BNL Home
July 2016
Sunday Monday Tuesday Wednesday Thursday Friday Saturday

1

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7

  1. Particle Physics Seminar

    3 pm, Small Seminar Room, Bldg. 510

    Hosted by: 'Michael Begel'

    Matter constitutes 30% of the energy content of the Universe. The remaining 70% is what is called dark energy, which exhibits unusual repulsive gravitational interactions. On the matter sheet, only 5% is of known nature, i.e. matter such as found in atoms, in stars, in planets etc. From observations on all astrophysical and cosmological scales we know that most of it, i.e. 25%, is dark matter (DM) of unknown nature. The nature of DM is one of the most important open problems in science. The ongoing hunt for DM is multi-pronged and interdisciplinary involving cosmology and astrophysics, particle and nuclear physics as well as detector technology. In this talk we will focus on the direct detection of the dark matter constituents, the so called weakly interacting massive particles (WIMPs), in underground labs. The detection consists of measuring the energy deposited in the detector by the recoiling nucleus, after its elastic collision with a WIMP (spin independent or spin induced). In obtaining the event rates one needs models about the WIMP interaction and density in our vicinity as well as its velocity distribution. No events have so far been observed, only exclusion plots on the nucleon cross sections have been obtained, which will be discussed. Since the expected rates are very small and the usual experimental signature is not different from that of the backgrounds, we will discuss some special signatures that might aid in the analysis of the experiments such as the time dependence of the signal (modulation effect) and the option of inelastic scattering, possible in some special targets, by detecting γ-rays following the de-excitation of the nucleus.

8

  1. Nuclear Physics Seminar

    2 pm, Small Seminar Room, Bldg. 510

    Hosted by: 'Matthew Sievert'

    Fluctuations of conserved charges are important observables that offer insight into the phase structure of strongly interacting matter. Around critical points, such as the chiral critical endpoint of QCD, higher order cumulants of the relevant quantities show universal behavior. The universal behavior of baryon number cumulants can be studied in effective models that lie in the same universality class as QCD. Such a model is for example the Quark Meson model. In my talk I discuss what one can learn from effective field theory studies of fluctuations and present my results obtained using the Functional Renormalization Group method in the Quark Meson model.

9

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10

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11

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12

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13

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14

  1. RIKEN Lunch Seminar

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

    Hosted by: 'Hiroshi Ohki'

    Anomalous chiral transport processes, with the notable examples of Chiral Magnetic Effect (CME) and Chiral Magnetic Wave (CMW), are remarkable phenomena that stem from highly nontrivial interplay of QCD chiral symmetry, axial anomaly, and gluonic topology. The heavy ion collisions, in which topological fluctuations generate chirality imbalance, and very strong magnetic fields $|\vec{\bf B}|\sim m_\pi^2$ are present during the early stage of such collisions, provide a unique environment to study these anomalous chiral transport processes. Significant experimental efforts have been made to look for signals of CME and various other signals of anomalous chiral transport effects in heavy ion collisions. Crucial for such efforts, is the theoretical development of quantitative simulations based on hydrodynamics that incorporates chiral anomaly, implements realistic initial conditions and properly accounts for possible backgrounds. We will introduce our recent progress to understand CME qualitatively, based on a 2+1D viscous hydrodynamics framework

  2. Particle Physics Seminar

    3 pm, Small Seminar Room, Bldg. 510

    Hosted by: '''Michael Begel'''

    Tau leptons are notoriously difficult particles to work with in the environment of a hadron collider due to their short lifetime and heavy enough mass for semi-hadronic decay. In this talk I will present the physics motivation for working with taus in spite of the challenges. And I will describe the work my group is involved with, from the first measurement of tau polarization at a hadron collider, to Higgs-tagging and searches for heavy, exotic particles. I will also describe the landscape for physics with taus at ATLAS as we look into Run2 and beyond.

15

  1. Particle Physics Seminar

    10 am, Small Seminar Room, Bldg. 510

    Hosted by: 'Jyoti Joshi'

    The past few years have brought several remarkable neutrino-related discoveries and experimental anomalies indicating that these elusive particles might hold clues to some of the most profound questions in particle physics such as matter-antimatter asymmetry and the possibility of additional low-mass neutrino states. Further exploration of these clues require technological advances in neutrino detection. Liquid Argon Time Projection Chambers (LArTPCs) are imaging detectors that present neutrino interactions with the detail of bubble chambers, but with an electronic data acquisition and processing. Various efforts are ongoing at Fermi National Accelerator Laboratory (Fermilab) to develop this intriguing technology. MicroBooNE is a 170 ton LArTPC which recently started collecting data with Fermilab's Booster Neutrino Beam. In addition to addressing the recent low-energy electromagnetic anomaly observed by the MiniBooNE experiment, the exceptional particle identification capability of MicroBooNE will make it possible for the first time to measure low-energy (~1 GeV) neutrino cross-sections in argon with high precision thereby providing invaluable inputs to develop nuclear models needed for future long-baseline neutrino oscillation experiments. MicroBooNE is also leading the way for an extensive short-baseline neutrino physics program at Fermilab and also serves as a R&D project towards a long-baseline multi-kiloton scale LArTPC detector. This talk will start by giving a brief overview of LArTPC efforts at Fermilab, followed by a description of the MicroBooNE experiment, its current status and first physics results along with some future projections.

  2. NSLS-II Friday Lunchtime Seminar Series

    12 pm, NSLS-II Bldg 744 (LOB 4), room 156

    Hosted by: 'L. Carr, S. Chodankar and B. Ocko'

16

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17

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18

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20

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21

  1. Particle Physics Seminar

    3 pm, Small Seminar Room, Bldg. 510

    Hosted by: ''Xin Qian''

    The IceCube neutrino telescope at the South Pole has measured the atmospheric muon neutrino spectrum as a function of zenith angle and energy. Using IceCube's full detector configuration we have performed a search for eV-scale sterile neutrinos. Such a sterile neutrino, motivated by the anomalies in short-baseline experiments, is expected to have a significant effect on the $\bar{\nu_\mu}$ survival probability due to matter induced resonant effects for energies of order 1 TeV. This effect makes this search unique and sensitive to small sterile mixings. In this talk, I will present the results of the IceCube sterile neutrino search.

22

  1. Nuclear Physics Seminar

    2 pm, Small Seminar Room, Bldg. 510

    Hosted by: 'Matthew Sievert'

    Transport coefficients in two systems are addressed via holographic methods originating from the AdS/CFT. The first system is a neutral conformal fluid. In linearised hydrodynamics, beyond shear viscosity, all order gradient expansion can be efficiently resummed into two momenta-dependent transport coefficient functions. The second system is an e/m current coupled via chiral anomaly to an axial U(1) current. The anomaly-free all order transport coefficients are resummed into three momenta-dependent functions, the diffusion function and two conductivities. Anomaly-induced transport, resummed to all orders, generalises the chiral-magnetic effect (CME) and related phenomena. Novel, anomaly-induced non-linear effects will be presented too.

23

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24

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25

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26

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27

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28

  1. JUL

    28

    Thursday

    Particle Physics Seminar

    3 pm, Small Seminar Room, Bldg. 510

    Thursday, July 28, 2016, 3:00 pm

    Hosted by: ''Thomas Ullrich''

    The accelerator-based neutrino-oscillation program, aimed for the measurement of oscillation parameters and observing the leptonic CP violation, is moving full steam ahead. However, the recent measurements have revealed unexpected and interesting neutrino interaction physics, and exposed the inadequacy of the relativistic Fermi gas (RFG) based Monte-Carlo generators (in describing neutrino-nucleus scatterings) resulting in large systematic uncertainties. A more detailed and careful neutrino-nucleus modeling, covering the whole experimental kinematical space, is inevitable in order to achieve the unprecedented precision goal of the present and future accelerator-based neutrino-oscillation experiments. In this talk, I will present a microscopic Hartree-Fock (HF) and continuum random phase approximation (CRPA) approach to electroweak scattering off nuclei from low energy (threshold) to the intermediate energy region. As a necessary check to test the reliability of this approach, I will first present a electron-nucleus (^12 C, ^16 O, ^40 Ca) cross section comparison (in the kinematics range of interest) with the data to validate the model. Then, I will present flux-folded (anti)neutrino cross section calculations and comparison with the measurements of MiniBooNE and T2K experiments. I will draw special attention to the contribution emerging from the low-energy nuclear excitations, at the most forward scattering bins, in the signal of MiniBooNE and T2K experiments and their impact on the non-trivial differences between muon-neutrino and electron-neutrino cross sections. These effects remain inaccessible in the (current) relativistic Fermi-gas (RFG) based Monte-Carlo generators.

29

  1. JUL

    29

    Friday

    Nuclear Physics Seminar

    2 pm, Small Seminar Room, Bldg. 510

    Friday, July 29, 2016, 2:00 pm

    Hosted by: 'Matthew Sievert'

    High Pt Dijet production in ep/eA DIS at small x (high energy) involves the expectation value of a trace of four Wilson lines, i.e. the quadrupole. At leading power the isotropic part can be expressed as the conventional Weizsacker-Williams gluon distribution. On the other hand, the distribution of linearly polarized gluons determines the amplitude of the ~ cos(2phi) anisotropy of the transverse momentum imbalance. I shall also discuss the operator that determines the next-to-leading power correction, its expectation value in a Gaussian theory (at large Nc), and the resulting .

30

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31

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  1. JUL

    28

    Thursday

    Particle Physics Seminar

    "Modeling electron- and neutrino-nucleus scattering in kinematics"

    Presented by Vishvas Pandey, Ghent University

    3 pm, Small Seminar Room, Bldg. 510

    Thursday, July 28, 2016, 3:00 pm

    Hosted by: ''Thomas Ullrich''

    The accelerator-based neutrino-oscillation program, aimed for the measurement of oscillation parameters and observing the leptonic CP violation, is moving full steam ahead. However, the recent measurements have revealed unexpected and interesting neutrino interaction physics, and exposed the inadequacy of the relativistic Fermi gas (RFG) based Monte-Carlo generators (in describing neutrino-nucleus scatterings) resulting in large systematic uncertainties. A more detailed and careful neutrino-nucleus modeling, covering the whole experimental kinematical space, is inevitable in order to achieve the unprecedented precision goal of the present and future accelerator-based neutrino-oscillation experiments. In this talk, I will present a microscopic Hartree-Fock (HF) and continuum random phase approximation (CRPA) approach to electroweak scattering off nuclei from low energy (threshold) to the intermediate energy region. As a necessary check to test the reliability of this approach, I will first present a electron-nucleus (^12 C, ^16 O, ^40 Ca) cross section comparison (in the kinematics range of interest) with the data to validate the model. Then, I will present flux-folded (anti)neutrino cross section calculations and comparison with the measurements of MiniBooNE and T2K experiments. I will draw special attention to the contribution emerging from the low-energy nuclear excitations, at the most forward scattering bins, in the signal of MiniBooNE and T2K experiments and their impact on the non-trivial differences between muon-neutrino and electron-neutrino cross sections. These effects remain inaccessible in the (current) relativistic Fermi-gas (RFG) based Monte-Carlo generators.

  2. JUL

    29

    Friday

    Nuclear Physics Seminar

    "Azimuthal anisotropy and the distribution of linearly polarized gluons in DIS dijet production at high energy"

    Presented by Adrian Dumitru, Baruch College

    2 pm, Small Seminar Room, Bldg. 510

    Friday, July 29, 2016, 2:00 pm

    Hosted by: 'Matthew Sievert'

    High Pt Dijet production in ep/eA DIS at small x (high energy) involves the expectation value of a trace of four Wilson lines, i.e. the quadrupole. At leading power the isotropic part can be expressed as the conventional Weizsacker-Williams gluon distribution. On the other hand, the distribution of linearly polarized gluons determines the amplitude of the ~ cos(2phi) anisotropy of the transverse momentum imbalance. I shall also discuss the operator that determines the next-to-leading power correction, its expectation value in a Gaussian theory (at large Nc), and the resulting .

  3. AUG

    5

    Friday

    Particle Physics Seminar

    "Study of the detection of supernova neutrinos"

    Presented by Hanyu Wei, Tsinghua University

    10 am, Small Seminar Room, Bldg. 510

    Friday, August 5, 2016, 10:00 am

    Hosted by: 'Xin Qian'

    A core-collapse supernova explosion would release an enormous amount of neutrinos, the detection of which could yield answers to many questions of supernova dynamics and neutrino physics. The collective neutrinos from all the past supernovae all over the universe (supernova relic neutrinos) are also observable, and their detection would provide us an insight of the stellar evolution and cosmology. In this talk, I will first introduce the supernova burst neutrinos as well as supernova relic neutrinos. Then, i will present the design, characteristics, and sensitivity of an online trigger system of supernova burst neutrinos at Daya Bay. I will also present a search for supernova burst neutrinos at Daya Bay using about 600 days of data. At last, a sensitivity study of the discovery potential for supernova relic neutrinos with a slow liquid scintillator will be presented, which is highly recommended to kilo-ton-scale detectors.

  4. AUG

    12

    Friday

    HET/RIKEN Seminar

    "TBA"

    Presented by Stefano Di Vita, DESY

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

    Friday, August 12, 2016, 12:15 pm

    Hosted by: 'Pier Paolo Giardino'

  5. OCT

    5

    Wednesday

    HET/RIKEN Seminar

    "TBA"

    Presented by Marco Farina, Rutgers University

    2 pm, Small Seminar Room, Bldg. 510

    Wednesday, October 5, 2016, 2:00 pm

    Hosted by: 'Pier Paolo Giardino'

  6. OCT

    6

    Thursday

    Particle Physics Seminar

    "Dark Interactions: perspective from theory and experiment"

    9 am, Small Seminar Room, Bldg. 510

    Thursday, October 6, 2016, 9:00 am

    Hosted by: 'Michael Begel'

  7. OCT

    26

    Wednesday

    HET/RIKEN Seminars

    "TBA"

    Presented by Stefania Gori, University of Cincinnati

    2 pm, Small Seminar Room, Bldg. 510

    Wednesday, October 26, 2016, 2:00 pm

    Hosted by: 'Pier Paolo Giardino'

  1. Nuclear Physics Seminar

    "Transport Functions from Fluid/Gravity Correspondence"

    Presented by Michael Lublinsky, Ben-Gurion University

    Friday, July 22, 2016, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: 'Matthew Sievert'

    Transport coefficients in two systems are addressed via holographic methods originating from the AdS/CFT. The first system is a neutral conformal fluid. In linearised hydrodynamics, beyond shear viscosity, all order gradient expansion can be efficiently resummed into two momenta-dependent transport coefficient functions. The second system is an e/m current coupled via chiral anomaly to an axial U(1) current. The anomaly-free all order transport coefficients are resummed into three momenta-dependent functions, the diffusion function and two conductivities. Anomaly-induced transport, resummed to all orders, generalises the chiral-magnetic effect (CME) and related phenomena. Novel, anomaly-induced non-linear effects will be presented too.

  2. Particle Physics Seminar

    "Results from the Search for eV-Sterile Neutrinos with IceCube"

    Presented by Dr. Carlos Arguelless Delgado, Massachusetts Institute of Technology

    Thursday, July 21, 2016, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: ''Xin Qian''

    The IceCube neutrino telescope at the South Pole has measured the atmospheric muon neutrino spectrum as a function of zenith angle and energy. Using IceCube's full detector configuration we have performed a search for eV-scale sterile neutrinos. Such a sterile neutrino, motivated by the anomalies in short-baseline experiments, is expected to have a significant effect on the $\bar{\nu_\mu}$ survival probability due to matter induced resonant effects for energies of order 1 TeV. This effect makes this search unique and sensitive to small sterile mixings. In this talk, I will present the results of the IceCube sterile neutrino search.

  3. NSLS-II Friday Lunchtime Seminar Series

    "Effect of Hydrophobic and Hydrophilic Silica Nano Particles on the Dynamics of Phospholipid Films, an XPCS Investigation"

    Presented by Luigi Cristofolini, University of Parma, Italy

    Friday, July 15, 2016, 12 pm
    NSLS-II Bldg 744 (LOB 4), room 156

    Hosted by: 'L. Carr, S. Chodankar and B. Ocko'

  4. Particle Physics Seminar

    "MicroBooNE: marking a Nu era in Precision Neutrino Physics"

    Presented by Dr. Sowjanya Gollapinni, KSU

    Friday, July 15, 2016, 10 am
    Small Seminar Room, Bldg. 510

    Hosted by: 'Jyoti Joshi'

    The past few years have brought several remarkable neutrino-related discoveries and experimental anomalies indicating that these elusive particles might hold clues to some of the most profound questions in particle physics such as matter-antimatter asymmetry and the possibility of additional low-mass neutrino states. Further exploration of these clues require technological advances in neutrino detection. Liquid Argon Time Projection Chambers (LArTPCs) are imaging detectors that present neutrino interactions with the detail of bubble chambers, but with an electronic data acquisition and processing. Various efforts are ongoing at Fermi National Accelerator Laboratory (Fermilab) to develop this intriguing technology. MicroBooNE is a 170 ton LArTPC which recently started collecting data with Fermilab's Booster Neutrino Beam. In addition to addressing the recent low-energy electromagnetic anomaly observed by the MiniBooNE experiment, the exceptional particle identification capability of MicroBooNE will make it possible for the first time to measure low-energy (~1 GeV) neutrino cross-sections in argon with high precision thereby providing invaluable inputs to develop nuclear models needed for future long-baseline neutrino oscillation experiments. MicroBooNE is also leading the way for an extensive short-baseline neutrino physics program at Fermilab and also serves as a R&D project towards a long-baseline multi-kiloton scale LArTPC detector. This talk will start by giving a brief overview of LArTPC efforts at Fermilab, followed by a description of the MicroBooNE experiment, its current status and first physics results along with some future projections.

  5. Particle Physics Seminar

    "Physics with Taus at ATLAS"

    Presented by Sarah Demers

    Thursday, July 14, 2016, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: '''Michael Begel'''

    Tau leptons are notoriously difficult particles to work with in the environment of a hadron collider due to their short lifetime and heavy enough mass for semi-hadronic decay. In this talk I will present the physics motivation for working with taus in spite of the challenges. And I will describe the work my group is involved with, from the first measurement of tau polarization at a hadron collider, to Higgs-tagging and searches for heavy, exotic particles. I will also describe the landscape for physics with taus at ATLAS as we look into Run2 and beyond.

  6. RIKEN Lunch Seminar

    "CME in Chiral Viscous Hydrodynamics"

    Presented by Shuzhe Shi, Indiana University

    Thursday, July 14, 2016, 12:30 pm
    Building 510, Room 2-160

    Hosted by: 'Hiroshi Ohki'

    Anomalous chiral transport processes, with the notable examples of Chiral Magnetic Effect (CME) and Chiral Magnetic Wave (CMW), are remarkable phenomena that stem from highly nontrivial interplay of QCD chiral symmetry, axial anomaly, and gluonic topology. The heavy ion collisions, in which topological fluctuations generate chirality imbalance, and very strong magnetic fields $|\vec{\bf B}|\sim m_\pi^2$ are present during the early stage of such collisions, provide a unique environment to study these anomalous chiral transport processes. Significant experimental efforts have been made to look for signals of CME and various other signals of anomalous chiral transport effects in heavy ion collisions. Crucial for such efforts, is the theoretical development of quantitative simulations based on hydrodynamics that incorporates chiral anomaly, implements realistic initial conditions and properly accounts for possible backgrounds. We will introduce our recent progress to understand CME qualitatively, based on a 2+1D viscous hydrodynamics framework

  7. Nuclear Physics Seminar

    "Modeling chiral criticality and its consequences for heavy-ion collisions"

    Presented by Gabor Almasi, GSI

    Friday, July 8, 2016, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: 'Matthew Sievert'

    Fluctuations of conserved charges are important observables that offer insight into the phase structure of strongly interacting matter. Around critical points, such as the chiral critical endpoint of QCD, higher order cumulants of the relevant quantities show universal behavior. The universal behavior of baryon number cumulants can be studied in effective models that lie in the same universality class as QCD. Such a model is for example the Quark Meson model. In my talk I discuss what one can learn from effective field theory studies of fluctuations and present my results obtained using the Functional Renormalization Group method in the Quark Meson model.

  8. Particle Physics Seminar

    "Dark Matter in the Cosmos-The Hunt to find it in the Laboratory"

    Presented by John D. Vergados

    Thursday, July 7, 2016, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: 'Michael Begel'

    Matter constitutes 30% of the energy content of the Universe. The remaining 70% is what is called dark energy, which exhibits unusual repulsive gravitational interactions. On the matter sheet, only 5% is of known nature, i.e. matter such as found in atoms, in stars, in planets etc. From observations on all astrophysical and cosmological scales we know that most of it, i.e. 25%, is dark matter (DM) of unknown nature. The nature of DM is one of the most important open problems in science. The ongoing hunt for DM is multi-pronged and interdisciplinary involving cosmology and astrophysics, particle and nuclear physics as well as detector technology. In this talk we will focus on the direct detection of the dark matter constituents, the so called weakly interacting massive particles (WIMPs), in underground labs. The detection consists of measuring the energy deposited in the detector by the recoiling nucleus, after its elastic collision with a WIMP (spin independent or spin induced). In obtaining the event rates one needs models about the WIMP interaction and density in our vicinity as well as its velocity distribution. No events have so far been observed, only exclusion plots on the nucleon cross sections have been obtained, which will be discussed. Since the expected rates are very small and the usual experimental signature is not different from that of the backgrounds, we will discuss some special signatures that might aid in the analysis of the experiments such as the time dependence of the signal (modulation effect) and the option of inelastic scattering, possible in some special targets, by detecting γ-rays following the de-excitation of the nucleus.

  9. RIKEN Lunch Seminar

    "Kondo effect in QCD"

    Presented by Sho Ozaki, Keio University

    Thursday, June 30, 2016, 12:30 pm
    Building 510, Room 2-160

    Hosted by: ''Hiroshi Oki''

    In condensed matter physics, Kondo effect is known as an enhancement of electrical resistance of impure metals with decreasing temperature/energy. This phenomenon is the first known example of asymptotic freedom in physics, which is found well before the discovery of that of QCD. Kondo effect is caused by the combination of the following ingredients: In addition to the existence of a heavy impurity, (i) Fermi surface, (ii) quantum fluctuations (loop effects), (iii) non-Abelian nature of interaction (e.g. spin-flip interaction in the case of condensed matter physics). In this talk, I will discuss Kondo effect realized in QCD. We found the characteristic behavior of Kondo effect in quark matter with heavy quark impurity. There, the color exchange interaction mediated by gluons plays the role of the third condition (iii) for the appearance of Kondo effect. Furthermore, we found a novel type of Kondo effect induced by strong magnetic fields. In addition to the fact that the magnetic field dose not affect the color degrees of freedom, dimensional reduction to 1+1 dimensions and degenerate quarks in lowest Landau level play essential role for the magnetically induced QCD Kondo effect.

  10. Physics Colloquium

    "Solving the World's Problems on the Back of a Cocktail Napkin"

    Presented by Lawrence Weinstein, Old Dominion University

    Tuesday, June 28, 2016, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: ''''Robert Pisarski''''

    Why don't we all drive electric cars? Does it really matter if you don't recycle that plastic water bottle? If the Sun were made of gerbils, would the Earth be incinerated? How can we answer these questions without relying on experts? This talk will cover the principles of estimating, introduce the "Goldilocks" categories of answers, and then look at some of the big (and small) questions of our time, including: Paper or plastic? Gasoline or electric cars? Should we pee before flying?

  11. Nuclear Physics Seminar

    "Two Photon Exchange and the Proton Form Factor Problem"

    Presented by Lawrence Weinstein, Old Dominion University

    Tuesday, June 28, 2016, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: 'Oleg Eyser'

    The electromagnetic form factors of the proton as measured by polarized and unpolarized electron scattering experiments differ by up to a factor of three at large momentum transfer. Calculations show that this discrepancy can be reconciled by treating the interaction in 2nd Born Approximation, i.e., including two photon exchange (TPE). While calculation of TPE effects is highly model dependent, these effects can be measured directly by comparing elastic electron-proton and positron-proton scattering. Three experiments, TPE at Jefferson Lab, VEPP-3 at Novosibirsk, and OLYMPUS at DESY, measured this. VEPP-3 and OLYMPUS used alternating monochromatic e+ and e- beams in storage rings; TPE created a tertiary mixed simultaneous e+/e- beam covering a wide range of energies. This talk will present the proton form factor problem, the experimental effort to measure the positron-electron ratio (with special emphasis on the Jefferson Lab experiment), and the results.

  12. Nuclear/Riken Theory Committee

    "On Pressure Isotropization in Heavy-Ion Collisions"

    Presented by Bin Wu, The Ohio State University

    Friday, June 24, 2016, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: ''Soeren Schlichting''

    In this talk, I would like to start with a brief introduction to non-equilibrium quantum field theory in the Schwinger-Keldysh formalism. This formalism provides a systematic way to study isotropization and other time-dependent non-equilibrium (and equilibrium) phenomena in heavy-ion collisions. I shall first discuss the foundation of classical field approximations (CSA), which is an important tool to study the evolution at very early stages. It is, however, found to be non-renormalizable. This helps us understand better the applicability of such an approximation. it is now well-known that isotropization can not be established before the breakdown of the CSA. We then use another approximation, the quasi-particle approximation (the Boltzmann equation), to study the isotropization in a scalar field theory. Our result shows explicitly the importance of quantum effects. Motivated by these observations, we have been studying whether the isotropization can be reached before the dense system of gluons, produced in the collisions of two big nuclei, becomes too dilute to be studied perturbatively in the Schwinger-Keldysh formalism. Some preliminary results shall be reported.

  13. RIKEN Lunch Seminar

    "Leading log resummation in high-energy parton production in QCD matter"

    Presented by Bin Wu, The Ohio State University

    Thursday, June 23, 2016, 12:30 pm
    Building 510, Room 2-160

    Hosted by: 'Hiroshi Oki'

  14. Physics Colloquium

    "Sterile Neutrinos as the Origin of Dark and Baryonic Matter"

    Presented by Mikhail Shaposhnikov, EPFL

    Tuesday, June 21, 2016, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: 'Robert Pisarski'

    I will discuss how three sterile neutrinos alone can simultaneously explain neutrino oscillations, the observed dark matter, and the baryon asymmetry of the Universe without new physics above the Fermi scale. The experimental prospects to search for these particles will be outlined.

  15. Nuclear Physics Seminar

    "The Quest for the Origin of the Proton's Sea"

    Presented by Paul Reimer, Argonne National Lab

    Tuesday, June 21, 2016, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: 'Oleg Eyser'

    The proton is a composite particle in which the binding force is responsible for the majority of its mass. To understand this structure, the distributions and origins of the quark-antiquark pairs produced by the strong force must be measured. The SeaQuest collaboration is using the Drell-Yan process to elucidate antiquark distributions in the proton and to study the modification of these distributions when the proton is held within a nucleus. Preliminary results based on a fraction of the anticipated final data set will be presented.

  16. Nuclear Physics Seminar

    "Lattice constraints on the thermal dilepton and photon rate"

    Presented by Olaf Kaczmarek, Bielefeld University

    Friday, June 17, 2016, 2 pm
    Small Seminar Room, Bldg. 510

    We estimate the dilepton and photon production rate from an SU(3) plasma at temperatures of about 1.1 Tc to 1.5 Tc. Lattice results for the vector current correlator at zero and non-zero momenta are extrapolated to the continuum limit and analyzed with the help of phenomenological and perturbative input for the corresponding spectral functions. We compare our results with NLO weak-coupling results, hydrodynamics, and a holographic model. At vanishing invariant mass we extract the photon rate which for k>3T is found to be close to the NLO weak-coupling prediction. For k

  17. RIKEN Lunch Seminar

    "Static and dynamic screening effect on the resonant $\alpha-\alpha$ scattering in a QED plasma"

    Presented by Xiaojun Yao, Duke University

    Thursday, June 16, 2016, 12:30 pm
    Building 510, Room 2-84

    Hosted by: 'Hiroshi Oki'

  18. Environmental & Climate Sciences Department Seminar

    "High-Resolution Photography of Clouds from the Surface: Retrieval of Cloud Optical Depth down to Centimeter Scales"

    Presented by Stephen Schwartz, Environmental and Climate Sciences Department

    Thursday, June 16, 2016, 11 am
    Conference Room, Bldg 815E

    Initial results are presented of a analysis of high resolution photographs of clouds at the ARM SGP site in July, 2015. A commercially available camera having 35-mm equivalent focal length up to 1200 mm (nominal resolution as fine as 6 µrad, which corresponds to 12 mm for cloud height 2 km) is used to obtain a measure of zenith radiance of a 40 m x 40 m domain as a two-dimensional image consisting of 3456 x 3456 pixels (12 million pixels). Downwelling zenith radiance varies substantially within single images and between successive images obtained at 4-s intervals. Variation in zenith radiance found on scales down to about 10 cm is attributed to variation in cloud optical depth (COD). Attention here is directed primarily to optically thin clouds, COD less than roughly 3. A radiation transfer model used to relate downwelling zenith radiance to COD and to relate the counts in the camera image to zenith radiance, permits determination of COD and cloud albedo on a pixel-by-pixel basis. COD for thin clouds determined in this way exhibits considerable variation, for example, an order of magnitude within the 40 m domain examined here and 50% over a distance of 1 m. An alternative to the widely used areal or temporal cloud fraction, denoted radiative cloud fraction, also evaluated on a pixel-by-pixel basis, is introduced. This highly data-intensive approach, which examines cloud structure on scales 3 to 5 orders of magnitude finer than satellite products, opens new avenues for examination of cloud structure and evolution.

  19. C-AD Accelerator Physics Seminar

    ""Design Considerations for the 1.3GHz SRF Cavity for ARIEL at TRIUMF""

    Presented by Dr. Philipp Kolb, BNL

    Wednesday, June 15, 2016, 4 pm
    Bldg. 911B - Large Conf. Rm. Rm A202

    "The Advanced Rare IsotopE Laboratory (ARIEL) at TRIUMF will triple the available rare isotope beam (RIB) time for experiments. The major part of ARIEL is the 50 MeV, high intensity cw eLINAC based on 1.3GHz SRF cavities. An eventual addition to the eLINAC is a recirculating beam line to allow FEL-ERL operation in addition to the RIB production beam. To avoid multipass beam break-up (BBU), the design of the SRF cavity had to be modified to reduce the shunt impedance of dipole higher order modes (HOM). Work on the cavity design and HOM load measurements will be shown as well as results of the vertical and horizontal cavity tests."

  20. Condensed-Matter Physics & Materials Science Seminar

    "Quantiative Determination of the the Fluctuations Leading to Superconductivity in Cuprates"

    Presented by Chandra Varma, University of California, Riverside

    Tuesday, June 14, 2016, 1:30 pm
    ISB Bldg. 734, Conf. Rm. 201 (upstairs)

    Hosted by: 'Peter D. Johnson'

    I will report on Laser based ARPES of unprecedented accuracy and stability (taken by the group of Xingjiang Zhou, IOP, Beijing), together with a method of analysis suggested by me (and carried out with the group of Han-Yong Choi, Asia Pacific Center for Theoretical Physics, Korea), to quantitatively extract the e↵ective frequency and momentum dependent interactions of fermions in both the full symmetry (normal) and the d-wave (pairing) symmetry in a family of cuprates. The results are remarkably simple. The principal interactions are of the form: I(k, k',w)~g0 [(1−cos(20k)cos(20'k)]F(w) They are separable functions of momentum and frequency, the first part is the repulsive part and the second part is the attractive d-wave part. F(w) is nearly constant with an upper-energy cutoff of about 0.4eV. The dimensionless coupling constant g0 ~ 0.15. These results were predicted in a theory of superconductivity and of the strange metal phase by quantum-critical fluctuation of loop-currents. They also rule out several alternatives proposed. I will also comment on the normal state and superconductivity in the Fe-based compounds.

  21. Nuclear Physics Seminar

    "Measurement of high-mass muon pairs from ultraperipheral lead-lead collisions with the ATLAS detector at the LHC"

    Presented by Peter Steinberg, BNL

    Tuesday, June 14, 2016, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: 'Oleg Eyser'

    Exclusive dimuon pairs with invariant mass Mμμ>10 GeV have been measured in ultra-peripheral lead-lead collisions at √sNN=5.02 TeV, using an integrated luminosity of 515 μb−1 taken with the ATLAS detector at the LHC in 2015. These very low-multiplicity interactions were recorded using an experimental trigger requiring a muon, low total transverse energy recorded in the calorimeter system, gaps at forward angles, and a reconstructed track. Events are selected to have no-other final state particles than a pair of opposite-sign dimuons. The cross section for dimuon pairs in Pb+Pb collisions is presented as a function of pair mass (Mμμ) and pair rapidity (Yμμ) and is well-described by calculations of Pb+Pb→Pb(*)+Pb(*)+μ+μ− using STARLIGHT 1.1 calculations. These data will improve the understanding of the strong electromagnetic fields surrounding the nucleus, which enable future UPC measurements utilizing these high energy probes.

  22. Nuclear Seminar

    "Generalizations of relativistic hydrodynamics"

    Presented by Piotr Surowka, Harvard

    Friday, June 3, 2016, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: 'Yi Yin'

    Recent developments have shown that relativistic Landau and Lifshitz hydrodynamics does not possess the most general structure. It has to generalized to account for new phenomena. I will show how to do that in two directions. One will include parity-odd transport contributions connected to anomalies, the other will capture a dissipative fluid coupled to non-Abelian degrees of freedom such as color currents or spin currents. I will mention possible applications to quark-gluon plasma and condensed matter systems.

  23. Nuclear Seminar

    "Global Hyperon Polarization in Semicentral Heavy Ion Collisions Measured by STAR"

    Presented by Mike Lisa, Ohio State University

    Tuesday, May 31, 2016, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: 'Oleg Eyser'

    Non-central collisions between ultra-relativistic heavy ions involve thousands of h-bar of angular momentum. Some of this angular momentum may be transferred to the quark-gluon plasma through shear forces that generate a vortical substructure in the hydrodynamic flow field. Understanding this fundamental femtoscopic substructure may be crucial, as we move beyond boost-invariant scenarios and rely more on sophisticated three-dimensional viscous models of the plasma. The vortical nature of the system is expected to polarize the spins of hadrons that eventually emerge. Lambda and Anti-Lambda hyperons, which reveal their polarization through their decay topology, should be polarized similarly in the direction of the system's angular momentum. These same collisions are also characterized by dynamic magnetic fields with magnitude as large as 10^{14} Tesla. Magnetic effects have been the focus of intense study in recent years due to their relevance to the Chiral Magnetic Effect (CME) and other novel phenomena. A splitting between Lambda and Anti-Lambda polarization may signal a magnetic coupling and provide a quantitative estimate of the field strength at freeze out. Physically, this strength depends on the conductivity of the QGP. The STAR Collaboration has made the first observation of global hyperon polarization along the direction of the angular momentum in non-central Au+Au collisions at Beam Energy Scan energies. Our preliminary results indicate that the QGP created at RHIC is the highest-vorticity fluid ever created in the laboratory. A magnetic splitting is hinted at, but the improved statistics and resolution achievable with future runs are required to make a definitive measurement of the magnetic field.

  24. Particle Physics Seminar

    "Searching for Sterile Neutrinos with MINOS"

    Presented by Ashley Timmons, University of Manchester

    Thursday, May 26, 2016, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: '''Xin Qian'''

  25. RIKEN Lunch Seminar

    "Lefschetz-thimble path integral for studying the sign problem and Silver Blaze phenomenon"

    Presented by Yuya Tanizaki, RBRC

    Thursday, May 26, 2016, 12:30 pm
    Building 510, Room 2-160

    Hosted by: 'Hiroshi Ohki'

    Recently, Picard-Lefschetz theory gets much attention in the context of the sign problem, because it enables us to study the system with the complex classical action nonperturbatively by employing the semiclassical analysis. In this seminar, after its brief introduction, I will apply it to the one-site Hubbard model. This model has a severe sign problem, which looks quite similar to that of the finite-density QCD at low temperatures. By solving this model using the Lefschetz-thimble path integral, we are trying to understand the structure of the sign problem of finite-density QCD. Especially, I give a qualitative picture (or speculation) about the early-onset problem of the baryon number density, called the baryon Silver Blaze problem. The complex Langevin method will also be discussed if time allows.

  26. High Performance Computing and Programming Event

    "OpenACC and GPU Hands-on workshop"

    Presented by Presented by NVIDIA instructor Bob Crovella

    Wednesday, May 25, 2016, 8:30 am
    Stony Brook University

    NVIDIA and the Institute for Advanced Computational Science (IACS) at Stony Brook University are pleased to be organizing a 2-day High Performance Computing and Programming event. Presented by NVIDIA instructor Bob Crovella, the workshop will introduce programming techniques using OpenACC and will include topics such as optimization and profiling methods for GPU programming.

  27. Nuclear Physics Seminar

    "Exploring the Neutron Spin Structure"

    Presented by Matt Posik, Temple University

    Tuesday, May 24, 2016, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: 'Oleg Eyser'

    Jefferson Lab experiment E06-014, performed in Hall A, made measurements of the double-spin asymmetries and absolute cross sections in both the DIS and resonance regions by scattering longitudinally polarized electrons at beam energies of 4.74 and 5.89 GeV from a longitudinally and transversely polarized 3He target. Through these measurements various aspects of the neutron spin structure were investigated. The g2 nucleon spin-dependent structure function contains information beyond the simple parton model description of the nucleon. It provides insight into quark-gluon correlations and a path to access the confining local color force a struck quark experiences just as it is hit by the virtual photon due to the remnant di-quark. The quantity d2, a measure of this local color force, has its information encoded in an x2 weighted integral of a linear combination of spin structure functions g1 and g2 and thus is dominated by the valence-quark region at large momentum fraction x. To date, theoretical calculations and experimental measurements of the neutron d2 differ by about two standard deviations. Therefore E06-014 made a precision measurement of this quantity. The polarized quark distributions were also investigated through measurements of the virtual photon-nucleon asymmetry A1^n, the structure function ratio g1/F1, and quark ratio (delta d+delta d_bar)/(d+d_bar). The E06-014 results for the spin structure functions (g1,g2) on 3He, dn2, An1, (delta d+delta d_bar)/(d+d_bar), and our extractions of the neutron color electric and magnetic forces will be presented.

  28. High Performance Computing and Programming

    "OpenACC and GPU Hands-on workshop"

    Presented by Presented by NVIDIA instructor Bob Crovella

    Tuesday, May 24, 2016, 8:30 am
    Stony Brook University

    NVIDIA and the Institute for Advanced Computational Science (IACS) at Stony Brook University are pleased to be organizing a 2-day High Performance Computing and Programming event. Presented by NVIDIA instructor Bob Crovella, the workshop will introduce programming techniques using OpenACC and will include topics such as optimization and profiling methods for GPU programming.

  29. Nuclear Theory/RIKEN Seminar

    "The jet quenching parameter q-hat, and its relation to the TMDPDF"

    Presented by Abhijit Majumdar, Wayne State University

    Friday, May 20, 2016, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: '''Soeren Schlichting'''

    Based on prior work by the JET collaboration, the importance of the factorization and scale evolution of the jet quenching parameter q-hat will be outlined. This will turn out to be important for both phenomenological extractions of q-hat as well as for first principle determinations on the lattice. I will argue that for jets at RHIC and LHC, q-hat does not lie within the range of Bjoerken-x where small x effects would be considered to be dominant. Given this situation, q-hat will be found to be an integral over an operator product separated in both light-cone and transverse distance, but somewhat different from a ``traditional'' TMDPDF. This new distribution will be studied at Next-to-Leading Order and the fate of non-standard divergences discussed.

  30. Particle Physics Seminar

    "Searches for New Physics in boosted diboson topologies at ATLAS"

    Presented by Carmacho Toro, University of Chicago

    Thursday, May 19, 2016, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: 'Michael Begel'

    The large increase in collision energy that the LHC reached in Run 2 provides an unprecedented opportunity to search for new physics beyond the Standard Model (SM). Various extensions of the SM predict the existence of heavy resonances at the TeV scale, which couple predominantly to the Higgs and electroweak gauge bosons. At high resonance masses the hadronic decay products of these energetic bosons tend to be highly collimated and the usual identification techniques fail to disentangle the decay products of our bosons. In this seminar I will describe the jet-substructure techniques explored by ATLAS analyses and present the results of the ATLAS searches using Run-2 data.

  31. RIKEN Lunch Seminar

    "Kosterlitz-Thouless transition and chiral rotation in external electromagnetic field"

    Presented by Gaoqing Cao, Fudan University

    Thursday, May 19, 2016, 12:30 pm
    Building 510, Room 2-160

    Hosted by: ''Daniel Pitonyak''

    In 2+1 dimensional system, the most important phase transition should be of the Kosterlitz-Thouless (KT) type. We determined the KT transition temperature T_KT as well as the mass melting temperature T^* as a function of the magnetic field. It is found that the pseudogap domain T_KT < T < T^* is enlarged with increasing strength of the magnetic field. The influence of a chiral imbalanceμ_5 was also studied. We found that even a constant axial chemical potential μ_5 can lead to inverse magnetic catalysis of the KT transition temperature in 2+1 dimensions. This is actually the de Haas—van Alphen oscillation. Furthermore, we studied the QCD vacuum structure under the influence of an electromagnetic field with a nonzero second Lorentz invariant I_2=E·B. We showed that the presence of I_2 can induce neutral pion (π_0) condensation in the QCD vacuum through the electromagnetic triangle anomaly. Within the frameworks of chiral perturbation theory at leading small-momenta expansion as well as the Nambu—Jona-Lasinio model at leading 1/Nc expansion, a universal dependence of the π_0 condensate on I_2 was found. The stability of the π_0-condensed vacuum is also discussed.

  32. HET/RIKEN Seminar

    "Higgs Pair Production in Extensions of the Standard Model"

    Presented by Ramona Groeber, Roma Tre

    Wednesday, May 18, 2016, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: 'Pier Paolo Giardino'

    Higgs pair production is not only interesting as a probe of the trilinear Higgs self-coupling, but beyond the Standard Model physics can influence the Higgs pair production cross section in many different ways, for example by new couplings, new loop particles or new resonances. In this talk, I will address the question whether we could see for the first time deviations from the Standard Model in Higgs pair production assuming that no deviations were seen before. Furthermore, for certain models I will show how higher order corrections influence the cross section.

  33. Condensed-Matter Physics & Materials Science Seminar

    "Equilibrium States and Dynamics of Spin Assemblies in Magnetic Thin Films, Heterostructures and Nanostructured Entities"

    Presented by Ramesh B. Budhani, Indian Institute of Technology Kanpur

    Tuesday, May 17, 2016, 11 am
    Building 480, Conference Room

    Hosted by: 'Lijun Wu'

    The orientation of spin assemblies in ferromagnetic thin films and nanostructures can take a variety of shapes depending on the relative strength of factors contributing to their magnetic free energy. These factors are derived from the direct quantum mechanical exchange between the electronic spins or those mediated by impurities, and those associated with the size, shape, crystallographic structure, strain, dipolar interactions and external fields. Here we present three cases where the orientational dynamics has been studied as functions of temperature, magnetic field strength and the elapsed time after acquiring a particular configuration. These studies are based on magnetic force microscopy and bulk magnetometry measurements on strain epitaxial films of La0.67Ca0.33MnO3, and lithographically patterned submicron size ring assemblies of permalloy and Co/Pd multilayers, which also form artificial spin ices. Towards the end of this lecture we will discuss interface driven magnetic and electronic phenomena in magnetic thin films.

  34. Condensed-Matter Physics & Materials Science Seminar

    "Dirac Materials"

    Presented by Alexander Balatsky, Los Alamos National Laboratory

    Monday, May 16, 2016, 11 am
    ISB Bldg. 734, Conf. Rm. 201 (upstairs)

    Hosted by: 'Peter D. Johnson'

    Discoveries of superfluid phases in 3He, high Tc superconductors, graphene and topological insulators have brought into focus materials where quasiparticles are described by same Dirac equation that governs behavior of relativistic particles. I will discuss how this class of materials, called Dirac materials, exhibits unusual universal features seen in numerous realizations: Klein tunneling, chiral symmetries and impurity resonances. Goal of this talk is to explore these similarities and discuss the unique role of symmetries that protect Dirac spectrum and possible routes to generate gaps due to many body instabilities. We will also discuss ongoing investigation of the symmetries of Dirac materials, quantum imaging, and means to control their properties. At the end we will propose to use modern tools to design artificial Dirac Materials. One example would be the design Bosonic Dirac materials that host bosonic Dirac excitations, something that would not be possible in particle physics.

  35. Nuclear Theory/RIKEN Seminar

    "Evolution of the jet opening angle distribution in holographic plasma"

    Presented by Andrei Sadofyev, MIT

    Friday, May 13, 2016, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: ''Soeren Schlichting''

    Energetic jets are particularly interesting probes of QGP created in heavy ion collisions. Recently a lot of progress was made in attempting to describe the jet evolution in holography. In this talk I'll present an application of a simple dual model to study the jet substructure starting with energy and angle distributions from pQCD. In particular I will show that there are two competing effects: (1) each individual jet widens as it propagates through plasma; (2) the final jet opening angle distribution becomes narrower since wider jets lose more energy and less likely to survive. So, the mean opening angle for jets with a given energy can easily shift toward smaller angles, even while every jet in the ensemble broadens.

  36. Particle Physics Seminar

    "Muon antineutrino oscillations at T2K"

    Presented by Jordan Myslik, University of Victoria

    Thursday, May 12, 2016, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: 'Xin Qian'

    The T2K ("Tokai to Kamioka") experiment is a long-baseline neutrino oscillation experiment in Japan. A beam of muon neutrinos or muon antineutrinos is produced at the Japan Proton Accelerator Research Complex (J-PARC) in Tokai. The unoscillated neutrino flux is measured by the near detector complex 280 m from the proton target, and the oscillated neutrino flux is measured by the far detector, Super-Kamiokande, 295 km away. Using a beam of muon neutrinos, T2K has performed precise measurements of muon neutrino disappearance, and discovered muon neutrino to electron neutrino oscillation by measuring electron neutrino appearance. Since the summer of 2014, T2K has been taking data using a beam of muon antineutrinos, and has released the results of both a muon antineutrino disappearance analysis and an electron antineutrino appearance analysis, both using antineutrino beam data up to the summer of 2015. This talk will discuss these analyses, going into detail about the role played by the near detector, and looking at future directions.

  37. RIKEN Lunch Seminar

    "The Functional Renormalization Group Method and Delayed Magnetic Catalysis"

    Presented by Stefan Rechenberger, University of Darmstadt

    Thursday, May 12, 2016, 12:30 pm
    Building 510, Room 2-160

    Hosted by: ''Daniel Pitonyak''

    This talk will start with a very general introduction to the Functional Renormalization Group method, a powerful non-perturbative tool which can be applied to various problems. The second part of the talk will demonstrate this by discussing the influence of an external magnetic field on the chiral phase transition in the theory of strong interaction. The Functional Renormalization Group analysis shows that, driven by gluon dynamics, the chiral critical temperature decreases for small values of the magnetic field. For large values of the external field, however, the phase transition temperature increases.

  38. HET/RIKEN Seminar

    "Axions and Topology"

    Presented by Simon Mages, Forschungszentrum Juelich

    Wednesday, May 11, 2016, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: ''Tomomi Ishikawa''

    This talk will be centered around the calculation of the high temperature topological susceptibility in QCD. It will provide some background on our motivation from cosmology and particle physics, which is the dependence of axion physics on non-perturbative QCD. I will show our recent results on the quenched high temperature topological susceptibility and discuss difficulties with this conventional approach, which render dynamical studies unfeasible. I will also present our new approach based on formulating QCD on a non-orientable manifold, which is a promising candidate to solve issues related to topological freezing and the divergence of autocorrelations when approaching the continuum limit.

  39. Nuclear Theory/RIKEN seminar

    "Fluid dynamics for the anisotropically expanding quark-gluon plasma"

    Presented by Dennis Bazow, The Ohio State University

    Friday, May 6, 2016, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: ''Soeren Schlichting''

    Local momentum anisotropies become large in the early stages of the quark-gluon plasma created in relativistic heavy-ion collisions, due to the extreme difference in the longitudinal and transverse expansion rates. In such situations, fluid dynamics derived from an expansion around an isotropic local equilibrium state is bound to break down. Instead, we subsume the slowest nonhydrodynamic degree of freedom (associated with the deviation from momentum isotropy) at leading order defining a local anisoptropic quasi-equilibrium state, thereby treating the longitudinal/transverse pressure anisotropy nonperturbatively. Perturbative transport equations are then derived to deal with the remaining residual momentum anisotropies creating a complete transient effective theory called viscous anisotropic hydrodynamics. This approach has been shown to dramatically outperform viscous hydrodynamics in several simplified situations for which exact solutions exits but which share with realistic expansion scenarios the problem of large dissipative currents. We will discuss the present status of applying viscous anisotropic hydrodynamics to the phenomenological description of the quark-gluon plasma in realistic expansion scenarios.

  40. Particle Physics Seminar

    "Probing the Nature of Neutrinos with Double Beta Decay"

    Presented by Liang Yang, University of Illinois at Urbana-Champaign

    Thursday, May 5, 2016, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: 'Xin Qian'

    Understanding fundamental properties of neutrinos is of compelling interest to the nuclear and particle physics community. The discovery of neutrino oscillations is one of our first hints of physics beyond the Standard Model. Searching for neutrinoless double decay can provide key insights into the neutrino mass generation mechanism and put stringent constraints on the absolute neutrino mass scale. Such a rare decay, if exists, would signify the Majorana nature of neutrinos and the non-conservation of lepton number. In the past decade, large ultra-low background liquid xenon detectors have emerged as a promising technology that can push the neutrinoless double beta decay search to unprecedented sensitivity. In this talk I will describe recent results and prospects of current generation experiment EXO-200, as well as the R&D program for future tonne scale detector nEXO.

  41. RIKEN Lunch Seminar

    "Vorticity in heavy-ion collisions and cold atoms"

    Presented by Xu-Guang Huang, Fudan University

    Thursday, May 5, 2016, 12:30 pm
    Building 510, Room 2-160

    Hosted by: ''Daniel Pitonyak''

    Vorticity describes the local rotation of the fluid. I will talk about our recent study of the event-by-event generation of flow vorticity in heavy-ion collisions. Several special properties of the vorticity in heavy-ion collisions will be discussed, e.g., the impact parameter dependence, the collision energy dependence, the spatial distribution, the event-by-event fluctuation of the magnitude and azimuthal direction. Vorticity can drive vector and axial current in chiral quark-gluon plasma via the chiral vortical effect. I will discuss the collective gapless mode, the chiral vortical wave, emerging from CVE and its experimental implications in heavy-ion collisions. Finally, I will consider the rotating trapped cold atomic gases and show that when there is a Weyl spin-orbit coupling such cold atomic gases provide a desktop simulator of the chiral magnetic effect and chiral separation effect.

  42. HET/RIKEN Seminar

    "Calculating TMDs and DPDs on the lattice"

    Presented by Andreas Schaefer, University of Regensburg

    Wednesday, May 4, 2016, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: 'Tomomi Ishikawa'

  43. Physics Colloquium

    "eRHIC Machine Design"

    Presented by Thomas Roser, BNL

    Tuesday, May 3, 2016, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: 'Robert Pisarski'

    With the addition of a 20 GeV polarized electron accelerator to the existing Brookhaven Relativistic Heavy Ion Collider (RHIC), the world?s only high energy heavy ion and polarized proton collider, a future eRHIC facility will be able to produce polarized electron-nucleon collisions at center-of-mass energies of up to 145 GeV and cover the whole science case as outlined in the Electron-Ion Collider White Paper and endorsed by the 2015 Nuclear Physics Long Range Plan with high luminosity. The presentation will describe the eRHIC design concepts and recent efforts to reduce the technical risks of the project.

  44. High Tc Superconductor Seminar

    "Cooper-like paring and energy gap induced by ion electronic polarizability"

    Presented by Yizhak Yacoby, Racah Institute of Physics, Hebrew University, Israel

    Monday, May 2, 2016, 1:30 pm
    Bldg. 734, ISB Conference Room 201 (upstairs)

    Hosted by: ''Ron Pindak and Ivan Bozovic''

    We propose a model of Cooper-like pairing induced by the large ion polarizabilities of O2- in Bismutates and Cuprates and As3- and Se2- in the iron pnictides*. We show that the electrical potential field induced by a charge carrier contains in its vicinity pockets of negative potential causing charge carriers to attract each other. Using this model we calculate the approximate pairing and gap energies showing they are compatible with the gap energies measured in high-Tc superconductors. Furthermore we show that the isotope effect, coherence length, and the gap energy dependence on doping are consistent with those observed in high-Tc systems. * Work done in collaboration with Yakov Girshberg

  45. Nuclear Theory/RIKEN Seminar

    "Going with the flow: sign problem, Lefschetz thimbles and beyond"

    Presented by Gokce Basar, University of Maryland

    Friday, April 29, 2016, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: '''Soeren Schlichting'''

    Monte Carlo method, a robust way of studying field theories and many body systems, suffers from the sign problem when the action is complex. This includes an important set of problems such as most field theories, including QCD, and strong correlated electronic systems at finite density, as well as computation of real time quantities like transport coefficients. I will show that lifting the path integration to a complex manifold provides a way to ameliorate the sign problem, and introduce a new algorithm for carrying on such a computation. I will give some quantum mechanical examples with severe sign problems, including finite density of fermions and real time observables where Monte Carlo simulations can be profitably performed by this method. Finally I will discuss the 3+1d Bose gas with nonzero chemical potential.

  46. Particle Physics Seminar

    "Higgs' invisible branching fraction at the LHC"

    Presented by Tae Min Hong, University of Pennsylvania

    Thursday, April 28, 2016, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: 'Michael Begel'

    Does the Higgs have a large invisible branching fraction? Two approaches are presented. The first is an indirect constraint of the invisible branching fraction using precision Higgs couplings measurements. The second is a direct search of invisible decays. In particular, I will discuss in detail two of ATLAS's results: the H -> WW in VBF, which is one of the strongest inputs for the couplings and the evidence for VBF Higgs production, and the H -> invisible in VBF, which gives the strongest direct limit. Comparisons with CMS's results are made.

  47. RIKEN Lunch Seminar

    "Solving QCD2"

    Presented by Alexei Tsvelik, BNL

    Thursday, April 28, 2016, 12:30 pm
    Building 510, Room 2-160

    Hosted by: 'Daniel Pitonyak'

    We study a (1+1)-dimensional version of the famous Nambu-Jona-Lasinio model of Quantum Chromodynamics (QCD2) both at zero and finite chemical potential. We use non- perturbative techniques (non-Abelian bosonization and Truncated Conformal Space Approach). At zero chemical potential we describe a formation of fermion three-quark (nucleons and ?-baryons) and boson (two-quark mesons, six-quark deuterons) bound states and also a formation of a topo- logically nontrivial phase. When the chemical potential exceeds the critical value, the model has a rich phase diagram which includes phases with density wave and superfluid quasi-long-range (QLR) order and also a phase of a baryon Tomonaga-Luttinger liquid (strange metal). The QLR order results as a condensation of scalar mesons (the density wave) or six-quark bound states (deuterons).

  48. HET/RIKEN Seminar

    "Heavy Higgs Resonance Dip"

    Presented by Sunghoon Jung, SLAC

    Wednesday, April 27, 2016, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: ''Cen Zhang''

    We discuss overlooked resonance shapes of heavy Higgs bosons that arise from the resonance-continuum interference with a complex phase. They include pure resonance dips and nothingness. We derive conditions under which they are produced and we modify narrow width approximation suitable for them. We then discuss how MSSM heavy Higgs searches at the LHC can be challenged and changed.

  49. Physics Colloquium

    "Neutrino Physics and Mass from Cosmology"

    Presented by Marilena Loverde, Stony Brook University

    Tuesday, April 26, 2016, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: 'Robert Pisarski'

    Cosmic background neutrinos are nearly as abundant as cosmic microwave background photons, but their mass, which determines the strength of their gravitational clustering, is unknown. Neutrino oscillation data gives a strict lower limit on neutrino mass, while cosmological datasets provide the most stringent upper limit. Even if the neutrino masses are the minimum required by oscillation data, their gravitational effects on structure formation will nevertheless be detectable in — and in fact required to explain — data within the next decade. I will discuss the physical effects of the cosmic neutrino background on structure formation and present a new signature that may be used to measure neutrino mass with large galaxy surveys.

  50. Center for Functional Nanomaterials Seminar

    "Disordered water phases from ambient to ultrahigh pressure"

    Presented by Roberto Car, Princeton University

    Tuesday, April 26, 2016, 11 am
    CFN, Bldg. 735, 2nd Fl. Seminar Room

    Hosted by: 'Deyu Lu'

    Center for Functional Nanomaterials Special Seminar Disordered water phases from ambient to ultrahigh pressure Roberto Car Princeton University Tuesday, April 26, 2016 11:00 a.m. CFN, Bldg. 735, 2nd floor Seminar Room The unusual properties of water, including the thermodynamic anomalies of the liquid, the existence of more than one amorphous ice form, and the abnormal mobilities of the water ions, derive from the tetrahedral network of hydrogen bonds that hold the molecules together. Under applied pressure the topology of the network changes but local tetrahedrality is preserved as the system explores a variety of different phases until at extreme pressure the molecules dissociate into ions and the hydrogen bonds collapse. Modern ab-initio simulations provide a unifying picture of these processes. In this talk, I will review recent progress in these studies stressing connections between theory, simulation, and experiment. Bio Roberto Car of Princeton University is Ralph W. Dornte professor for chemistry with a simultaneous appointment at the Material Sciences Institute of the university. He is a professor in the Theory Department, of the Fritz Haber Institute of the Max Planck Society. His research focus is theory and numerical simulation (classical and quantum) of condensed and molecular systems. He studied physics and attained a doctorate in 1971 in nuclear technology at the Politecnico di Milano. After being professor for physics at SISSA in Trieste (1984-1991), and at University of Geneva (1991-1999) he joined Princeton University in 1999. In 2007, a birthday symposium was held at ICTP. He received the Aneesur Rahman prize in computational physics. The Aneesur Rahman Prize is the highest honor given by the American Physical Society for work in computational physics.

  51. C-AD Accelerator Physics Seminar

    Presented by Malek Haj Tahar, BNL

    Friday, April 22, 2016, 4 pm
    Large Conference Room, Bldg. 911B, Rm. A202

    "The problem of nuclear waste continues to raise lots of concerns of whether the nuclear power should continue when the issue of how to deal with its waste has not yet been resolved. After reviewing the history of the nuclear waste problem in the United States of America and other countries, the question of how to remediate this problem is tackled and several options discussed. The focus is on the Accelerator Driven System option, a hybrid technique combining a particle accelerator with a subcritical core. The scope includes technical considerations from the proton accelerator and up to the reactor core."

  52. Nuclear Theory/RIKEN seminar

    "A higher spin theory of neutral excitations of fractional quantum Hall fluids"

    Presented by Dam T. Son, University of Chicago

    Friday, April 22, 2016, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: '''Soeren Schlichting'''

  53. Particle Physics Seminar

    "New constraints on cosmic inflation from the Keck Array"

    Presented by Chris Sheehy, University of Chicago

    Thursday, April 21, 2016, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: 'Anze Slosar'

    The Keck Array, part of the BICEP/Keck program of small aperture cosmic microwave background (CMB) telescopes, is currently taking data at the South Pole in Antarctica. The goal of the BICEP/Keck program is to detect the B-mode pattern in the CMB's polarized anisotropy that would be a signature of cosmic inflation, or, barring a detection, to set upper limits that rule out some of the most favored theoretical scenarios. Previous results from BICEP2 and the Keck Array that detected B-modes at high significance consisted of data taken only at 150 GHz, and which could therefore not conclusively distinguish between a cosmological vs. galactic origin for the signal. A subsequent joint analysis with the Planck satellite collaboration that invoked their comparatively noisy but multifrequency maps revealed a large component of the signal to be from polarized thermal emission of galactic dust. In this talk, I will present the results from the first year of observations with Keck's new 95 GHz receivers. These results set the most stringent limits on cosmic inflation to date and mark the point at which CMB polarization now constrains inflation better than any other data set.

  54. RIKEN Lunch Seminar

    "Color fluctuation phenomena in high energy hadron & photon-A collisions"

    Presented by Mark Strikman, Penn State University

    Thursday, April 21, 2016, 12:30 pm
    Building 510, Room 2-160

    Hosted by: ''Daniel Pitonyak''

    Compositeness of the bound states and the Lorentz slowing down of high energy interactions in QED and QCD lead to emergence of new coherent phenomena. We focus on the phenomena related to the fluctuations of the strength of interaction (color fluctuations phenomena). First we consider gross violations of the Glauber model for centrality dependence of production of the leading jets in pA scattering predicted earlier within QCD and recent evidence for this phenomenon from the studies of hard pA collisions at the LHC and dAu collisions at RHIC. Color fluctuations also explain a large suppression of the cross section of coherent vector meson photoproduction as compared to the Glauber model observed recently in the ultraperipheral collisions at LHC. We outline perspectives of future studies of the color fluctuation phenomenon in ultraperipheral heavy ion collisions at the LHC and electron - nucleus colliders.

  55. Environmental & Climate Sciences Department Seminar

    "Improved Tandem Measurement Techniques for Gas Phase Nanoparticle Analysis"

    Presented by Vivek Rawat, University of Minnesota

    Wednesday, April 20, 2016, 11 am
    Conference Room, Bldg 815E

    Hosted by: 'Jian Wang'

    Non-spherical, chemically inhomogeneous nanoparticles are encountered in a number of natural and engineered environments, including combustion systems, reactors used in gas-phase materials synthesis, and in ambient air. To better characterize these complex nanoparticles, tandem measurement techniques are well suited, in which analytes are characterized by two orthogonal properties (e.g. size and mass). Tandem measurement techniques have been applied in a number of situations; however, there are still a considerable number of fundamental developments needed to advance these approaches. Specifically, new instrument combinations (with existing instruments) and appropriate data inversion routines need to be developed to determine combined two-dimensional mass-size distribution functions, pure mass distribution and for mobility-mass analysis for sub 2-nm clusters (ions). With this motivation, we first develop and apply a data inversion routine to determine the number based size-mass distribution function (two dimensional distribution) from tandem differential mobility analyzer-aerosol particle mass analyzer (DMA-APM) measurements, while correcting for multiple charging, instrument transfer functions and other system efficiencies. This two dimensional distribution can be used to calculate the number based size distribution or the mass based size distribution. We employ this technique to analyze various spherical and non-spherical nanoparticles and examine the validity of this approach by comparing the calculated size distribution functions and mass concentrations with direct measurements of these quantities. In a second study, we utilize a transversal modulation ion mobility spectrometer (TMIMS) coupled with a mass spectrometer (MS) to study vapor dopant induced mobility shifts of sub 2 nm ion clusters. Isopropanol vapor is introduced into the TMIMS, shifting the mobilities of ions to varying extents depending on ion surface chemistry, which provides an improved separa

  56. Physics Colloquium

    "The nature of the composite fermion in quantum Hall liquids"

    Presented by Dam Thanh Son, University of Chicago

    Tuesday, April 19, 2016, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: 'Robert Pisarski'

    The quantum Hall liquids are some of the most nontrivial strongly interacting states of matter. Experiments have established the existence of the composite fermion as an effective degree of freedom of quantum Hall systems near half filling. A long-standing problem of existing theories of the composite fermion is the lack of particle-hole symmetry of the lowest Landau level. I will describe how the particle-hole symmetry took a central role in recent theoretical discussions of the fractional quantum Hall effect; in particular, how a recent synthesis, motivated by the physics of graphene and topological insulators, has lead to a new understanding of the low-energy quasiparticle of the half-filled Landau level. According to the new picture, the composite fermion is a Dirac particle, with a gauge but non-Chern-Simons interaction. Distinctive consequences of the new proposal are outlined.

  57. Nuclear Theory/RIKEN seminar

    "Vorticular fluid and Lambda Polarization in High-energy Heavy-ion Collisions"

    Presented by Xin-Nian Wang, LBNL/CCNU

    Friday, April 15, 2016, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: ''Soeren Schlichting''

    The strongly coupled quark-gluon plasma created in high-energy heavy-ion collisions has rich vortical structures that are caused by global total orbital angular momentum and transverse evolution of longitudinal flow. Fermions (quarks in sQGP phase and baryons in the hadronic phase) in such a vorticular fluid are naturally polarized due to spin-orbital. I will discuss both local and global quark polarization and how one can use the lambda polarization in the final state to study the vortical structure and constrain the transport properties of sQGP.

  58. Particle Physics Seminar

    "Nuclear reactor antineutrinos, hard to detect but with a traceable lineage."

    Presented by Alejandro Sonzogni, BNL

    Thursday, April 14, 2016, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: 'Xin Qian'

    The antineutrino spectrum from nuclear reactors can be calculated using the so-called "summation method", which requires precise knowledge of the fission yield and decay properties of the about 1000 radionuclides produced in a reactor following the fission of the actinide fuel. Alternatively, the antineutrino spectra can also be calculated using the "conversion method", which relies on precisely measured electron spectra. We have recently updated both decay and fission data that enabled us to a) identify the nuclides that contributes the most at different energy regions, b) derive a systematic of the IBD cross section integrated spectra as function of Z and A, similar to that of beta-delayed neutrons, c) asses if an excess of antineutrinos observed at around 5.5 MeV can be discerned using nuclear data.

  59. Center for Functional Nanomaterials Seminar

    "Sub-50 fs Photophysics and Photochemistry of Transition Metal Complexes and Polyhalomethanes"

    Presented by Sergey Mikhailovich Matveev, Bowling Green State University

    Monday, April 11, 2016, 1:30 pm
    CFN, Bldg. 735, 1st floor conf. rm. A

    Hosted by: 'Mircea Cotlet'

    Lowest energy electronic excited states (LEES) in transition metal complexes are the states most relevant for practical photophysical and photochemical processes. We investigated relaxation dynamic of two systems – copper chloride dianion with strong Jahn-Teller effect and hexabromoiridate dianion with spin-spin coupling, utilizing 2000 nm near-IR femtosecond (100 fs) pump-probe spectroscopy. In both systems, the Franc- Condon excited states of the transition metal complexes undergo internal conversion to the ground electronic states, but with significantly different lifetimes (55 fs and 360 ps, respectively), despite the fact that the metal-centered states are separated by the same energy gap (~5000 wavenumbers) from the respective ground state. This difference is explained by presence of a conical intersection between the first excited electronic and the ground states in the Cu(II) system due to strong Jahn-Teller linear distortion whereas the involved potential energy surfaces for the Ir(IV) complex are nested directly one above another. Another project under consideration is the ultrafast mechanisms of polyhalomethanes on the example of diiodomethane. This molecule has a tractable number of degrees of freedom, and, therefore, has served in literature as a model system for bond dissociation processes in both gas and condensed phases. In this work we implemented the state-of-the-art ultrafast (~35 fs) transient absorption experiment (supported by the most accurate multireference quantum chemical methods) to understand the UV photodissociation mechanism of methylene iodide molecules. We discovered previously unsuspected photochemical pathway in the UV photochemistry of methylene iodide, in which electronically excited molecules, rather than simply dissociate, undergo direct ~50-fs isomerization through a conical intersection into isomeric species. Host: Mircea Cotlet

  60. HET/PARTICLE/RBRC Seminar

    ""Recent Highlights from CMS and from the 13 TeV run at the LHC""

    Presented by Albert de Roeck, CERN/University of Antwerp

    Friday, April 8, 2016, 2 pm
    Large Seminar Room, Bldg. 510

    Hosted by: '''Amarjit Soni'''

  61. Particle Physics Seminar

    "Dark Matter Search Results from PICO-2L"

    Presented by Chanpreet Amole, Queen's University, SNOLAB

    Thursday, April 7, 2016, 10 am
    Small Seminar Room, Bldg. 510

    Hosted by: 'Xin Qian'

    New data are reported from a second run of the 2-liter PICO-2L C3F8 bubble chamber with a total exposure of 129 kg-days at a thermodynamic threshold energy of 3.3 keV. These data show that measures taken to control particulate con-tamination in the superheated fluid resulted in the absence of the anomalous back-ground events observed in the first run of this bubble chamber. One single nuclear-recoil event was observed in the data, consistent both with the predicted background rate from neutrons and with the observed rate of unambiguous multiple-bubble neutron scattering events. The chamber exhibits the same excellent electron-recoil and alpha decay rejection as was previously reported. These data provide the most stringent direct detection constraints on WIMP- proton spin-dependent scattering to date for WIMP masses < 50 GeV/c2.

  62. 'Science on Tap'

    "A Conversation With Paul Sorensen"

    Presented by Paul Sorensen, Brookhaven Lab

    Tuesday, April 5, 2016, 7 pm
    Stony Brook Yacht Club

    Hosted by: ''Alan Alda Center for Communicating Science''

    Paul Sorensen recreates the birth of the universe, smashing the nuclei of gold atoms together with such extreme violence that they melt into a cosmic soup that hasn't existed since the universe was a microsecond old. In conversation with Stony Brook University's journalism professor, Steven Reiner, Sorensen will bring to vivid life the epic endeavor to create in Brookhaven National Laboratory's atom smasher minute specks of the hottest matter ever made on Earth, and tell us what these fleeting fireballs may reveal about the origin of everything, including ourselves.

  63. Physics Colloquium

    "Hunting for WIMPs in Panda Land"

    Presented by Xiangdong Ji, University of Maryland

    Tuesday, April 5, 2016, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: ''''Robert Pisarski''''

    Weakly interacting massive particles (WIMPs), with properties similar to those of a heavy neutrino, have been a leading candidate for the 27% dark matter in the Universe. Direct detection experiments by detecting the nuclear recoils from elastic scattering of WIMPs with atomic nuclei have made huge strides in the last decade, improving the sensitivity by some five orders of magnitude. In this talk, I will describe the results from an adventure of searching for WIMPs with the PandaX, currently the most sensitive running liquid xenon dark matter detector, in the world's deep underground lab in the high mountains, western China.

  64. Nuclear Theory/RIKEN seminar

    "Studying Nucleons in Soliton Models"

    Presented by Song Shu, Stonybrook University

    Friday, April 1, 2016, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: ''Soeren Schlichting''

    Both chiral solitons and confined solitons are discussed at finite temperatures and densities in effective models. Based on the solitons the nucleon properties are studied in thermal medium. The nucleon mass in medium is carefully calculated. It is showed that the chiral solitons could even survive after the chiral phase transition, while confined solitons collapse after the system is deconfined.

  65. Particle Physics Seminar

    "Milicharge: A Proposal"

    Presented by Ben Kaplan, New York University

    Thursday, March 31, 2016, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: ''Michael Begel''

    I will present the status of the MilliQan experiment, a milli-charged particle detector we propose to install at LHC P5. The experiment would be commissioned during the next LHC shutdown in a service tunnel ~30m above the CMS interaction point, behind ~15m of rock. I will present the theoretical motivation for building the detector, its proposed experimental design, and the expected sensitivity to milli-charged particles.

  66. RIKEN Lunch Seminar

    "Sphalerons Far From Equilibrium and Associated Phenomena"

    Presented by Mark Mace, Stony Brook University

    Thursday, March 31, 2016, 12:30 pm
    Building 510 Room 2-160

    Hosted by: 'Daniel Pitonyak'

    In this talk, I will present a first computation of sphalerons in the glasma; the highly occupied, weakly coupled gluon dominated pre-equilibrium matter created at early times after an ultra-relativistic heavy ion collisions. The sphaleron transition is a well known ingredient in the generation of anomalous vector current from a strong external magnetic field, the so-called Chiral Magnetic Effect. We perform classical-statistical real-time lattice simulations to study the dynamics of these topological transitions; simplifying our description by employing SU(2) gauge fields and neglecting the longitudinal expansion for this first study. I will show that the non-equilibrium sphaleron transition rate is time dependent and non-Markovian, in addition to being dominant in comparison to the thermal equilibrium sphaleron transition rate. In addition, we can measure the scaling and separation of physical scales in analogy to those from thermal equilibrium, in order to parameterize this rate and understand the approach to equilibrium. I will then demonstrate that it is the magnetic screening length, which we extract non-perturbatively, that controls this rate. Additionally, I will briefly mention studies of related anomalous transport effects that we plan on studying using this first principles classical-statistical real-time lattice technology.

  67. Condensed-Matter Physics & Materials Science Seminar

    "Topological Insulators and Dirac Semimetals - Recent Progress in New Materials"

    Presented by Robert J. Cava, Princeton University

    Thursday, March 31, 2016, 10 am
    Large Seminar Room, Bldg. 510

    Hosted by: ''Peter D. Johnson''

    "New materials give new properties" describes the goal of our solid state chemistry research program. This goal would be much easier to attain if there was a reliable way to predict the stability of an unknown non-molecular solid, then predict what its properties would be, then make it as a real material and then finally test it, but unfortunately that is not the case; establishing such a process is the grand challenge in contemporary solid state chemistry, and so we have to operate differently. Our discussions with experimental and theoretical physicists teach us about current issues in the electronic and magnetic properties of matter, and our chemistry background teaches us how to think about crystal structures and bonding; our work is about trying to put these two cultures together to find new materials. In this talk I will describe some of our recent results in Topological Insulators and Dirac and Weyl Semimetals.

  68. Physics Colloquium

    "Quark-Gluon Plasma: An Old and New Phase of Quantum Matter"

    Presented by Jinfeng Liao, Indiana University

    Tuesday, March 29, 2016, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Robert Pisarski

    The use of fire was instrumental for human civilization. Early conception of varied phases of matter as well as transitions among them, perhaps developed from e.g. burning wood and heating water. Those ancient pursuits continue into the modern quest for understanding the structure of matter under extreme conditions: what's the phase of matter when heated to unprecedented temperature? The answer to this question relies upon our understanding of the strong nuclear force, which is described by quantum chromodynamics (QCD). First principle calculations of QCD predict that the normal nuclear matter, when heated to be hot enough, will change into a new phase of matter called the quark-gluon plasma (QGP). In fact, the QGP was an old phase of matter that occupied the early universe shortly after the Big Bang. Today, such primordial droplets of QGP can be re-created repeatedly and measured precisely in relativistic heavy ion collisions (often called the Little Bangs). Remarkable discoveries have been made at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) that together reveal the QGP as a nearly perfect quantum liquid with superior opaqueness. We will discuss a number of novel properties of QGP. In particular we will highlight the recent progress on how certain unusual transport phenomena stemming from microscopic chiral anomaly, which is intrinsically quantum mechanical, could manifest themselves in the macroscopic QGP fluid. A very brief survey will be given on the theoretical developments, the experimental search in heavy ion collisions, as well as the recent exciting progress of such physics in Dirac and Weyl semimetals.

  69. Particle Physics Seminar

    "Exotic BSM Higgs Decays and proposed LHC Benchmarks"

    Presented by Shufang Su

    Thursday, March 24, 2016, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: 'Bill Marciano'

  70. Condensed-Matter Physics & Materials Science Seminar

    "Phase transitions in strongly correlated systems from diagrammatic multi-scale methods"

    Presented by Andrey Antipov, University of Michigan

    Thursday, March 24, 2016, 1:30 pm
    Bldg. 734, ISB Conf. Rm. 201 (upstairs)

    Hosted by: ''Alexei Tsvelik''

    The dynamical mean field theory (DMFT) has become the standard tool in describing strongly correlated electron materials. While it captures the quantum dynamics of local fields, it neglects spatial correlations. To describe e.g. anti-ferromagnetism, unconventional superconductivity or frustration a proper treatment of non-local correlations is necessary. Diagrammatic multi-scale approaches offer an elegant option to accomplish this: the difficult correlated part of the system is solved using a non-perturbative many-body method, whereas 'easier', 'weakly correlated' parts of the problem are tackled using a secondary perturbative scheme. Here we employ such a method, the dual fermion approach, to problems of charge and spin ordering in Falicov-Kimball and Hubbard models by constructing a systematic diagrammatic extension on top of DMFT. Near the critical point model we study the interplay between charge and spin excitations and long-range fluctuations. We show that such multi-scale approach is indeed capable of capturing the non mean-field nature of the critical point of the lattice model and correctly describes the transition to mean-field like behavior as the number of spatial dimensions increases. Our numerical method is available as a freely distributed open-source code.

  71. Special RIKEN/HET Seminar

    "Axion Phenomenology from Unquenched Lattice QCD"

    Presented by Guido Martinelli, Rome University

    Thursday, March 24, 2016, 11 am
    Large Seminar Room, Bldg. 510

    Hosted by: '''Hiroshi Oki'''

    We investigate the topological properties of Nf = 2 + 1 QCD with physical quark masses, both at zero and finite temperature. At zero temperature both finite size and finite cut-off effects have been studied by comparing the continuum extrapolated results for the topological susceptibility χ with the predictions from chiral perturbation theory. At finite temperature, we explore a region going from Tc up to around 4Tc, where continuum extrapolated results for the topological susceptibility and for the fourth moment of the topological charge distribution are obtained. While the fourth moment converges to the dilute instanton gas prediction the topological susceptibility differs strongly both in the size and in the temperature dependence. This results in a shift of the axion dark matter window of almost one order of magnitude with respect to the instanton computation.

  72. Physics Colloquium

    "Flavor Physics for Non Experts : (A Theory) Overview"

    Presented by Guido Martinelli, Rome University

    Tuesday, March 22, 2016, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Robert Pisarski

    The status of the Unitarity Triangle including the most recent results from LHC, will be presented. Different possibilities for detecting, in the quark sector, signals of physics beyond the Standard Model will be considered. The conclusion is that, even allowing for general New Physics loop contributions, the generalized Unitarity Triangle must be very close to the Standard Model one. Together with direct searches of new particles at LHC, this result strongly constraints models of New Physics.

  73. Condensed-Matter Physics & Materials Science Seminar

    "SU(N) symmetric tensor network simulations of strongly correlated quantum many-body systems"

    Presented by Andreas Weichselbaum, Ludwig Maximilians University

    Tuesday, March 22, 2016, 1:30 pm
    Small Seminar Room, Bldg. 510

    Hosted by: ''Alexei Tsvelik''

    Tensor network simulations have emerged as a powerful algebraic framework for the simulation of strongly correlated quantum many-body systems. Their great appeal lies in the fact that they are exact in that they do no rely on small parameters. They significantly extend exact diagonalization to much larger system sizes in (effective) 1D or 2D all the way to the thermodynamic limit. I will give a brief introduction based on the hugely successful methods such as the numerical renormalization group (NRG) or the density matrix renormalization group (DMRG) with focus on multi-orbital systems, both symmetric and non-symmetric. A versatile numerical tool in that respect is my recently developed tensor library QSpace that can efficiently deal with generic symmetry settings including SU(N). After a brief motivation via the prototypical symmetric multi-orbital system of iron impurities in gold or silver, I will present recent results on a dynamical mean-field theory (DMFT) study concerning the coherent-incoherent crossover in iron-pnictides, followed by recent work on the spin-1 Heisenberg kagome lattice and preliminary results on SU(N) spin ladders.

  74. Condensed-Matter Physics & Materials Science Seminar

    "From Molecular Beam Epitaxy to high magnetic field Quantum Oscillations"

    Presented by Yoshiharu Krockenberger, NTT Basic Research Laboratories

    Monday, March 21, 2016, 1:30 pm
    Bldg.480 Conf. Rm

    Hosted by: 'Ivan Bozovic'

    Cuprate superconductors present a major challenge in condensed matter physics not only due to their electron correlations but also due to their complex crystal structure. Complex crystal structures, i.e. various cations at various lattice positions, demand for the utmost caretaking when synthesizing them. In particular, Molecular Beam Epitaxy is the foremost versatile tool and technique that allows for the synthesis of such materials without the necessity to compromise on impurity phases. First, I introduce our custom designed Molecular Beam Epitaxy equipment which is empowered by e-guns, not effusion cells, and controlled by electron impact emission spectroscopy. After presenting several material systems I present high magnetic field quantum oscillation data on films synthesized by our Molecular Beam Epitaxy systems.

  75. Nuclear Theory/RIKEN Seminar

    "Duality, Dimensions and Reduction on the Lattice"

    Presented by Joel Giedt, Rensselaer Polytechnic Institute

    Friday, March 18, 2016, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

    Montonen and Olive found evidence that a duality could exist in Yang-Mills with adjoint scalars. In this scheme, the 't Hooft-Polyakov monopole forms a gauge triplet with the photon, leading to a theory equivalent to the Georgi-Glashow model but with magnetic charge replacing electric charge. The duality is believed to be realized in N=4 super-Yang-Mills. We are pursuing numerical, nonperturbative evidence for this S-duality using our lattice formulation. Two lines of approach are being taken, which I will discuss. First, we attempt to show that there is a value of the gauge coupling for which the W boson mass is equal to the monopole mass. Second, we are relating the 't Hooft loop to the Wilson loop at this self-dual coupling. On a somewhat unrelated topic, we also discuss the determination of anomalous dimensions on the lattice. In the dual gravitational picture these correspond to masses of fields in the bulk, so that some aspects of the gauge-gravity duality could be tested by such determinations. In particular in N=4 super-Yang-Mills there are predictions for the dimensions of non-protected operators at the self-dual point, based on the superconformal bootstrap.

  76. HET/RIKEN Seminar

    ""Operator Bases and Effective Field Theories""

    Presented by Brian Henning, Yale University

    Wednesday, March 16, 2016, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: 'Cen Zhang'

  77. Physics Colloquium

    "Hot-dense Lattice QCD: Supercomputing Extreme Matter"

    Presented by Swagato Mukherjee, BNL

    Tuesday, March 15, 2016, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: 'Rob Pisarski'

    I will discuss the role of supercomputing in revealing the phases and properties of the hot-dense quark-gluon matter created during relativistic heavy-ion collisions. I will present a brief overview of the recent achievements of ab-initio lattice Quantum Chromodynamiecs computations at non-zero temperatures and densities.

  78. Particle Physics Seminar

    "New SUSY Results from ATLAS"

    Presented by Max Swiatlowski

    Thursday, March 10, 2016, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Michael Begel

  79. Condensed-Matter Physics & Materials Science Seminar

    "Real-space Visualization of the Superconducting Proximity effect and Josephson tunneling on Nano-sized Pb thin film"

    Presented by Howon Kim, Institute for Solid State Physics, University of Tokyo, Japan

    Wednesday, March 9, 2016, 11 am
    ISB Bldg. 734 Conf. Rm. 201 (upstairs)

    Hosted by: Kazuhiro Fujita

    The proximity and Josephson effects are well-known phenomenon and widely used terms in superconductivity. Due to the recent advances in fabrication techniques those phenomenon has been extensively studied to give a new insight to the superconductor-based device applications. Nevertheless, many of these works addressed macroscopic properties of the samples, and thus local information is still missing. In this talk, I will discuss how we can realize the proximity effect and Josephson effect using scanning tunneling microscope at a nanometer scale. In the first part of the talk, we address how the local surface structure can influence on the proximity effect at the interface between superconducting two-dimensional Pb islands and a single-atomic-layer metal by performing local tunneling spectroscopy. From the spectroscopic mapping taken around the Pb-based S/N interface, we observed the gap at the Fermi energy, reminiscent of the superconducting gap, propagating into the metal region (proximity effect) and its depth decaying with the distance from the interface. Additionally, we observed that the propagation of the gap is terminated by the steps of the substrate and enhancement of the gap-depth in the area between the interface and the step edge. The experimental results are compared with the results of quasi-classical theory based on the Usadel equation. [1] The second part of the talk addresses atomic-scale S-S junctions by using scanning tunneling microscopy and spectroscopy. In our local conductance measurements between superconducting Pb islands on Si(111) or Ge(111) and Pb layers on the end of PtIr tip apex, we observed evolution of not only the normal-state conductance [2] but also a zero-bias peak (ZBP) from tunnel to atomic contact, which corresponds to the Josephson current, with a decrease in the tip-substrate distance on the different atomic sites on the surface crystalline lattice of the substrate. With a help of multiple Andreev reflectio

  80. Environmental & Climate Sciences Department Seminar

    "Plant respiration: lessons from high latitudes for ecosystem carbon balance modelling"

    Presented by Paul P. Gauthier, Princeton University

    Wednesday, March 9, 2016, 11 am
    John Dunn Seminar Room, Bldg. 463

    Hosted by: Alistair Rogers

    Climate-mediated changes in ecosystem C balance are accepted as an important component of the biosphere response to climate change. Plant respiration and photosynthesis are major drivers of this balance but our lack of understanding of the controls and constrains surrounding their interaction stalls our capacity to predict future ecosystem changes. Using a new O2 isotopes method for measuring leaf functional traits, I will present a new approach to estimate the rate of leaf respiration in the light and its biochemical origin in temperate and arctic plants. The role of plant respiration as a key player for plant adaptation will also be discussed in the context of plant respiration modelling.

  81. RIKEN Lunch Seminar

    "Investigation of anomalous dynamics and the Chiral Magnetic Effect far from equilibrium"

    Presented by Niklas Mueller, University of Heidelberg

    Thursday, March 3, 2016, 12:30 pm
    Building 510, Room 2-160

    Hosted by: Daniel Pitonyak

    We investigate the impact of the Adler-Bell-Jackiw axial anomaly on the real-time dynamics of gauge theories in the strong field regime. By studying and comparing Abelian gauge theories, such as QED, with non-Abelian systems, we try to clarify the role of topological properties and initial conditions relevant far from equilibrium. We show that the Abelian version of the Chiral Magnetic Effect, which has been predicted in the context of ultra-relativistic heavy ion collisions, can result in non-trivial experimental signatures, which could possibly be observed in future high-intensity laser experiments. Further I will report on recent investigations of chiral production mechanisms in strong non-Abelian gauge fields and I will discuss the influence of topological objects such as sphalerons, far from equilibrium. Moreover I will show first results of the studies we have undertaken since my arrival here at BNL and discuss how the combination of these studies might be used to shed more light on the role played by anomalies in the early stages of a heavy ion collision.

  82. HET/RIKEN Seminar

    "Accurate event simulation for colliders"

    Presented by Stefan Prestel, SLAC

    Wednesday, March 2, 2016, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Cen Zhang

  83. Physics Colloquium

    "Detection of Gravitational Waves and the First Observation of a Binary Black Hole Merger"

    Presented by Imre Bartos, Columbia University

    Tuesday, March 1, 2016, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Peter Petreczky

    On September 14th 2015 the gravitational wave signature of a binary black hole merger was detected by the LIGO observatories. This marks the beginning of a completely new era of modern physics, the dawn of gravitational-wave astrophysics. We will discuss the discovery, its impact and its consequences.

  84. Nuclear Physics Seminar

    "Beam Energy Dependence of the Third Harmonic of Azimuthal Correlations in Au+Au Collisions at RHIC"

    Presented by Paul Sorensen, BNL

    Tuesday, March 1, 2016, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: Oleg Eyser

    I will present results from a harmonic decomposition of two-particle azimuthal correlations measured with the STAR detector in Au+Au collisions for energies ranging from 7.7 GeV to 200 GeV. v3 is studied as a function of the pseudorapidity di erence between particle pairs. Non-zero v3 is directly related to the previously observed large- narrow- ridge correlations and has been shown in models to be sensitive to the existence of a low viscosity Quark Gluon Plasma (QGP) phase. For sufficiently central collisions, v3 persist down to an energy of 7.7 GeV suggesting that QGP may be created even in these low energy collisions. In peripheral collisions at these low energies however, v3 is consistent with zero. When scaled by pseudorapidity density of charged particle multiplicity per participating nucleon pair, v3^2 for central collisions shows a minimum near 20 GeV.

  85. Particle Physics Seminar

    "Observation of Gravitational Waves from a Binary Black Hole Merger by LIGO"

    Presented by Sergey Klimenko, University of Florida

    Monday, February 29, 2016, 3 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Erin Sheldon

    On September 14, 2015 at 09:50:45 UTC the Laser Interferometer Gravitational-wave Observatory (LIGO) Hanford, WA, and Livingston, LA, observatories detected a strong coincident signal. The signal matches the waveform predicted by general relativity for the inspiral merger of a pair of black holes and the ringdown of the resulting single black hole. A century after the fundamental predictions of Einstein and Schwarzschild, the gravitational waves are captured. I will present the details of this observation and discuss the results.

  86. Nuclear Theory/RIKEN Seminar

    "Real time method of thermal field theory"

    Presented by Samir Mallik, Saha Institute of Nuclear Physics

    Friday, February 26, 2016, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

    I review the basic ideas of real time formulation of thermal field theory. Then I like to consider the following topics in this formulation: 1) thermal propagator for a scalar field 2) spectral representation of two-point functions for arbitrary fields 3) perturbation expansion 4) one-loop self -energy 5) dilepton production

  87. Particle Physics Seminar

    "Project 8: tritium decays, neutrino masses, and single-electron spectroscopy"

    Presented by Prof. Ben Monreal, UC Santa Barbara

    Friday, February 26, 2016, 10 am
    Small Seminar Room, Bldg. 510

    Hosted by: Xin Qian

    Beta decay kinematics are, in principle, sensitive to the absolute values of the neutrino masses. Many decades of work with tritium decay have shown m_nu to be in the range 0—2.0 eV; require improvement in spectrometer resolution, statistics, and systematics. The KATRIN experiment will push the limits of classical techniques to reach 0.2 eV sensitivity. The Project 8 is developing what we hope is the next step in beta electron spectroscopy; we can now perform precise electron energy measurements, in-situ in a low-pressure gaseous source, by cyclotron radiation energy spectroscopy (CRES). I will show recent results from the Project 8 prototype, including the first CRES measurements in krypton, and our path to first molecular tritum measurements and to a future large atomic tritium experiment.

  88. Particle Physics Seminar

    "Giant detectors in solution-mined salt caverns"

    Presented by Prof. Ben Monreal, UC Santa Barbara

    Thursday, February 25, 2016, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Xin Qian

    Many of particle physics' most interesting observables (neutrinos, dark matter, proton decay) require detectors installed underground. In many cases, the constraints associated with mines—-limited roof spans, limited sites, safety, and excavation costs—- are beginning to limit the scope of our experiments. The energy and chemical industries have 100 years of experience with a different type of underground space: solution-mined salt caverns. These are obtained by drilling into large salt formations and dissolving the salt with water. The caverns obtained can be enormous, deep, stable and above all inexpensive—-but of course they have their own access and pressure constraints. In this talk, I will argue that a wide range of desirable detector technologies, including giant gas TPCs, might be deployed with these caverns. In particular, I will talk about an (untested) TPC gas mixture I devised with these caverns in mind, but which may prove useful in conventional labs too.

  89. RIKEN Lunch Seminar

    "Lambda_c - N interaction from lattice QCD"

    Presented by Takaya Miyamoto, Yukawa Institute for Theoretical Physics, Kyoto University

    Thursday, February 25, 2016, 12:30 pm
    Building 510 Room 2-160

    Hosted by: Hiroshi Oki

    Recently, a new approach to investigate hadron interactions in lattice QCD has been proposed[1] and developed extensively by the HAL QCD Collaboration[2]. This method can be easily applied to heavy baryon systems even though it is difficult to obtain experimental data of heavy baryons. We have investigated the interaction between Lambda_c and nucleon (N) from lattice QCD using the HAL QCD method. This is the first step to understand charmed-baryon interaction in lattice QCD. In this talk, we present the current status of our research project onLambda_c-N interactions as well as future prospects. This talk is based on PoS (LATTICE 2015) 090.

  90. Brookhaven Lecture

    "512th Brookhaven Lecture: Quarks, Gluons & Lattice QCD: Cooking the 'Perfect' Soup With Supercomputers"

    Presented by Swagato Mukherjee, Physics Department at Brookhaven Lab

    Wednesday, February 24, 2016, 4 pm
    Berkner Hall Auditorium

  91. Nuclear Theory/RIKEN Seminar

    "Lattice QCD investigations of quark transverse momentum in hadrons"

    Presented by Michael Engelhardt, New Mexico State University

    Friday, February 19, 2016, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

    An ongoing program of evaluating transverse momentum dependent parton distributions (TMDs) within lattice QCD is reviewed, summarizing recent progress with respect to several challenges faced by such calculations. These lattice calculations are based on a definition of TMDs through hadronic matrix elements of quark bilocal operators containing staple-shaped gauge connections. A parametrization of the matrix elements in terms of invariant amplitudes serves to cast them in the Lorentz frame preferred for a lattice calculation. Results presented include data on the naively T-odd Sivers and Boer-Mulders effects, as well as the transversity and a worm-gear distribution. Correlating quark transverse momentum with impact parameter, one can extract quark orbital angular momentum directly,including both the Ji as well as the Jaffe-Manohar definitions.

  92. Nuclear/Riken Theory Seminar

    "The Transverse Structure of the Nucleon"

    Presented by Marc Schlegel, University of Tuebingen

    Friday, February 19, 2016, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

    Perturbative QCD based on the Parton Model of the nucleon is a very successful theoretical approach to describe high-energy processes at particle accelerators and colliders. In particular, parton distribution functions are key ingredients of this approach and give information on the partonic substructure of the nucleon. As such they deliver a one-dimensional picture of how the parton momenta are distributed in the nucleon. In this talk extensions of the parton model are presented which provide access to more detailed information on the dynamics of partons in the nucleon. In particular observables involving transversely polarized nucleons are discussed. They can be described in terms of dynamical quark-gluon correlations which in turn can be studied at an Electron-Ion Collider. Another extension of the parton model takes into account the intrinsic transverse motion of the partons. In this approach - called Transverse Momentum Dependent (TMD) factorization - one can study three-dimensional distributions of the parton momenta. In addition, implications of the transverse motion of gluons in the nucleon will be discussed for LHC physics.

  93. Particle Physics Seminar

    "Weighing the Giants: Anchoring Cluster Cosmology"

    Presented by Adam Mantz, SLAC National Accelerator Laboratory

    Thursday, February 18, 2016, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Erin Sheldon

    The gas mass fractions and the distribution in mass and redshift of the galaxy cluster population provide powerful probes of cosmology, constraining the cosmic matter density, the amplitude of the matter power spectrum, properties of dark energy, and the mass of neutrinos, among other parameters. Historically, these tests have been limited by the absolute accuracy of cluster mass determinations. Here, mass measurements from weak lensing have an advantage over estimates based on observations of the intracluster medium (ICM), because the former are nearly unbiased and can be straightforwardly tested against simulations. I will describe recent cosmological constraints obtained from an analysis of X-ray selected cluster samples, incorporating extensive gravitational lensing data from the Weighing the Giants project — the first cluster cosmology study to consistently integrate a lensing mass calibration, including a rigorous quantification of all systematic uncertainties. The results highlight the power and potential of galaxy clusters, which constrain both the expansion of the Universe and the growth of cosmic structure, and their complementarity with other probes such as type Ia supernovae, large-scale galaxy surveys, and the cosmic microwave background.

  94. Physics Colloquium

    "Physics opportunities at future circular colliders"

    Presented by LianTao Wang, University of Chicago

    Tuesday, February 16, 2016, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Robert Pisarski

    Following the discovery of the Higgs boson, there has been a lot discussion about the next step in high energy physics. Among different options, a couple of newly proposed next generation circular colliders, including FCC at CERN and CEPC/SPPC in China, have attracted a lot of attention. Through preliminary studies in the past couple of years, an exciting picture of their physics capabilities has emerged. In this talk, I will give an overview on this topic, focusing on some of the most important questions in high energy physics they can help addressing

  95. Nuclear Physics Seminar

    "Precision Jet Physics to Probe Strong Dynamics"

    Presented by Dr. Daekyoung Kang, Los Alamos National Laboratory

    Tuesday, February 16, 2016, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: Oleg Eyser

    Jets produced in the high energy collision of quarks and gluons at colliders are bunches of collimated particles traveling along the same direction. Jet productions are extensively studied in various colliders in search for new physics beyond the standard model and as a probe of new state of matter like QGP. In this talk, I will discuss jet study at a high precision as a new tool to probe strong dynamics in electron-proton collider. As an example, I will show the new tool can be used to determine the strong coupling constant and to improve our understanding of nuclear structure such as a parton distribution function of proton. With new level of precision not previously available for jets, the jet physics will provide one of milestones at the early stage of future Electron-Ion collider.

  96. Nuclear Theory/RIKEN Seminar

    "Understanding the structure of hadrons through spin observables in hard-scattering processes"

    Presented by Daniel Pitonyak, BNL

    Friday, February 12, 2016, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

    Almost all of the visible matter in the universe is built from hadrons, which are composed of quarks and gluons. One of the main challenges in nuclear physics is to understand this complex internal structure. In this talk, I will discuss how hard-scattering processes that involve the spin of hadrons give us insight into aspects of their inner-workings that otherwise would be inaccessible. I will focus on phenomena that arise when hadrons carry spin transverse to their direction of motion, which allow us to examine them in 3D and analyze correlations between their quarks and gluons. I will also consider a new attempt to resolve the so-called "spin crisis" of how the proton gets its spin by looking at how much spin can be carried by small-x quarks and gluons.

  97. High Energy Theory/Particle Physics Seminar

    "Illuminating the Dark Side of Particle Physics"

    Presented by Eder Izaguirre, Perimeter Institute

    Thursday, February 11, 2016, 3 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Sally Dawson

  98. Condensed-Matter Physics & Materials Science Seminar

    "Berezinskii-Kosterlitz-Thouless-like transition in a highly underdoped La2-xSrxCuO4"

    Presented by Dragana Popovic, NHMFL Tallahassee

    Thursday, February 11, 2016, 1:30 pm
    Bldg. 734, ISB Conf. Rm. 201 (upstairs)

    Hosted by: Cedomir Petrovic

    In two-dimensional superconductors, the transition to the metallic state takes place via thermal unbinding of vortex-antivortex pairs, as described by the Berezinskii-Kosterlitz-Thouless (BKT) theory. The occurrence of the BKT transition in bulk underdoped samples of cuprate superconductors, which are highly anisotropic, layered materials, has been controversial. Therefore, the nature of the superconducting transition in highly underdoped thick films of La2-xSrxCuO4 has been investigated using the in-plane transport measurements. Both the temperature dependence of the paraconductivity above the transition and the nonlinear current-voltage (I-V) characteristics across it exhibit the main signatures of the BKT transition. Moreover, the quantitative comparison of the superfluid stiffness, extracted from the I-V data, with the renormalization-group results for the BKT theory, reveals a large value of the vortex-core energy, strongly suggesting that the relevant length scale controlling the BKT-like transition in this layered material involves a few coupled layers. Finally, measurements of the fluctuations of the resistance with time (i.e. noise) provide evidence for the critical slowing down of the dynamics and the onset of correlated behavior. The details of the observed dynamical critical behavior of the BKT transition and the role of disorder will be discussed.

  99. High Energy Theory

    "Heavy Mesons in Jets"

    Presented by Adam Leibovich, University of Pittsburgh

    Wednesday, February 10, 2016, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Sally Dawson

  100. Center for Functional Nanomaterials Seminar

    "In situ studies of nucleation and growth of nanoparticles under realistic conditions"

    Presented by Elena Schevchenko, Argonne National Laboratory

    Monday, February 8, 2016, 11 am
    Conference Room A, Bldg. 735

    Hosted by: Oleg Gang

    The progress in colloidal synthesis allowed reaching a high degree of controls in synthesis of nanoparticles. As a result, nanoparticles come in many different shapes, sizes and compositions. Combining multiple components within individual nanoparticles or doping of nanoparticles are simple ways to control chemical and physical properties at nanoscale to obtain efficient catalysts and advanced energy conversion and storage systems. However the successful synthetic protocols are based on empirical rules based on numerous trials and errors and often the mechanism of nucleation and growth of nanoparticles remains unclear. I will present in situ study on the nucleation and growth kinetics and the temporal changes in the crystal structure of the metal dumbbell NPs (e.g. CoPt3/Au, Pt/Au and PtFe/Au). Using synchrotron small- and wide-angle X-ray scattering (SAXS/WAXS) techniques we were able to catch the transient stages of structural and volumetric changes of NPs. We found that in the early stage of the reaction intermediate core/shell heterostructure is formed prior to dumbbells. The transition of the core/shell into the dumbbell occurs via strain relaxation of the pseudomorphic Au shell resulting in the nucleation of a strain-free Au domain. I will discuss the formation and doping process of iron and iron oxide NPs in real time by in situ synchrotron X-ray absorption spectroscopy. In our study we revealed that the mass flow of the metal triggered by oxidation is responsible for the internalization of the dopant (molybdenum) adsorbed at the surface of the host iron NPs. The new oxidation induced doping mechanism allows control over the doping levels by varying the amount of dopant precursor. Our in situ studies also showed that the dopant precursor substantially changes the reaction kinetics of formation of iron and iron oxide NPs.

  101. High Energy Theory

    "The Vector Portal: A Window to a Dark Sector"

    Presented by Eder Izaguirre, Perimeter

    Friday, February 5, 2016, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: Sally Dawson

  102. RIKEN Lunch Seminar

    "Kinetic regime of hydrodynamic fluctuations"

    Presented by Yukinao Akamatsu, Stony Brook University

    Thursday, February 4, 2016, 12:30 pm
    Building 510 Room 2-160

    Hosted by: Hiroshi Ohki

    Hydrodynamics is an effective theory of systems close to equilibrium. It has been applied to description of fireballs created in the heavy-ion collisions. With growing interests in fluctuation of observables, theoretical identification of its origin is crucial. One of such origins is thermal fluctuation required by the fluctuation-dissipation theorem. In this talk, I will present a new insight into the thermal fluctuation of hydrodynamics by separating the hard and soft scales in a given background. As an illustration, we adopt the Bjorken expansion as a background. The kinetic description of hard modes allows us simple interpretation of renormalization, long-time tails, and fractional powers of derivative expansion.

  103. Physics Colloquium

    "The New Big Science: the Changing Research Ecology at US Materials Science Facilities"

    Presented by Robert Crease, Stony Brook University and, Catherine Westfall, Michigan State University

    Tuesday, February 2, 2016, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Robert Pisarski

    "We talk about a phase shift that has taken place over the past few decades at US national labs, in which large-scale materials science accelerators rather than high-energy physics accelerators became marquee projects at most major basic research laboratories in the post-Cold War era, accompanied by important changes in the character and culture of the research ecosystem at these laboratories. We consider some features, periodization, funding, and challenges of this phase shift, known as the "New Big Science."

  104. Office of Educational Programs Event

    "2016 High School Science Bowl"

    Saturday, January 30, 2016, 8 am
    Berkner Hall Auditorium

  105. Nuclear Theory/RIKEN Seminar

    "New aspects of QCD dynamics at high density: Jet evolution in the QGP and wave turbulence""

    Presented by Yacine Mehtar-Tani, INT Seattle

    Friday, January 29, 2016, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

    An essential feature of the parton shower that form a jet evolving in vacuum is color coherence that suppresses large angle soft gluon radiation and thus, ensuing the collimation of the jet. In the presence of dense QCD matter jet constituents suffer a rapid color randomization and thus an alteration of color coherence: as a result a medium-induced gluon cascade, that can be described by a classical Makovian process, develop at large angles with respect to the jet axis [3]. A remarkable phenomenon emerges from such a cascade: the energy spectrum (of jet constituents) exhibits a scaling behavior, akin to wave turbulence, characterized by a constant flow of energy from the forward energetic patrons towards low momentum gluons down to the temperature of the plasma where energy is dissipated [4]. This picture is in agreement with a recent CMS analysis of missing energy in asymmetric dijet events where the energy balance is recovered at large angles and very soft particles [5]. In the second part of the talk I will discuss radiative corrections to jet observables that were shown to exhibit large double logarithmic enhancements. Owing to a large separation of time scales we have shown that these large corrections can be reabsorbed in a renormalization of the jet-quenching parameter q^, preserving the probabilistic picture of the parton cascade [6]. This result leads us to question the standard viewpoints of the coupling of jets to the medium: the naive perturbative approach based on a leading order calculation and the AdS/CFT correspondence for strongly coupled plasmas. I will briefly invoke in the final part of my talk the various questions that remain to be addressed. Indeed, despite the recent progress much remains to be understood about jet fragmentation in a dense medium in order to construct a systematic and predictive approach to jet-quenching from first principles.

  106. Physics Colloquium

    "Whole-brain neuronal connectivity mapping in the Mouse"

    Presented by Partha Mitra, Cold Spring Harbor Laboratory

    Tuesday, January 26, 2016, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Robert Pisarski

  107. Nuclear Physics Seminar

    "A Nuclear Physicist's Journey In Business: Lessons From the Front Office"

    Presented by Daniel Magestro, Ph.D., International Institute for Analytics

    Monday, January 25, 2016, 11 am
    Large Seminar Room, Bldg. 510

    Hosted by: Oleg Eyser

    Companies in every industry are continually increasing their usage of large data sets and advanced statistical methods to understand customers and markets, improve operations, and forecast future business needs. The corresponding business demand for skilled analytical talent and "data scientists" has created a large talent gap for many companies that is predicted to surpass 100,000 nationally. Much of the talent gap arises from the hybrid skill set needed by data scientists that combines problem solving, technical, and communication skills. I will argue that the uniquely broad skill set of research scientists, and particularly experimental physicists in large collaborations, can bridge the growing talent gap for truly innovative companies.

  108. Particle Physics Seminar

    "Cross correlations with CMB secondaries: constraining cosmological parameters and cluster astrophysics"

    Presented by Nick Battaglia, Princeton University

    Thursday, January 21, 2016, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Anze Slosar

    High resolution CMB experiments, such as ACT, SPT, and the Planck satellite are making precision measurements of the secondary anisotropies caused by the thermal Sunyaev Zel'dovich (tSZ) effect from galaxy clusters. However, our ability to obtain cosmological information from this tSZ signal is limited by our theoretical understanding of the baryons in clusters and groups. I will discuss how cross-correlation methods are providing new windows into the messy "Gastrophysics" of the intracluster medium and the potential for these methods to constrain various cosmological parameters.

  109. Brookhaven Lecture

    "511th Brookhaven Lecture: 'Following Fission Fragments: Nuclear Data for New Neutrino Physics'"

    Libby McCutchan, Nuclear Science & Technology Department at Brookhaven Lab

    Wednesday, January 20, 2016, 4 pm
    Berkner Hall Auditorium

    Hosted by: Thomas Watson

  110. Physics Colloquium

    "A bottom-up approach to modeling the sensory cortex"

    Presented by Luca Mazzucato, Stony Brook University

    Tuesday, January 19, 2016, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Robert Pisarski

    In response to sensory stimulation, neurons can generate sequences of complex activation patterns. Yet, neurons in the sensory cortex are active even in the absence of overt sensory stimulation, producing a large amount of 'ongoing,' i.e. spontaneously generated, neural activity that is often indistinguishable from noise. Research in the last two decades suggests that ongoing neural activity may shed light on the architecture and dynamics of neural circuits. Here, I present a new framework encompassing both ongoing and stimulus-evoked neural activity, combining hidden Markov model analysis of neural recordings with biologically realistic models of cortical networks based on spiking neurons. This framework has been applied successfully to the sensory cortex and can be extended to other cortical systems. In the taste system, it has revealed new properties of single neurons and of neural populations, including a reduction of multi-stability and neural dimensionality in response to sensory stimuli, pointing to the existence of local neural clusters (yet to be experimentally confirmed). Using the analytical tools of effective mean field theory, one can explain these properties as emergent features of the network dynamics.

  111. Particle Physics Seminar

    "Search for Higgs Bosons produced in association with top quarks with the ATLAS detector"

    Presented by Professor Vivek Jain, SUNY Albany

    Thursday, January 14, 2016, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Ketevi Assamagan

    Due to the large measured mass of the top quark, the Yukawa coupling of the top quark (yt) is much stronger than that of other quarks. The observation of the t¯tH production mode would allow for a direct measurement of this coupling, to which other Higgs production modes are only sensitive via loop effects. Since yt is expected to be close to unity, it is also argued to be the quantity that might give insight into the scale of new physics. Using various Higgs decay modes, we report on the status of this search using data collected with the ATLAS detector at 7 and 8 TeV collision energies.

  112. RIKEN Lunch Seminar

    "Confinement and Chiral symmetry breaking from an Interacting Instanton-dyon ensemble for 2 colors and Nf flavors"

    Presented by Rasmus Larsen, Stony Brook University

    Thursday, January 14, 2016, 12:30 pm
    Building 510 Room 2-160

    Hosted by: Daniel Pitonyak

    I will present numerical results based on an interacting ensemble of instanton-dyons, that explains the connection between chiral symmetry breaking and confinement. The instanton-dyons have the nice properties to behave as monopoles at low temperatures, and as instantons at high temperatures. We will see how the scaling behavior of the instanton-dyons creates a Polyakov loop dependent potential, which forces the Polyakov loop to the confining value as the density of dyons increases at lower temperatures. For 2 flavors we find that the dominating configuration in the ensemble exhibit a chiral symmetry transition at the same temperature as the confinement transition, within accuracy. The important factor in explaining confinement and chiral symmetry breaking is the density of the Instanton-dyons.

  113. Physics Colloquium

    "From neV to MeV: Short-Range Fermion"

    Presented by Or Hen, Laboratory for Nuclear Science, MIT

    Tuesday, January 12, 2016, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Robert Pisarski

    The atomic nucleus is composed of two different kinds of fermions, protons and neutrons. If the protons and neutrons did not interact, the Pauli exclusion principle would force the majority fermions, usually neutrons, to higher average momentum. In this talk I will present results from high-energy proton and electron scattering experiments, which show that short-range interactions between the fermions form correlated, high-momentum, neutronproton pairs. Thus, in neutron-rich nuclei the probability of finding a highmomentum (k>kFermi) proton (a minority Fermion) is greater than that of a neutron (a majority Fermion). This has wide ranging implications for atomic, nuclear, atomic, and astro physics, including neutrino-nucleus interactions, the EMC effect, the NuTeV anomaly, the nuclear symmetry energy and more. This feature is universal for imbalanced interacting Fermi systems and can also be observed experimentally in two-spin states ultra-cold atomic gas systems.

  114. Nuclear Physics Seminar

    "Short-Range Correlations in Nuclei â€" Current Status and Future Perspectives"

    Presented by Or Hen, Laboratory for Nuclear Science, MIT

    Tuesday, January 12, 2016, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: Oleg Eyser

    Results from recent experiments show that short-range interactions between the fermions form correlated, high-momentum, neutron-proton pairs. These pairs account for 20% - 25% of the nucleons in medium and heavy nuclei and dominate the momentum distribution of nucleons above the Fermi momentum of the nucleus. The observed dominance of these Short-Range Correlated (SRC) pairs by neutron-proton pairs shows the dominance of the tensor part of the nucleon-nucleon interaction at short distances. Recent works have shown that the existence and nature of SRC pairs has wide ranging implications for atomic, nuclear and astro physics, including neutrino-nucleus scattering, the EMC effect, the NuTeV anomaly, the nuclear symmetry energy. In this talk I will present the use of hard exclusive reactions for the study of SRCs, and discuss several open questions for next-generation experiment to address. I will present an experimental program based on proton, electron, and neutrino beams that can run at Dubna, GSI, JLab, Fermilab and perhaps even at BNL. I will also discuss the possibility of studying SRC pairs and their partonic structure at an EIC, using the method of spectator tagging in Quasi-elastic and Deep-Inelastic kinematics.

  115. Particle Physics Seminar

    "Reactor Antineutrino Flux and Spectrum"

    Presented by Mr. Chao Zhang, BNL

    Thursday, January 7, 2016, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Xin Qian

    Nuclear reactors are one of the most intense, pure, controllable, cost-effective, and well-understood sources of neutrinos. Reactors have played a major role in the study of neutrino oscillations, a phenomenon that indicates that neutrinos have mass and that neutrino flavors are quantum mechanical mixtures. Accurate knowledge of reactor antineutrino production was crucial for those reactor experiments to achieve their goals. With the newest measurements from Daya Bay, I will revisit our current understanding of reactor antineutrino flux and spectrum, and its implications to future experiments.

  116. Condensed-Matter Physics & Materials Science Seminar

    "Electron Transport through a Proximitized Nanowire"

    Presented by Leonid Glazman, Yale University

    Thursday, January 7, 2016, 1:30 pm
    Bldg. 734, ISB Conf. Rm. 201 (upstairs)

    Hosted by: Alexei Tsvelik

    Motivated by recent experiments on InAs nanowires with epitaxial Al we investigate the two-terminal conductance of a short proximitized nanowire. We identify the leading electron transport processes at zero applied magnetic field as well as at finite fields, which suppress the induced superconducting gap and drive the system towards the topological transition. In the conventional superconducting phase, the conductance is controlled by the sequential Cooper pair tunneling if the induced gap exceeds the charging energy of the nanowire, and by the elastic single-electron processes if the gap becomes smaller than the charging energy. The latter mechanism yields smaller values of the linear conductance and strongly asymmetric Coulomb blockade peaks, which may explain some experimental findings. Finally, we develop a quantitative theory for the conductance evolution across the transition into the topologically-nontrivial phase.

  117. Physics Colloquium

    "Search for hidden sector and invisible particles in the decay of the Higgs boson"

    Presented by Ketevi Assamagan, BNL

    Tuesday, January 5, 2016, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Peter Petreczky

    The discovery of a Higgs boson at the LHC opens new research areas for instance the search for beyond-the-Standard-Model physics in the decays of the discovered Higgs boson. In events with large missing energy associated with jets, we search for the vector boson fusion production of the Higgs boson with forward jets, and the Higgs boson decays to invisible particles that result in large missing energy in the detector. An interpretation is done for the search for dark matter as a weakly interacting massive particle (WIMP) in the Higgs boson decays. We further carry out a statistical combination with other searches of Higgs boson decays to invisible particles to improve sensitivity. The current ATLAS exclusion limit combining all these searches is the best limit so far at the LHC on the invisible decay of the Higgs boson and the Higgs portal dark matter. In data events with four leptons in the final state, consistent with the decay of the Higgs boson to four leptons, we search for light-beyond-the-Standard-Model gauge boson Zdark that decay to a pair of same flavor and opposite sign leptons (electrons or muons): H -> Z(Zdark) Zdark -> 4l. The light gauge boson Zdark is predicted in extensions to the Standard Model to explain the muon g-2 anomaly and provide a candidate for dark matter.

  118. RIKEN Lunch Seminar

    "Baryon interactions from Lattice QCD by Luscher's finite volume method and HAL QCD method"

    Presented by Takumi Iritani, Stony Brook University

    Thursday, December 17, 2015, 12:30 pm
    Building 510 Room 2-160

    Hosted by: Hiroshi Oki

    Both Luscher's finite volume method and HAL QCD method are used to analyze the hadron-hadron interaction in lattice QCD. However, some systematic discrepancies are reported between them.For example, Luscher's method shows the bound states of both deuteron and di-neutron at the heavy pion mass,while these channels are scattering states from HAL QCD method. In this talk, to understand the deviations between them, we investigate the baryon interaction from both methods with the same lattice setups.From a systematic comparison of two methods, we clarify the problems in the previous studies. We also discuss the improvement of the analyses.

  119. Physics Colloquium

    "Experimental study of chiral and matter-antimatter symmetries at RHIC"

    Presented by Aihong Tang, BNL

    Tuesday, December 15, 2015, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Peter Petreczky

    Symmetries and the physics laws that they dictate are fundamental in describing the physical world. In this talk I discuss two fundamental symmetries that are well suited to be studied at RHIC, namely, the chiral symmetry and the matter-antimatter symmetry. Under the hot and dense condition at RHIC, quarks and gluons are set free from protons and neutrons, making it feasible for the chiral symmetry to be restored. A restored chiral symmetry is a necessary requirement for the Chiral Magnetic Wave (CMW), a novel QCD phenomena, to propagate. The CMW has experimental consequences — it leads to the separation of elliptic flow between charged pions, which will be discussed in this talk. On the other hand, the abundantly produced antimatter at RHIC offers a unique opportunity to study the matter-antimatter symmetry. In particular the nuclear force between two antinucleons has not been measured previously, although the corresponding force for nucleons or nuclei has been well studied for decades. In this talk I will discuss the measurement of the nuclear force between two antiprotons and compare to that between protons. As direct information on the interaction between two antiprotons, one of the simplest systems of antinucleons, this result provides an elemental ingredient for understanding the structure of more complex antinuclear and their properties.

  120. Nuclear Physics Seminar

    "New surprises from RHIC-Spin: forward neutron transverse single spin asymmetry from p+A collisions from PHENIX"

    Presented by Alexander Bazilevsky, BNL

    Tuesday, December 15, 2015, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: Oleg Eyser

    A surprisingly large transverse single spin asymmetry (A_N) in forward neutron production was discovered during the first polarized proton RHIC run in 2002. It was immediately utilized for monitoring proton beam polarization in experimental collision regions at RHIC. Later it was shown that one pion exchange model for forward neutron production was successful to describe both cross section and A_N. RHIC new data from polarized proton on nucleus collisions from RHIC 2015 run brought new surprise - a strong dependence of the asymmetry on nucleus size (or charge). Results also were found to strongly depend on particle production in other rapidity regions, indicating that there might be multiple neutron production mechanisms generating single spin asymmetry.

  121. Condensed-Matter Physics & Materials Science Seminar

    "Soft mode branches, quantum central peak, and strong isotropic negative thermal expansion above a perovskite quantum phase transition"

    Presented by Jason Hancock, University of Connecticut

    Monday, December 14, 2015, 1:30 pm
    ISB Conf. Room 201 (upstairs), Bldg. 734

    Hosted by: Mark Dean

    The importance of perovskite-structured materials to modern science cannot be understated, as they harbor diverse behavior and landscape of novel competing and intertwined phases. The structural phases of perovskites are critical to defining the framework of electronic conduction and magnetic exchange pathways in this interesting and technologically relevant class of materials. Large, isotropic negative thermal expansion is known to exist in only a handful of materials, beginning with the discovery of ZrW2O8 in the 1990s. In 2010, perovskite fluoride ScF3 was discovered to have a similarly profound negative thermal expansion (NTE) effect, shrinking in response to heat over a 1000 K temperature window with a linear thermal expansion coefficient lower than -10-5/K. Another curious property of this material is the structural stability â€" ScF3 retains a simple cubic structure and four atom unit cell from cryogenic temperature to its high melting point of 1800 K. ScF3 material does not feature the interesting phase competition of electrons and spin enjoyed by many of its oxide and fluoride cousins and can be classified as an ionic insulator. However the superlative nature of the NTE effect has motivated us to dive deeply into the lattice dynamics using high energy resolution inelastic X-ray scattering on strain-free single crystals. Surprisingly, we find that an entire optical mode branch circumscribing the Brillouin zone boundary softens to nearly zero frequency as the temperature T approaches T=0. ScF3 at T=0 thus sits in extreme proximity to a quantum phase transition. We interpret this result in the context of better studied trifluorides and examine in detail the disorder phase diagram. In addition, concomitant with softening of the optic branch, a quasielastic "central peak" (CP) emerges and strengthens toward low temperature, further bolstering the identification of a T=0 phase transition. The CP phe

  122. Nuclear Theory/RIKEN seminar

    "Evolution of gluon TMDs: from small to moderate x"

    Presented by Andrey Tarasov, Jefferson Lab

    Friday, December 11, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

    Recently we obtained an evolution equation for gluon TMDs, which addresses a problem of unification of different kinematic limits. It describes evolution in the whole range of Bjorken x and transverse momentum k⊥. I plan to discuss this evolution equation and show how in different kinematic regimes it yields several well-known and some previously unknown results.

  123. Particle Physics Seminar

    "Kinematic weak lensing"

    Presented by Eric Huff, Ohio State University

    Thursday, December 10, 2015, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Erin Sheldon

    Kinematic measurements hold some promise of dramatically enhancing the prospects of traditional weak lensing. In this talk I outline the method and describe how it eliminates or suppresses the effects of traditional weak lensing systematic errors arising from shear calibration, photometric redshifts, and intrinsic alignments. I also discuss what it would take to scale kinematic lensing up to a level competitive with other advanced dark energy probes.

  124. Condensed-Matter Physics & Materials Science Seminar

    "TBA"

    Presented by TBA, Stony Brook

    Thursday, December 10, 2015, 2:45 pm
    2nd Fl seminar room, Bldg. 734

    Hosted by: Alexei Tsvelikl

  125. Condensed-Matter Physics & Materials Science Seminar

    "Magnetotransport in Weyl and Dirac Metals"

    Presented by Gustavo Monteiro, Stony Brook University

    Thursday, December 10, 2015, 1:30 pm
    ISB Building, Room 201

    Hosted by: Alexei Tsvelik

    Dirac (Weyl) metals are characterized by the linear dispersion of electron quasiparticles, with the Dirac (Weyl) point hidden inside a Fermi surface. In this talk, I will refer to the so-called chiral kinetic theory to describe within the same framework both the negative magnetoresistance caused by the chiral magnetic effect (CME) and quantum oscillations in the magnetoresistance (SdH effect) due to the existence of the Fermi surface in these materials. I will also argue about the role of Fermi arcs and their contribution for the SdH modes. At last, I will discuss the relevance of obtained results to recent measurements on Cd As .

  126. RIKEN Lunch Seminar

    "Phase structure of lattice QCD with Wilson and twisted-mass fermions including isospin breaking"

    Presented by Derek Horkel, University of Washington

    Thursday, December 10, 2015, 12:30 pm
    Building 510 Room 2-160

    Hosted by: Hiroshi Oki

    As the precision frontier of particle physics continues to develop, the field of lattice QCD has risen to the challenge. Modern lattice simulations, have increasingly included light non-degenerate up and down quark masses and electromagnetism. Previously answered questions about the vacuum structure of QCD on the lattice must be reexamined when these isospin breaking effects are included. If not careful, lattice practitioners may simulate in non-physical phases which cannot be extrapolated to the continuum limit. Using chiral perturbation theory, I will discuss where these non-physical phases can arise for Wilson and twisted mass fermions. I will also explain some of the complications which arise when tuning the up and down twisted quark masses to their critical values in the presence of electromagnetism.

  127. HET/RIKEN Seminar

    "Developments in Scattering Amplitudes"

    Presented by Ulrich Schubert, MPI, Munich

    Wednesday, December 9, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Sally Dawson

  128. Physics Colloquium

    "What Stubs and Sparkles Will Tell Us About Exploding Stars"

    Presented by Kate Scholberg, Duke University

    Tuesday, December 8, 2015, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Peter Petreczky

    When a massive star collapses at the end of its life, nearly all of the gravitational binding energy of the resulting remnant is released in the form of neutrinos. I will discuss the nature of the core-collapse neutrino burst and what we can learn about particle physics and about astrophysics from the detection of these neutrinos. I will cover supernova neutrino detection techniques in general, current supernova neutrino detectors, and prospects for specific future experiments.

  129. Nuclear Physics Seminar

    "Measurement of the transverse single-spin asymmetry in p+p->W±/Z0 at RHIC"

    Presented by Salvatore Fazio, BNL

    Tuesday, December 8, 2015, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: Oleg Eyser

    We present the measurement of the transverse single-spin asymmetry of weak boson production in transversely polarized proton-proton collisions at s√=500 GeV by the STAR experiment at RHIC. The measured observable is sensitive to the Sivers function, one of the transverse momentum dependent parton distribution functions, which is predicted to have the opposite sign in proton-proton collisions from that observed in deep inelastic lepton-proton scattering. These data provide the first experimental investigation of the non-universality of the Sivers function, fundamental to our understanding of QCD. The measured observable is also sensitive to the currently unconstrained Sivers function for the sea-quarks and to the evolution of the transverse-momentum dependent distribution functions.

  130. Nuclear Theory/RIKEN Seminar

    "Semi-classics, complex saddles and real path integrals"

    Presented by Tin Sulejmanpasic, North Carolina State University

    Friday, December 4, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

    I will discuss the use of semi-classics and instanton calculus and argue that, contrary to common wisdom, complex solutions of the equations of motion are a necessary ingredient of any semi-classical expansion. In particular, I will show that without the complex solutions semi-classical expansion of supersymmetric theories cannot be reconciled with supersymmetry. This has a natural interpretation in the Picard-Lefschetz theory.

  131. HET/RIKEN Lunch Seminar

    "TBA"

    Presented by Mattia Bruno and Pier Paolo Giardino, BNL

    Friday, December 4, 2015, 12 pm
    Building 510 Room 2-160

    Hosted by: Amarjit Soni

  132. RIKEN Lunch Seminar

    "Sterile neutrino dark matter produced after the QCD phase transition"

    Presented by Louis Lello, University of Pittsburgh

    Thursday, December 3, 2015, 12:30 pm
    Building 510 Room 2-160

    Hosted by: Daniel Pitonyak

    Sterile neutrinos are SU(2) singlets that mix with active neutrinos via a mass matrix, its diagonalization leads to mass eigenstates that couple via standard model vertices. We study the production of sterile neutrinos in the early universe from pion decays shortly after the QCD phase transition in the absence of a lepton asymmetry. We introduce the quantum kinetic equations that describe their production, freeze out and decay and discuss the various processes that lead to their production in a wide range of temperatures assessing their feasibility as dark matter candidates. We consider the production of heavy neutrinos in the mass range < 140MeV from pion decay shortly after the QCD crossover including finite temperature corrections to the pion form factors and mass. We consider the different decay channels that allow for the production of heavy neutrinos showing that their frozen distribution functions exhibit effects from "kinematic entanglement" and argue for their viability as mixed dark matter candidates. We discuss abundance, phase space density and stability constraints and argue that heavy neutrinos with lifetime >1/H0 freeze out of local thermal equilibrium.

  133. Physics Colloquium

    "Exotic Hadrons"

    Presented by Eric Swanson, University of Pittsburgh

    Tuesday, December 1, 2015, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Peter Petreczky

    A series of novel and unusual hadrons have been discovered since 2003. This talk will present an overview of these states with the purpose of learning what they reveal about the nonperturbative structure of Quantum Chromodynamics.

  134. Nuclear Theory/RIKEN Seminar

    "Transversity Distribution and Collins Fragmentation Functions with QCD Evolution"

    Presented by Alexei Prokudin, Jefferson Lab

    Friday, November 20, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

    We study the transverse momentum dependent (TMD) evolution of the Collins azimuthal asymmetries in e+eâˆ' annihilations and semi-inclusive hadron production in deep inelastic scattering (SIDIS) processes. All the relevant coefficients are calculated up to the next-to-leading logarithmic (NLL) order accuracy. By applying the TMD evolution at the approximate NLL order in the Collins-Soper-Sterman (CSS) formalism, we extract transversity distributions for u and d quarks and Collins fragmentation functions from current experimental data by a global analysis of the Collins asymmetries in back-to-back di-hadron productions in e+eâˆ' annihilations measured by BELLE and BABAR Collaborations and SIDIS data from HERMES, COMPASS, and JLab HALL A experiments. The impact of the evolution effects and the relevant theoretical uncertainties are discussed. We further discuss the TMD interpretation for our results, and illustrate the unpolarized quark distribution, transversity distribution, unpolarized quark fragmentation and Collins fragmentation functions depending on the transverse momentum and the hard momentum scale. We make detailed predictions for future experiments and discuss their impact.

  135. HET/RIKEN Lunch Seminar

    "Collider Phenomenology of the Right Handed Heavy Neutrinos"

    Presented by Arindam Das, University of Alabama

    Friday, November 20, 2015, 12 pm
    Building 510 Room-2-160

    Hosted by: Amarjit Soni

    We study the collider signature of pseudo-Dirac heavy neutrinos in the inverse seesaw scenario, where the heavy neutrinos with mass at the electro-weak scale can have sizable mixings with the Standard Model neutrinos, while providing the tiny light neutrino masses by the inverse seesaw mechanism. Based on a simple, concrete model realizing the inverse seesaw scenario, we fix the model parameters so as to reproduce the neutrino oscillation data and to satisfy other experimental constraints, assuming two typical flavor structures of the model and the different types of hierarchical light neutrino mass spectra. For completeness, we also consider a general parametrization for the model parameters by introducing an arbitrary orthogonal matrix and the nonzero Dirac and Majorana phases. We perform a parameter scan to identify an allowed parameter region which satisfies all experimental constraints. With the fixed parameters, we analyze the heavy neutrino signal at the LHC through trilepton final states with large missing energy and at the ILC through a single lepton plus dijet with large missing energy.

  136. Brookhaven Women In Science (BWIS) Event

    "Thousand Shades of Grey: From High School Intern to Medical Imaging Physics Graduate"

    Megan Russ, University of Buffalo Toshiba Stroke and Vascular Research Center

    Thursday, November 19, 2015, 4:30 pm
    Large Seminar Room, Bldg. 510

    Refreshments served before the talk.

  137. RIKEN Lunch Seminar

    "Viscous Velocity Gradient Correction to Thermal Photon Emission Rate at Strong Coupling"

    Presented by Kiminad Mamo, University of Illinois at Chicago

    Thursday, November 19, 2015, 12:30 pm
    Building 510 Room 2-160

    Hosted by: Daniel Pitonyak

    We compute the correction to the thermal photon emission rate in first order of shear components of fluid velocity gradients in near-equilibrium hydrodynamic plasma at strong coupling regime using the real-time Schwinger-Keldysh formalism in AdS/CFT correspondence. We find that the gradient correction to the thermal photon emission rate at strong coupling is about 0.3 - 0.4 times of the equilibrium rate.

  138. Physics Colloquium

    "IceCube: the High-energy Universe and Multimessenger Astrophysics with Neutrinos"

    Presented by Imre Bartos, Columbia University

    Tuesday, November 17, 2015, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Peter Petreczky

    Astrophysical processes that produce the observed energetic cosmic particles (up to 10^20 eV) and high-energy gamma radiation involve extreme non-thermal acceleration, strongly constraining the list of possible sources. Nevertheless, the origin of the most energetic cosmic rays, and the electromagnetic emission mechanism in extreme sources such as gamma-ray bursts, are currently unknown. Neutrinos may well be the silver bullet to unravel these processes. They can reveal the hadronic nature of the emission, and due to their weak interaction they lead right back to the source. The IceCube neutrino observatory at the South Pole has recently discovered a cosmic flux of TeV-PeV neutrinos, making the first step in lifting the curtain on cosmic particle accelerators. I will discuss recent multimessenger observational developments, and source candidates in the high-energy universe. I will describe plans and capabilities for the next-generation neutrino detector IceCube-Gen2.

  139. Nuclear Physics Seminar

    "PHENIX measurements of single electrons from semi-leptonic charm and bottom hadron decays in Au+Au collisions"

    Presented by Dr. Darren McGlinchey, University of Colorado, Boulder

    Tuesday, November 17, 2015, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: Jin Huang

    Measurements of the modification of heavy quarks in heavy ion collisions provide constraints on energy loss in the Quark Gluon Plasma. The dead cone effect predicts a mass ordering to the modification, with the heavier bottom quark being less modified than the charm quark due to suppression of forward radiation. Therefore, measuring the modification of charm and bottom quarks separately can provide additional constraints on energy loss calculations. Previous PHENIX measurements of heavy flavor electrons indicated a substantial suppression relative to binary scaled p+p collisions at high transverse momentum. However, the inability to separate the contributions from charm and bottom hadron decays prevented a full understanding of the modification. Using the precise tracking capabilities provided by the PHENIX barrel Silicon Vertex Detector (VTX), we are now able to separate the contributions from charm and bottom hadrons to the measured heavy flavor electrons as a function of transverse momentum in Au+Au collisions at sqrt(s_NN)=200 GeV. These results will be discussed and compared with theoretical models.

  140. Nuclear Theory/RIKEN Seminar

    "Linearly resummed hydrodynamics from gravity"

    Presented by Yanyan Bu, Ben Gurion University of the Negev

    Friday, November 13, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

    Using fluid/gravity correspondence, we study all-order resummed hydrodynamics in a weakly curved spacetime. The underlying microscopic theory is a finite temperature \mathcal{N}=4 super-Yang-Mills theory at strong coupling. To linear order in the amplitude of hydrodynamic variables and metric perturbations, the fluid's stress-energy tensor is computed with derivatives of both the fluid velocity and background metric resummed to all orders. In addition to two viscosity functions, we find four curvature induced structures coupled to the fluid via new transport coefficient functions, which were referred to as gravitational susceptibilities of the fluid (GSF). We analytically compute these coefficients in the hydrodynamic limit, and then numerically up to large values of momenta. We extensively discuss the meaning of all order hydrodynamics by expressing it in terms of the memory function formalism, which is also suitable for practical simulations. We also consider Gauss-Bonnet correction in the dual gravity, which is equivalent to some 1/N corrections in the dual CFT. To leading order in the Gauss-Bonnet coupling, we find that the memory function is still vanishing.

  141. HET/RIKEN Lunch Seminar

    "Flavor physics with Lambda_b baryons"

    Presented by Stefan Meinel, RBRC/ARIZONA

    Friday, November 13, 2015, 12 pm
    Building 510 Room 2-95

    Hosted by: Amarjit Soni

  142. Joint RIKEN Lunch/HET Seminar

    "Gluon-fusion Higgs production: the final frontier"

    Presented by Elisabetta Furlan, ETH, Zurich

    Thursday, November 12, 2015, 12:30 pm
    Building 510 Room 2-160

    Hosted by: Tomomi Ishikawa

    The gluon-fusion Higgs production cross section has been recently computed through the next-to-next-to-next to leading order (N^3LO) in QCD. This unprecedented level of accuracy is crucial to exploit fully the LHC data in the validation of the Standard Model and in the search for potential (small) deviations due to new physics. I will give an overview of the tools that we employed to achieve this result, from the framework of heavy-quark effective theories to the analytical and mathematical machinery that we developed. I will conclude with some results and future prospects.

  143. Nuclear Theory/RIKEN Seminar

    "Massless QED in three dimensions with even number of flavors"

    Presented by Rajamani Narayanan, Florida International University

    Friday, November 6, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

    Massless QED in three (two space and one Euclidean time) with even number of flavors does not break parity. There are analytical arguments for chiral symmetry to be spontaneously broken and some numerical evidence supporting these arguments. An interesting "open" question is the possibility of a critical number of flavors below which chiral symmetry is broken. Numerical results obtained using dynamical Wilson fermions will be presented with emphasis on the behavior of the low lying eigenvalues of the Wilson Dirac operator. Finite volume analysis will be used to obtain conclusions about the absence or presence of a chiral condensate.

  144. Particle Physics Seminar

    "LAr TPC data reconstruction"

    Presented by Dorota Stefan, CERN/NCBJ Warsaw Poland

    Thursday, November 5, 2015, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Elizabeth Worcester

    In recent years, there is much interest in building massive liquid argon time projection (LAr TPC) detectors to measure among others CP violation in leptonic sector, search for nucleon decay and study a core-collapse supernova via neutrinos. Data collected by ICARUS and ArgoNuet proved that LAr TPC calorimetric and spatial resolutions are excellent. The detector technology with no doubts is much advanced, resulting with plans for the next generation of liquid argon experiments: the short baseline (SBN) and the long baseline (DUNE) are on the horizon. The LAr TPC evolved from the bubble chambers preserving the high resolution of tracking. Data analysis requires automatic event reconstruction that can understand and efficiently use the high granularity images provided by detector. The talk will cover the most recent advances in the reconstruction techniques, and also possible ways of developments since we are still on the way towards the ultimate tool for the optimal data analysis.

  145. RIKEN Lunch Seminar

    "Neural Engineering, Healing the Brain Through Electromagnetic Stimulation"

    Presented by Adam Lichtl, Delta Brain, Inc.

    Thursday, November 5, 2015, 12:30 pm
    Building 510 Room 2-160

    Hosted by: Daniel Pitonyak

  146. Condensed-Matter Physics & Materials Science Seminar

    "Pixelated detection in Differential Phase Contrast Interesting properties of pixelated STEM"

    Presented by Matus Krajnak, University of Glasgow, United Kingdom

    Thursday, November 5, 2015, 11 am
    Bldg.480 Conf. Rm

    Hosted by: Yimei Zhu

    The application of differential phase contrast (DPC) imaging to the study of polycrystalline magnetic thin films and nanostructures in scanning transmission electron microscopy (STEM) has been hampered by the strong diffraction contrast resulting from the granular structure of the materials. In my talk I will demonstrate how a pixelated detector has been used to detect the bright field disk in aberration corrected STEM. I will explain subsequent processing of the acquired data, which allows efficient enhancement of the magnetic contrast in the resulting images. Initial results from a charged coupled device (CCD) camera demonstrate the highly efficient nature of this improvement over previous methods. Further hardware development with the use of a direct radiation detector, the Medipix3, also shows the possibilities where the reduction in collection time is more than an order of magnitude compared to the CCD. This allows subpixel measurement of the beam deflection due to the magnetic induction. Whilst the detection and processing is data intensive we have demonstrated highly efficient DPC imaging whereby pixel by pixel interpretation of the induction variation is realised with great potential for nanomagnetic imaging. In my talk I will also show advantages of using pixelated DPC in imaging of magnetic skyrmion structures in single crystal FeGe helimagnet which can provide their inner structure. I will advocate for pixelated STEM and explain how advantageous it can be in standard experiments and point to some new developments which it can provide.

  147. C-AD Accelerator Physics Seminar

    "On the Development, Characterization, and Application of New Extraction Chromatographic Resins"

    Presented by Dr. Steffen Happel, TRISKEM

    Monday, November 2, 2015, 4 pm
    Bldg. 911B, Large Conf. Rm. Rm.A202

    Hosted by: Dmitri Medvedev

    «An overview will be given over a number of new extraction chromatographic resins that have been developed over the last few years. Further to characterisation data (mainly DW values of selected elements) their application in various domains will be discussed. Examples given will include decommissioning and radioactive waste monitoring (e.g. Cl-36/I-129 and Sn-126), environmental monitoring (e.g. direct extraction and separation of Pb and Sr from aqueous samples) and the production of isotopes for medical purposes (e.g. production of Cu isotopes from Ni or Zn targets, the separation of Zr from Y targets and the separation of Sn from large Cd targets)."

  148. Nuclear Theory/RIKEN Seminar

    "Observable consequences of event-by-event fluctuations of HBT radii"

    Presented by Christopher J. Plumberg, Ohio State University

    Friday, October 30, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

    One of the major lessons from the field of heavy-ion physics in the past several years has been the significance of the role played by event-by-event fluctuations in the evolution of a heavy-ion collision. Their important effects on many momentum-space observables (particle yields and spectra, anisotropic flows, etc.) have already been studied systematically, and some of the properties of their event-by-event distributions, and their consequences for the extraction of medium properties such as the specific viscosity of the quark-gluon plasma (QGP), are already known. In this talk it is pointed out that similar event-by-event fluctuations of spatiotemporal observables provide complementary constraints on our understanding of the dynamical evolution of heavy-ion collisions. The relation of Hanbury Brown-Twiss (HBT) radii extracted from ensemble-averaged correlation function measurements to the mean of their event-by-event probability distribution is clarified, and a method to experimentally determine the mean and variance of this distribution is proposed and demonstrated using an ensemble of fluctuating events generated with the viscous hydrodynamic code VISH2+1. The sensitivity of the mean and variance of the HBT radii to the specific QGP shear viscosity η/s is studied using simulations with the same code. We report sensitivity of the mean pion HBT radii and their variances to the temperature dependence of η/s near the quark-hadron transition at a level similar (10-20%) to that which was previously observed for elliptic and quadrangular flow of charged hadrons.

  149. Condensed-Matter Physics & Materials Science Seminar

    "The Internal Structure of a Vortex in a Two-Dimensional Superfluid with Long Healing Length"

    Presented by Igor Aleiner, Columbia University

    Thursday, October 29, 2015, 2 pm
    Bldg. 734, ISB Conf. Rm. 201

    Hosted by: Alexei Tsvelik

    We analyze the motion of quantum vortices in a two-dimensional bosonic superfluid within Popov's hydrodynamic description. In the long healing length limit (where a large number of particles are inside the vortex core) the superfluid dynamics is determined by saddle points of Popov's action, which, in particular, allows for weak solutions of the Gross-Pitaevskii equation. We solve the resulting equations of motion for a vortex moving with respect to the superfluid and find the reconstruction of the vortex core to be a non-analytic function of the force applied on the vortex. This response produces an anomalously large dipole moment of the vortex and, as a result, the spectrum associated with the vortex motion exhibits narrow resonances lying {\em within} the phonon part of the spectrum, contrary to traditional view. (in collaboration with O. Agam and A. Klein)

  150. Condensed-Matter Physics & Materials Science Seminar

    "MITs, magnetism, and dopants: Probing the nanoscale using advanced STEM"

    Presented by Jack Y. Zhang, University of California Santa Barbara

    Thursday, October 29, 2015, 11 am
    Bldg.480 Conf. Rm

    Hosted by: Yimei Zhu

    Perovskite oxides remain a material class with properties that are still difficult to predict. Strong electron correlations, coupling between electron, lattice, spin and orbital degrees of freedoms, combined with the versatility of the structure itself, result in a wide range of properties and unique emergent phenomena that only occur at heterointerfaces. Understanding the origin of these properties is the first step to successfully control and tailor these materials for useful application. To that end, we utilize the scanning transmission electron microscope to characterize a number of titanate and nickelate compounds, in order to develop a link between the atomic structure and electrical/magnetic properties. Using real-space and diffraction techniques, we can probe the local atomic structures of thin film interfaces and quantum wells. We also continue the development of using quantitative STEM intensities for precise and accurate determination of 3D dopant atom configurations. Using variable detector angles, we demonstrate an improvement in 3D dopant locations on a test sample.

  151. HET/RIKEN Seminar

    "N-jettiness subtraction scheme"

    Presented by Xiaohui Liu, University of Maryland

    Wednesday, October 28, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Cen Zhang

  152. Nuclear Theory/RIKEN Seminar

    "Thermal photons from a modern hydrodynamical model of heavy ion collisions"

    Presented by Jean-Francois Paquet, Stonybrook University

    Friday, October 23, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

    Early fluid-dynamical calculations of direct photon spectra and momentum anisotropy were found to be systematically smaller than measurements from the RHIC and the LHC, an observation that became known as the "direct photon puzzle". I will show that the use of a modern hydrodynamical model of heavy ion collisions and of the latest photon emission rates greatly improves agreement with both ALICE and PHENIX data, supporting the idea that thermal photons are the dominant source of direct photon momentum anisotropy in heavy ion collisions. The event-by-event hydrodynamical model used includes, for the first time, both shear and bulk viscosities, along with second order couplings between the two viscosities. Calculations using different photon emission rates will be shown, including one that takes into account the effect of confinement on photon emission. The effect of both shear and bulk viscosities on the photon rates will be shown to have a measurable effect on the photon momentum anisotropy.

  153. HET/RIKEN Lunch Seminar

    "Lattice QCD applications to inclusive tau decays and related topics"

    Presented by Taku Izubuchi, BNL

    Friday, October 23, 2015, 12 pm
    Building 510 Room 2-160

    Hosted by: Amarjit Soni

  154. Particle Physics Seminar

    "Light Sterile Neutrinos: An Experimental Overview"

    Presented by Jonathan Link, Center for Neutrino Physics, Virginia Tech

    Thursday, October 22, 2015, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Elizabeth Worcester

    Persistent, unproven hints of an eV-scale sterile neutrino have been around since the late 1990's, when the LSND signal was shown to be incompatible with the emerging 3-neutrino oscillation framework. More recent results from MiniBooNE and T2K as well as reanalyses of reactor neutrino and gallium source data continue to suggest the possibility of this new physics, but no experiment has been able to definitively demonstrate or for that matter rule out their existence. This talk will review the current state of the sterile neutrino and examine one possible experimental test using a new reactor neutrino detector technology designed to address the particular challenges of a short-baseline reactor neutrino experiment.

  155. RIKEN Lunch Seminar

    "Walking and conformal dynamics in many-flavor QCD"

    Presented by Hiroshi Ohki, RIKEN BNL Research Center

    Thursday, October 22, 2015, 12:30 pm
    Building 510 Room 2-160

    Hosted by: Tomomi Ishikawa

    We present our lattice results of SU(3) gauge theory with many flavors, in particular with Nf=8, as a model of a walking or conformal gauge theory. We study the scaling properties of various hadron spectra including the (pseudo)scalar, vector, and baryon channels. From the Nf dependence of the theory, possible signals of walking or conformal dynamics will be discussed.

  156. HET/RIKEN Seminar

    "Phenomenology of semileptonic B-meson decays with form factors from lattice QCD"

    Presented by Ran Zhou, Fermilab

    Wednesday, October 21, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Tomomi Ishikawa

    The exclusive semileptonic $B$-meson decays $B\to K(\pi)\ell^+\ell^-$, $B \to K(\pi)\nu\bar\nu$, and $B\to\pi\tau\nu$ are used to extract the CKM elements and probe new physics beyond Standard Model. The errors of the form factors used to be an important source of the uncertainties in the theoretical predictions. Recent developments in lattice-QCD provide more accurate form factors and enable us to have better theoretical predictions. In this talk, I will present the latest lattice-QCD results of the form factors in the semileptonic $B$-meson decays processes. In addition, I will compare the theoretical predictions and recent experimental results. The tension between the Standard Model and semileptonic $B$-meson decay experimental data will be discussed.

  157. Condensed-Matter Physics & Materials Science Seminar

    "Three dimensional topological semimetal Cd3As2: insights from magneto-optical spectroscopy"

    Presented by Ana Akrap, University of Geneva, Switzerland

    Wednesday, October 21, 2015, 1:30 pm
    Bldg. 480 Conf. Room

    Hosted by: Chris Homes

    Cd3As2 is a three-dimensional Dirac semimetal, with two Dirac cones around the Gamma point shifted away from each other along the (001) direction. It is known that the Dirac cones appear due to band inversion, although their exact scale is not clear at the moment. I will talk about zero-field optical conductivity, and high-field magneto-reflectivity of this material, and address some of the open questions regarding the band structure.

  158. Condensed-Matter Physics & Materials Science Seminar

    "TBA"

    Presented by Sasa Dordevic, University of Akron

    Tuesday, October 20, 2015, 1:30 pm
    Building 734, Room 201

    Hosted by: Cedomir Petrovic

    Infrared and magneto-optical studies of topological insulators Spectroscopic techniques are an important tool in studies of novel materials. I will review recent infrared and magneto-optical studies of 3D topological insulators Bi2Se3, Bi2Te3, Sb2Te3 and Bi1-xSbx. A number of issues will be discussed, such as the cyclotron resonance and its field dependence, electronic inhomogeneities, and electron-phonon coupling. We find that in Bi2Se3 charge carriers are indeed strongly coupled to an optical phonon, causing its asymmetric (Fano) lineshape. Moreover, we show that the asymmetry of the phonon can be switched from negative to positive, with the application of magnetic field. This is the so-called Fano q reversal, which to the best of our knowledge has not been observed before in topological insulators.

  159. Condensed-Matter Physics & Materials Science Seminar

    "GW+DMFT: a diagrammatically controlled ab initio theory of strong correlation in real materials"

    Presented by Sangkook Choi, Rutgers University

    Tuesday, October 20, 2015, 11 am
    Building 734, Room 201

    Hosted by: Robert Konik

    The first principles description of strongly-correlated materials is currently regarded as one of the greatest challenges in condensed matter physics. In contrast to the weakly-correlated materials, one-particle picture based on the Fermi liquid theory fails because electrons in strongly-correlated materials are neither fully localized on the atomic sites nor fully itinerant in the crystal. One of the most successful approaches to strongly-correlated materials is the dynamical mean field theory (DMFT). Its successes revived the interest in the long-sought goal of achieving a diagrammatically controlled ab initio theory by combining GW and DMFT Feynman graphs. In this talk, I'll introduce GW+DMFT approaches and present our new methodology grounded on the combination of the quasiparticle self-consistent GW approximation (QSGW) and DMFT. I will also show how QSGW+DMFT approach improves the spectral properties of open-d and -f shell systems in comparison to other theories. I will conclude with the challenges ahead and its potential roles in materials design.

  160. Nuclear Theory/RIKEN Seminar

    "Next-to-leading order JIMWLK from wave function formalism"

    Presented by Yair Mulian, Ben Gurion University of the Negev

    Friday, October 16, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

  161. Particle Physics Seminar

    "Recent Results from the BaBar Experiment"

    Presented by David Norvil Brown, University of Louisville

    Thursday, October 15, 2015, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Ketevi A. Assamagan

    The BaBar Experiment was initially designed to study CP-Violation in B-meson decays. However, due to the general-purpose and high-quality design of the detector, it has been utilized for studies of many topics beyond the weak flavor realm. I will present a selection of recent results from BaBar, including topics from B physics and beyond. The results selected include a first observation of a mode which is an interesting piece in the puzzle about baryonic B-meson decays; a measurement of time-dependent asymmetries in a B-meson decay; a measurement of Collins asymmetries in u, d, and s quark fragmentation; and a search for long-lived particles predicted in many beyond the Standard Model theories.

  162. Condensed-Matter Physics & Materials Science Seminar

    Presented by Sergey Zvyagin, High Magnetic Field Laboratory, Helmholtz Center Dresden, Germany

    Thursday, October 15, 2015, 1:30 pm
    Building 734, Room 201

    Hosted by: Cedomir Petrovic

    Spin dynamics in triangular-lattice antiferromagnets Cs2CuBr4 and Cs2CuCl4: high-field ESR studies Sergei Zvyagin Dresden High Magnetic Field Laboratory (HLD) Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany A spin-1/2 Heisenberg antiferromagnet (AF) on a triangular lattice is the paradigmatic model in quantum magnetism and in the focus of recent experimental and theoretical studies. Here, we present results of high-field electron spin resonance (ESR) studies of spin-1/2 Heisenberg AFs Cs2CuCl4 and Cs2CuBr4 with distorted triangular-lattice structures in magnetic fields up to 50 T [1]. In the magnetically saturated phase, quantum fluctuations are fully suppressed, and the spin dynamics is defined by ordinary magnons. This allows us to accurately describe the magnetic excitation spectra in both materials and, using the harmonic spin-wave theory, to determine their exchange parameters. The approach has a broader impact and can be potentially used for any quantum magnet with reduced (e.g., by the staggered Dzyaloshinskii-Moriya interaction) translational symmetry, resulting, as predicted, in emergence of a new exchange mode above Hsat. We found that a substantial zero-field energy gap, Î"~9.5 K, observed in the low-temperature excitation spectrum of Cs2CuBr4, is present below and well above TN, being a characteristics of low-dimensional spin-correlated state. The experimental data are compared with results of model spin-wave-theory calculations for spin-1/2 triangular lattice AF. This work was supported by the DFG. [1] S. A. Zvyagin, D. Kamenskyi, M. Ozerov, J. Wosnitza, M. Ikeda, T. Fujita, M. Hagiwara, A. I. Smirnov, T. A. Soldatov, A. Ya. Shapiro, J. Krzystek, R. Hu, H. Ryu, C. Petrovic, and M. E. Zhitomirsky, Phys. Rev. Lett. 112, 077206, 2014

  163. RIKEN Lunch Seminar

    "pQCD thermodynamics with massive quarks"

    Presented by Thorben Graf, Institut für Theoretische Physik, Johann Wolfgang Goethe-Universität

    Thursday, October 15, 2015, 12:30 pm
    Building 510 Room 2-160

    Hosted by: Daniel Pitonyak

    Results for several thermodynamic quantities within the next-to-leading order calculation of the thermodynamic potential in perturbative QCD at finite temperature and chemical potential including non-vanishing quark masses are presented. These results are compared to lattice data and to higher-order optimized perturbative calculations to investigate the trend brought about by mass corrections. Furthermore, the equation of state for nonvanishing isospin density was investigated within the introduced framework and the findings are also presented.

  164. Physics Colloquium

    "Random Matrices in Physics"

    Presented by Hans A. Weidenmuller, Max-Planck-Institut fur Kernphysik, Heidelberg, Germany

    Tuesday, October 13, 2015, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Robert Pisarski

    What can we say about a physical system when we know next to nothing about it? In classical physics, the principles of thermodynamics and a few system-specific parameters suffice to make predictions. In quantum physics, random matrices have similar predictive power. That approach-referred to as random-matrix theory-has found wide applications in recent years, in quantum physics and beyond. The use of random matrices in quantum chaos, in complex many-body systems, in disordered systems and in quantum chromodynamics will be presented. Furher applications in physics and mathematics will be briefly mentioned.

  165. Special Nuclear Theory Seminar

    "Inclusive Hadron Production as a Probe of Saturation Physics on the Energy Frontier"

    Presented by David Zaslavsky, Central China Normal University

    Friday, October 9, 2015, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

    With a foundation of almost two decades of theoretical research, the saturation formalism is widely considered a strong candidate to describe the behavior of small-x gluons in high-energy collisions. However, the formalism has proven difficult to test. There is a pressing need for precise numerical results from the saturation formalism to use in comparisons with collider data. Fortunately, recent progress in the cross section for inclusive hadron production in pA collisions shows that it may be just the kind of precise result the community needs. The calculation of the NLO corrections, starting in 2012, achieved impressive reductions in the theoretical and numerical uncertainties, although the result becomes negative at high p⊥. Still, precise predictions at moderate p⊥ can be made and tested, and could be strong evidence toward showing the viability of the saturation model. In this talk, I introduce the recent modifications to the dipole splitting functions that complete the NLO corrections and help offset the negativity observed in earlier results. I'll also present the latest numerical results for the full LO+NLO cross section, including the first comparison with LHC pilot run data. For forward rapidity at both RHIC and the LHC, we have found excellent agreement with the data throughout the range in which the calculation is valid.

  166. Condensed-Matter Physics & Materials Science Seminar

    "TBATopological Nodal-Line Fermions in Strong Spin-Orbit Metal PbTaSe2"

    Presented by Tay-Rong Chang, National Tsing Hua University Taiwan, Taiwan

    Thursday, October 8, 2015, 1:30 pm
    ISB Bldg. 734, Conf. Rm. 201 (upstairs)

    Hosted by: Wei Ku

    In a typical three-dimensional metal, the low-energy excitations are found on a two-dimensional closed Fermi surface in momentum space. Topological semimetals, by contrast, can support one-dimensional Fermi lines or zero-dimensional Fermi-Weyl points, at locations in momentum space, where the valence and conduction bands touch. While the degeneracy points in Weyl semimetals are robust against any perturbation that preserves translational symmetry, nodal lines require protection by additional crystalline symmetries such as mirror reflection. In this talk, I will demonstrate the prediction of topological nodal-line states in the non-centrosymmetric compound single-crystalline PbTaSe2 with strong spin-orbit coupling based on the first-principles electronic structure calculations. Remarkably, the spin-orbit nodal lines in PbTaSe2 are not only protected by the reflection symmetry but also characterized by an integer topological invariant. Our theoretical analysis illustrate the physical mechanism underlying the formation of the topological nodal-line states and associated surface states. The calculated surface states for (001) surface with Pb-termination are in good agreement with angle-resolved photoemission (ARPES) measurements [1]. [1] arXiv:1505.03069, G. Bian, T.-R. Chang, R. Sankar, et al.

  167. Particle Physics Seminar

    "Top Quark Precision Physics and the Fate of the Universe"

    Presented by Andreas Jung, Purdue University

    Thursday, October 1, 2015, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Ketevi A. Assamagan

    The talk will discuss recent measurements in the top quark sector, the heaviest known elementary particle known so far, performed at the Fermilab Tevatron Collider and at the LHC. I will highlight Tevatron results that are competitive to those at the LHC, especially regarding the top quark mass and production asymmetry. The talk will also present CMS results on the top quark mass and Yukawa coupling. I will discuss the implications for the standard model electroweak sector regarding the vacuum stability. I will conclude with an outlook towards the high luminosity phase of the LHC and the CMS silicon detector upgrades required for the high luminosity phase.

  168. Particle Physics Seminar

    "Recent Results From Daya Bay"

    Presented by Gaosong Li, Shanghai Jiao Tong University

    Monday, September 28, 2015, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Elizabeth Worcester

    The Daya Bay Reactor Neutrino Experiment is designed to measure the neutrino mixing angle 13 with unprecedented precision. The experiment utilizes multiple pairs of identical antineutrino detectors (ADs) at different baselines from three pairs of reactor cores to minimize systematic uncertainties. In 2012, Daya Bay made the first definitive measurement of a non-zero value for 13 using the first 55 days of data collected with six ADs by measuring the antineutrino rate deficit. With the final two ADs installed, Daya Bay resumed data taking in full 8-AD configuration in late 2012. More than 1 (0.15) million electron antineutrino candidates had been collected with the near (far) site detectors by the end of 2013, significantly improving the precision on 13. In addition to precision measurement of neutrino oscillation parameters, analyses exploring various other physics potential are carried out. In this talk, I will present the latest results on neutrino oscillation parameters, the search for a light sterile neutrino and the measurement of reactor neutrino flux and spectrum.

  169. Condensed-Matter Physics & Materials Science Seminar

    "Inelastic Neutron Scattering of Manganese Pnictide Compounds LaMnPO and CaMn2Sb2"

    Presented by Daniel McNally, Stony Brook University/BNL

    Monday, September 28, 2015, 11 am
    Bldg. 480

    Hosted by: Mark Dean

    I will report on two different projects that used inelastic neutron scattering measurements to determine 1. The origin of the charge gap in LaMnPO [1] 2. The origin of the magnetic frustration in CaMn2Sb2 [2] 1. I present my inelastic neutron scattering measurements over a wide range of temperatures on a powder sample of the antiferromagnetic insulator LaMnPO, that exhibits long range antiferromagnetic order below TN = 375 K. I used these measurements to determine a) the strength of the inter-site magnetic exchange interactions SJ1 = 34 meV, SJ2 = 10 meV b) the temperature Tmax = 700 K (>> TN) where 2D magnetic correlations are no longer important. I then present high temperature optical spectroscopy measurements on single crystals of LaMnPO that show a charge gap persists above TN and Tmax. These experimental results show that long range magnetic order and exchange interactions play only a limited role in the formation of the charge gap in LaMnPO. Instead, density functional theory plus dynamical mean field theory calculations show that Hund's coupling is critical for the formation of the charge gap in LaMnPO, as well as related square net Mn pnictide compounds such as BaMn2As2 [D.E. McNally et al. PRB 92 115142 (2015)]. I will show that this work supports the view that multi-orbital electronic correlations are important in the isostructural iron pnictide based superconductors. 2. I present my inelastic neutron scattering measurements on single crystals of the antiferromagnetic insulator CaMn2Sb2, that forms a corrugated honeycomb lattice of Mn spins that order below TN = 85 K, rather low for a Mn pnictide compound. I observed sharp dispersive 3D spin wave excitations up to energy transfers of 25 meV. I used a Heisenberg model to analyze the excitations and determine the first, second and c-axis exchange interactions J1, J2, Jc. I use the determined ratio J2/J1 = 0.17 to situate CaMn2Sb2 on the theoretical phase diagram of the ho

  170. ATLAS/HET Joint Lunch Seminar

    "Constraints on New Physics via Higgs Boson Couplings and Invisible Decays with the ATLAS Detector"

    Presented by Ketevi Assamagan, Brookhaven National Laboratory

    Friday, September 25, 2015, 12 pm
    Building 510 Room 2-160

    Hosted by: Amarjit Soni

    The ATLAS experiment at the LHC has measured the Higgs boson couplings and mass, and searched for invisible Higgs boson decays, using multiple production and decay channels with up to 4.7 fb$^{-1}$ of $pp$ collision data at $\sqrt{s}=7$ TeV and 20.3 fb$^{-1}$ at $\sqrt{s}=8$ TeV. In the current study, the measured production and decay rates of the observed Higgs boson in the $\gamma\gamma$, $ZZ$, $WW$, $Z\gamma$, $bb$, $\tau\tau$, and $\mu\mu$ decay channels, along with results from the associated production of a Higgs boson with a top-quark pair, are used to probe the scaling of the couplings with mass. Limits are set on parameters in extensions of the Standard Model including a composite Higgs boson, an additional electroweak singlet, and two-Higgs-doublet models. Together with the measured mass of the scalar Higgs boson in the $\gamma\gamma$ and $ZZ$ decay modes, a lower limit is set on the pseudoscalar Higgs boson mass of $m_{A}>370$ GeV in the ``hMSSM'' simplified Minimal Supersymmetric Standard Model. Results from direct searches for heavy Higgs bosons are also interpreted in the hMSSM. Direct searches for invisible Higgs boson decays in the vector-boson fusion and associated production of a Higgs boson with $W/Z$ ($Z\to ll$, $W/Z \to jj$) modes are statistically combined to set an upper limit on the Higgs boson invisible branching ratio of 0.25. The use of the measured visible decay rates in a more general coupling fit improves the upper limit to 0.23, constraining a Higgs portal model of dark matter.

  171. Condensed-Matter Physics & Materials Science Seminar

    "Single-atom Impurity Effects in Iron-based Superconductors"

    Presented by Shuheng H. Pan, Institute of Physics, Chinese Academy of Sciences

    Friday, September 25, 2015, 11 am
    ISB Bldg. 734, Conf. Rm. 201 (upstairs)

    Hosted by: Yimei Zhu

    Impurities can break Cooper-pairs into quasi-particles with energy states inside the superconducting gap. The characteristics of such in-gap states reflect accordingly the properties of the superconducting ground state. Therefore, impurity effects in superconductors have always been important subjects in the fundamental study of superconductivity. A single-atom impurity is an ideal model for both experimental and theoretical study of impurity effects on superconductivity. With high resolution STM/S technique, such proposal has been successfully realized. In this talk, I will present some of our high resolution STM/S studies of single-atom impurity effects in iron-based superconductors and discuss their implications to the microscopic mechanism of iron-based superconductivity.

  172. Particle Physics Seminar

    "Time Delay Cosmology"

    Presented by Eric Linder, Berkeley/LBNL

    Thursday, September 24, 2015, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Anze Slosar

    Thousands of strong gravitational lenses will be found by time domain surveys such as DES and LSST. Time delays between multiple images can be used to form a geometric time delay distance, a cosmological probe with some unique sensitivities and complementarities. I consider three aspects: 1) the cosmology impact, 2) the statistics challenge of accurate estimation of time delays between noisy, gappy lightcurves and recent results from LSST's blind Time Delay Challenge, and 3) optimization of limited followup resources. I will also present new theory and instrument concepts for cosmic redshift drift, a direct probe of cosmic acceleration with a Hubble time delay. Methods for both probes have interesting overlaps with exoplanet searches.

  173. Condensed-Matter Physics & Materials Science Seminar

    "A Giant Phonon Anomaly associated with Superconducting Fluctuations in the Pseudogap Phase of Cuprates"

    Presented by Yehua Liu, ETH, Switzerland

    Thursday, September 24, 2015, 1:30 pm
    Bldg 734, 2nd Fl Conference Room

    Hosted by: Robert Konik

    Recent observations of a Giant Phonon Anomaly at the onset of the pseudogap, has revealed another surprising property of this phase. The opening of the pseudogap in underdoped cuprates breaks up the Fermi surface, which in turn can cause a breakup of the superconducting d-wave order parameter into two subband amplitudes and to a low energy Leggett mode due to phase fluctuations between them. This leads to a large increase in the temperature range of superconducting fluctuations due to an overdamped Leggett mode. Almost resonant scattering of intersubband phonons to a state with a pair of Leggett modes, causes anomalously strong phonon damping. In the ordered state, the Leggett mode develops a finite energy, suppressing the anomalous phonon damping but leading to an anomaly in the phonon dispersion.

  174. HET/RIKEN Seminar

    "The Surprising Emergent Phenomena of Perturbative QCD"

    Presented by Andrew J. Larkoski, MIT

    Wednesday, September 23, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Cen Zhang

  175. Nuclear Theory/RIKEN Seminar

    "Single inclusive particle production at NLO: revised and improved"

    Presented by Alex Kovner, University of Connecticut

    Friday, September 18, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

    We discuss the recent improvement of the NLO calculation of single inclusive particle production in pA collisions within the CGC formalizm. The two points that have not been addressed previously, and are treated consistently in the current approach are the Ioffe time cutoff on the configurations that can participate in the scattering, and the careful treatment of the evolution interval.

  176. Particle Physics Seminar

    "CMB Constraints DM Annihilation/Sum of the neutrino masses from CMB observations"

    Presented by Neelima Sehgal, Stony Brook University

    Thursday, September 17, 2015, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Ketevi Assamagan

    I will present the latest constraints on the properties of annihilating dark matter and on the sum of the neutrino masses from CMB observations. I will focus on what has been learned so far from the Planck satellite and current ground-based CMB experiments. I will also discuss what we can expect in the future in terms of constraining dark matter and neutrino properties from near-future ground-based experiments, such as Advanced ACTPol, and the planned DOE CMB-S4 project.

  177. Condensed-Matter Physics & Materials Science Seminar

    "Atomic spin chain realization of a model for quantum criticality"

    Presented by Rianne van den Berg, Universiteit van Amsterdam, Netherlands

    Thursday, September 17, 2015, 1:30 pm
    Bldg 734, 2nd Fl Conference Room

    Hosted by: Robert Konik

    The ability to manipulate single atoms has opened up the door to constructing interesting and useful quantum structures from the ground up. On the one hand, nanoscale arrangements of magnetic atoms are at the heart of future quantum computing and spintronic devices; on the other hand, they can be used as fundamental building blocks for the realization of textbook many-body quantum models, illustrating key concepts such as quantum phase transitions, topological order or frustration. Step-by-step assembly promises an interesting handle on the emergence of quantum collective behavior as one goes from one, to few, to many constituents. To achieve this, one must however maintain the ability to tune and measure local properties as the system size increases. We use low-temperature scanning tunneling microscopy to construct arrays of magnetic atoms on a surface, designed to behave like spin-1/2 XXZ Heisenberg chains in a transverse field, for which a quantum phase transition from an antiferromagnetic to a paramagnetic phase is predicted in the thermodynamic limit. Site-resolved measurements on these finite size realizations reveal a number of sudden ground state changes when the field approaches the critical value, each corresponding to a new domain wall entering the chains. We observe that these state crossings become closer for longer chains, indicating the onset of critical behavior. Our results present opportunities for further studies on quantum behavior of many- body systems, as a function of their size and structural complexity.

  178. C-AD Accelerator Physics Seminar

    "Attainment of Electron Beam Suitable for Medium Energy Electron Cooling"

    Presented by Dr. Sergei Seletskiy, BNL-Photon Science

    Thursday, September 17, 2015, 11 am
    Bldg 911B, Large Conf. Rm., Rm A202

    ""The Recycler Electron Cooler (REC) at Fermilab advanced the electron cooling to the MeV-range energies. The REC performance depended critically on the quality of electron beam. In my presentation I will describe various aspects of development of the REC and the techniques used to obtain the electron beam suitable for the cooling process."

  179. Nuclear Theory/RIKEN Seminar

    "The equation of state of QCD at finite temperature and chemical potential(s)"

    Presented by Michael Strickland, Kent State University

    Friday, September 11, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

  180. Center for Functional Nanomaterials Seminar

    "Fluctuation Electron Microscopy â€" probing higher order structural correlations in disordered materials by coherent diffraction Soft Matter Enhanced Electrochemical Energy Storage and 3D Photonic Crystals"

    Presented by J. Murray Gibson, Department of Physics, Northeastern University, Boston

    Thursday, September 10, 2015, 11 am
    CFN, Building 735, 2nd floor - Seminar Conf. Rm.

    Hosted by: Eric Stach

    Center for Functional Nanomaterials J. Murray Gibson Department of Physics, Northeastern University, Boston Fluctuation Electron Microscopy â€" probing higher order structural correlations in disordered materials by coherent diffraction Soft Matter Enhanced Electrochemical Energy Storage and 3D Photonic Crystals Thursday, September 10, 2015 11:00 a.m. Seminar Room, 2nd Fl. The conventional pair-correlation function, measured directly from diffraction, is a powerful tool to measure short-range order on the scale of chemical bonds and next neighbors. With sufficiently well-defined long range order, the 2-body function clearly reveals symmetry and periodicity. Diffraction techniques have thus been incredibly successful at the short-range in teaching us about the structure of liquids and amorphous solids, and at the other scale most of what we know about the crystalline structure of matter. However the 2-body function has a potential "blind spot" for ordering at intermediate length scales, typically up to of order ten bond lengths. Studies of amorphous materials by other techniques suggest that there can be pronounced medium-range ordering on the nanoscale and that it can significantly affect physical properties. It is now recognized that higher-order correlation functions (3 and 4 body) are far more sensitive to medium-range order and that that they can be accessed experimentally from coherent diffraction experiments. One of the earliest techniques to examine this was fluctuation microscopy (FM), developed by Treacy and Gibson1 for electron microscopy (FEM) and applied early to demonstrate medium-range order and the effect of annealing in amorphous germanium2. In more recent years, with the freer access to coherent sources of electrons and x-rays, more people are using FEM and developing related techniq

  181. C-AD Accelerator Physics Seminar

    "Multipass Energy Recovery Experiment at Jefferson Lab's CEBAF"

    Presented by Dr. Todd Satogata, JLAB

    Wednesday, September 9, 2015, 4 pm
    Bldg. 911A, Snyder Seminar Room

    "The CEBAF recirculating linac accelerator has recently completed 12 GeV upgrade development, and plans to commission full energy accelerator setup this fall. With upgrade commissioning nearly complete, there is a new collaboration between BNL and Jefferson Lab that is developing a proposal for a multi-pass energy recovery experiment. This talk summarizes the current state of 12 GeV CEBAF, technical challenges for multi-pass energy recovery, and collaboration goals and technical progress for this multi-pass energy recovery experiment."

  182. Joint Nuclear Physics and Particle Physics Seminar

    "Understanding the nature of neutrinos via neutrinoless double-beta decay"

    Presented by Wenqin Xu, Los Alamos National Laboratory

    Tuesday, September 8, 2015, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: Jin Huang

    Neutrinos provide a critical portal to physics beyond the Standard Model, yet the nature of neutrinos is largely unknown, including the neutrino mass hierarcy and if neutrinos are Majorana particles. Majorana particles are fermions that are their own antiparticles. Neutrinos being Majorana particles would explicitly violate lepton number conservation, and would pave the way to understand the matter-antimatter asymmetry in the universe. Neutrinoless double-beta (0 ) decay is a hypothesized process where two neutrons decay into two protons and two electrons simultaneously without emitting neutrinos. It is possible only if neutrinos are Majorana particles, and it is the only feasible way to experimentally establish the Majorana or Dirac nature of neutrinos. The observation of 0 decay would also provide complementary information related to neutrino masses. After decades of experimental e orts, the next generation 0 decay experiments will have a signi cant discovery potential to observe 0 decay, if neutrinos are indeed Majorana particles. In this talk, we will discuss the physics of neutrinoless double beta decay and review the experiments searching for it. We will focus on the Majorana Demonstrator, a 40-kg modular Germanium detector array, which searches for 0 decay in 76Ge and aims at demonstrating a path forward to next generation 0 decay experiments.

  183. Nuclear Theory/RIKEN Seminar

    "Asymptotic freedom of gluons in the Fock space"

    Presented by Stanislaw Glazek, University of Warsaw

    Friday, September 4, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

    Asymptotic freedom of gluons is defined in terms of scale-dependent renormalized QCD Hamiltonian operators that act in the Fock space. These operators are calculable in a new way [1,2], by solving a double-commutator differential equation [3], where the derivative is with respect to a scale parameter defined within the renormalization group procedure for effective particles (RGPEP). The RGPEP equation and its solutions are invariant with respect to boosts and may serve as a tool in attempts to dynamically explain the parton and constituent models of hadrons in QCD. The third-order QCD solution of the RGPEP equation to be discussed [2], provides an explicit example of how asymptotic freedom of gluons is exhibited in the scale-dependence of Hamiltonians as operators in the Fock space. This example also prepares ground for the fourth-order calculations of effective strong interactions using the same RGPEP equation [3], to facilitate Hamiltonian studies of many strong-interaction processes, e.g., those that involve heavy quarkonia in relativistic motion. Applications to other sectors of the Standard Model than the strong interactions await development, while only preliminary results are currently available in the domain of precise calculations in QED[4]. [1] Dynamics of effective gluons, S. D. Glazek, Phys. Rev. D63, 116006, 29p (2001). [2] Asymptotic freedom in the front-form Hamiltonian for gluons, M. Gomez-Rocha, S. D. Glazek, arXiv:1505.06688 [hep-ph], to appear in Phys. Rev. D. [3] Perturbative formulae for relativistic interactions of effective particles, S. D. Glazek, Acta Phys. Pol. B43, 1843, 20p (2012). [4] Calculation of size for bound-state constituent

  184. RIKEN Lunch Seminar

    "Analytic solution of the Boltzmann equation in the early universe"

    Presented by Jorge Noronha, University of Sao Paulo

    Thursday, September 3, 2015, 12:30 pm
    Building 510 Room 2-160

    Hosted by: Daniel Pitonyak

    A general method for exactly computing the nonlinear collision term of the Boltzmann equation for a massless relativistic gas in a homogeneous and isotropic spacetime is presented. This approach is used to find an exact analytical solution of the nonlinear relativistic Boltzmann equation in a Friedmann-Robertson-Walker spacetime. This solution can be used to investigate analytically the interplay between global expansion and local thermalization in rapidly evolving systems.

  185. HET/RIKEN seminar

    "Effective Field Theory of Heavy WIMP Annihilation"

    Presented by Matthew Baumgart, Rutgers University

    Wednesday, August 26, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Chien-Yi Chen

  186. Nuclear Physics Seminar

    "Orbital angular momentum and generalized transverse momentum distribution"

    Presented by Mr. Yong Zhao, University of Maryland

    Tuesday, August 25, 2015, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: Oleg Eyser

    Recent advances in theory have shown that it is possible to directly calculate the canonical quark and gluon orbital angular momentum contributions to the proton spin in lattice QCD. When boosted to the infinite momentum frame, the quark and gluon orbital angular momentum operators defined in the gauge-invariant nucleon spin sum rule of X. S. Chen et al. are the same as those derived from generalized transverse momentum distributions. The latter reduce to the canonical orbital angular momenta in the light-cone gauge, and can be measured in high-energy scattering experiments. I will show that these orbital angular momentum operators can be defined locally, and discuss the strategies of calculating their matrix elements in lattice QCD.

  187. Special Nuclear Theory/RIKEN seminar

    "Thermodynamics and topology from lattice QCD"

    Presented by Michael Muller-Preussker, Humboldt University Berlin

    Monday, August 24, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

    Recent efforts to investigate the thermodynamics of lattice QCD with N_f=2+1+1 fermion degrees of freedom at realistic strange and charm quark masses and at various up and down quark mass values within the framework of Wilson twisted mass fermion discretization are discussed. Comparing with recently published results in the N_f=2 case we are going to present results for the pseudo-critical temperature and preliminary results on the way to the thermodynamic equation of state. Moreover, we would like to discuss various methods to determine the topological susceptibility as a function of the temperature.

  188. Center for Functional Nanomaterials Seminar

    "Caught in the Act! Live Observations of Catalysts Using High-pressure Scanning Probe Microscopy"

    Presented by Irene M. N. Groot, Leiden Institute of Physics and Leiden Institute of Chemistry, the Netherlands

    Friday, August 21, 2015, 10 am
    CFN, Bldg. 735, first fl. conference room A

    Hosted by: Anibal Boscoboinik

    Center for Functional Nanomaterials Seminar Caught in the Act! Live Observations of Catalysts Using High-pressure Scanning Probe Microscopy Irene M. N. Groot Leiden Institute of Physics and Leiden Institute of Chemistry, the Netherlands Friday, August 21, 2015 10:00 am Bldg. 735 â€" Conf. Rm. A Recently it has become clear that essential differences can exist between the behavior of catalysts under industrial conditions (high pressure and temperature) and the (ultra) high vacuum conditions of traditional laboratory experiments. Differences in structure, composition, reaction mechanism, activity, and selectivity have been observed. These observations indicated the presence of the so-called pressure gap, and made it clear that meaningful results can only be obtained at high pressures and temperatures. However, most of the techniques traditionally used to study catalysts and their reactions were designed to operate under (ultra) high vacuum conditions. To bridge the pressure gap, the last years have seen a tremendous effort in designing new instruments and adapting existing ones to be able to investigate catalysts in situ under industrially relevant conditions. This talk focuses on the development of scanning probe microscopy for operando observations of active model catalysts. In our group, we have developed set-ups that combine an ultrahigh vacuum environment for model catalyst preparation and characterization with a high-pressure flow reactor cell, integrated with either a scanning tunneling microscope or an atomic force microscope. With these set-ups we are able to perform atomic-scale investigations of well-defined model catalysts under industrial conditions. Additionally, we combine the structural information from scanning probe microscopy with time-resolved mass spectrometry measurements on the gas mixture that leaves the re

  189. Particle Physics Seminar

    "New Optical Techniques for Studying Vacuum Birefringence"

    Presented by Carol Y. Scarlett, Florida A&M University

    Thursday, August 20, 2015, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Elizabeth Worcester

    The search for Axions, a particle theorized to explain the lack of CP violation in strong physics and suspected to contribute if not explain galactic dark matter, has lead to ever-sensitive techniques to study induced vacuum birefringence. What remains an issue: many of the measurable parameters that could give evidence for this illusive particle scale with the square of the birefringent angle (proportional to the photon-axion coupling constant). This talk will look at new techniques that can generate measurables that scale linearly (first order) with an induced birefringence. This has the potential to extend significantly the range through which cavity experiments can probe the vacuum of space in performing searches for axions and other exotic particles.

  190. Computational Science Center Seminar

    "High Performance Spatial Queries and Analytics for Spatial Big Data"

    Presented by Fusheng Wang, SUNY SB

    Tuesday, August 18, 2015, 10:30 am
    John Dunn Seminar Room, Bldg. 463

    Support of high performance queries and analytics on large volumes of spatial data becomes increasingly important in many application domains, including geospatial problems and emerging scientific applications such as pathology imaging. There are two major challenges for managing and querying massive spatial data: the explosion of spatial data, and the high computational complexity of spatial queries due to its multi-dimensional nature. Our goal is to develop a general framework to support high performance spatial queries and analytics for spatial big data on MapReduce and CPU-GPU hybrid platforms. In this talk, I will present a scalable and high performance spatial data warehousing system Hadoop-GIS for running large scale spatial queries on Hadoop and Spark. Hadoop-GIS achieves scalable and efficient queries through optimized spatial partitioning, multi-level indexing, customizable spatial query engine RESQUE and implicit parallel spatial query execution. I will introduce applications of the system to support pathology imaging analytics and social media analytics.

  191. Nuclear Theory/RIKEN Seminar

    "Initial state correlations, entanglement entropy and all that"

    Presented by Michal Lublinsky, Ben Gurion University of the Negev

    Friday, August 14, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

    I will discuss high energy collisions of dilute on dense systems (pA) and review some ideas about initial-state induced correlations.

  192. Particle Physics Seminar

    "Exciting New Results From LHCb"

    Presented by Sheldon Stone, Syracuse University

    Thursday, August 13, 2015, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Elizabeth Worchester

    LHCb has presented groundbreaking new results this summer in exotic particle spectroscopy and searches for new physics.

  193. RIKEN Lunch Seminar

    "Discrimination of large quantum ensembles"

    Presented by Emilio Bagan, GIQ, Physics Dept., UAB, Spain and Hunter College of the CUNY

    Thursday, August 13, 2015, 12:30 pm
    Building 510, Room 2-160

    Hosted by: Daniel Pitonyak

    "Hypothesis testing is arguably the most common and elementary task in information processing (e.g., we constantly make decisions based on incomplete information). Its quantum version, quantum state discrimination, is likewise central in quantum information processing. The talk gives an introduction to the topic, focussing on discrimination of a large amount of identically prepared systems. In this limit, a powerful bound on the error rate can be derived. In classical statistics this is know as Chernoff bound. The quantum version of the Chernoff bound will be presented and discussed."

  194. HET/RIKEN Seminar

    "Constraining Extended Higgs Sectors at the LHC and Beyond"

    Presented by Tania Robens, Technical University of Dresden

    Wednesday, August 12, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Sally Dawson

  195. Physics Colloquium

    "Life after Physics: A look back on 20 years in Finance"

    Presented by Andreas Gocksch

    Tuesday, August 11, 2015, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Robert Pisarski

    After 10 years of research in High Energy Theory this BNL graduate ('83-'85 and '88-'93) followed the call of Wall Street. In my talk I reflect on over 20 years in the financial industry with an emphasis on highlighting possible career choices for young people that might one day be faced with searching for a "life after Physics". Along the way I also hope to leave the audience with an understanding of some basic facts about Finance and an appreciation for the utility of the physicist's toolkit in the "real world". *This talk may be of especial interest to students.

  196. Nuclear Theory/RIKEN seminar

    "Inclusive Hadron Spectra: LHC data, fragmentation, towards NNLO, and all that"

    Presented by Marco Stratmann, University of Tuebingen

    Friday, August 7, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

  197. HET/RIKEN seminar

    "Higgs coupling deviations, vacuum stability and new bosons at the TeV scale"

    Presented by Raffaele D'Agnolo, Institute for Advanced Study

    Wednesday, August 5, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Chien-Yi Chen

    Higgs coupling measurements can shed light on the nature of electroweak symmetry breaking. However it is not trivial to go beyond generic intuitions, such as the expectation that natural theories generate large deviations, and make precise statements. In this talk I will show in a model independent way that measuring deviations at the LHC implies the existence of new bosons between a few TeV and a few hundred TeV. This is true in general, including theories where new fermions produce the deviations.

  198. Nuclear Theory/RIKEN seminar

    "Generalized Landau-level representation for spin-1/2 fermions and its applications"

    Presented by Igor Shovkovy, Arizona State University

    Friday, July 31, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

    I will discuss the recently proposed generalized Landau-level representation for charged fermions in an external magnetic field. After demonstrating its key advantages over the other existing representations, I will mention several of its applications. One of them is the quantum Hall effect in graphene, where the new representation is essential for a sufficiently detailed theoretical description, in which all the dynamical parameters are running functions of the Landau-level index. The other application is the chiral asymmetry induced in dense relativistic matter in an external magnetic field. The quantitative measure of such an asymmetry is the chiral shift parameter that measures a relative shift of the longitudinal momenta (along the direction of the magnetic field) in the dispersion relations of opposite chirality fermions. Using the language of solid state physics, the corresponding ground state of dense relativistic matter could be interpreted as a Weyl metal state. Incidentally, the exact same mechanism also works in real Dirac metals.

  199. C-AD Accelerator Physics Seminar

    "Muon Accelerators: R&D Towards Future Neutrino Factory and Lepton Collider Capabilities"

    Presented by Mark Palmer, Fermilab

    Thursday, July 30, 2015, 3:30 pm
    Building 911B, Large Conference Room, Second Floor

    This talk will describe the evolution of Muon accelerator R&D. An overview of what has been accomplished under the U.S. Muon Accelerator Program (MAP), what remains to be done, and how the elements of the program are evolving will be presented.

  200. RIKEN Lunch Seminar

    "P-odd Spectral Density at Weak Coupling: Photon Emission and Second"

    Presented by Ho-Ung Yee, University of Illinois at Chicago

    Thursday, July 30, 2015, 12:30 pm
    Building 510 Room 2-160

    Hosted by: Daniel Pitonyak

    The P-odd spectral density of current correlation functions appears in several physical observables which are related to chiral anomaly, and is a sensitive probe of microscopic dynamics which is less protected by symmetry alone. We discuss two examples of their appearance: photon emission and the second order transport coefficient from chiral anomaly. We describe leading order weak coupling computations for these examples.

  201. HET/RIKEN Seminar

    "Probing Charm-Yukawa at LHC, Status and Prospects"

    Presented by Kohsaku Tobioka, Weizmann Institute/Tel Aviv University

    Wednesday, July 29, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Chien-Yi Chen

  202. Physics Colloquium

    "Exotic and conventional hadrons from lattice QCD"

    Presented by Sasa Prelovsek, University of Ljubljana, Jefferson Lab

    Tuesday, July 28, 2015, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Rob Pisarski

    Faced with the recent experimental discoveries of pentaquarks and tetraquarks, one would like to establish whether these states arise directly from the fundamental theory of strong interactions - QCD. I will present how the exotic and conventional hadrons are investigated with ab-initio lattice QCD simulations. The approach will be illustrated with recent lattice results on the charmonium-like states Zc and X(3872), conventional resonances, bound states and pentaquarks.

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