are behind these phenomena from a quantum field-theoretical point of view. Further, I present a four-loop renormalization group study for the determination of the Dirac fermions' critical behavior and compare to the predictions of complementary approaches such as quantum Monte Carlo and the conformal bootstrap. Finally, I will also comment on the possibility to test duality conjectures with these calculations.
142. Joint YITP/HET Theory Seminar

     "Jet Substructure and Monte Carlo Simulations with Neural Networks"

     Presented by Maxim Perelstein, Cornell

     Wednesday, November 7, 2018, 2:30 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Sally Dawson
143. Nuclear Theory / RIKEN Seminar

     "Diffractive Electron-Nucleus Scattering and Ancestry in Branching Random Walks"

     Presented by Alfred Mueller, Columbia

     Friday, November 2, 2018, 2 pm
     CFNS Seminar Room 2-38

     Hosted by: Niklas Mueller
144. HET Lunch Discussion

     "A Tale of Two Anomalies"

     Presented by Hooman Davoudiasl, BNL

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

     Hosted by: Christoph Lehner
145. NSLS-II Friday Lunchtime Seminar

     "Materials Tribology: An Application-Driven Field with Rich Opportunities for Fundamental Studies of Surface Chemistry, Physics, Structure"

     Presented by Brandon A. Krick, Department of Mechanical Engineering and Mechanics, Lehigh University

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

     Hosted by: Ignace Jarrige

     The significant economic (~3-6% of developed countries GDP) and environmental (several percent of our annual energy consumption) impacts of friction and wear make tribology is an important, application-driven field. However, there is an opportunity and need for inherently fundamental studies on surface chemistry, physics and structure to elucidate fundamental mechanisms for friction and wear. The non-equilibrium and transient nature of shear-induced changes caused by contacting surfaces in relative motion requires both in situ and ex situ advanced characterization techniques; many of these only available at the light source at Brookhaven. A brief overview of shear-induced (sliding friction/wear) alterations of surfaces will be presented for material systems including: - environmental and tribochemistry molybdenum disulphide based coatings for space applications - shear-induced band bending in GaN - mechanochemistry of polymer nanocomposites
146. Particle Physics Seminar

     "Search of the rare decay of KL→π0νν at J-PARC"

     Presented by Yu-Chen, Tung

     Thursday, November 1, 2018, 3 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Chao Zhang

     J-PARC KOTO is a dedicated experiment to search for the rare KL→π0νν decay. This decay is special not only because of its direct CP violating process, but also its theoretical cleanness. In the standard model, the branching ratio of KL→π0νν is calculated to be 3×10-11 with only a few percent uncertainty, which provides a clean base to explore new physics through finding deviations from the standard model. In the recently released results of data collected in 2015, the sensitivity of search was improved by an order of magnitude from the previous result and no event was observed in the signal region, with the prediction of 0.4 background event. In this talk, I will report the analysis and DAQ plan toward the sensitivity of O(-11).
147. RIKEN Lunch Seminar

     "DIS on "Nuclei" using holography"

     Presented by Kiminad Mamo, Stony Brook University

     Thursday, November 1, 2018, 12 pm
     Building 510, Room 2-160

     Hosted by: Yuta Kikuchi
148. HET Seminar

     "Unveiling New Physics Through Angular Distributions at the LHC"

     Presented by Rodolfo Capdevilla, Notre Dame

     Wednesday, October 31, 2018, 2:30 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Gopolang Mohlabeng

     Angular distributions are commonly used in high precision measurements at colliders. In this talk, we will use the Collins-Soper angular distribution with two goals; to identify the quantum numbers of the mediators in a simplified dark matter model, and to enhance the signal to background ratio of resonance searches in W gamma production at the LHC with the use of the so called Radiation Amplitude Zero.
149. Physics Colloquium

     "Cosmic Chandlery with Thermonuclear Supernovae"

     Presented by Alan Calder, Stony Brook University

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

     Hosted by: Rob Pisarski

     Thermonuclear (Type Ia) supernovae are bright stellar explosions distinguished by light curves that can be calibrated to allow for their use as "standard candles" for measuring cosmological distances. Our research investigates how properties of the host galaxy such as composition and age influence properties of the progenitor system, which in turn influence the thermonuclear burning during an event and thus its brightness. I will present the results from ensembles of simulations addressing the influence of age and composition on the brightness of an event. These results show that the outcome depends sensitively on the nuclear burning, particularly weak interactions. Thus precise measurement of the largest possible scales of the Universe requires accurately capturing physics at some of the smallest scales.
150. Particle Physics Seminar

     "Preparing Physics Software for the Future - the HEP Software Community"

     Presented by Benedikt Hegner, BNL

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

     Hosted by: Alessandro Tricoli

     Particle physics has an ambitious and broad experimental programme for the coming decades. This programme requires large investments in detector hardware, either to build new facilities and experiments, or to upgrade existing ones. Similarly, it requires commensurate investment in the R&D of software to acquire, manage, process, and analyse 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 the efforts complement each other. In this spirit, the High Energy Physics community created a white paper (arXiv:1712.06982) to describe and define the R&D activities required to prepare for this software upgrade. This presentation describes the expected software and computing challenges and the already taken steps to tackle them
151. C-AD Accelerator Physics Seminar

     "HL-LHC Crab Cavities and Recent Beam Tests in the SPS Machine"

     Presented by Dr. Rama Calaga, CERN

     Wednesday, October 24, 2018, 4 pm
     Bldg. 911B, Second Floor, Large Conf. Rm., Rm. A2

     The design, development and challenges of the fabrication of the DQW crab cavity cryomodule is outlined. The successful installation and beam tests with protons in the SPS machine are presented along lessons learned and future plans for the HL-LHC series manufacturing.
152. Physics Colloquium

     "Quest for quark-gluon plasma"

     Presented by Edward Shuryak, SBU

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

     Hosted by: Andrei Nomerotski
153. Nuclear Theory/RIKEN Seminar

     "Studying out-of-equilibrium Quark-Gluon Plasma with QCD kinetic"

     Presented by Aleksas Mazeliauskas, University of Heidelberg

     Friday, October 19, 2018, 2 pm
     Building 510, CFNS Seminar Room 2-38

     Hosted by: Niklas Mueller

     In relativistic heavy nucleus collisions an ultra-dense, high-temperature state of nuclear matter is created with de-confined quarks and gluons. Understanding how the non-equilibrium Quark-Gluon Plasma thermalizes is important in connecting the initial state physics with the emergent hydrodynamic behavior of the QGP at later times. In this talk, I will use weakly coupled QCD kinetic theory with quark and gluon degrees of freedom to study the QGP evolution in the far-from-equilibrium regime, where it exhibits universal scaling, and its approach to thermal and chemical equilibrium.
154. Particle Physics Seminar

     "Stronger together: combining searches for new heavy resonances"

     Presented by Viviana Cavaliere, Brookhaven National Lab

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

     Hosted by: Alessandro Tricoli

     Many theories beyond the Standard Model predict new s-channel resonances decaying into two bosons (WW,ZZ,WZ,WH,ZH) and possibly leptons (ll, lv). This talk will summarize the recent ATLAS combination of heavy resonances searches which places stringent constraints on the couplings to boson, quarks and leptons taking advantage of the statistical combination of searches in different channels. Prospect for future resonances searches at HL-LHC and HE-LHC will be discussed as well.
155. RIKEN Lunch Seminar

     "Valence parton distribution function of pion using lattice"

     Presented by Nikhil Karthik, BNL

     Thursday, October 18, 2018, 12 pm
     Building 510, Room 2-160

     Hosted by: Yuya Tanizaki
156. HET Seminar

     "Flavor Physics in Lattice QCD as a Window into BSM Physics: |Vcb| and the B -> D* l nu Semileptonic Decay"

     Presented by Alejandro Vaquero, University of Utah

     Wednesday, October 17, 2018, 2:30 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Aaron Meyer

     Flavor physics provides a rich variety of phenomena that can be used to probe the SM without requiring the high energies present only in the largest particle accelerators. Among the quantities that could be employed to perform precision test of the SM, the CKM matrix elements takes up a prominent place. This lecture deals with the |V_{cb}| CKM matrix element, whose determinations through inclusive and exclusive decays currently display a 2\sigma discrepancy, and show how lattice QCD methods can reduce the uncertainty in the theoretical estimates and rule out (or not) the existence of unknown physics at play.
157. Center for Functional Nanomaterials Seminar

     "Probing nanostructured materials atom by atom: An ultra-high resolution aberration-corrected electron microscopy study"

     Presented by Dr. Nasim Alem, Penn State University

     Wednesday, October 17, 2018, 10 am
     CFN, Bldg 735, Conference Room B, 2nd Floor

     Hosted by: Chuck Black

     Defects can have a profound effect on the macroscale physical, chemical, and electronic properties of nanostructures. They can lead to structural distortions, introduce extra states in the band gap and give rise to excess potential locally at buried interfaces. While defects and interfaces have been a well-studied subject for decades, little is known about their local atomic and chemical structure, sub-Angstrom structural distortions within their vicinity, and their stability and transition dynamics under extreme conditions. Using ultra-highresolution aberration-corrected S/TEM imaging and spectroscopy, this talk will discuss our recent efforts on the determination of the defect chemistry and sub-Angstrom relaxation effects in nanostructures around dopants, grain boundaries, domain walls, and interfaces in the family of 2D crystals, complex oxides, and diamond carbon nanothreads. In the family of 2D crystal transition metal dichalcogenides (TMDs) alloys, we show how the formation of chemically ordered states and vacancy/dopant coupling leads to unusual relaxation effects around dopant-vacancy complexes. In addition, we explore stability and transition dynamics of defects leading to grain boundary migration in monolayer TMDs under electron beam irradiation. This talk also presents how ferroelectric polarization emerges at the atomic level across the domain walls in single phase and hybrid complex oxide systems and the impact of this emergence on the macroscale properties. Finally, we uncover the atomic and chemical structure of the carbon nanothreads using low dose high resolution electron microscopy. Bio: Nasim Alem is an assistant professor in the Materials Science and Engineering department at the Penn State University. Nasim received her B.S. degree in Metallurgical Engineering from Sharif University of Technology, Tehran, Iran and her M.S. degree in Materials Science and Engineering from Worcester Polytechnic Institute. She received her PhD from the Ma
158. Nuclear Physics Seminar

     "Energy dependence of jet quenching signatures in heavy-ion collisions"

     Presented by James Brandenburg

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

     Hosted by: Rongrong Ma

     High-pT partons traveling through the quark-gluon plasma (QGP) lose energy due to strong interactions. This effect, called jet-quenching, is attributed to collisional and radiative energy losses as high-pT partons travel through and interact with the dense medium. Over the years jet-quenching has become well established in high-energy heavy-ion collisions. In high-energy A+A collisions, the observation of jet-quenching is considered to be clear evidence of QGP formation. The Beam Energy Scan program at RHIC provided a unique opportunity to study the QCD phase diagram and to search for the turn off of key QGP signatures, such as jet-quenching, at sufficiently low collision energies. The collision energy dependence of jet-quenching effects, quantified through the nuclear modification factor (Rcp) of charged and identified hadrons will be discussed. The limitations of Rcp as an observable will be discussed and compared with a more differential technique for quantifying jet-quenching. Finally, the outlook for improved jet-quenching measurements in the second phase of the RHIC Beam Energy Scan will be presented.
159. Condensed-Matter Physics & Materials Science Seminar

     "In-situ Investigation of Crystallization of a Metallic Glass by Bragg Coherent X-ray Diffraction"

     Presented by Bo Chen, Tongji University, China

     Monday, October 15, 2018, 11 am
     ISB Bldg. 734, Conf. Rm. 201 (upstairs)

     Hosted by: Ian Robinson

     The crystallization behaviour of metallic glass (MG) has long been investigated ever since the discovery of these important functional materials [1]. Compared with crystalline and amorphous extremes, mate-rials containing crystalline precipitates within an otherwise amorphous MG or partially crystallized ma-terials have distinct properties that could be a way of tuning the materials' characteristics. Several methods including powder X-ray diffraction (XRD), transmission electron microscope (TEM) and se-lected area electron diffraction (SAED) are usually combined to characterize the degree of crystalline structure in amorphous materials. Until now, these methods, however, have failed to show the crystal-lization of individual crystal grains in three dimensions. In this work, the in-situ Bragg coherent X-ray diffraction imaging (BCDI) [2, 3] reveals the grain growth and the strain variation of individual crystals up to the sizes of a few hundred nanometers from the pure Fe-based MG powder during heating. We have found that there is preferential growth along one direction during the crystal formation; there is fractal structure around the developing crystal surface; there is also strain relaxation within the growing crystals while cooling. The work supports a two-step crystallization model for the Fe-based MG during heating. This could help to pave the way for designing partially crystalline materials with their at-tendant soft magnetic, anti-corrosive and mechanical properties. References [1] D. H. Kim, W. T. Kim, E. S. Park, N. Mattern, and J. Eckert, Prog. Mater. Sci. 2013, 58, 1103. [2] M. A. Pfeifer, G. J. Williams, I. A. Vartanyants, R. Harder and I. K. Robinson, Nature 2006, 442, 63. [3] I. K. Robinson and R. Harder, Nat. Mater. 2009, 8, 291.
160. Nuclear Theory/RBRC Seminar

     "Anyonic particle-vortex statistics and the nature of dense quark matte"

     Presented by Srimoyee Sen, University of Arizona

     Friday, October 12, 2018, 2 pm
     Building 510, Room 2-38

     Hosted by: Andrey Tarasov

     We show that Z_3-valued particle-vortex braiding phases are present in high density quark matter. Certain mesonic and baryonic excitations, in the presence of a superfluid vortex, have orbital angular momentum quantized in units of 1/3. Such non-local topological features can distinguish phases whose realizations of global symmetries, as probed by local order parameters, are identical. If Z_3 braiding phases and angular momentum fractionalization are absent in lower density hadronic matter, as is widely expected, then the quark matter and hadronic matter regimes of dense QCD must be separated by at least one phase transition.
161. NSLS-II Colloquium Series

     "Biophysical Studies of an RNA Virus particle and its Maturation: Insights into an Elegantly Programmed Nano-machine"

     Presented by John E. (Jack) Johnson, Department of Integrative Structural and Computational Biology, The Scripps Research Institute

     Thursday, October 11, 2018, 4 pm
     Large Seminar Room, Bldg. 510

     Hosted by: John Hill

     Nudaurelia Capensis ? Virus (N?V) is a eukaryotic, quasi-equivalent, RNA virus, with a T=4 surface lattice, where maturation is dramatic (a change in particle size of 100Å) and is novel in that it can be investigated in vitro. Here we use X-ray crystallography, biochemistry, Small Angle X-ray Scattering, and electron cryo-microscopy and image reconstruction (CryoEM), to characterize maturation intermediates, an associated auto-catalytic cleavage, the kinetics of morphological change and to demonstrate that regions of N?V subunit folding are maturation-dependent and occur at rates determined by their quasi-equivalent position in the capsid. Matsui, T., Lander, G. C., Khayat, R., and Johnson, J. E. 2010. Subunits fold at position-dependent rates during maturation of a eukaryotic RNA virus. Proc Natl Acad Sci U S A 107:14111-5. Veesler, D., and Johnson, J.E. 2012. Virus Maturation. Annual review of biophysics 41:473-496. Doerschuk, P. C., Gong, Y., Xu, N., Domitrovic, T., and Johnson, J. E. 2016. Virus particle dynamics derived from CryoEM studies. Curr Opin Virol 18:57-63.
162. Particle Physics Seminar

     "Higgs to beauty quarks"

     Presented by Caterina Vernieri, SLAC

     Thursday, October 11, 2018, 3 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Alessandro Tricoli

     The Higgs boson discovery at the LHC marked a historic milestone in the study of fundamental particles and their interactions. Over the last six years, we have begun measuring its properties, which are essential to build a deep understanding of the Higgs sector of the Standard Model and to potentially uncover new phenomena. The Higgs' favored decay mode to beauty (b) quarks (~60%) had so far remained elusive because of the overwhelming background of b-quark production due to strong interactions. Observing the Higgs decay to b-quarks was one of the critical missing pieces of our knowledge of the Higgs sector. Measuring this decay is a fundamental step to confirm the mass generation for fermions and may also provide hints of physics beyond the Standard Model. The CMS observation of the decay of the SM Higgs boson into a pair of b-quarks exploiting an exclusive production mode (VH) is yet another major milestone. This experimental achievement at the LHC, considered nearly impossible in the past, makes use of several advanced machine learning techniques to identify the b-quark distinctive signature, improve the Higgs boson mass resolution, and discriminate the Higgs boson signal from background processes.
163. HET/RIKEN Seminar

     "A Universally Enhanced Light-quarks Yukawa Couplings Paradigm"

     Presented by Shaouly Bar-Shalom, Technion

     Wednesday, October 10, 2018, 2:30 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Sally Dawson
164. NSLS-II Friday Seminar

     "Highly Active and Stable Carbon Nanosheets Supported Iron Oxide for Fischer-Tropsch to Olefins Synthesis"

     Presented by Congjun Wang, National Energy Technology Laboratory, Pittsburgh, PA

     Friday, October 5, 2018, 12 pm
     NSLS-II Bldg. 743 Rm 156

     Hosted by: Ignace Jarrige

     Light olefins production utilizes the energy intensive process of steam cracking. Fischer-Tropsch to olefins (FTO) synthesis potentially offers a more sustainable alternative. Here we show a promising FTO catalyst comprised of iron oxide nanoparticles supported on carbon nanosheets (CNS) fabricated from the carbonization of potassium citrate, which incorporates well dispersed K-promoter throughout the CNS support. This catalyst exhibits, to the best of our knowledge, the highest iron time yield of 1790–1990 μmolCO/gFe•s reported in the literature, 41% light olefins selectivity, and over 100 hours stable activity, making it one of the best performing FTO catalysts. Detailed characterization, including synchrotron X-ray spectroscopy, illustrates that the CNS support facilitates iron oxide reduction to metallic iron, leading to efficient transformation to the active iron carbide phase during FTO reaction. Since K is a commonly used promoter, our K-promoted CNS support potentially has broad utility beyond the FTO reactions demonstrated in the current study.
165. Particle Physics Seminar

     "SB/BNL Joint Cosmo seminar: Weighing Galaxy Clusters with Weak Lensing in Hyper Suprime-Cam Survey"

     Presented by Dr. Elinor Medezinski, Princeton University

     Thursday, October 4, 2018, 3 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Chi-Ting Chang

     The most fundamental question in observational cosmology today is what is the nature of dark energy and dark matter. Clusters of galaxies serve as beacons to the growth of structure over cosmic scales, making them a sensitive cosmological tool. However, accurately measuring their masses has been notoriously difficult. Weak lensing provides the best direct probe of the cluster mass, both the baryonic and dark components, but it requires high-quality wide-field imaging and careful control of systematics. With its unprecedentedly deep and exquisite seeing, the Subaru Hyper Suprime-Cam (HSC) survey is an ongoing campaign to observe 1,400 square degrees to r~26, providing the closest precursor to LSST. In this talk, I will present our new field-leading results from the first HSC data release of ~150 square degrees that encompass thousands of clusters. Harnessing our new HSC survey, I measure benchmark weak lensing cluster masses with improved methodology, and reconcile previous tension on cosmological parameters between the SZ and CMB within the Planck survey. In the next decade, LSST and WFIRST will discover hundreds of thousands of galaxy clusters, peering deep to the epoch of formation. I will describe these surveys and the multifold breakthrough science we will achieve in the new era of astronomy.
166. Special Particle Physics Seminar

     "Latest XENON1T results"

     Presented by Qing Lin, Columbia University

     Thursday, October 4, 2018, 1 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Chao Zhang

     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 latest results from XENON1T. Details about the XENON1T detector as well as the data analysis techniques will also be covered.
167. Nuclear Physics Seminar

     "Exploring the Phase Diagram with Succeptibility Scaling Functions: Epic Voyage or Just Another Bad Trip"

     Presented by Roy A Lacey, Stony Brook University

     Tuesday, October 2, 2018, 11 am
     Small Seminar Room, Bldg. 510

     Hosted by: Jiangyong Jia

     A major goal of the ongoing experimental programs at RHIC is to chart the QCD phase diagram.Pinpointing the location of the first order phase boundary which terminates at a critical end point (CEP), in the temperature versus baryon chemical potential (T,µB) plane of this phase diagram, is key to this mapping. Finite-Size-Finite-Time succeptibility scaling functions can give crucial insight on these essential landmarks of the phase diagram. I will discuss recent attempts to extract and use such scaling functions to pin down the location of the CEP, as well as the associated critical exponents required to identify its universality class.
168. Particle Physics Seminar

     "(Somewhat) New ideas in ultralight DM searches:"

     Presented by Babette Döbrich, CERN

     Monday, October 1, 2018, 3 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Alessandro Tricoli

     The search for ultra-light Dark Matter particles complements the search for more ``classical'' Dark Matter candidates at the GeV scale in an important fashion. I will review the motivation of the QCD axion, highlighting ongoing established techniques and set-ups and explain in detail a novel technique based on microwave filters (RADES), ongoing at CERN. Finally I will present results of one of the possibly cheapest experiments for ultralight Dark Photon Dark Matter (FUNK) achieving competitive results.
169. Nuclear Theory/RIKEN Seminar

     "Neutrinoless double beta decay in effective field theory"

     Presented by Jordy De Vries, UMass Amherst

     Friday, September 28, 2018, 2 pm
     Building 510, CFNS Seminar Room 2-38

     Hosted by: Chun Shen

     Next-generation neutrinoless double-beta decay experiments aim to discover lepton-number violation in order to shed light on the nature of neutrino masses. A non-zero signal would have profound implications by demonstrating the existence of elementary Majorana particles and possibly pointing towards a solution of matter-antimatter asymmetry in the universe. However, the interpretation of the experimental signal (or lack thereof) requires care. First of all, a single nonzero measurement would indicate lepton-number violation but will not identify the underlying source. Second, complicated hadronic and nuclear input is required to connect the experimental data to a fundamental description of lepton-number violation. In this talk, I will use effective field theories to connect neutrinoless double-beta decay measurements to the fundamental lepton-number-violating source.
170. Particle Physics Seminar

     "Measurements of the branching fraction and time-dependent CP asymmetries for B0 -> J/psi pi0 decays"

     Presented by Bilas Pal, BNL

     Thursday, September 27, 2018, 3 pm
     Small Seminar Room, Bldg. 510

     Hosted by: David Jaffe

     Measurements of the time-dependent CP asymmetries and branching fraction of B0 -> J/psi pi0 will be discussed. The CP asymmetry parameters for the decay B0 -> J/psi pi0 have previously been measured by BaBar and Belle experiments, but the results of mixing induced CP asymmetry (S) were not in good agreement with each other. Furthermore, the BaBar result lies outside the physically allowed region. Previous Belle measurements were based on 535M BB-bar pairs. We updated the measurements using the final Belle data set of 772M BB-bar pairs.
171. Condensed-Matter Physics & Materials Science Seminar

     "Universality and quantum criticality of the one-dimensional spinor Bose gas"

     Thursday, September 27, 2018, 1:30 pm
     ISB Bldg. 734 Conf. Rm. 201

     Hosted by: Igor Zaliznyak

     We investigate the universal thermodynamics of the two-component one-dimensional Bose gas with contact interactions in the vicinity of the quantum critical point separating the vacuum and the ferromagnetic liquid regime. We find that the quantum critical region belongs to the universality class of the spin-degenerate impenetrable particle gas which, surprisingly, is very different from the single-component case and identify its boundaries with the peaks of the specific heat. In addition, we show that the compressibility Wilson ratio, which quantifies the relative strength of thermal and quantum fluctuations, serves as a good discriminator of the quantum regimes near the quantum crit- ical point. Remarkably, in the Tonks-Girardeau regime the universal contact develops a pronounced minimum, reflected in a counterintuitive narrowing of the momentum distribution as we increase the temperature. This momentum reconstruction, also present at low and intermediate momenta, signals the transition from the ferromagnetic to the spin-incoherent Luttinger liquid phase and can be detected in current experiments with ultracold atomic gases in optical lattices.
172. HET Seminar

     "Loop-Induced Single Top Partner Production and Decay at the HL-LHC"

     Presented by Jeong Han Kim, Kansas University

     Wednesday, September 26, 2018, 2 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Sally Dawson
173. Sustainable Energy Technologies Department

     "Advances in Ultra-High Energy Resolution STEM-EELS"

     Presented by Tracy C. Lovejoy, Nion R&D

     Wednesday, September 26, 2018, 2 pm
     Bldg. 734, Room 201

     Hosted by: Feng Wang

     The capabilities of scanning transmission electron microscopes (STEMs) have advanced very significantly in the last two decades. The first major advance was the successful implementation of electron-optical aberration correction, which allowed the STEMs to reach direct sub-angstrom resolution in 2002 [1]. This improvement made the imaging and spectroscopy of single atoms straightforward. A very recent major development has been the improvement of energy resolution of EELS due to the introduction of a new generation of monochromators and ultra-stable electron spectrometers. The Ultra-High Energy Resolution Monochromated EELS-STEM (U-HERMES™) system developed by Nion combines a dispersing-undispersing ground-potential monochromator [2], a bright cold-field-emission gun, an advanced aberration corrector, and a new EEL spectrometer. The latest version of the system allows 5 meV energy resolution EELS and has achieved 1.07 Å spatial resolution at the sample at 30kV when monochromating, and it greatly extends the capabilities of vibrational spectroscopy in the EM, introduced 4 years ago [3]. U-HERMES™ has so far been used for: damage-free identification of different bonds including hydrogen bonds in guanine [4]; probing atomic vibrations at surfaces and edges of nano-objects with nm-level spatial resolution [5]; achieving sub-nm spatial resolution in images obtained with dark-field EELS vibrational signals [6]; nanoscale mapping of phonon dispersion curves [7]; nanoscale temperature determination by electron energy gain spectroscopy [8]; identification of different isotopes by vibrational spectroscopy in the EM [9]; vibrational spectroscopy of ice; and vibrational fingerprinting of biological molecules.
174. Physics Colloquium

     "Unraveling the nucleon's mass and spin structure at an Electron-Ion Collider"

     Presented by Yoshitaka Hatta, BNL and Kyoto University

     Tuesday, September 25, 2018, 3:30 pm
     Large Seminar Room, Bldg. 510

     Hosted by: Rob Pisarski

     The US-based Electron-Ion Collider (EIC) is a future high-luminosity, polarized collider dedicated to the physics of the nucleon/nucleus structure. Among the many physics problems that can be addressed at the EIC, I will focus on the origin of the mass and spin of the nucleon, namely, how they can be understood in terms of quarks' and gluons' degrees of freedom. I will give a review of the mass and spin decompositions in QCD and discuss possible experimental observables.
175. Particle Physics Seminar

     "Searches for decays of a Higgs boson into pairs of light (pseudo)scalars with the ATLAS detector"

     Presented by Ljiljana Morvaj

     Tuesday, September 25, 2018, 10:30 am
     Small Seminar Room, Bldg. 510

     Hosted by: Alessandro Tricoli

     The branching ratio of the Standard Model (SM) Higgs boson to non-SM or "exotic" states is currently constrained to be less than 34% at 95% confidence level. This opens possibility to search for new particles in the decays of the Higgs boson. Such searches could provide a unique access to hidden-sector states that are singlets under the SM gauge transformations. A search for decays of the Higgs boson to a pair of new spin–0 particles, H → aa, where the a–bosons decay to a b-quark pair and a muon pair, is presented in this seminar. The analysis uses 36.1 fb−1 of proton-proton collisions data with √s = 13 TeV recorded by the ATLAS experiment at the LHC in 2015 and 2016. No deviation from the Standard Model prediction is observed and limits on Br(H → aa → bbμμ) are set in the a–boson mass range of 20–60 GeV. Searches in other final states, such as four b-quarks (H → aa → 4b) and two jets and two photons (H → aa → ggγγ), are also discussed.
176. Nuclear Theory/RIKEN Seminar

     "Status of Pythia 8 for an Electron-Ion Collider"

     Presented by Ilkka Helenius, University of Tubingen

     Friday, September 21, 2018, 2 pm
     Building 510, CFNS Seminar Room 2-38

     Hosted by: Andrey Tarasov

     Pythia 8 is a general-purpose Monte-Carlo event generator widely used to simulate high-energy proton-proton collisions at the LHC. Recently it has been extended to handle also other collision systems involving lepton and heavy-ion beams. In this seminar I will review the current Pythia 8 capabilities in processes relevant to an Electron-Ion Collider (EIC) and discuss about the projected future improvements. The relevant processes can be divided into two regions based on the virtuality of the intermediate photon: deeply inelastic scattering (DIS) at high virtualities and photoproduction at low virtualities. I will begin with an introduction of the event generation steps in Pythia 8 and then briefly discuss how the DIS processes can be simulated. Then I present our photoproduction framework and compare the results to the HERA data for charged-hadron and dijet production in lepton-proton collisions. In particular I discuss about the role of multiparton interactions in photon-proton interactions with resolved photons and how these can be constrained with the existing HERA data. Then I discuss how the same framework can be applied to ultra-peripheral heavy-ion collisions at the LHC where one can study high-energy photon-nucleus interactions in a kinematic region comparable to EIC. Finally I will show our first predictions for dijet production in these events and quantify the contribution of diffractive events according to the hard diffractionmodel that has been recently implemented into Pythia 8.
177. HET Lunch Discussions

     "GeV-Scale Messengers of Planck-Scale Dark Matter"

     Presented by Gopolang Mohlabeng, BNL

     Friday, September 21, 2018, 12:15 pm
     Building 510, Room 2-160

     Hosted by: Christoph Lehner
178. Particle Physics Seminar

     "The Belle II Experiment"

     Presented by Bryan Fulsom, PNNL

     Thursday, September 20, 2018, 3 pm
     Small Seminar Room, Bldg. 510

     Hosted by: David Jaffe

     The first generation of B-Factories, BaBar and Belle, operated over the previous decade and produced many world-leading measurements related to flavor physics. Their discoveries contributed to the awarding of the 2008 Nobel Prize in Physics. The Belle II experiment, now underway at the KEK laboratory in Japan, is a substantial upgrade of both the Belle detector and the KEKB accelerator. It aims to collect 50 times more data than existing B-Factory samples. This will provide unprecedented sensitivity to new physics signatures in the flavor sector. This talk will present the upgrade efforts of the Belle II experiment, results from its recent first e+e- collisions, and the future physics opportunities the experiment will provide.
179. Condensed-Matter Physics & Materials Science Seminar

     "Multiloop functional renormalization group: Exact flow equations from the self-consistent parquet relations"

     Presented by Fabian Kugler, Ludwig-Maximilians-Universitat Munchen, Germany

     Thursday, September 20, 2018, 1:30 pm
     ISB 734 Conference Room 201

     Hosted by: Andreas Weichselbaum

     The functional renormalization group (fRG) is a versatile, quantum-field-theoretical formulation of the powerful RG idea and has seen a large number of successful applications. The main limitation of this framework is the truncation of the hierarchy of flow equations, where typically effective three-particle interactions are neglected altogether. From another perspective, the parquet formalism consists of self-consistent many-body relations on the one- and two-particle level and allows for the most elaborate diagrammatic resummations. Here, we unify these approaches by deriving multiloop fRG flow equations from the self-consistent parquet relations [1]. On the one hand, this circumvents the reliance on higher-point vertices within fRG and equips the method with quantitative predictive power [2]. On the other hand, it enables solutions of the parquet equations in previously unaccessible regimes. Using the X-ray-edge singularity as an example, we introduce the formalism and illustrate our findings with numerical results [3]. Finally, we discuss applications to the 2D Hubbard model [4] and the combination of multiloop fRG with the dynamical mean-field theory. [1] F. B. Kugler and J. von Delft, arXiv:1807.02898 (2018) [2] F. B. Kugler and J. von Delft, PRB 97, 035162 (2018) [3] F. B. Kugler and J. von Delft, PRL 120, 057403 (2018) [4] A. Tagliavini, C. Hille, F. B. Kugler, S. Andergassen, A. Toschi, and C. Honerkamp, arXiv:1807:02697 (2018)
180. Physics Colloquium

     "Potential and Issues for Future Accelerators and Ultimate"

     Presented by Stephen Brooks, BNL

     Tuesday, September 18, 2018, 3:30 pm
     Large Seminar Room, Bldg. 510

     Hosted by: Andrei Nomerotski

     Particle colliders have been remarkably successful tools in particle and nuclear physics. What are the future trends and limitations of accelerators as they currently exist, and are there possible alternative approaches? What would the ultimate collider look like? This talk examines some challenges and possible solutions. Accelerating a single particle rather than a thermal distribution may allow exploration of more controlled interactions without background. Also, cost drivers are possibly the most important limiting factor for large accelerators in the foreseeable future so emerging technologies to reduce cost are highlighted.
181. Special Particle Physics Seminar

     "Flavor physics and CP violation - Recent results from combined BaBar+Belle measurements, ongoing work at LHCb, and prospects for the new physics searches at Belle II"

     Presented by Markus Roehrken, CERN

     Monday, September 17, 2018, 1 pm
     Small Seminar Room, Bldg. 510

     Hosted by: David Jaffe

     During the 2000s, the BaBar experiment at SLAC (Stanford/USA) and the Belle experiment at KEK (Tsukuba/Japan) performed a very successful flavor physics program. BaBar and Belle discovered CP violation in the B meson system and put tight experimental constraints on the quark-flavor sector of the Standard Model. The excellent experimental confirmation of the theory predictions by BaBar and Belle led to the Nobel Prize in physics for Makoto Kobayashi and Toshihide Maskawa in 2008. Continuing on these efforts, the new high-luminosity accelerator SuperKEKB and the next-generation B factory experiment Belle II recently started operation at KEK in Japan. SuperKEKB is designed to operate at an instantaneous luminosity of 8x10^35/cm^2/s, which is a factor 40 higher than the world record achieved by its predecessor KEKB. The upgraded Belle II detector will collect data samples about two orders of magnitudes larger than those of the BaBar and Belle experiments. In this talk, we introduce to flavor physics and CP violation. We will present recent results of a combined analysis campaign, which for the first time makes simultaneous use of the large final data samples of BaBar and Belle in single physics analyses. The approach provides access to an integrated luminosity of about 1.1 inverse attobarn, and thus allows to perform early Belle II-like measurements. In addition, ongoing work of the speaker at LHCb is reported. At the end of the talk, the prospects for the new physics searches in heavy flavor decays governed by quantum-loop effects at Belle II are briefly discussed.
182. HET Lunch Seminar

     "Isospin-breaking corrections to decay amplitudes in lattice QCD"

     Presented by Davide Giusti, Roma 3, INFN

     Friday, September 14, 2018, 12:15 pm
     Building 510, Room 2-160

     Hosted by: Mattia Bruno
183. Particle Physics Seminar

     "Probing the Higgs Yukawa couplings at the LHC"

     Presented by Konstantinos Nikolopoulos

     Thursday, September 13, 2018, 3 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Alessandro Tricoli

     The Higgs boson observation by ATLAS and CMS Collaborations at the CERN Large Hadron Collider has completed the Standard Model; the culmination of a century of discoveries. Despite the overwhelming success of the Standard Model to-date, the origin of fermion masses through Yukawa couplings to the Higgs doublet is loosely constrained experimentally and offers opportunities for BSM physics contributions. The status of the determination of the Higgs boson Yukawa couplings at the LHC will be presented and the prospects for the future will be discussed.
184. RIKEN Lunch Seminar

     "Giant photocurrent in asymmetric Weyl semimetals from the helical magnetic effect"

     Presented by Yuta Kikuchi, RBRC

     Thursday, September 13, 2018, 12:30 pm
     Building 510, Room 2-160
185. Joint BNL/RIKEN HET Seminar

     "Higgs pair production via gluon fusion at NLO QCD"

     Presented by Julien Baglio, Tuebingen U.

     Wednesday, September 12, 2018, 2 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Sally Dawson

     Since the discovery of a Higgs boson in 2012 at CERN, accessing its properties is one of the main goals of the Large Hadron Collider (LHC) experimental collaborations. The triple Higgs coupling in particular is a primary target as it would be a direct probe of the shape of the scalar potential at the origin of the electroweak-symmetry-breaking mechanism, and is directly accessed via the production of a pair of Higgs bosons. In this view, it is of utmost importance to reach high precision in the theoretical prediction of Higgs boson pair production cross section at the LHC. I will present in this talk the calculation of the 2-loop QCD corrections to the Higgs-pair-production cross section via gluon fusion, that is the main production mechanism, including the top-quark mass effects in the loops. It will be shown that they can be significant in the Higgs-pair-mass differential distributions.
186. Nuclear Theory/RBRC Seminar

     "Temperature, Mass, Flavor: Emerging Phase Structure of SU(3) Gauge Theories with Fundamental Quarks"

     Presented by Ivan Horvath, University of Kentucky

     Friday, September 7, 2018, 2 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Rob Pisarski

     Recently we have outlined the general phase structure of the above relevant theory set, inferred from probing the glue by external Dirac probes. Its novelty and simplicity stems from the conclusion that changes in temperature, mass and number of flavors lead to analogous dynamical effects. In this talk I will review that picture, and introduce an important refinement of it that is currently emerging in the thermal corner of the phase diagram.
187. Condensed-Matter Physics & Materials Science Seminar

     "Pair-breaking quantum phase transition in superconducting nanowires"

     Presented by Andrey Rogachev, University of Utah

     Friday, September 7, 2018, 11 am
     ISB Bldg. 734 Conference Room 201 (upstairs)

     Hosted by: Ivan Bozovic

     Quantum phase transitions (QPT) between distinct ground states of matter are widespread phenomena, yet there are only a few experimentally accessible systems where the microscopic mechanism of the transition can be tested and understood. In this talk we will report on discovery that a magnetic-field driven quantum phase transition in MoGe superconducting nanowires can be fully explained by the critical theory of pair-breaking transitions characterized by a correlation length exponent v≈1 and dynamic critical exponent z≈ 2. We find that in the quantum critical regime, the electrical conductivity is in agreement with a theoretically predicted scaling function and, moreover, that the theory quantitatively describes the dependence of conductivity on the critical temperature, field magnitude and orientation, nanowire cross-sectional area, and microscopic parameters of the nanowire material. At the critical field, the conductivity follows a T^(d–2)/z dependence predicted by phenomenological scaling theories and more recently obtained within a holographic framework. Our work uncovers the microscopic processes governing the transition: the pair-breaking effect of the magnetic field on interacting Cooper pairs overdamped by their coupling to electronic degrees of freedom. It also reveals the universal character of continuous quantum phase transitions. In the talk we will also briefly comment on reliability of the finite-size scaling analysis, origin of zero-bias anomaly in wires and implication of our finding for QPT in superconducting films.
188. RIKEN/NT & Quantum Computing Seminar

     "Quantum Uncertainty and Quantum Computation"

     Presented by Ivan Horvath, University of Kentucky

     Thursday, September 6, 2018, 12:30 pm
     Building 510, Room 2-160

     Hosted by: Rob Pisarski

     I will discuss the uncertainty in quantum mechanics as a property reflecting the "quantity" (measure) on the set of possible probing outcomes. This is in contrast to the commonly used "spectral distance" (metric). An unexpected insight into the nature of quantum uncertainty (and that of measure) is obtained as a result. One of the motivations for considering measure uncertainty is that it is directly relevant for assessing the efficiency of quantum computation.
189. Special Particle Phyics Seminar

     "LHCb"

     Presented by Angelo Di Canto, CERN

     Wednesday, September 5, 2018, 10:30 am
     Small Seminar Room, Bldg. 510

     Hosted by: Chao Zhang
190. Nuclear Physics Seminar

     "Neutron production and capture in stellar nucleosynthesis:^{22}Ne(\Alpha,n)^{25}Mg reaction and radiative neutron captures of radioactive nuclei"

     Presented by Shuya Ota, Texas A&M University

     Tuesday, September 4, 2018, 11 am
     Small Seminar Room, Bldg. 510

     Hosted by: Jin Huang

     Most of elements heavier than Fe in the Universe are produced by a series of neutron capture reaction and ??-decay in stars. The s-process, which occurs under moderate neutron environments (~107-10 neutrons/cm3) such as in He burning of massive stars, is responsible for producing almost half of the heavy elements. Neutrons for the s-process environment is believed to be supplied by two dominant reactions, one of which is 22Ne(?,n)25Mg reaction. This reaction in massive stars is dominated by a few resonance reactions. Nevertheless, there remain large uncertainties about contribution of the reaction to the s-process nucleosynthesis because the reaction cross sections are too small for direct measurements due to Coulomb barrier (E? = 400-900 keV in the lab system). In the first half of this seminar, I will present our experiment to determine these resonance strengths with a cyclotron accelerator at Texas A&M University. The experiment was performed by an indirect approach using 6Li(22Ne,25Mg+n)d ?-transfer reaction, in which resonance properties such as neutron decay branching ratios of produced 26Mg were studied by measuring deuterons, ?-ray, and 26Mg in coincidence using large arrays of Si and Ge, and a magnetic spectrometer. Our results showed neutron production from 22Ne(?,n)25Mg reaction can be about 10 times lower than past measurements. The effect of our measurements on the s-process nucleosynthesis will be discussed. In the second half of this seminar, I will present our experiments to determine neutron capture cross sections of radioactive nuclei using the Surrogate Reaction method [1]. Neutron capture reactions for the s-process involve relatively long-lived nuclei neighboring stability in the nuclear chart. Therefore, the Surrogate Reaction, which creates the same compound nuclei as the neutron capture reaction using a stable beam and target, can be a useful approach. On the other hand, the r- process, which produces the other half
191. HET Lunch Discussions

     "Lattice QCD and precision physics from long to short distances: an overview of my 3 years at BNL"

     Presented by Mattia Bruno, BNL

     Friday, August 31, 2018, 12:15 pm
     Building 510, Room 2-95

     Hosted by: Christoph Lehner
192. Special Nuclear Theory/RIKEN Lunch Seminar

     "Signal-to-noise issues in non-relativistic quantum matter: from entanglement to thermodynamics"

     Presented by Joaquin Drut, University of North Carolina

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

     Hosted by: Rob Pisarski

     Non-relativistic quantum matter, as realized in ultracold atomic gases, continues to be a remarkably versatile playground for many-body physics. Experimentalists have exquisite control over temperature, density, coupling, and shape of the trapping potential. Additionally, a wide range of properties can be measured: from simple ones like equations of state to more involved ones like the bulk viscosity and entanglement. The latter has received much attention due to its connection to quantum phase transitions, but it has proven extremely difficult to compute: stochastic methods display exponential signal-to-noise issues of a very similar nature as those due to the infamous sign problem affecting finite-density QCD. In this talk, I will present an algorithm that solves the signal-to-noise issue for entanglement, and I will show results for strongly interacting systems in three spatial dimensions that are the first of their kind. I will also present a few recent explorations of the thermodynamics of polarized matter and other cases that usually have a sign problem, using complexified stochastic quantization.
193. Nuclear Physics Seminar

     "Probe strong magnetic field in QGP with dielectrons from photon-photon interactions"

     Presented by Zhangbu Xu, BNL

     Tuesday, August 28, 2018, 11 am
     Small Seminar Room, Bldg. 510

     Hosted by: Rongrong Ma

     We presents first measurements of $e^+e^-$ pair production from light-light scattering in non-central heavy ion collisions. The excess yields peak distinctly at low transverse momentum with sqrt() between 40 to 60 MeV/c. The excess yields can be explained only when the photon-photon interactions are included in model calculations. However, the measured pT^2 distributions are significantly broader than model calculation and are different between Au+Au and U+U. Our measurements provide a possible experimental evidence of the existence of strong electromagnetic field. And I will discuss its possible impact on emerging phenomena in hadronic heavy-ion collisions, such as Chiral Magnetic Effect.
194. Condensed-Matter Physics & Materials Science Seminar

     "Spinon Confinement and a Longitudinal Mode in One Dimensional Yb2Pt2Pb"

     Presented by Bill Gannon, Department of Physics and Astronomy, Texas A&M University

     Thursday, August 23, 2018, 1:30 pm
     ISB Bldg. 734 Conf. Rm. 201 (upstairs)

     Hosted by: Alexei Tsvelik

     Abstract: The Yb3+ magnetic moments in Yb2Pt2Pb are seemingly classical, since the large spin-orbit coupling of the 4f-electrons and the crystal electric field dictate a J = +/-7/2 Yb ground state doublet. Surprisingly, the fundamental low energy magnetic excitations in Yb2Pt2Pb are spinons on one dimensional chains, shown to be in good agreement with the behavior expected with the XXZ Hamiltonian for nearly isotropic, S = +/-1/2 magnetic moments. We have performed new high resolution neutron scattering measurements to examine the properties of these excitations in a magnetic field. In fields larger than 0.5 T, the chemical potential closes the gap to the spinon dispersion, modifying the quantum continuum through the formation of a spinon Fermi surface. This leads to the formation of spinon bound states along the chains, coupled to a longitudinally polarized interchain mode at energies below the quantum continuum. The ground state doublet nature of the Yb ions ensures that at all fields, transverse excitations are virtually nonexistent, allowing direct measurement of the mode dispersion.
195. RIKEN Lunch Seminar

     "Non-abelian symmetries and applications in tensor networks"

     Presented by Andreas Weichselbaum, BNL

     Thursday, August 23, 2018, 12:30 pm
     Building 510, Room 2-160
196. Special HET Seminar

     "The Higgs Potential: A Path Toward Discovery"

     Presented by Pier Paolo Giardino, BNL

     Tuesday, August 21, 2018, 1:30 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Sally Dawson
197. Nuclear Theory/RBRC Seminar

     "Computation of the shear viscosity in QCD at (almost) next to leading order"

     Presented by Derek Teaney, Stony Brook University

     Friday, August 17, 2018, 2 pm
     Building 510, Room 2-38
198. HET Lunch Discussions

     "Lattice QCD Study of Exclusive Channels in the Muon HVP"

     Presented by Aaron Meyer, BNL

     Friday, August 17, 2018, 12:15 pm
     Building 510, Room 2-160

     Hosted by: Christoph Lehner

     The hadronic vacuum polarization is a dominant contribution to the theoretical uncertainty of the muon anomalous magnetic moment. Both the R-ratio and Lattice QCD may be used to compute the HVP contribution from theory, and the theoretical uncertainties for both methods are statistically precise in regions that are complimentary to each other. For lattice QCD, the long-distance region dominates the statistical uncertainty. By explicitly studying exclusive channels of the HVP diagram with lattice QCD, it is possible to reconstruct the long-distance behavior of the correlation function. This has the effect of replacing the statistical uncertainty with a significantly smaller systematic uncertainty. With this long-distance reconstruction, it will be possible to achieve a precision with a lattice-only calculation similar to that of the R-ratio method.
199. RIKEN Lunch Seminar

     "Universality in Classical and Quantum Chaos"

     Presented by Masanori Hanada, YITP

     Thursday, August 16, 2018, 12:30 pm
     Building 510, Room 2-160

     Hosted by: Enrico Rinaldi

     We study the chaotic nature of classical and quantum systems. In particular, we will study the detail of the Lyapunov growth. We will show the evidence that the spectrum of Lyapunov exponents admits universal description by Random Matrix Theory, and systems dual to black holes exhibit 'strong' universality.
200. Physics Colloquium

     "Quantum computing for deuteron"

     Presented by Thomas Papenbrock, University of Tennessee

     Tuesday, August 14, 2018, 3:30 pm
     Large Seminar Room, Bldg. 510

     Hosted by: Peter Petreczky
201. Special HET Seminar

     "New Dark Matter Signals in Neutrino Detectors"

     Presented by Yue Zhang, Northwestern

     Tuesday, August 14, 2018, 1:30 pm
     Small Seminar Room, Bldg. 510
202. Special HET Seminar

     "New Dark Matter Signals in Neutrino Detectors"

     Presented by Yue Zhang, Northwestern

     Monday, August 13, 2018, 1:30 pm
     Small Seminar Room, Bldg. 510
203. Nuclear Theory/RBRC Seminar

     "Electric conductivity of hot and dense quark matter in a magnetic field"

     Presented by Yoshimasa Hidaka, RIKEN

     Friday, August 10, 2018, 2 pm
     Building 510, Room 2-38

     Hosted by: Rob Pisarski
204. Condensed-Matter Physics & Materials Science Seminar

     "Advances in high energy electron holography"

     Presented by Dr. Toshiaki Tanigaki, Hitachi, Japan

     Friday, August 10, 2018, 1:30 pm
     Conference room in building 480

     Hosted by: MG Han

     Advances in High-Voltage Electron Holography T. Tanigaki Research & Development Group, Hitachi, Ltd. Email: toshiaki.tanigaki.mv@hitachi.com Electron holography can observe electromagnetic field inside materials and devices at high-resolution around atomic scale. The high penetration power of a high energy electron wave is crucial to observing magnetic structures, which exist only in thick samples. It is particularly crucial in three-dimensional (3D) observations, which require a series of sample observations with the sample increasingly tilted so that the projected sample thickness increases with the tilt angle. As an example of this, magnetic vortex cores confined in stacked ferromagnetic (Fe) discs were observed three-dimensionally by using vector-field electron tomography with a 1.0 MV holography electron microscope [1]. To invent new functional materials and devices for establishing a sustainable society, methods for controlling atomic arrangements in small areas such as interfaces have become important [2,3]. Electron holography is a powerful tool for analyzing the origins of functions by observing electromagnetic fields and strains at high resolutions. The advantages of high-voltage electron holography are high resolution and penetration power due to high energy electron waves. The quest for finding the ultimate resolution through continuous improvements on holography electron microscopes led to the development of an aberration corrected 1.2 MV holography electron microscope [4,5] (Figure 1). We describe recent results obtained by using the high-voltage electron holography. Spatial resolution of 1.2 MV holography electron microscope reached 0.043 nm at high-resolutions, when the sample was placed in a high magnetic field of the objective lens [4]. Under the observation conditions, in which the sample was placed in a field-free position for observing a magnetic field, the spatial res
205. Special HET Seminar

     "Searching for physics beyond the Standard Model at the Intensity Frontier"

     Presented by Martin Hoferichter, University of Washington

     Thursday, August 9, 2018, 1:30 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Sally Dawson
206. Special Particle Physics Seminar

     "Deep Neural Network Techniques R&D for Data Reconstruction of Liquid Argon TPC Detectors"

     Presented by Kazuhiro Terao, SLAC National Accelerator Laboratory

     Tuesday, August 7, 2018, 10 am
     Small Seminar Room, Bldg. 510

     Hosted by: Chao Zhang

     Liquid Argon Time Projection Chambers (LArTPCs) are capable of recording images of charged particle tracks with breathtaking resolution. Such detailed information will allow LArTPCs to perform accurate particle identification and calorimetry, making it the detector of choice for many current and future neutrino experiments. However, analyzing such images can be challenging, requiring the development of many algorithms to identify and assemble features of the events in order to reconstruct neutrino interactions. In the recent years, we have been investigating a new approach using deep neural networks (DNNs), a modern solution to a pattern recognition for image-like data in the field of Computer Vision. A modern DNN can be applied for various types of problems such as data reconstruction tasks including interaction vertex finding, pixel clustering, and particle/topology type identification. We have developed a small inter-experiment collaboration to share generic software tools and algorithms development effort that can be applied to non-LArTPC imaging detectors. In this talk I will discuss the challenges of LArTPC data reconstruction, recent work and future plans for developing a full LArTPC data reconstruction chain using DNNs.
207. Special HET Seminar

     "A New Frontier in the Search for Dark Matter"

     Presented by Gordan Krnjaic, FNAL

     Monday, August 6, 2018, 1:30 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Sally Dawson

     The gravitational evidence for the existence of dark matter is overwhelming; observations of galactic rotation curves, the CMB power spectrum, and light element abundances independently suggest that over 80% of all matter is "dark" and beyond the scope of the Standard Model. However, its particle nature is currently unknown, so discovering its potential non-gravitational interactions is a major priority in fundamental physics. In this talk, I will survey the landscape of light dark matter theories and and introduce an emerging field of fixed-target experiments that are poised to cover hitherto unexplored dark matter candidates with MeV-GeV masses. These new techniques involve direct dark matter production with proton, electron, and *muon* beams at various facilities including Fermilab, CERN, SLAC, and JLab. Exploring this mass range is essential for fully testing a broad, predictive class of theories in which dark matter abundance arises from dark-visible interactions in thermal equilibrium in the early universe.
208. Summer Sundays

     "Atom Smashing Fun with the Relativistic Heavy Ion Collider"

     Sunday, August 5, 2018, 10 am
     Berkner Hall, Room B
209. Special HET Seminar

     "New Neutrino Interactions: Breaking Degeneracies and Relaxing Sterile Tensions"

     Presented by Peter Denton, Niels Bohr

     Friday, August 3, 2018, 1:30 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Sally Dawson
210. Particle Physics Seminar

     "Significant Excess of Electron-Like Events in the MiniBooNE Short-Baseline Neutrino Experiment"

     Presented by William Louis, Los Alamos National Lab

     Thursday, August 2, 2018, 3 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Chao Zhang

     The MiniBooNE experiment at Fermilab observes a total electron-neutrino event excess in both neutrino and antineutrino running modes of 460.5 +- 95.8 events (4.8 sigma) in the energy range from 200-1250 MeV. The MiniBooNE L/E distribution and the allowed region from a two-neutrino oscillation fit to the data are consistent with the L/E distribution and allowed region reported by the LSND experiment. All of the major backgrounds are constrained by in-situ event measurements, so non-oscillation explanations would need to invoke new anomalous background processes. Although the data are fit with a two-neutrino oscillation model, other models may provide better fits to the data. The MiniBooNE event excess will be further studied by the Fermilab short-baseline neutrino (SBN) program.
211. RIKEN Lunch Seminar

     "Nucleon isovector axial charge in 2+1-flavor domain-wall QCD with physical mass"

     Presented by Shigemi Ohta, IPNS, KEK

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

     Hosted by: Enrico Rinaldi
212. Condensed-Matter Physics & Materials Science Seminar

     "Imaging Non-equilibrium Dynamics in Two-Dimensional Materials"

     Presented by Kenneth Beyerlein, Max Planck Institute for the Structure and Dynamics of Matter, Germany

     Wednesday, August 1, 2018, 11 am
     ISB Bldg. 734, Conf. Rm. 201 (upstairs)

     Hosted by: Ian Robinson

     The interfaces in thin film heterostructures dictate the performance of an electronic device. Understanding their behavior upon exposure to light is important for advancing photovoltaics and spintronics. However, producing an atomic image of these dynamics is an under-determined problem without a unique solution. In this talk, I will show how a set of ultrafast soft X-ray diffraction rocking curves can be spliced together to add constraints to the phase retrieval problem. In doing so, the anti-ferromagnetic order through a NdNiO3 film after illumination of the substrate with a mid-Infrared laser pulse will be imaged. Notably, a disordered phase front initiated at the substrate interface is shown to evolve at twice the speed of sound. This time-spliced imaging technique opens a new window into the correlated dynamics of two-dimensional materials.
213. Special Particle Physics Seminar

     "Dark Matter Annual Modulation with SABRE"

     Presented by Lindsey Bignell, Australian National University

     Tuesday, July 31, 2018, 1:30 pm
     Small Seminar Room, Bldg. 510

     Hosted by: David Jaffe

     SABRE is a dark matter direct detection experiment with a target of ultra-pure NaI(Tl). Our experiment is motivated by the DAMA result; a long-standing and highly statistically significant modulation of the count rate in their NaI(Tl) detector that is consistent with that expected from the dark matter halo. However, a number of other direct detection experiments, using different target materials, exclude the dark matter parameter space implied by DAMA for the simplest WIMP-nucleus interaction models. SABRE hopes to carry out the first model-independent test of the DAMA claim, with sufficient sensitivity to confirm or refute their result. SABRE will also operate identical detectors in the northern and southern hemisphere, to rule out seasonally-modulated backgrounds. The southern detector will be housed at the first deep underground laboratory in the Southern Hemisphere: the Stawell Underground Physics Laboratory. This talk will give an overview of the SABRE design and its predicted sensitivity, as well as an update on the proof-of-principle detector which will be operating this summer.
214. Sambamurti Lecture

     "Capturing the Inner Beauty of the Quark Gluon Plasma"

     Presented by Jin Huang, Brookhaven National Laboratory

     Friday, July 27, 2018, 3:30 pm
     Large Seminar Room, Bldg. 510

     Hosted by: John Haggerty

     The Quark Gluon Plasma (QGP) filled the universe in the first microsecond after the Big Bang and today is routinely recreated in high energy nuclear collisions at RHIC and the LHC. While experiments have revealed an array of surprising QGP properties, such as perfect fluidity, extreme vorticity, and near total opaqueness to hard scattered quarks and gluons, the detailed physics that gives rise to these properties remains a focus of forefront research. Heavy quarks, particularly the very heavy beauty quark, provide the means to clarify the connection between the microscopic physics of the QGP and its larger scale properties. Beauty quarks – or b-quarks – are produced rarely in collisions at RHIC, and the planned sPHENIX experiment will be equipped with a high rate vertex tracker enabling precision measurements of b-quark observables, such as B-meson suppression and flow, the differential suppression of Upsilon states and a number of observables related to b-quark jets. These b-quark probes will provide crucial information about the microscopic description of QGP at RHIC energies. In this talk, I will explain b-quark physics in the QGP, current measurements, the program at the planned sPHENIX experiment and its relevance to the future Electron Ion Collider.
215. Nuclear Theory/RIKEN Seminar

     "Jets as a probe of transverse spin physics"

     Presented by Zhongbo Kang, UCLA

     Friday, July 27, 2018, 2 pm
     Building 510, CFNS Seminar Room 2-38

     Hosted by: Chun Shen

     Jets are collimated spray of hadrons that are naturally produced in high energy colliders. They are powerful probes of many different aspects of QCD dynamics. In this talk, we will demonstrate how to use jets to explore the transverse momentum dependent (TMD) physics. A novel TMD framework to deal with back-to-back two particle correlations is presented, with which we could study the Sivers asymmetry for photon+jet or dijet production in transversely polarized proton-proton collisions. At the end of the talk, we also show how jet substructure could be used to explore the TMD fragmentation functions. We expect these studies to have important applications at RHIC in the future.
216. Nuclear Theory Seminar

     "Medium Modification of Jet Substructure in the Opacity Expansion"

     Presented by Matthew Sievert, Los Alamos

     Friday, July 27, 2018, 11 am
     Building 510, CFNS Seminar Room 2-38

     Hosted by: Yacine Mehtar-Tani

     The modification of jets and their substructure in the presence of quark-gluon matter, beyond solely the quenching of their production, is a cornerstone of jet tomography. Although the nature of different nuclear environments can vary widely, the manner in which an external potential leads to a modification of jets and their substructure is universal and applies to both hot and cold nuclear matter. An order-by-order calculation of the medium modifications is possible on the basis of the opacity expansion, a series which can be truncated at finite order if the average number of scatterings in the quark-gluon matter is not too large. Other methods exist which can resum the full opacity series into a path integral formalism that remains applicable at very high opacities. In this talk, I will present a new calculation in the opacity expansion approach which computes the gluon substructure of a quark jet with exact kinematics at second order in opacity. I will also derive a set of recursion relations which can be used to construct higher orders terms in the opacity expansion to any finite order. And finally, I will compare this approach to the resumed path integral formalism, discussing the strengths and weaknesses of both methods and opportunities to study their overlap.
217. Condensed-Matter Physics & Materials Science Seminar

     "Atomic level structural characterization of materials by electron microscopy"

     Presented by Shize Yang, Center for Functional Nanomaterials

     Thursday, July 26, 2018, 4 pm
     Bldg. 480, Conference Room

     Hosted by: Yimei Zhu

     In recent years, with the development of technologies, electron microscopy techniques have been widely developed. Important advancement has been achieved on in-situ electron microscopy, cryogenic electron microscopy, electron tomography, advanced electron energy loss spectroscopy etc. In this talk I will briefly introduce and show how those techniques provide a vital role in the structural characterization of 2D materials, catalysts and battery materials.
218. Physics Summer School

     "Working with High-Performance Astronomical CCD"

     Presented by Andrei Nomerotski, BNL

     Thursday, July 26, 2018, 12:30 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Mary Bishai and Anze Slosar
219. Nuclear Theory Seminar

     "Jet fragmentation in a QCD plasma: Universal quark/gluon ratio and wave turbulence"

     Presented by Soeren Schlichting, University of Washington

     Thursday, July 26, 2018, 11 am
     Building 510, CFNS Seminar Room 2-38

     Hosted by: Yacine Mehtar-Tani

     We investigate the radiative break-up of a highly energetic quark or gluon in a high-temperature QCD plasma. Within an inertial range of momenta T
220. Nuclear Physics Seminar

     "Tale of coherent photon products: from UPC to HHIC"

     Presented by Wangmei Zha, University of Science and Technology of China

     Tuesday, July 24, 2018, 11 am
     Small Seminar Room, Bldg. 510

     Hosted by: Rongrong Ma
221. Chemistry Department Seminar

     "Triggered Reversible Phase Transformation between Layered and Spinel Structure via Intercalated Hetero Species in Sodium Birnessite"

     Presented by Yong-Mook Kang, Department of Energy and Materials Engineering, Dongguk University-Seoul, Seoul, 04620, Republic of Korea., Korea, Republic of (South)

     Monday, July 23, 2018, 11 am
     Room 300, 3rd Flr. Chemistry Bldg. 555

     Hosted by: Xiao-Qing Yang

     Phase transformation of layered structure into spinel structure has been detrimental for most of layered oxide cathodes. Even if a lot of efforts have been made to relieve this highly irreversible phase transformation, there have been few successful results. However, we firstly observed the possibility to make this irreversible phase transformation extremely reversible by utilizing Na- birnessite (NaxMnO2•yH2O; Na-bir) as a basic structural unit, which has distinctive layered structure containing crystal water. Herein, the crystal water in the structure contributes to generating metastable spinel-like phase, which is the key factor for making this unusual reversibility happen. The reversible structural rearrangement between layered and spinel-like phases during electrochemical reaction could activate new cation sites and enhance ion diffusion with higher structural stability. This unprecedented reversible phase transformation between spinel and layered structure was deeply analyzed via combined ex situ soft and hard X-ray absorption spectroscopy (XAS) analysis with in situ X-ray diffraction (XRD). Fundamental mechanism on this reversible phase transformation was theoretically elucidated and confirmed by kinetic investigation using first-principle calculation. These results provide deep insight into novel class of intercalating materials which can deal with highly reversible framework changes, and thus it can pave an innovative way for the development of cathode materials for next- generation rechargeable batteries.
222. HET Special Seminar

     "The Quest for Dark Sectors"

     Presented by Claudia Frugiuele, Weizmann

     Friday, July 20, 2018, 10 am
     Small Seminar Room, Bldg. 510

     Hosted by: Sally Dawson

     Dark sectors are ubiquitous in physics beyond the Standard Model (SM), and may play a role in explaining many of the long-standing problems of the SM such as the existence of dark matter or the electroweak hierarchy problem. By definition, dark sectors are not charged under any of the known forces. Discovering their possible existence is thus challenging. I will describe how a a broad program combining particle, nuclear and atomic physics experiments can effectively probe a large region of the parameter space. I will show how the unique signatures of such physics can already be searched for with existing/planned experiments, including neutrino-proton fixed-target experiments and precision atomic measurements.
223. Physics Summer School

     "Silicon detectors"

     Presented by Gabriele Giacomini

     Thursday, July 19, 2018, 12:30 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Mary Bishai and Anze Slosar
224. RIKEN Lunch Seminar/Special Nuclear Theory Seminar

     "Neutrino Scattering on Quantum Computers"

     Presented by Alessandro Roggero, University of Washington

     Thursday, July 19, 2018, 12:30 pm
     Building 510, Room 2-160

     Hosted by: Rob Pisarski
225. Environmental & Climate Sciences Department Seminar

     "Invariant and insensitive: climate model microphysics as a scaling problem"

     Presented by Mikael Witte, National Center for Atmospheric Research

     Thursday, July 19, 2018, 11 am
     Conference Room Bldg 815E

     Hosted by: Yangang Liu

     Clouds are inherently multiscale phenomena: the particles that make up clouds are typically microns to millimeters, while the large-scale circulations that drive cloud systems can be hundreds of kilometers across. Limited computational power and the need to accurately represent the large-scale circulations in numerical simulations of the atmosphere make explicit inclusion of cloud microphysics a practical impossibility. In the last 20 years there has been a shift toward representing microphysics as scale-aware processes. Despite this shift, many unanswered questions remain regarding the scaling characteristics of microphysical fields and how best to incorporate that information into parameterizations. In this talk, I will present results from analysis of high frequency in situ aircraft measurements of marine stratocumulus taken over the southeastern Pacific Ocean aboard the NCAR/NSF C-130 during VOCALS-REx. First, I will show that cloud and rain water have distinct scaling properties, indicating that there is a statistically and potentially physically significant difference in the spatial structure of the two fields. Covariance of cloud and rain is a strong function of length/grid scale and this information can easily be incorporated in large-scale model parameterizations. Next I will show results from multifractal analysis of cloud and rain water to understand the spatial structure of these fields, the results of which provide a framework for development of a scale-insensitive microphysics parameterization. Finally, I compare observed microphysical scaling properties with those inferred from large eddy simulations of drizzling stratocumulus, applying the same analyses as applied to the aircraft observations. We find that simulated cloud water agrees well with the observations but the drizzle field is substantially smoother than observed, which has implications for the ability of limited-area models to adequately reproduce the spatial structure o
226. Condensed-Matter Physics & Materials Science Seminar

     "Mechanism of strange metal and strange metal state near a heavy fermion quantum critical point"

     Presented by Chung-Hou Chung, Department of Electrophysics, National Chiao-Tung University, Taiwan

     Wednesday, July 18, 2018, 1:30 pm
     ISB Bldg. 734 Conference Room 201

     Hosted by: Alexei Tsvelik

     Strange metal (SM) behaviors with non-Fermi liquid (NFL) properties, generic features of heavy fermion systems near quantum phase transitions, are yet to be understood microscopically. A paradigmatic example is the magnetic field-tuned quantum critical heavy fermion metal YbRh2Si2 (YRS), revealing a possible SM state over a finite range of fields at low temperatures when substituted with Ge. Above a critical field, the SM state gives way to a heavy Fermi liquid with Kondo correlation. The NFL behavior shows most notably a linear-in-temperature electrical resistivity and a logarithmic-in-temperature followed by a power-law-in-temperature in the specific heat coefficient at low temperatures [1]. We propose a mechanism to explain it: a quasi-2d fluctuating anti-ferromagnetic short-range resonating-valence-bond (RVB) spin-liquid competing with the Kondo correlation (Fig. 1) [2]. Applying renormalization group analysis on an effective field theory beyond a large-N approach to an antiferromagnetic Kondo-Heisenberg model, we identify the critical point, and explain remarkably well the SM behavior. Our theory goes beyond the well-established framework of quantum phase transitions and serves as a new basis to address open issues of the non-Fermi liquid behavior in quantum critical heavy-fermion compounds, such as: the strange superconductivity observed in the "115" family CeMIn5 (M=Co, Rh)[3]. References: [1] J. Custers et al., Nature 424, 524 (2003); J. Custers et al., Phys. Rev. Lett. 104, 186402 (2010). [2] Yung-Yeh Chang, Silke Paschen, and Chung-Hou Chung, Phys. Rev. B 97, 035156 (2018). [3] Y. Y. Chang,, F. Hsu, S. Kirchner, C. Y. Mou, T. K. Lee and C. H. Chung (un-published).
227. C-AD Accelerator Physics Seminar

     "Coherent THz Radiation from Plasma Oscillation Driven by Laser Pulses"

     Presented by Dr. Min Sup Hur, Physics Department - UNIST Korea

     Tuesday, July 17, 2018, 4 pm
     Bldg. 911B, 2nd floor - Large Conference Room

     Hosted by: Dr. Bingping Xiao

     Plasma, a gas of electric charges, exhibits a fundamental oscillating behavior, the plasma oscillation. Similar to the classical harmonic oscillator, but charged, the plasma oscillation is potentially an outstanding source of coherent, monochromatic radiation with high intensity and high frequency. However, harnessing the plasma oscillation and taking the radiation out of it are never trivial problems. In this presentation, I introduce one novel method to generate an isolated plasma dipole oscillation by colliding laser pulses in a plasma, eventually to obtain a quasi-narrowband, powerful THz emission. The conceptual connection of the idea to the astrophysical plasma emission is also addressed.
228. Physics Summer School

     "Physics Summer School: Introduction to Statistics for Particle Physics"

     Presented by Xin Qian, Brookhaven Lab

     Tuesday, July 17, 2018, 12:30 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Mary Bishai & Anze Slosar
229. Nuclear Theory/RIKEN Seminar

     "Confronting hydrodynamic predictions with Xe-Xe heavy-ion collision data"

     Presented by Matt Luzum, Univeristy of Sao Paulo

     Friday, July 13, 2018, 2 pm
     Building 510, CFNS Seminar Room 2-38

     Hosted by: Chun Shen

     Comparing collision systems of different size, at near the same collision energy, offers us the opportunity to probe the scaling behavior and therefore the nature of the system itself. Recently, we made predictions for Xe-Xe collisions at 5.44 TeV using viscous hydrodynamic simulations, noting that the scaling from the larger Pb-Pb system is rather generic, and arguing that robust predictions can be made that do not depend on details of the model. Here we confront our predictions with measurements that were subsequently made in a short Xe-Xe run at the LHC by the ALICE, ATLAS, and CMS collaborations. We find that the predictions are largely confirmed, with small discrepancies that could point the way to a better understanding of the medium created in such collisions.
230. RIKEN Lunch Seminar

     "Topological structures in finite temperature QCD"

     Presented by Rasmus Larsen, BNL

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

     Hosted by: Yuya Tanizaki

     We report our study on the properties of the topological structures present in the QCD medium. We use dynamical domain wall fermion configurations on lattices of size 32^3x8 and detect the topological structures through the zero modes of the overlap operator. We explicitly show that the properties of the zero modes of the QCD Dirac operator agrees well with that of calorons with non-trivial holonomy. Different profiles of the zero modes are observed, ranging from solutions that are localized in all four spacetime dimensions, to profiles that are localized in the spatial directions, and constant along the temporal extent of the lattice. This indicates towards the presence of instanton-dyons in the hot QCD medium around Tc, where the distance between dyons control the shape and extent of the zero modes.
231. Physics Summer School

     "Intro to neutrino physics"

     Presented by Mary Bishai, BNL

     Thursday, July 12, 2018, 12:30 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Mary Bishai and Anze Slosar
232. Condensed-Matter Physics & Materials Science Seminar

     "Electron-microscopy-guided designing of ferroelectric materials for nonvolatile memories and multifunctional nanodevices"

     Presented by Linze Li, University of California @ Irvine

     Thursday, July 12, 2018, 11 am
     Bldg. 480, Conference Room

     Hosted by: Yimei Zhu

     As a prototypical example of functional oxides, ferroelectric materials have been utilized in a broad range of electronic, optical, and electromechanical applications and hold the promise for the design of future high-density nonvolatile memories and multifunctional nanodevices. The utilities of ferroelectrics are derived from the structures and switching of ferroelectric domains, or from their coupling to other material functionalities. In recent years, advanced imaging techniques based on aberration-corrected scanning transmission electron microscopy (STEM) and in situ transmission electron microscopy (TEM) have become powerful methods to characterize ferroelectric oxides, allowing nanoscale polarization states to be unambiguously determined with sub-Angstrom resolution, and allowing domain switching processes to be directly resolved in real time. In this presentation I will show several examples of applying advanced STEM or TEM-based techniques to the study of the static and dynamic properties of domains and domain walls in ferroelectric and multiferroic BiFeO3 thin films. Atomic structures and electrical switching behaviors of charged domain walls have been observed. A strong interaction between the ferroelectric polarization and nanoscale impurity defects has been discovered, and a new route to the production of exotic polarization states by utilizing such interaction has been proposed and established. These findings open up the possibility for the designing of novel ferroelectric materials and multifunctional devices with nanoscale structural defects or charged domain walls as essential components.
233. Physics Summer School

     "Introduction to flavor physics"

     Presented by Bilas Pal, BNL

     Tuesday, July 10, 2018, 12:30 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Mary Bishai and Anze Slosar
234. Joint Nuclear Physics and High Energy Physics Seminar

     "Parity-Violating and Parity-Conserving Asymmetries in ep and eN Scattering in the Qweak Experiment"

     Presented by Wouter Deconinck, College of William & Mary

     Tuesday, July 10, 2018, 11 am
     Small Seminar Room, Bldg. 510

     Hosted by: Jin Huang

     The Standard Model provides the current best description of fundamental particles and forces, but among other limitations it fails to account for dark matter which could manifest itself as more massive particles. Precision measurements of well predicted observables in the Standard Model allow for highly targeted tests for physics beyond the Standard Model. The Qweak experiment at Jefferson Lab has made the first precise determination of the weak charge of the proton in elastic scattering of longitudinally polarized electrons from unpolarized protons. To achieve the required precision to measure the small parity-violating asymmetry of -226.5 ± 9.3 parts per billion, we directed a high current polarized electron beam on a liquid hydrogen target and integrated scattered events in eight azimuthally symmetric fused silica Cerenkov detectors. We find a value for the weak charge of proton of 0.0719 ± 0.0045, in agreement with predictions of the Standard Model. This result rules out leptoquark masses below 2.3 TeV and excludes generic new semi-leptonic parity-violation physics beyond the Standard Model below 3.5 TeV. To correct for the contributions from background processes, we conducted several additional parity-violating and parity-conserving asymmetry measurements with different kinematics (elastic and through the production of a Delta resonance), polarization (longitudinal and transverse), and targets (protons, electrons, aluminum, and carbon). I will discuss the results of the main experiment and highlight several ancillary results of interest to experiments at future facilities.
235. Office of Educational Programs Event

     "High School Research Program Begins"

     Monday, July 9, 2018, 8 am
     Berkner Hall Auditorium

     Hosted by: Aleida Perez
236. Physics Summer School

     "TBA"

     Thursday, July 5, 2018, 12:30 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Mary Bishai and Anze Slosar
237. HET Special Seminar

     "Charting the Unknown with Theory and Experiments"

     Presented by Duccio Pappadopulo, NYU

     Tuesday, July 3, 2018, 1:30 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Sally Dawson
238. Physics Summer School

     "Cosmology with Ground-Based Optical Surveys"

     Presented by Erin Sheldon, BNL

     Tuesday, July 3, 2018, 12:30 pm
     Building 510, Room 2-160

     Hosted by: Mary Bishai and Anze Slosar
239. Condensed-Matter Physics & Materials Science Seminar

     "Room-temperature magnetic spiral order induced by disorder"

     Presented by Christopher Mudry, Paul Scherrer Institut, Switzerland

     Monday, July 2, 2018, 1:30 pm
     ISB Bldg. 734 Conf. Rm. 201 (upstairs)

     Hosted by: Alexei Tsvelik

     Upon cooling, the compound YBaCuFeO5 undergoes a phase transition to an antiferromagnetic long-range ordered phase. Upon further cooling, a second phase transition to a magnetic spiral phase takes place. The latter transition temperature depends on the sample preparation and can reach room temperature. We propose a mechanism to explain the transition to a magnetic spiral ordered phase due to frustrating magnetic interactions that are introduced randomly along a single crystallographic direction as caused by a particular type of chemical disorder. This mechanism could open the way to high-temperature multiferroism.
240. HET Lunch Discussions

     "Pion-pion scattering with physical quark masses from lattice QCD"

     Presented by Dan Hoying, UConn

     Friday, June 29, 2018, 12:15 pm
     Building 510, Room 2-160

     Hosted by: Christoph Lehner
241. NSLS-II Friday Lunchtime Series

     "Investigating slow kinetic processes using synchrotron radiation: A case study of cement hydration in nuclear waste cements"

     Presented by Claire L. Corkhill, University of Sheffield, United Kingdom

     Friday, June 29, 2018, 12 pm
     NSLS-II Bldg. 743 Room 156

     Hosted by: M. Abeykoon, S. Chodankar, B. Ocko, J. Thieme, G. Wang
242. Particle Physics Seminar

     "First results from PROSPECT: The Precision Reactor Oscillation & Spectrum experiment"

     Presented by David Jaffe, BNL

     Thursday, June 28, 2018, 3 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Chao Zhang

     PROSPECT is a short-baseline reactor antineutrino experiment designed to search for eV-scale sterile neutrino oscillations and measure the 235U antineutrino energy spectrum from the High Flux Isotope Reactor at Oak Ridge National Laboratory. Deployed in early 2018, the 4ton, segmented, 6Li-loaded liquid scintillator detector began commissioning in March of this year. The detector consists of 154 segments that span a baseline of 7-9m from the compact highly enriched uranium core, enabling coverage of a wide range of oscillation parameter space. Full-scale prototypes have demonstrated excellent energy resolution and pulse-shape discrimination that will reject cosmogenic backgrounds and produce an unparalleled measurement of the 235U antineutrino spectrum. The first results of PROSPECT on sterile neutrino oscillations will be presented.
243. HET Seminar

     "Constraining Effective Field Theories with Machine Learning"

     Presented by Johann Brehmer, New York University

     Wednesday, June 27, 2018, 2 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Christopher Murphy

     An important part of the LHC legacy will be precise limits on indirect effects of new physics, parameterized for instance in an Effective Field Theory (EFT). But measuring these parameters in complex processes is often challenging for established analysis methods. We present powerful new inference techniques based on machine learning. They scale well to complicated problems with many parameters and observables and do not require any approximations on the parton shower or detector effects. In an example analysis of WBF Higgs production we show that they enable us to put stronger bounds on EFT parameters than established methods, demonstrating their potential to improve the new physics reach of the LHC legacy results. We also comment on the application of these new "likelihood-free" or "simulator-based" inference techniques to a broad class of problems outside of particle physics, for instance in cosmology, epidemiology, and genetics.
244. Condensed-Matter Physics & Materials Science Seminar

     "Imaging of Local Structure and Dynamics in Hard and Soft Condensed Matter Systems"

     Presented by Dmitry Karpov, New Mexico State University

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

     Hosted by: Ian Robinson

     With advancement of coherent probes there is a shift from integral studies to highly localized studies in either spatial or temporal domains. Nanostructures and low dimensional phenomena, correlated fluctuations and associated transitions directly benefit from new instrumental capabilities. Studies of ferroelectric and magnetic materials and of their local behavior allow both to test fundamental physics concepts and provide access to technologies with direct practical applications. Topological phase transitions and topological defects are among the topics that are actively pursued in modern materials science. In recent study [1] conducted by our group we were able to visualize three-dimensional topological vortex structure in a volume of individual ferroelectric nanoparticle of barium titanate under external electric field using Bragg coherent diffractive imaging technique. Among other things we observed: (i) electric field induced structural transition from mixture of tetragonal and monoclinic phases to dominant monoclinic phase; (ii) controllable switching of vortex chirality; (iii) vortex mediated behavior of the nano-domains in the particle; (iv) and that the core of the vortex in the volume behaves as a nanorod of zero ferroelectric polarization which can be rotated by external electric field and can serve as a conducting channel for charge carriers. These findings can be used in the design of novel nanoelectronics devices and for creating artificial states of matter. Better understanding of the materials behavior at the nanoscale requires ways of probing anisotropies of the refractive index. Using polarized laser light, we've developed a method [2] termed birefringent coherent diffractive imaging that allows to extract projections of dielectric permittivity tensor in nematic liquid crystal. Further expanding this tool into full-vectorial mode shows that the method can be applied for imaging of magnetic domains, cellular structures, and ot
245. Condensed-Matter Physics & Materials Science Seminar

     "Theories of transport scaling in disordered semimetals and topological spin-nematic excitonic insulators in graphite under high magnetic field"

     Presented by Ryuichi Shindo, Peking University, China

     Thursday, June 21, 2018, 1:30 pm
     ISB Bldg. 734 Conf. Rm. 201 (upstairs)

     Hosted by: Alexei Tsvelik

     In the first part of my talk, I will talk about transport scaling theories in disordered Weyl semimetal [1,2]. In electronic band structure of solid state material, two band touching points with linear dispersion (called as `Weyl node') appear in pair in the momentum space. When they annihilate with each other, the system undergoes a quantum phase transition from Weyl semimetal (WSM) phase to a band insulator (BI) phase. The continuous phase transition is recently discovered in solid state materials [3]. The phase transition is described by a critical theory with a `magnetic dipole' like object in the momentum space. The critical theory hosts a disorder-driven quantum multicritical point, which is encompassed by three quantum phases, WSM phase, BI phase, and diffusive metal (DM) phase. Based on the renormalization group argument, we clarify transport scaling properties around the Weyl node at the quantum multicritical point as well as all phase boundaries among these three phases [1,2]. In the second part of my talk, I will argue that three-dimensional topological excitonic insulator is realized in graphite under high magnetic field [4,5]. Graphite under high magnetic field exhibits consecutive metal-insulator (MI) transitions as well as re-entrant insulator-metal (IM) transition at low temperature. We explain these enigmatic insulator phases as manifestation of excitonic insulator phases with spin nematic orderings ("SNEI" phases). Especially, we explain unusual field-dependences of in-plane resistivity in the graphite experiment by surface transports via 2+1 massless surface Dirac fermion in one of the SNEI phases [4,5]. [1] https://arxiv.org/abs/1803.09051, under review [2] https://arxiv.org/abs/1710.00572, selected as PRB editors' suggestion [3] Tian Liang, et.al., Science Advances, 3, e1602510 (2017) [4] https://arxiv.org/abs/1802.10253, under review [5] in preparation &
246. Physics Summer School

     "Physics Summer School: Why we need physics beyond the Standard Model"

     Presented by Hooman Davoudiasl, BNL

     Thursday, June 21, 2018, 12:30 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Mary Bishai and Anze Slosar
247. Condensed-Matter Physics & Materials Science Seminar

     "Fermi-Surface Reconstruction in Nd-doped CeCoIn5"

     Presented by Elizabeth Green, Dresden High Magnetic Field Laboratory

     Thursday, June 21, 2018, 11 am
     ISB Bldg. 734 Seminar Room 201 (upstairs)

     Hosted by: Cedomir Petrovic

     Heavy fermion compounds are well known to exhibit novel properties when exposed to high magnetic fields. Most notably CeCoIn5 exhibits a field-induced superconducting state at high magnetic fields known as the Qphase. Recent neutron scattering measurements show a similar Q-vector for the 5% Nd-doped CeCoIn5 at zero applied magnetic field [1] which has initiated intense theoretical and experimental work on this doping series. In this talk I will present de Haas-van Alphen effect measurements which indicate a drastic Fermi-surface reconstruction occurs between 2 and 5% Nd-doping levels. The cylindrical Fermi surface, believed to play a crucial role in superconductivity in these materials, develops a quasi-three-dimensional topology with increased doping levels thus reducing the likelihood of an enhanced nesting scenario, previously given as a possible explanation for the Q-phase. However, effective masses remain relatively unchanged up to 10% Nd indicating the crossing of a spin density wave type of quantum critical point. In addition, I will present evidence that by substituting Ce with Nd the electronic pairing potential may be altered. These results help elucidate the reasoning for the emergence of the Q-phase seen in the 5% Nd sample and may be relevant to other heavy fermion compounds. [1] S. Raymond et al., JPSJ 83, 013707 (2014).
248. Physics Colloquium

     "Subatomic Swirls and Massive Magnetic Fields - Lambda Polarization in Heavy Ion Collisions at RHIC"

     Presented by Michael Lisa, Ohio State University

     Tuesday, June 19, 2018, 3:30 pm
     Large Seminar Room, Bldg. 510

     Hosted by: Peter Petreczky

     Last year, the STAR Collaboration at RHIC published the first observation of global hyperon polarization in heavy ion collisions. This polarization may be used to extract rotational substructure of the flow field. The result represented a striking validation of the near-equilibrium hydrodynamic paradigm and established the quark-gluon plasma at RHIC as by far the most vortical fluid in nature. More recent studies quantify the vortical structure systematics to challenge hydro models in detail. In addition to the rotational fluid substructure, hyperon polarization should probe the strong magnetic fields expected in heavy ion collisions. Measuring these fields is crucial for establishing and quantifying the so-called Chiral Magnetic Effect at RHIC. Experimental uncertainties are currently too large to conclusively measure the magnetic field, but detector upgrades at STAR and dedicated running at RHIC may allow a breakthrough in this year's (2018) run.
249. Condensed-Matter Physics & Materials Science Seminar

     "X-ray Scattering as a Tool for Understanding Nanostructured Materials"

     Presented by Robert Koch, Alfred University

     Tuesday, June 19, 2018, 1:30 pm
     ISB Bldg. 734, Conf. Rm. 201 (upstairs)

     Hosted by: Ian Robinson

     Materials with significant local distortions from the bulk average structure often show novel and useful properties. Identifying and quantifying the nature and extent of this correlated disorder1 is however quite challenging, as traditional crystallography and the associated tools often do not adequately describe such nanostructured materials. This is a manifestation of the "nanostructure problem"2 and the solution requires complex modelling incorporating multiple techniques. This talk focuses on the application of X-ray scattering and complex modelling as tools for understanding various nanostructured materials, including nanocrystalline nickel with large clusters of planar defects, interlayered non-silicon photovoltaics, geometrically frustrated ternary alkaline earth hexaborides, manganese dioxide nanosheet assemblies, and nanostructured noble metal alloys. Complex modelling leveraging both standard techniques as well as genetic algorithms, Markov chain Monte Carlo, and machine learning together provide synergistic understanding spanning length scales from a few Ångstrom to hundreds of nanometers. Additionally, an example of how complex modelling can be used to shed understanding on the nature of crystallographic disorder in superconducting alloys of 2H-TaSe2−xSx is discussed. A potential model is proposed whereby alloys of 2H-TaSe2−xSx are composed of interlayered sheets with two unique c-axes. This model is consistent with the observed 00l Bragg profile broadening trend and may help explain the suppression of charge density waves and maximization of superconductivity in these systems. 1. Keen, D. A. & Goodwin, A. L. The crystallography of correlated disorder. Nature 521, 303–309 (2015). 2. Billinge, S. J. L. & Levin, I. The problem with determining atomic structure at the nanoscale. Science 316, 561–565 (2007).
250. Physics Summer School: Introduction to Particle Physics

     Presented by Bill Morse, BNL

     Tuesday, June 19, 2018, 12:30 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Mary Bishai and Anze Slosar
251. Nuclear Physics Seminar

     "Measurements of charm, bottom, and Drell-Yan via dimuons in p+p and p+Au collisions at sNN=200 GeV with PHENIX at RHIC"

     Presented by Yue Hang Leung, Stonybrook University

     Tuesday, June 19, 2018, 11 am
     Small Seminar Room, Bldg. 510

     Hosted by: Jin Huang

     Dilepton spectra are a classic probe to study ultra-relativistic heavy ion collisions. At RHIC energies, the dimuon continuum is dominated by correlated pairs from charm and bottom semi-leptonic decays and the Drell-Yan process. In this talk, we present measurements of µµ pairs from charm, bottom, and Drell-Yan in p+p and p+Au collisions at sNN = 200 GeV. Differential yields from charm and bottom in p+p collisions will be presented and implications for the relative contributions from different heavy flavor production mechanisms will be discussed. We will also present results of bottom yields in p+Au collisions and discuss the implications on cold nuclear matter effects. This study also enables first measurements of the Drell-Yan cross-section at s_{NN} = 200 GeV. Studying Drell-Yan production in p+Au collisions is a clean probe for modifications of the initial state. The Drell-Yan differential cross-sections in p+p collisions and progress on p+Au collisions will be presented.
252. HET Lunch Discussions

     "Discussion of Mainz workshop of g-2 Theory Initiative"

     Presented by Mattia Bruno and Aaron Meyer, BNL

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

     Hosted by: Christoph Lehner
253. Particle Physics Seminar

     "Jet substructure in ATLAS at the LHC – a tool for discoveries and measurements"

     Presented by Peter Loch, University of Arizona

     Thursday, June 14, 2018, 3 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Alessandro Tricoli

     The ATLAS experiment at the Large Hadron Collider (LHC) applies jet substructure analysis techniques to extract the internal energy flow in high energy jets produced in the proton-proton collisions in searches for new physics as well as in Standard Model (SM) measurements. In this talk we will introduce the most commonly applied techniques and present an overview of results from the respective performance evaluations. In addition, we will discuss selected configurations of tagging algorithms designed to extract two- or three-prong energy flow patterns inside a jet, as generated by decays of SM particles like the W-boson or the top quark, or possible new heavy particles indicating physics beyond the SM. A brief presentation of recent results from searches and SM measurements, including the recent measurement of the internal structure of light quark and gluon jets, concludes the talk.
254. Condensed-Matter Physics & Materials Science Seminar

     "Doublon-holon origin of the subpeaks at the Hubbard band edges"

     Presented by Seung-Sup Lee, Ludwig-Maximilians-University, Germany

     Thursday, June 14, 2018, 1:30 pm
     ISB Bldg. 734 Conf. Rm. 201 (upstairs)

     Hosted by: Andreas Weichselbaum

     Dynamical mean-field theory (DMFT) studies frequently observe a fine structure in the local spectral function of the SU(2) Fermi-Hubbard model (i.e., one-band Hubbard model) at half filling: In the metallic phase close to the Mott transition, subpeaks emerge at the inner edges of the Hubbard bands. Here we demonstrate that these subpeaks originate from the low-energy effective interaction of doublon-holon pairs, by investigating how the correlation functions of doublon and holon operators contribute to the subpeaks [1, 2]. We use the numerical renormalization group (NRG) as a DMFT impurity solver to obtain the correlation functions on the real-frequency axis with improved spectral resolution [3]. A mean-field analysis of the low-energy effective Hamiltonian [2] provides results consistent with the numerical result. The subpeaks are associated with a distinctive dispersion that is different from those for quasiparticles and the Hubbard bands. Also, the subpeaks become more pronounced in the SU(N) Hubbard models for larger number N of particle flavors, due to the increased degeneracy of doublon-holon pair excitations. Hence we expect that the sub-peaks can be observed in the photoemission spectroscopy experiments of multi-band materials or in the ultracold atom simulation of the SU(N) Hubbard models. [1] S.-S. B. Lee, J. von Delft, and A. Weichselbaum, Phys. Rev. Lett. 119, 236402 (2017). [2] S.-S. B. Lee, J. von Delft, and A. Weichselbaum, Phys. Rev. B 96, 245106 (2017). [3] S.-S. B. Lee and A. Weichselbaum, Phys. Rev. B 94, 235127 (2016).
255. Condensed-Matter Physics & Materials Science Seminar

     "Defects and their functional properties in multiferroic hexagonal systems"

     Presented by Shaobo Cheng, McMaster University Canada

     Monday, June 11, 2018, 2:30 pm
     Bldg. 480, Conference Room

     Hosted by: Yimei Zhu

     As a main component of quantum materials, multiferroic materials, which simultaneously have multiple orderings, hold promise for use in the next generation of memory devices. Taking advantage of the state-of-the-art transmission electron microscopy techniques, we have systematically studied the defects induced emergent phenomena in multiferroic hexagonal systems. Two single phase multiferroic hexagonal systems will be covered in this talk: YMnO3 and LuFe2O4. YMnO3 is a classic single phase multiferroic material with geometric ferroelectricity. The effects oxygen vacancies, partial edge dislocations, and interfacial atomic reconstructions will be presented. LuFe2O4 is a well-known multiferroic system with charge ordering origin. The effects of twins and interstitial oxygen in LuFe2O4 single crystalline sample will be discussed. The structural-property relationship for both systems has been tried to be established in our studies. Our findings demonstrate the structural flexibility of both manganites and ferrites, and open the door to new tunable multifunctional applications.
256. Center for Functional Nanomaterials Seminar

     "Heterostructures for Nanoelectronics and Photovoltaics"

     Presented by Deep Jariwala, University of Pennsylvania

     Monday, June 11, 2018, 1:30 pm
     CFN, Bldg. 735, Conference Room A, 1st Floor

     Hosted by: Don DiMarzio & Mircea Cotlet

     The isolation of a growing number of two-dimensional (2D) materials has inspired worldwide efforts to integrate distinct 2D materials into van der Waals (vdW) heterostructures. While a tremendous amount of research activity has occurred in assembling disparate 2D materials into "all-2D" van der Waals heterostructures,1, 2 this concept is not limited to 2D materials alone. Given that any passivated, dangling bond-free surface will interact with another via vdW forces, the vdW heterostructure concept can be extended to include the integration of 2D materials with non-2D materials that adhere primarily through noncovalent interactions.3 In the first part of this talk I will present our work on emerging mixed-dimensional (2D + nD, where n is 0, 1 or 3) heterostructure devices performed at Northwestern University. I will present two distinct examples of gate-tunable p-n heterojunctions.4-6 I will show that when a single layer n-type molybdenum disulfide (MoS2) (2D) is combined with p-type semiconducting single walled carbon nanotubes (1D), the resulting p-n junction is gate-tunable and shows a tunable diode behavior with rectification as a function of gate voltage and a unique anti-ambipolar transfer behavior.4 The same concept when extended to p-type organic small molecule semiconductor (pentacene) (0D) and n-type 2D MoS2 leads to a tunable p-n junction with a photovoltaic effect and an asymmetric anti-ambipolar transfer response.6 I will present the underlying charge transport and photocurrent responses in both the above systems using a variety of scanning probe microscopy techniques as well as computational methods. Finally, I will show that the anti-ambipolar field effect observed in the above systems can be generalized to other semiconducting heterojunction systems and extended over large areas with practical applications in wireless communication circuits.5 The second part of talk will discuss my more recent work performed at Caltech on photovo
257. Physics Colloquium

     "How we got the government we have, and why scientists should engage with it"

     Presented by Benn Tannenbaum, Sandia National Laboratory

     Tuesday, June 5, 2018, 3:30 pm
     Large Seminar Room, Bldg. 510

     Hosted by: Andrei Nomerotski

     It seems like a terrible time to be a scientist in the United States. Federal budgets aren't being passed, and when they are, funding for science never seems to increase. The debate over immigration reform—including what to do about visas for high-skilled workers, such as scientists—is stalled. Everyone agrees that cybersecurity is a problem, but no one seems to have a solution. Meanwhile, we have no meaningful debate in Congress or in the administration on climate change or energy policy. This lecture will cover how we got here, why we are stuck, some speculation on how the current administration is impacting research, and how the scientific community can impact policy.
258. Nuclear Theory/RIKEN Seminar

     "Liouville action, high multiplicity tail and shape of proton"

     Presented by Vladimir Skokov, BNL

     Friday, June 1, 2018, 2 pm
     CFNS Seminar Room, 2-38

     Hosted by: Chun Shen

     In this talk I violate the common wisdom "one seminar — one message" and discuss two seemingly unrelated results in the framework of the dilute-dense CGC approach: the effect of spatial eccentricity of the projectile (proton) shape on the second harmonic in double-inclusive gluon production and the theoretical description of the high gluon multiplicity tail. I will show that these two superficially unrelated results in combination may lead to unexpected consequences for the phenomenology of p-A collisions.
259. HET Lunch Discussions

     "Nucleon Charges and Form Factors from Lattice QCD"

     Presented by Yong-Chull Jang, BNL

     Friday, May 25, 2018, 12:15 pm
     Building 510, Room 2-160

     Hosted by: Christoph Lehner
260. Joint Nuclear Theory/RIKEN/CFNS Seminar

     "Novel QCD Physics at an Electron-Ion Collider"

     Presented by Stanley Brodsky, SLAC National Accelerator Laboratory, Stanford University

     Friday, May 25, 2018, 10:30 am
     Building 510, CFNS Seminar Room 2-38

     Hosted by: Chun Shen

     An electron-ion collider can test many fundamental features of QCD for hadron and nuclear physics, including flavor-dependent antishadowing in deep inelastic electron-nucleus scattering, the breakdown of sum rules for nuclear structure functions, the role of ``hidden-color " degrees of freedom, and the effects of "color transparency" on the baryon-to-meson anomaly observed at high transverse momentum in heavy-ion collisions. I will also discuss intrinsic heavy quark phenomena and the production of exotic multiquark states at the EIC. On the theory side, I will discuss the new insights into color confinement that one obtains from light-front holography, including supersymmetric features of the meson, baryon, and tetraquark spectroscopy. The Principle of Maximum Conformality (PMC) can be used to systematically eliminate renormalization scale ambiguities and thus obtain scheme-independent pQCD predictions.
261. Particle Physics Seminar

     "K+ to pi+ nu nubar- First result from NA62 experiment"

     Presented by Bob Velghe, TRIUMF

     Thursday, May 24, 2018, 3 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Chao Zhang

     The K+ to pi+ nu nubar decay has been attracting interest for many decades. The accurate measurement of its branching ratio is a powerful test of the Standard Model (SM) and could reveal effects beyond the SM. As the decay occurs at the level of 1 in a 10 billion kaon disintegration, many experimental challenges have to be overcome. The CERN NA62 experiment uses a novel kaon decay-in-flight technique to observe K+ to pi+ nu nubar. The analysis of the 2016 data set was used to establish the method by allowing us to reach the 10^-10 single event sensitivity. The preliminary NA62 result on K+ to pi+ nu nubar from the analysis of the full 2016 data set will be presented.
262. Condensed-Matter Physics & Materials Science Seminar

     "Developing theoretical understanding of non-equilibrium phenomena"

     Presented by Alexander Kemper, North Carolina State University

     Thursday, May 24, 2018, 1:30 pm
     ISB Bldg. 734 Conf. Rm. 201 (upstairs)

     Hosted by: Peter D. Johnson

     In this talk, I will present an overview of some of our recent results in the area of non-equilibrium many-body theory. Experimental developments are enabling the study of electrons and atoms in the time domain with ever increasing resolution. The theoretical development has been somewhat lacking, and remains mostly rooted in extensions of equilibrium models. Our work has been to put the theoretical modeling on a firmer footing. Through numerical solution of the equations of motion, we can directly evaluate experimentally relevant spectra. These may be analyzed with the benefit of knowing the precise model and correlation functions that underlie the spectra. Most of the talk will focus on the interaction between a system of electrons interacting with several degrees of freedom, including the lattice, impurity scattering, and each other. Typically, non-equilibrium results are analyzed through a framework that relies on equilibrium intuition. Our results show that the validity of this type of analysis falls on a spectrum that varies from correct to wholly incorrect, which I will illustrate with specific examples. This line of thinking will be further developed by considering the flow of energy between various subsystems.
263. HET Seminar

     "Towards NLO parton showers"

     Presented by Stefan Prestel, Fermilab

     Wednesday, May 23, 2018, 2 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Christopher Murphy

     Parton showers aim to consistently model the evolution of the soft and collinear structure of QCD. As such, they are important pieces of event generator software. Parton shower methods have, since their inception, been limited to lowest order precision. For a consistent NLO event generator framework, and to reduce the uncertainties inherent in a lowest-order approach, it is important to push parton showers beyond lowest order precision. In this talk, I will discuss recent advances within the Dire parton shower (of Pythia and Sherpa) to construct a consistent NLO parton shower.
264. Particle Physics Seminar

     "CERN openlab R&D for the LHC Run3 and Run4"

     Presented by Maria Girone, CERN

     Tuesday, May 22, 2018, 3 pm
     Small Seminar Room, Bldg. 510

     Hosted by: Sergey Panitkin

     LHC Run3 and Run4 represent an unprecedented challenge for HEP computing in terms of both data volume and complexity. New approaches are needed for how data is collected and filtered, processed, moved, stored and analysed if these challenges are to be met with a realistic budget. To develop innovative techniques we are fostering relationships with industry leaders. CERN openlab is a unique resource for public-private partnership between CERN and leading Information Communication and Technology (ICT) companies. Its mission is to accelerate the development of cutting-edge solutions to be used by the worldwide HEP community. In 2018, CERN openlab started its phase VI with a strong focus on tackling the upcoming LHC challenges. Several R&D programs are ongoing in the R&D areas of data centre technologies and infrastructures. computing performance and software, machine learning and data analytics. This talk gives an overview of the various innovative technologies that are currently being explored by CERN openlab VI and discusses the long-term strategies that are pursued by the LHC communities with the help of industry in closing the technological gap in processing and storage needs expected in Run3 and Run4.
265. Instrumentation Division Seminar

     "The ATLAS ITK Strip Detector for High-Luminosity LHC"

     Presented by Stefania Stucci, CERN, Italy

     Tuesday, May 22, 2018, 2:30 pm
     Large Conference Room, Bldg. 535

     The High-Luminosity LHC operations are scheduled to start in 2026. The ATLAS experiment is currently preparing for an upgrade of the inner tracking detector. The radiation damage at the maximum integrated luminosity of 4000/fb implies integrated hadron fluencies over 2x10^16 neq/cm2 requiring replacement of the existing Inner Detector. An all-silicon Inner Tracker (ITk) is proposed with a pixel detector surrounded by a strip detector. The current prototyping phase, targeting an ITk Strip Detector consisting of a four-layer central barrel and forward regions composed of six disks at each end, will be described. In this contribution I will present the design of the ITk Strip Detector and the preparations for production.

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