BNL Home
February 2016
Sunday Monday Tuesday Wednesday Thursday Friday Saturday

1

  1. No events scheduled

2

  1. Physics Colloquium

    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."

3

  1. No events scheduled

4

  1. RIKEN Lunch Seminar

    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.

5

  1. High Energy Theory

    11 am, Small Seminar Room, Bldg. 510

    Hosted by: Sally Dawson

6

  1. No events scheduled

7

  1. No events scheduled

8

  1. Center for Functional Nanomaterials Seminar

    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.

9

  1. No events scheduled

10

  1. High Energy Theory

    2 pm, Small Seminar Room, Bldg. 510

    Hosted by: Sally Dawson

11

  1. Condensed-Matter Physics & Materials Science Seminar

    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.

  2. High Energy Theory/Particle Physics Seminar

    3 pm, Large Seminar Room, Bldg. 510

    Hosted by: Sally Dawson

12

  1. FEB

    12

    Today

    Nuclear Theory/RIKEN Seminar

    2 pm, Small Seminar Room, Bldg. 510

    Friday, February 12, 2016, 2:00 pm

    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.

13

  1. No events scheduled

14

  1. No events scheduled

15

  1. No events scheduled

16

  1. FEB

    16

    Tuesday

    Nuclear Physics Seminar

    11 am, Small Seminar Room, Bldg. 510

    Tuesday, February 16, 2016, 11:00 am

    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.

  2. FEB

    16

    Tuesday

    Physics Colloquium

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

    Tuesday, February 16, 2016, 3:30 pm

    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

17

  1. No events scheduled

18

  1. FEB

    18

    Thursday

    Particle Physics Seminar

    3 pm, Small Seminar Room, Bldg. 510

    Thursday, February 18, 2016, 3:00 pm

    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.

19

  1. FEB

    19

    Friday

    Nuclear/Riken Theory Seminar

    11 am, Small Seminar Room, Bldg. 510

    Friday, February 19, 2016, 11:00 am

    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.

  2. FEB

    19

    Friday

    Nuclear Theory/RIKEN Seminar

    2 pm, Small Seminar Room, Bldg. 510

    Friday, February 19, 2016, 2:00 pm

    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.

20

  1. No events scheduled

21

  1. No events scheduled

22

  1. No events scheduled

23

  1. No events scheduled

24

  1. FEB

    24

    Wednesday

    Brookhaven Lecture

    4 pm, Berkner Hall Auditorium

    Wednesday, February 24, 2016, 4:00 pm

25

  1. FEB

    25

    Thursday

    RIKEN Lunch Seminar

    12:30 pm, Building 510 Room 2-160

    Thursday, February 25, 2016, 12:30 pm

    Hosted by: Hiroshi Oki

  2. FEB

    25

    Thursday

    Particle Physics Seminar

    3 pm, Small Seminar Room, Bldg. 510

    Thursday, February 25, 2016, 3:00 pm

    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.

26

  1. FEB

    26

    Friday

    Particle Physics Seminar

    10 am, Small Seminar Room, Bldg. 510

    Friday, February 26, 2016, 10:00 am

    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.

27

  1. No events scheduled

28

  1. No events scheduled

29

  1. FEB

    29

    Monday

    Particle Physics Seminar

    3 pm, Small Seminar Room, Bldg. 510

    Monday, February 29, 2016, 3:00 pm

    Hosted by: Erin Sheldon

  1. FEB

    12

    Today

    Nuclear Theory/RIKEN Seminar

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

    Presented by Daniel Pitonyak, BNL

    2 pm, Small Seminar Room, Bldg. 510

    Friday, February 12, 2016, 2:00 pm

    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.

  2. FEB

    16

    Tuesday

    Nuclear Physics Seminar

    "Precision Jet Physics to Probe Strong Dynamics"

    Presented by Dr. Daekyoung Kang, Los Alamos National Laboratory

    11 am, Small Seminar Room, Bldg. 510

    Tuesday, February 16, 2016, 11:00 am

    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.

  3. FEB

    16

    Tuesday

    Physics Colloquium

    "Physics opportunities at future circular colliders"

    Presented by LianTao Wang, University of Chicago

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

    Tuesday, February 16, 2016, 3:30 pm

    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

  4. FEB

    18

    Thursday

    Particle Physics Seminar

    "Weighing the Giants: Anchoring Cluster Cosmology"

    Presented by Adam Mantz, SLAC National Accelerator Laboratory

    3 pm, Small Seminar Room, Bldg. 510

    Thursday, February 18, 2016, 3:00 pm

    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.

  5. FEB

    19

    Friday

    Nuclear/Riken Theory Seminar

    "The Transverse Structure of the Nucleon"

    Presented by Marc Schlegel, University of Tuebingen

    11 am, Small Seminar Room, Bldg. 510

    Friday, February 19, 2016, 11:00 am

    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.

  6. FEB

    19

    Friday

    Nuclear Theory/RIKEN Seminar

    "Lattice QCD investigations of quark transverse momentum in hadrons"

    Presented by Michael Engelhardt, New Mexico State University

    2 pm, Small Seminar Room, Bldg. 510

    Friday, February 19, 2016, 2:00 pm

    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.

  7. FEB

    24

    Wednesday

    Brookhaven Lecture

    "512th Brookhaven Lecture: Swagato Mukherjee"

    Presented by Swagato Mukherjee, Physics Department at Brookhaven Lab

    4 pm, Berkner Hall Auditorium

    Wednesday, February 24, 2016, 4:00 pm

  8. FEB

    25

    Thursday

    RIKEN Lunch Seminar

    "TBA"

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

    12:30 pm, Building 510 Room 2-160

    Thursday, February 25, 2016, 12:30 pm

    Hosted by: Hiroshi Oki

  9. FEB

    25

    Thursday

    Particle Physics Seminar

    "Giant detectors in solution-mined salt caverns"

    Presented by Prof. Ben Monreal, UC Santa Barbara

    3 pm, Small Seminar Room, Bldg. 510

    Thursday, February 25, 2016, 3:00 pm

    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.

  10. FEB

    26

    Friday

    Particle Physics Seminar

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

    Presented by Prof. Ben Monreal, UC Santa Barbara

    10 am, Small Seminar Room, Bldg. 510

    Friday, February 26, 2016, 10:00 am

    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.

  11. FEB

    29

    Monday

    Particle Physics Seminar

    "TBD"

    Presented by Sergey Klimenko, University of Florida

    3 pm, Small Seminar Room, Bldg. 510

    Monday, February 29, 2016, 3:00 pm

    Hosted by: Erin Sheldon

  12. MAR

    2

    Wednesday

    HET/RIKEN Seminar

    "TBA"

    Presented by Stefan Prestel, SLAC

    2 pm, Small Seminar Room, Bldg. 510

    Wednesday, March 2, 2016, 2:00 pm

    Hosted by: Cen Zhang

  13. MAR

    3

    Thursday

    RIKEN Lunch Seminar

    "TBA"

    Presented by Niklas Mueller, University of Heidelberg

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

    Thursday, March 3, 2016, 12:30 pm

    Hosted by: Daniel Pitonyak

  14. MAR

    10

    Thursday

    Particle Physics Seminar

    "New SUSY Results from ATLAS"

    Presented by Max Swiatlowski

    3 pm, Small Seminar Room, Bldg. 510

    Thursday, March 10, 2016, 3:00 pm

    Hosted by: Michael Begel

  15. MAR

    16

    Wednesday

    HET/RIKEN Seminar

    "TBA"

    Presented by Brian Henning, Yale University

    2 pm, Small Seminar Room, Bldg. 510

    Wednesday, March 16, 2016, 2:00 pm

    Hosted by: Cen Zhang

  16. MAR

    17

    Thursday

    Particle Physics Seminar

    "TBA"

    3 pm, Small Seminar Room, Bldg. 510

    Thursday, March 17, 2016, 3:00 pm

  17. MAR

    18

    Friday

    Nuclear Theory/RIKEN Seminar

    "Duality, Dimensions and Reduction on the Lattice"

    Presented by Joel Giedt, Rensselaer Polytechnic Institute

    2 pm, Small Seminar Room, Bldg. 510

    Friday, March 18, 2016, 2:00 pm

    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.

  18. MAR

    22

    Tuesday

    Physics Colloquium

    "TBA"

    Presented by Guido Martinelli, Rome University

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

    Tuesday, March 22, 2016, 3:30 pm

    Hosted by: Robert Pisarski

  19. MAR

    24

    Thursday

    Joint RIKEN Lunch/HET Seminar

    "TBA"

    Presented by Guido Martinelli, Rome University

    12:30 pm, Building 510 Room 2-160

    Thursday, March 24, 2016, 12:30 pm

    Hosted by: Hiroshi Oki

  20. MAR

    24

    Thursday

    Particle Physics Seminar

    "Exotic BSM Higgs Decays and proposed LHC Benchmarks"

    Presented by Shufrang Su

    3 pm, Small Seminar Room, Bldg. 510

    Thursday, March 24, 2016, 3:00 pm

    Hosted by: Bill Marciano

  21. MAR

    29

    Tuesday

    Physics Colloquium

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

    Presented by Jinfeng Liao, Indiana University

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

    Tuesday, March 29, 2016, 3:30 pm

    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.

  22. MAR

    30

    Wednesday

    High Energy Theory

    "Pseudo-scalar Higgs Form Factors at 3-loops in QCD"

    Presented by Taushif Ahmed, IMSC, Chennai, India

    2 pm, Small Seminar Room, Bldg. 510

    Wednesday, March 30, 2016, 2:00 pm

    Hosted by: Sally Dawson

  23. MAR

    31

    Thursday

    RIKEN Lunch Seminar

    "TBA"

    Presented by Mark Mace, Stony Brook University

    12:30 pm, Building 510 Room 2-160

    Thursday, March 31, 2016, 12:30 pm

    Hosted by: Daniel Pitonyak

  24. MAR

    31

    Thursday

    Particle Physics Seminar

    "Milicharge: A Proposal"

    Presented by Ben Kaplan

    3 pm, Small Seminar Room, Bldg. 510

    Thursday, March 31, 2016, 3:00 pm

    Hosted by: Michael Begel

  25. APR

    5

    Tuesday

    Physics Colloquium

    "TBA"

    Presented by Xiangdong Ji, University of Maryland

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

    Tuesday, April 5, 2016, 3:30 pm

    Hosted by: Robert Pisarski

  26. APR

    7

    Thursday

    Particle Physics Seminar

    "Dark Matter Search Results from PICO-2L"

    Presented by Chanpreet Amole, Queen's University, SNOLAB

    3 pm, Small Seminar Room, Bldg. 510

    Thursday, April 7, 2016, 3:00 pm

    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.

  27. APR

    19

    Tuesday

    Physics Colloquium

    "TBA"

    Presented by Dam Thanh Son, University of Chicago

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

    Tuesday, April 19, 2016, 3:30 pm

    Hosted by: Robert Pisarski

  28. APR

    26

    Tuesday

    Physics Colloquium

    "TBA"

    Presented by Marilena Loverde, Stony Brook University

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

    Tuesday, April 26, 2016, 3:30 pm

    Hosted by: Robert Pisarski

  29. APR

    27

    Wednesday

    HET/RIKEN seminar

    "TBA"

    Presented by Sunghoon Jung, SLAC

    2 pm, Small Seminar Room, Bldg. 510

    Wednesday, April 27, 2016, 2:00 pm

    Hosted by: Cen Zhang

  30. MAY

    3

    Tuesday

    Physics Colloquium

    "TBA"

    Presented by Thomas Roser, BNL

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

    Tuesday, May 3, 2016, 3:30 pm

    Hosted by: Robert Pisarski

  31. MAY

    24

    Tuesday

    Physics Colloquium

    "TBA"

    Presented by Ralph James, BNL

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

    Tuesday, May 24, 2016, 3:30 pm

    Hosted by: Robert Pisarski

  32. JUN

    21

    Tuesday

    Physics Colloquium

    "TBA"

    Presented by Mikhail Shaposhnikov, EPFL

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

    Tuesday, June 21, 2016, 3:30 pm

    Hosted by: Robert Pisarski

  33. JUN

    28

    Tuesday

    Physics Colloquium

    "TBA"

    Presented by Larry Weinstein, Old Dominion University

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

    Tuesday, June 28, 2016, 3:30 pm

    Hosted by: Robert Pisarski

  1. 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

  2. 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.

  3. 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

  4. 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.

  5. 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

  6. 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.

  7. 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."

  8. Office of Educational Programs Event

    "2016 High School Science Bowl"

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

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  21. 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.

  22. 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.

  23. 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.

  24. 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.

  25. 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

  26. 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.

  27. 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.

  28. 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

  29. 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 .

  30. 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.

  31. 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

  32. 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.

  33. 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.

  34. 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.

  35. 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

  36. 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.

  37. 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.

  38. 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.

  39. 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.

  40. 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.

  41. 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.

  42. 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.

  43. 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.

  44. 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.

  45. 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

  46. 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.

  47. 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.

  48. 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.

  49. 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

  50. 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.

  51. 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)."

  52. 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.

  53. 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)

  54. 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.

  55. 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

  56. 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.

  57. 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

  58. 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.

  59. 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.

  60. 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.

  61. 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.

  62. 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.

  63. 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.

  64. 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

  65. 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.

  66. 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

  67. 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.

  68. 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.

  69. 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.

  70. 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.

  71. 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.

  72. 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.

  73. 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

  74. 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.

  75. 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.

  76. 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.

  77. 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.

  78. 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

  79. 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.

  80. 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.

  81. 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.

  82. 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."

  83. 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

  84. 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

  85. 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."

  86. 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.

  87. 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

  88. 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.

  89. 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

  90. 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.

  91. 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.

  92. 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

  93. 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.

  94. 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.

  95. 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.

  96. 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.

  97. 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."

  98. 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

  99. 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.

  100. 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

  101. 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.

  102. 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.

  103. 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.

  104. 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.

  105. 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

  106. 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.

  107. Nuclear Theory/RIKEN seminar

    "Resumming large radiative corrections in the high-energy evolution of the Color Glass Condensate"

    Presented by Edmond Iancu, CEA Saclay

    Friday, July 24, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Speren Schlichting

    The BK-JIMWLK equations describing the evolution of the Color Glass Condensate with increasing energy have recently been extended to next-to-leading order (NLO) accuracy. However, some of the NLO corrections turn out to be extremely large, since amplified by (double and single) `collinear' logarithms, i.e. logarithms of ratios of transverse momenta. This difficulty points towards the existence of large radiative corrections to all orders in $\alpha_s$, as generated by the transverse phase-space, which must be computed and resummed in order to restore the convergence of the perturbative expansion. In a couple of recent papers, we developed a resummation scheme in that sense, which achieves a complete resummation of the double-logarithmic corrections and a partial resummation of the single-logarithmic ones (including the running coupling effects). We have thus deduced a collinearly-improved version of the BK equation which includes the largest radiative corrections to all orders. To demonstrate the usefulness of this equation as a tool for phenomenology, for have used it for fits to the HERA data for electron-proton deep inelastic scattering at high energy. We have obtained excellent fits with a reduced number of free parameters and with initial conditions at low energy taken from perturbative QCD.

  108. Science on Screen

    "Where Physics Meets Fashion: 'Zoolander' With Ágnes Mócsy"

    Thursday, July 23, 2015, 7 pm
    Cinema Arts Centre in Huntington, New York

  109. High Energy Physics Seminar

    "New results from the hydrogen channel in Double Chooz"

    Presented by Rachel Carr, Columbia University

    Thursday, July 23, 2015, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Elizabeth Worcester

    Beginning in 2011, the Double Chooz experiment has produced increasingly precise measurements of the neutrino oscillation parameter sin22θ13. These measurements rely on the detection of reactor antineutrinos through the inverse beta decay (IBD) interaction. The most recent analysis uses IBD interactions followed by neutron capture on hydrogen, rather than the standard Gd capture channel. A new artificial neural network-based signal selection, novel background rejection techniques, and reduced detection systematics make this analysis far more sensitive than the original H-channel measurement in Double Chooz. The precision of this new sin22θ13 measurement approaches that of the Gd-channel measurement, demonstrating the possibility of performing high-sensitivity physics measurements without a Gd dopant.

  110. Condensed-Matter Physics & Materials Science Seminar

    "Discovery of Weyl fermions in condensed matter"

    Presented by Hong Ding, Inst. of Physics, Chinese Academy of Sciences, China

    Wednesday, July 22, 2015, 1:30 pm
    Bldg. 734, ISB Conf. Room 201 (upstairs)

    Hosted by: Peter D. Johnson

    In 1929, a German mathematician and physicist Hermann Weyl proposed that a massless solution of the Dirac equation represents a pair of new type of particles, the so-called Weyl fermions. However, their existence in particle physics remains elusive after more than eight decades, e.g., neutrino has been regarded as a Weyl fermion in the Standard Model until it was found to have mass. Recently, significant advances in both topological insulators and topological semimetals have provided an alternative way to realize Weyl fermions in condensed matter as an emergent phenomenon. Weyl semimetals are predicted as a class of topological materials that can be regarded as three-dimensional analogs of graphene breaking time reversal or inversion symmetry. Electrons in a Weyl semimetal behave exactly as Weyl fermions, which have many exotic properties, such as chiral anomaly, magnetic monopoles in the crystal momentum space, and open Fermi arcs on the surface. In this talk I will report our discovery of a Weyl semimetal in TaAs by observing Fermi arcs in the surface states and Weyl nodes in the bulk states using angle-resolved photoemission spectroscopy.

  111. C-AD Accelerator Physics Seminar

    ""A Holistic Approach to Accelerator Reliability Modeling""

    Presented by Miha Rescic, University of Huddersfield

    Wednesday, July 22, 2015, 1:30 pm
    Bldg 911B, Large Conf. Rm. Rm A202

    Hosted by: Steve Peggs/Kevin Brown

    "High reliability has become a crucial issue in the design and operation of accelerators due to the demands of specific applications (e.g. medical accelerators, neutron spallation sources, nuclear waste transmutation). This is particularly relevant for accelerator-driven neutron facilities and for Accelerator-Driven Systems technologies for waste transmutation. Until now, accelerator reliability analysis has mostly been performed using simplified methods either in the design phase of projects, or after the accelerator is operational. This talk discusses a holistic approach to accelerator reliability modeling using Hidden Markov Models to look for emergent behavior of the accelerator, using system-complexity agnostics datasets from the operating machine, e.g. beam current or charge."

  112. Condensed-Matter Physics & Materials Science Seminar

    "Imaging and Understanding Atomic-Scale Surface Interactions: Quantitative Investigations Using In Situ Electron Microscopy"

    Presented by Prof. Tevis Jacobs, University of Pittsburgh

    Monday, July 20, 2015, 1:30 pm
    Conference Room, Building 480

    Hosted by: Myung-Geun Han

    The atomic-scale mechanisms that govern the adhesion, mechanical deformation, and bonding of surfaces in contact are not well understood. Yet accurate description and prediction of such contact phenomena is critically important in advanced nanoscale applications, including scanning probe microscopy (e.g., nanoscale mapping of mechanical and functional properties), micro-/nano-electromechanical systems (e.g., actuators, switches), and nanomanufacturing processes (e.g., scanning probe lithography). In this talk, I will discuss contact and sliding tests on nanoscale tips of silicon and other technologically relevant materials. These tests were performed inside of a transmission electron microscope (TEM), enabling in situ interrogation of a contact interface while controlling the displacement of the bodies and measuring normal forces with sub-nanonewton resolution. Quantitative data were extracted using custom analysis routines to resolve the geometry of the contacting bodies, adhesive forces, and volumes removed due to sliding wear, all with unprecedented resolution. In the first part of the talk, TEM adhesion tests of carbon-based coatings on diamond performed using this setup will be discussed. Sub-nanonewton force resolution was paired with Angstrom-scale measurements of asperity geometry. Combined with complementary molecular dynamics simulations, these results revealed an order-of-magnitude reduction in apparent work of adhesion as tip roughness increased from atomic-scale corrugation to a root-mean-square value of 1 nm. These results demonstrate the strong effect of sub-nanoscale topography on adhesion, and highlight a key limitation of conventional approaches for measuring the work of adhesion. In the second part of the talk, in situ sliding tests of silicon tips sliding on diamond at low applied loads reveal that wear occurs by atomic attrition: gradual material removal at the atomic scale. The process can be accurately described using stress

  113. Nuclear Theory/RIKEN seminar

    "The LPM effect in energy loss and sequential bremsstrahlung"

    Presented by Peter Arnold, University of Virginia

    Friday, July 17, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

    High-energy particles passing through matter lose energy by showering via hard bremsstrahlung and pair production. At very high energy, the quantum duration of each splitting process, known as the formation time, exceeds the mean free time for collisions with the medium, leading to a significant reduction in the splitting rate, known as the Landau-Pomeranchuk-Migdal (LPM) effect. A long-standing problem in field theory has been to understand how to implement this effect in cases where the formation times of two consecutive splittings overlap. I will review why this question is interesting and discuss recent progress in the context of jet energy loss in quark-gluon plasmas.

  114. Instrumentation Division Seminar

    "Design of specific high speed converters at LPSC Grenoble"

    Presented by Daniel Dzahini, Laboratory of Subatomic Physics and Cosmology, Grenoble, France

    Wednesday, July 15, 2015, 2:30 pm
    Large Conference Room, Bldg. 535

    This presentation will describe the design of specific high speed and high resolution converters in LPSC Grenoble. ADC designs for calorimeters and different pixels detectors will be discussed in detail. Trends and constraints for future converter designs in DSM process will also be described.

  115. Condensed-Matter Physics & Materials Science Seminar

    "Revisiting Josephson junction phase dynamics and its codes"

    Presented by Francesco Tafuri, Seconda Università di Napoli & CNR-SPIN, Unità di Napoli, Italy

    Monday, July 13, 2015, 1:30 pm
    Bldg. 480 Conference Room

    Hosted by: Ivan Bozovic

    The Josephson effect is still a unique key towards a variety of frontier problems ranging from the detection of Majorana fermions to macroscopic quantum phenomena and qubit applications. Progress in material science in producing a larger variety of interfaces and in nanotechnologies applied to superconductivity, may promote a renewal on the paradigms of the phase dynamics of Josephson junctions with relevant consequences on a series of key issues. We will discuss some relevant experiments mostly realized on unconventional junctions, including hybrid devices, nano-junctions, and especially high critical temperature superconductors (HTS). Novel phenomena emerge because of the possibility of driving materials and junctions with an accurate control in unexplored regimes. We have investigated different micro-structural configurations, which offer a wide range of junction dynamical parameters. A transition from classical Josephson phase dynamics, which takes place in junctions characterized by low values of critical current density Jc, to a regime in which dissipation is driven by local heating processes, for high values of Jc. We demonstrate how non-equilibrium effects and local processes in constrained geometry are codified in the response of the junctions and can be disentangled from other effects. Escape dynamics turns as an active 'imaging' of nano-scale transport with an enormous potential and the ability of encoding subtle transport information in fluctuations. We speculate on possible intrinsic nanoscale ordering occurring in HTS systems. This transition is of relevance for all kinds of weak links including the emergent family of nano-hybrid junctions. Information on the search of quantum phase slips can be also derived. Experiments on reference systems as HTS nanowires and Josephson junctions with ferromagnetic spin-valve tunnel barriers (experiment made in collaboration with University of Cambridge) will be finally

  116. C-AD Accelerator Physics Seminar

    ""Cascaded Longitudinal Space Charge Amplifier for Short-Wavelength Radiation Generation at Fermilab's ASTA""

    Presented by Aliaksei Halavanau, Northern Illinois University

    Friday, July 10, 2015, 11 am
    Bldg 911B, Large Conf. Rm., Rm. A202

    "Longitudinal space charge (LSC) effects are generally considered as detrimental in free-electron lasers as they can seed unwanted energy modulations and emittance growth. There has however been an increasing interest in devising accelerator beam lines capable of sustaining this LSC instability as a mechanism to operate as a coherent light source. In such a cascaded longitudinal space charge amplifier (LSCA), initial noise present in the beam density is amplified via the interplay of longitudinal space charge forces and properly located dispersive sections. To date most of these studies have been carried out with a one-dimensional impedance model for the LSC. We use an available grid-less three-dimensional N-body ``Barnes-Hut'' algorithm to simulate the 3D space charge force in the beam combined with ELEGANT and explore the limitations of the 1D model often used. We investigate, via numerical simulations, the performances of a cascaded LSCA beam line at the Fermilab's Advanced Superconducting Test Accelerator (ASTA)."

  117. RIKEN Lunch Seminar

    "Short-distance matrix elements for D-meson mixing for 2+1 flavor lattice QCD"

    Presented by Chia Cheng Chang, University of Illinois at Urbana-Champaign

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

    Hosted by: Tomomi Ishikawa

  118. Nuclear Physics Seminar

    "In search of old and new anomalous chiral effects in heavy ion collisions"

    Presented by Jinfeng Liao, Indiana University

    Tuesday, June 30, 2015, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: Oleg Eyser

    The heavy ion collision provides a unique many-body environment where local domains of strongly interacting chiral medium may occur. Certain anomalous transport processes, forbidden in usual medium, become possible in such domains. These anomalous chiral effects have their microscopic origin at the fundamental quantum anomaly and manifest themselves macroscopically in hydrodynamic currents. In the first part of this talk we report our recent finding (arXiv:1504.03201) of a new gapless collective excitation, called the Chiral Vortical Wave (CVW) in a rotating quark-gluon plasma. The CVW wave equation will be derived, and we show that its solutions describe nontrivial CVW-induced charge transport. We further propose and estimate possible experimental signals. In the second part of this talk we report our state-of-the-art simulations of the long-sought-after Chiral Magnetic Effect (CME), performed in the anomalous hydrodynamic framework and taking into account identified background contributions (arXiV:1504.06906). We discuss the implications of our results for the experimental search of CME

  119. Condensed-Matter Physics & Materials Science Seminar

    "Microscopic engineering of complex oxide ground states"

    Presented by Derek Meyers, University of Arkansas

    Monday, June 29, 2015, 1:30 pm
    ISB Bldg. 734, Conf. Rm. 201 (upstairs)

    Hosted by: Mark Dean

    Transition metal oxides have come to the forefront of condensed matter research in the past several decades due to their highly diverse phase space and remarkable susceptibility to external tuning. This has lead to their prevalence in the pursuit of designer phases, i.e. room temperature superconductivity, topological phases, and etc. In this talk we explore several methods for engineering the ground state of these systems including "ordered doping", applied epitaxial strain, and superlattice heterostructuring in an effort to gain further insight into the microscopic origin of this tunability. We employ synchrotron based x-ray spectroscopy and resonant diffraction to elucidate the explicit origin of the observed anomalous behaviors. In particular, our results reveal the ability to mask the effects of spin-orbit coupling in heavier oxides and to suppress or enhance bulk phase transitions by design.

  120. Nuclear Theory/RIKEN Seminar

    "Event by Event fluctuations in pQCD + saturation + hydro model: pinning down QCD matter shear viscosity in AA collisions"

    Presented by Risto Paatelainen, University of Jyvaskyla

    Friday, June 26, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

    We introduce an event-by-event perturbative-QCD + saturation + hydro ("EKRT") framework for ultrarelativistic heavy-ion collisions, where we compute the produced fluctuating QCD-matter energy densities from next-to-leading order perturbative QCD using a saturation conjecture to control soft particle production, and describe the space-time evolution of the QCD matter with dissipative fluid dynamics, event by event. We perform a simultaneous comparison of the centrality dependence of hadronic multiplicities, transverse momentum spectra, and flow coefficients of the azimuth-angle asymmetries, against the LHC and RHIC measurements. We compare also the computed event-by-event probability distributions of relative fluctuations of elliptic flow, and event-plane angle correlations, with the experimental data from Pb+Pb collisions at the LHC. We show how such a systematic multi-energy and multi-observable analysis tests the initial state calculation and the applicability region of hydrodynamics, and in particular how it constrains the temperature dependence of the shear viscosity-to-entropy ratio of QCD matter in its different phases in a remarkably consistent manner.

  121. RIKEN Lunch Seminar

    "One-Flavor QCD and the Dirac Spectrum at $\theta=0$"

    Presented by Jacobus Verbaarschot, Stony Brook University

    Thursday, June 25, 2015, 12:30 pm
    Building 510 Room 2-160

    Hosted by: Daniel Pitonyak

    The chiral condensate of one-flavor QCD is continuous when the quark mass crosses zero. In the sector of fixed topological charge though, the chiral condensate becomes discontinuous at zero mass in the the thermodynamical limit. To reconcile these contradictory observations, we have evaluated the spectral density of the Dirac operator in the epsilon domain of one-flavor QCD. In this domain, we have obtained exact analytical expressions which show that the spectral density at $\theta = 0$ becomes a strongly oscillating function for negative quark mass with an amplitude that increases exponentially with the volume. As is the case for QCD at nonzero chemical potential, these strong oscillations invalidate the Banks-Casher formula and result in a chiral condensate that is continuous as a function of the quark mass. An additional subtlety is the effect of the topological zero modes which will be discussed as well.

  122. Nuclear Theory/RIKEN seminar

    "Jet angular broadening in Heavy-Ion collisions"

    Presented by Yacine Mehtar-Tani, University of Washington

    Friday, June 19, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

    The advent of the LHC opened up new perspectives for jet-quenching physics. For the first time, high enough energies are reached in heavy-ion experiments to produced jets in large numbers, and the unprecedented detector capabilities of ALICE, ATLAS and CMS, not only extend the kinematic range for the measurements previously performed at RHIC, but also allow to explore a variety of new jet-quenching observables. In this talk, I address the question of the angular broadening of jets in the presence of a dense QCD matter. I start by discussing the fundamental mechanisms underlying the formation of gluon cascades induced by multiple interactions of high energy jets with the quark-gluon plasma. Then, the rate equation that describes the evolution of the energy and angular distribution of the in-medium gluon shower is presented and solved. Two remarkable phenomena emerge. First and foremost the energy spectrum (of jet constituents) exhibits a scaling behavior characterized by a constant flow of energy towards low momenta akin to wave turbulence. As a result, energy is rapidly transported from the energy containing partons to low momentum gluons before it dissipates into the medium. Second, medium-induced gluon cascades develop and transport energy at parametrically large angles with respect to the jet axis. This picture is in semi-quantitive agreement with a recent CMS analysis of the missing energy in asymmetric dijet events where the energy balance is recovered at large angles and very soft particles.

  123. PubSci

    "Big Bang Physics and the Building Blocks of Matter"

    Thursday, June 18, 2015, 7 pm
    The Bahche 191 7th St, Brooklyn, NY 11215

    Invite your friends and colleagues to a lively discussion for the science-interested (or just plain curious) and chat with scientists in an informal and friendly way. No stuffy lectures â€" just a dynamic talk with a diverse audience and a lot of good cheer. Physicists who work at Brookhaven's particle collider will talk about how they explore what happened at the dawn of time from a Lab on Long Island. How did the Universe take shape? What binds matter together? How do we answer those questions?

  124. Particle Physics Seminar

    "Detection of Lensing of the CMB by Dark Matter Halos"

    Presented by Mathew S Madhavacheril, Stony Brook University

    Thursday, June 18, 2015, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Morgan May

    I will report on the first detection of lensing of the cosmic microwave background by dark matter halos. Halo lensing of the CMB provides a method for constraining cluster masses complementary to optical weak lensing, with the advantage that the source plane has a very well determined redshift and statistical properties. In this work, the lensing field was reconstructed from CMB temperature observations using the ACTPol telescope and stacked at the location of CMASS galaxies which trace dark matter halos of ~10^13 M_solar galaxy groups, providing a 3.2 sigma detection and a ~35% mass constraint. I will also briefly touch on the capabilities of future CMB experiments to use this method to constrain dark energy parameters.

  125. RIKEN Lunch Seminar

    "Self-similar evolution for inverse cascade of magnetic helicity driven by the chiral anomaly"

    Presented by Yi Yin, Brookhaven National Laboratory

    Thursday, June 18, 2015, 12:30 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Daniel Pitonyak

    We show by solving Maxwell's equations in the presence of chiral magnetic current that the chiral anomaly would induce the inverse cascade of magnetic helicity. We found at late time, the evolution of magnetic helicity spectrum is self-similar and axial charge decays as a power law in time. We visualize how a linked magnetic configuration would evolve into a knotted configuration in real space during such evolution.

  126. HET/RIKEN Lunch Seminar

    "Light Inflaton â€" hunting for it from CMB through the Dark Matter and down to the colliders"

    Presented by Fedor Bezrukov, RBRC/U Conn

    Friday, June 12, 2015, 12 pm
    Building 510 Room 2-95

    Hosted by: Amarjit Soni

  127. Particle Physics Seminar

    "Constraining the Standard Model and new physics with LHC data"

    Presented by Alessandro Tricoli, CERN

    Friday, June 12, 2015, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: Ketevi Assamagan

    The Large Hadron Collider (LHC) project at CERN Laboratory in Geneva has achieved one of its primary goals, i.e. the discovery of the Higgs boson particle, which completes the Standard Model of particle physics. However, no signatures of new physics beyond the Standard Model have been observed yet, despite thorough searches. Nature turns out to be subtle. The direct search will continue in the upcoming LHC runs, however new physics can also be pursued indirectly by looking for deviations of experimental results from predictions in measurements of Standard Model processes. The LHC has provided a large data set during its first years of operations. This has been used to perform measurements of Standard Model processes that constrain predictions in the strong and electro-weak sectors and are sensitive to new physics in a model-independent way, thanks to the high level of precision and the extent of their kinematic reach. A good understanding of these processes is of paramount importance for precision Higgs physics, as well as for searches for new physics, as they constitute irreducible backgrounds. After presenting a selection of highlights of recent Standard Model measurements from the LHC, I will discuss how the precision and phase space reach of these measurements will improve in future LHC runs, given the increase of centre-of-mass energy and integrated luminosity, emphasising some of the experimental challenges ahead.

  128. Particle Physics Seminar

    "Search for dark sector particles at Belle and Belle II"

    Presented by Igal Jaegle, University of Hawai`i at Mānoa

    Thursday, June 11, 2015, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Ketevi A. Assamagan

    The dark photon, A′,, and the dark Higgs boson, h′, are hypothetical constituents featured in a number of recently proposed Dark Sector Models. We will present a search for these particles in the so-called Higgs-strahlung channel, e+eâˆ'â†'A′h′, with h′â†'A′A′. We investigated ten exclusive final-states with A′â†'e+eâˆ', μ+μâˆ', or Ï€+Ï€âˆ', in the mass ranges 0.1 GeV/c2 <mA′<3.5 GeV/c2 and 0.2 GeV/c2 <mh′<10.5 GeV/c2. We also investigated three inclusive final-states, 2(e+eâˆ')X, 2(μ+μâˆ')X, and (e+eâˆ')(μ+μâˆ')X, where X denotes a dark photon candidate detected via missing mass, in the mass ranges 1.1 GeV/c2 <mA′<3.5 GeV/c2 and 2.2 GeV/c2 <mh′<10.5 GeV/c2. Using the entire 977fbâˆ'1 data set collected by Belle, we observed no significant signal. We will also discuss prospects for searches for light dark matter and the dark photon in the radiative decay process at Belle and Belle II.

  129. HET/RIKEN seminar

    "New physics in b—>s transitions after LHC run 1"

    Presented by Wolfgang Altmannshofer, Perimeter Institute

    Wednesday, June 10, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Chien-Yi Chen

    I will discuss interpretations of the recent updated angular analysis of the B->K*mu+mu- decay by the LHCb collaboration. A global fit to all relevant measurements probing the flavor changing neutral current b->s mu mu transition shows tensions with Standard Model expectations. Assuming hadronic uncertainties are estimated in a sufficiently conservative way, I will discuss the implications of the experimental results on new physics, both model independently as well as in the context of models with flavor changing Z' bosons.

  130. Nuclear Theory/RIKEN seminar

    "Novel mechanisms of charmonium suppression/enhancement in pA and AA collisions"

    Presented by Boris Kopeliovich, Universidad Tecnica Federico Santa Maria, Valparaiso

    Friday, June 5, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

    Charmonium production in pA collisions is known to be suppressed by shadowing and absorption. There are however nuclear effects, which enhance charmonium yield. They steeply rise with energy and seem to show up in LHC data for J/psi production in pA collisions. In the case of heavy ion collisions produced charmonia are additionally suppressed by final state interaction in the created dense medium. On the contrary to current evaluations of the melting effects caused by Debye screening, a charmonium produced with a large pT easily survives even at high temperatures. Another source of charmonium suppression, missed in previous calculations, color-exchange interactions with the medium, leads to suppression of a comparable magnitude. A quantitative comparison is performed.

  131. Condensed-Matter Physics & Materials Science Seminar

    "GGE and applications for integrable models"

    Presented by Garry Goldstein, Rutgers University

    Thursday, June 4, 2015, 4 pm
    ISB 2nd floor seminar room

    Hosted by: Robert Konik

    We consider quenches of integrable models. We derive a Yudson representation applicable to finite sized systems. Using this representation we find expressions for the time dependence of density density and related correlation functions for an arbitrary quench of the repulsive LiebLiniger gas. We use this to show that the GGE formalism is applicable to the long time limit for quenches of the Lieb-Liniger gas with sufficiently regular initial states. We then show that no similar GGE formalism applies to quenches for integrable models with bound states (such as the XXZ model or the Hubbard model). We study several specific examples of quenches, in particular quenches where the initial state is a Mott insulator or has low entropy. We find the exact quasiparticle density for such quenches and use it to study the long time limit of some correlation functions for the system. We also consider quenches of confined systems, in particular the Lieb-linger gas in a box. We show that the GGE formalism applies to the long time average of such quenches. We use this observation to compute the long time average quasiparticle density for some quenches similar to the Quantum Newton's cradle quench experiment. We also compute various correlation functions for the system in particular the probability distribution for the particle velocity.

  132. Condensed-Matter Physics & Materials Science Seminar

    "Band edge and photo induced superconductivity"

    Presented by Garry Goldstein, Rutgers

    Thursday, June 4, 2015, 1:30 pm
    2nd Fl Lecture Room ISB

    Hosted by: Robert Konik

    We discuss novel routes to obtain superconductivity in semiconductors. We consider a semiconductor with a band dispersion where there is a band edge, such as semiconductors with Rashba spin-orbit coupling or bilayer graphene with a voltage between the layers. We find robust superconductivity, both p-wave and s-wave depending on the type of band edge, for semiconductors with attractive interactions (such as those caused by phonon exchange) when we tune the chemical potential close to the band edge. We also consider photo induced superconductivity in a two band semiconductor. We use optical pumping to induce nonequilibrium populations within the bands. We find robust superconductivity for appropriate chemical potential and dispersion relations for the bands. This s-wave superconductivity can be induced by both repulsive and attractive interactions depending on the exact band dispersions. Various band geometries are discussed.

  133. RIKEN Lunch Seminar

    "Non-relativistic particles in a thermal bath"

    Presented by Antonio Vairo, Munich Technical University

    Thursday, June 4, 2015, 12:30 pm
    Building 510 Room 2-160

    Hosted by: Tomomi Ishikawa

  134. HET/RIKEN Seminar

    "Cascade Decays of a Leptophobic Boson"

    Presented by Bogdan Dobrescu, Fermilab

    Wednesday, June 3, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Chien-Yi Chen

  135. Physics Colloquium

    "Quarkonium with Effective field theories"

    Presented by Nora Brambilla, Munich Technical University

    Tuesday, June 2, 2015, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Peter Petreczky

    Quantum Chromodynamics (QCD) is the sector of the Standard Model of particle physics that describes the strong interaction, deceptively simple to formulate but notoriously difficult to solve. Heavy quarkonium is a multiscale system that probes the different energy regimes of QCD, from the high-energy region, where an expansion in the coupling constant is possible and precision studies may be done, to the low-energy region, dominated by confinement and the many manifestations of the nonperturbative strong dynamics. Properties of production and absorption of quarkonium in a medium are also crucial for the study of QCD at high density and temperature. On the theoretical side, the construction of new nonrelativistic effective field theories for quarkonium has recently revolutionized the field providing both a conceptual framework and a powerful calculational tool. On the experimental side, the diversity, quantity and accuracy of the data collected in the last few years at B and tau-charm factories and at RHIC and LHC experiments is impressive, featuring the observation of new states and new unexpected processes. I will discuss these theoretical and experimental advancements and their implications for our understanding of strong interactions.

  136. Nuclear Physics Seminar

    "Elliptic flow from anisotropic escape"

    Presented by Denes Molnar, Purdue University

    Tuesday, June 2, 2015, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: Jin Huang

    While hydrodynamics is regarded as the dominant paradigm for describing heavy-ion collisions at RHIC and LHC energies, its applicability to nuclear reactions is not very well understood. Open question remain about the mechanism of rapid thermalization, initial conditions, treatment of decoupling (conversion of the fluid to particles), finite system effects, and quantum corrections in very small systems, for example. In a recent work (arXiv:1502.05572) we showed that in the AMPT transport model elliptic flow is generated quite differently from hydrodynamics, mainly through anisotropic escape from the collision zone. I will demonstrate that this is, in fact, a general feature of kinetic theory, originating in the modest opacities <Ncoll> \sim 4-5 in AMPT calculations. Implications of the escape effect will be discussed together with connections to other hydro related problems such as proper particle distributions (arXiv:1404.8750) and anisotropic flow from quantum mechanics (arXiv:1404.4119).

  137. Particle Physics Seminar

    "LHCb Run I Results and Run II Prospects"

    Presented by Philip Ilten, Massachusetts Institute of Technology

    Thursday, May 28, 2015, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Ketevi A. Assamagan

    The LHCb detector is a forward arm spectrometer on the Large Hadron Collider, designed for the study of particles containing b or c quarks. A variety of recent results from the Run I dataset, taken from 2010 - 2013, will be presented, emphasizing the scope of the LHCb physics program. These areas include central exlusive production of quarkonia, exotic particle searches, precision electroweak cross-sections, CKM measurements, and more. Prospects for Run II measurements will be outlined.

  138. Condensed-Matter Physics & Materials Science Seminar

    "Transport properties of novel thermoelectric materials"

    Presented by Hang Chi, Department of Physics, University of Michigan

    Thursday, May 28, 2015, 11 am
    Bldg.480 Conf. Rm

    Hosted by: Qiang Li

    Thermoelectric materials can recover waste industrial heat and convert it to electricity as well as provide efficient local cooling of electronic devices. The efficiency (determined by the dimensionless figure-of-merit ZT) of such environmentally responsible and exceptionally reliable solid state energy conversion can be enhanced through (i) electronic band engineering (n-type Mg2Si-Mg2Sn solid solutions and p-type SnTe) and (ii) thermal conductivity reduction (Ge/Te double substituted CoSb3). Detailed transport and structure studies of Bi2Te3-based single crystals demonstrate that a bulk (semi-)insulating state for such a topological insulator can be achieved via group III (Tl or In) elemental doping, which opens an avenue for further investigations of transport phenomena related to surface states. Further systematic study in Bi2Te3-based molecular beam epitaxial (MBE) thin films grown on sapphire (0001) and/or BaF2 (111) substrates, reveal that the peak of phonon drag can be tuned by the choice of substrates with different Debye temperatures.

  139. Brookhaven Lecture

    "505th Brookhaven Lecture: 'Scanning the Structure of Steel From Nuclear Reactor Vessels'"

    Presented by Lynne Ecker, Nuclear Science & Technology Department

    Wednesday, May 27, 2015, 4 pm
    Berkner Hall Auditorium

    Hosted by: Thomas Watson

  140. Nuclear Physics Seminar

    "Probing Nucleon Structure Through Transversely Polarized Proton-proton Collisions at STAR"

    Presented by Jim L. Drachenberg, Valparaiso University

    Tuesday, May 26, 2015, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: Oleg Eyser

    At leading twist, a complete picture of the one-dimensional momentum structure of the nucleon requires knowledge of three types of parton distribution functions (PDFs): the unpolarized PDFs; the helicity PDFs; and the transversity PDF, related to the transverse polarization of quarks within a transversely polarized nucleon. Current global extractions of transversity are limited by the kinematic reach of existing semi-inclusive deep-inelastic scattering (SIDIS) experiments. Beyond the open questions of one-dimensional nucleon structure, myriad opportunities abound in exploring the multi-dimensional structure of the nucleon. A step toward this goal is to investigate the nature of the transverse momentum dependence (TMD) of nucleon parton densities and their relation to nucleon spin polarization. The STAR experiment at RHIC proposes to investigate these and other spin-related phenomena through the interaction of high-energy collisions between spin-polarized protons. In preliminary results from data collected in 2011 at $\sqrt{s}=500$ GeV and in 2012 at $\sqrt{s}=200$ GeV, STAR has observed the first non-zero spin asymmetries due to the effects of transversity in proton-proton collisions. Studying these effects through both jet+hadron and di-hadron production channels and across a range of collision energy yields the potential not only to extend understanding of transversity beyond the current kinematic reach but also to address longstanding theoretical questions concerning the universality and evolution of transversity and polarized fragmentation functions. From the 2011 dataset STAR has also released the first preliminary measurements sensitive to the Sivers TMD PDF in weak-boson production. Weak boson production provides an ideal tool for isolating the unconstrained sea-quark Sivers PDF and may provide sensitivity to the expected modified universality of the Sivers PDF when compared to SIDIS. These exploratory measurements pave the way for future higher precision inv

  141. RIKEN Lunch Seminar

    "Dysonian dynamics of the Ginibre ensemble"

    Presented by Piotr Warchol, Jagiellonian University

    Thursday, May 21, 2015, 12:30 pm
    Building 510 Room 2-160

    Hosted by: Tomomi Ishikawa

    I will present a study of the time evolution of Ginibre matrices whose elements undergo Brownian motion. The non-Hermitian character of the Ginibre ensemble binds the dynamics of eigenvalues to the evolution of eigenvectors in a non-trivial way, leading to a system of coupled nonlinear equations resembling those for turbulent systems. We will formulate a mathematical framework allowing simultaneous description of the flow of eigenvalues and eigenvectors, and unravel a hidden dynamics as a function of new complex variable, which in the standard description is treated as a regulator only. We shall solve the evolution equations for large matrices and demonstrate that the non-analytic behavior of the Green's functions is associated with a shock wave stemming from a Burgers-like equation describing correlations of eigenvectors. I will start by reviewing similar notions in a simpler, Hermitian setting. Joint work with Zdzislaw Burda, Jacek Grela, Maciej A. Nowak and Wojtek Tarnowski (Phys.Rev.Lett. 113 (2014) 104102).

  142. Nuclear Physics Seminar

    "Low pT photon production at confinement: The missing piece to the direct photon puzzle"

    Presented by Dr. Sarah Campbell, Columbia University

    Tuesday, May 19, 2015, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: Jin Huang

    Low pT direct photons in Au+Au collisions are produced in excess of the TAA-scaled p+p yields and with a large azimuthal anisotropy, v2. This talk considers that these low pT direct photons are produced by radially boosted quarks undergoing soft-gluon mediated quark-anti-quark interactions as the system becomes color-neutral. A Monte Carlo simulation of direct photons and Chi-squared comparisons of the published PHENIX direct photon and identified particle v2 data are used to test this description. The Monte Carlo simulation reproduces the shape of the direct photon pT excess and the resulting direct photon v2 agrees, despite being systematically low, with the published 0-20% and 20-40% Au+Au low pT direct photon v2 in both centralities. Comparisons to recent preliminary direct photon results will also be shown.

  143. Nuclear Theory/RIKEN seminar

    "Off-shell amplitudes and their applications"

    Presented by Piotr Kotko, Pennsylvania State University

    Friday, May 15, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

  144. C-AD Accelerator Physics Seminar

    "A Robinson Wiggler for Lifetime and Brilliant Improvement at the Metrology Light Source"

    Presented by Tobias Goetsch, Helmholtz-Zentrum, Germany

    Thursday, May 14, 2015, 4 pm
    Large Conf. Rm. Bldg. 911B, Rm. A202

    Hosted by: Wolfram Fischer

    "The beam lifetime in electron storage rings concerns machines running in decay mode as well as machines doing top-up. A standard procedure to increase the lifetime is via bunch lengthening as the lifetime depends on the electron density in the bunch. Bunch lengthening is typically achieved with higher harmonic (Landau) cavities. There are several advantages in using a different approach: it is possible to increase the bunch length by installing a transverse gradient (Robinson) Wiggler, which allows to transfer damping between the horizontal and the longitudinal plane. While increasing the bunch length, the horizontal emittance is being reduced yielding advantages regarding the source size depending on the magnet optics. At the Metrology Light Source, a primary source standard used by Germanys national metrology institute (Physikalisch-Technische Bundesanstalt), such a scheme is being investigated. The prospects are higher brilliance for the important beamlines together with a lifetime improvement in the order of 100 %."

  145. Particle Physics Seminar

    "Dark matter search results from the PandaX-I experiment"

    Presented by Mengjiao Xiao, Shanghai Jiao Tong University

    Thursday, May 14, 2015, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Elizabeth Worcester

    The dark matter is a leading candidate to explain gravitational effects observed in galactic rotational curves, galaxy clusters, and the large scale structure formation, etc. The nature of dark matter is one of the most fundamental problems in physics. Proposals of dark matter candidates usually involve new physics and new particles. Among the various candidates, one compelling class of particles are WIMPs (Weakly Interacting Massive Particles). WIMPs are being studied in colliders, indirect and direct detection experiments. In recent years, new techniques in WIMP direct detection using noble liquids (xenon, argon) have shown exceptional potential due to the capability of background suppression and discrimination, and scalability to large target masses. PandaX is a low threshold dual-phase xenon dark matter experiment operating at the China Jin-Ping Underground Laboratory (CJPL). The PandaX detector is staged. We released the first dark matter search data for PandaX-I on August 2014. In this talk, I will give an introduction to the PandaX-I detector, and then followed by the details of the physics analysis as well as the latest results.

  146. RIKEN Lunch Seminar

    "Geometrical scaling - a window to saturation"

    Presented by Michal Praszalowicz, Jagiellonian University

    Thursday, May 14, 2015, 12:30 pm
    Building 510 Room 2-160

    Hosted by: Daniel Pitonyak

    Geometrical is a consequence of a traveling wave solution of the non-linear QCD evolution equation, so called Balitski-Kovchegov equation. We shall demonstrate the existence of GS in various high energy reactions. Among different consequences of GS there is a linear rise of charged particle multiplicity (Nch) and mean transverse momentum (pT) with scattering energy. Furthermore, a correlation of meant pT and Nch is predicted to scale in a way that depends on the the way particles are produced from the volume excited in a hadron-hadron scattering. This is mostly visible in heavy ion collisions at different centralities.

  147. HET/RIKEN seminar

    "Colorless Top Partners and Naturalness"

    Presented by Gustavo Burdman, IAS/University of São Paulo

    Wednesday, May 13, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: CheinYi Chen

  148. Physics Colloquium

    "Where Did Half the Starlight in the Universe Go"

    Presented by Mark Devlin, University of Pennsylvania

    Tuesday, May 12, 2015, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Peter Yamin

    We believe that approximately half of all the light from stars is absorbed and reprocessed by dust. The resulting emission is grey body with a temperature near 30 Kelvin. The COBE satellite made the first measurements of the resulting Far Infrared Background (FIRB), but since that time, we have been unable to resolve the background into individual galaxies. The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) was designed to do this job. Its three bands at 250, 350, and 500 microns span the peak in emission for galaxies at z=1. I will discuss the BLAST experiment and present results from our measurements of resolved and unresolved galaxies. I will also discuss the implications for star formation in our own galaxy and how dust is changing the way we look at current and future searches for primordial gravity waves with the Cosmic Microwave Background.

  149. Nuclear Theory/RIKEN Seminar

    "Solving the NLO BK equation in coordinate space"

    Presented by Tuomas Lappi, University of Jyvaskyla

    Friday, May 8, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

    We present results from a numerical solution of the next-to-leading order (NLO) Balitsky-Kovchegov (BK) equation in coordinate space in the large Nc limit. We show that the solution is not stable for initial conditions that are close to those used in phenomenological applications of the leading order equation. We identify the problematic terms in the NLO kernel as being related to large logarithms of a small parent dipole size, and also show that rewriting the equation in terms of the "conformal dipole" does not remove the problem. Our results qualitatively agree with expectations based on the behavior of the linear BFKL equation.

  150. HET / Riken Lunch Seminar

    "Stealth Composite Dark Matter"

    Presented by Ethan Neil, RBRC/Colorado

    Friday, May 8, 2015, 12 pm
    Building 510 Room 2-95

    Hosted by: Amarjit Soni

  151. RIKEN Lunch Talk

    "NLO transverse momentum broadening and QCD evolution of qhat"

    Presented by Hongxi Xing, Los Alamos National Lab

    Thursday, May 7, 2015, 12:30 pm
    Building 510 Room 2-160

    Hosted by: Daniel Pitonyak

  152. Nuclear Theory/RIKEN Seminar

    "Applications of Soft-Collinear Effective theory to hadronic and nuclear collisions"

    Presented by Ivan Vitev, Los Alamos National Laboratory

    Friday, May 1, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

    Effective field theory (EFT) is a powerful framework based on exploiting symmetries and controlled expansions for problems with a natural separation of energy or distance scales. EFTs are particularly important in QCD and nuclear physics. An effective theory of QCD, ideally suited to jet applications, is Soft-Collinear Effective Theory (SCET). Recently, first steps were taken to extend SCET and describe jet evolution in strongly-interacting matter. In this talk I will demonstrate that the newly constructed theory, called SCETG, allows us to go beyond the traditional energy loss approximation in heavy ion collisions and unify the treatment of vacuum and medium-induced parton showers. It provides quantitative control over the uncertainties associated with the implementation of the in-medim modification of hadron production cross sections and allows us to accurately constrain the coupling between the jet and the medium. I will further show how SCET and SCETG can be implemented to evaluate reconstructed jet observables, such as jet shapes.

  153. HET/RIKEN seminar

    "Higgs as a Lamp Post of New Physics"

    Presented by JiJi Fan, Syracuse

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

    Hosted by: Chien-Yi Chen

  154. Nuclear Theory/RIKEN seminar

    "Heavy Hadrons under Extreme Conditions"

    Presented by Laura Tolos, Instituto de Ciencias del Espacio (IEEC-CSIC)

    Friday, April 24, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

    Hadrons under extreme conditions of density and temperature have captured the interest of particle and nuclear physicists as well as astrophysicists over the years in connection with an extensive variety of physical phenomena in the laboratory as well as in the interior of stellar objects, such as neutron stars. One of the physics goals is to understand the origin of hadron masses in the context of the spontaneous breaking of the chiral symmetry of Quantum Chromodynamics (QCD) at low energies in the non-perturbative regime and to analyze the change of the hadron masses due to partial restoration of this symmetry under extreme conditions. Lately other proper QCD symmetries have also become a matter of high interest, such as heavy-quark flavor and spin symmetries. These symmetries appear when the quark masses become larger than the typical confinement scale and they are crucial for characterizing hadrons with heavy degrees of freedom. In this talk I will address the properties of heavy hadrons under extreme conditions based on effective theories that incorporate the most appropriate scales and symmetries of QCD in each case. With the on-going and upcoming research facilities, the aim is to move from the light-quark to the heavy-quark sector and to face new challenges where heavy hadrons and new QCD symmetries will play a dominant role.

  155. Biological, Environmental, & Climate Sciences (BECS) Department Seminar

    "High-resolution CAM5 simulations of varying complexity"

    Presented by Kevin Reed, Stony Brook University

    Friday, April 24, 2015, 10 am
    Conference Room, Bldg 815E

    Hosted by: Ernie Lewis

    In our continued effort to understand the climate system and improve its representation in general circulation models (GCMs) it is crucial to develop new methods to evaluate these models. This is certainly true as the GCM community advances towards high horizontal resolutions (i.e., grid spacing less than 50 km), which will require interpreting and improving the performance of many model components. Idealized, or reduced complexity, frameworks can be used to investigate how model assumptions impact behavior across scales. This work makes use of a range of National Center for Atmospheric Research and Department of Energy Community Atmosphere Model version 5 (CAM5) simulations, ranging from simplified global radiative-convective equilibrium (RCE) simulations to full decadal simulations of present-day and future climate. The various CAM5 configurations provide useful insights into the model's ability to simulate extreme precipitation events and tropical cyclones. Furthermore, the impact of horizontal resolution and the choice of CAM5 dynamical core on the simulation of extreme events will be explored. Finally, time slice experiments using the Representative Concentration Pathway (RCP) 8.5 scenario for greenhouse gas concentrations are assessed and compared to present-day simulations. Overall, this work is part of a continued effort to understand how weather extremes may vary in a changing climate using next-generation high-resolution climate models.

  156. Particle Physics Seminar

    "(Real) Early Universe Cosmology with Quark Gluon Plasma"

    Presented by Niayesh Afshordi, Perimeter Institute for Theoretical Physics

    Thursday, April 23, 2015, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Morgan May

    An intriguing possibility that can address pathologies in both early universe cosmology (i.e. the horizon problem) and quantum gravity (i.e. non-renormalizability), is that particles at very high energies and/or temperatures could propagate arbitrarily fast. In this talk, I introduce Thermal Tachyacoustic Cosmology (TTC), i.e. this scenario with thermal initial conditions. We find that a phase transition in the early universe, around the scale of Grand Unified Theories (GUT scale; T∼10^{15} GeV), during which the speed of sound drops by several orders of magnitude within a Hubble time, can fit current CMB observations. However, I will then argue that cosmological bounds on the density of primordial black holes suggest that Lorentz invariance in the primordial thermal plasma may not recover until much lower temperatures, close to the QCD phase transition. This presents the exciting possibility of testing this scenario in the thermal plasma produced in relativistic heavy ion collisions.

  157. Particle Physics Seminar

    "Implications of Cosmological Observations for History of Early Universe"

    Presented by Ghazal Geshnizjani, University of Waterloo/ Perimeter Institute for Theoretical Physics

    Wednesday, April 22, 2015, 3 pm
    Building 510 Room 2-160

    Hosted by: Morgan May

    I will argue that any theory of early universe that matches cosmological observations should include a phase of accelerated expansion (i.e. inflation) or it has to break at least one of the following tenets of classical general relativity: Null Energy Conditions (NEC), sub-luminal signal propagation, or sub-Planckian energy densities. This proof extends to a large class of theories with higher (spatial) derivative or non-local terms in the action as well. Interestingly, only theories in the neighbourhood of Lifshitz points with ω ∝ k^0 and k^3 are excluded from the proof. I will also discuss in what sense detecting primordial gravitational waves is a smoking gun for inflation.

  158. Condensed-Matter Physics & Materials Science Seminar

    "Establishing an Atomistic Picture of Gas Adsorption in Metal Organic Frameworks"

    Presented by Anna Plonka, SUNY-Stony Brook, Poland

    Wednesday, April 22, 2015, 1:30 pm
    ISB Bldg. 734, Conf. Rm. 201 (upstairs)

    Hosted by: Simon Billinge/Emil Bozin

    Selective adsorption and sequestration of carbon dioxide from sources of anthropogenic emissions is important to mitigate the growing level of the atmospheric CO2. Solid state adsorbents, such as metal organic frameworks (MOFs), are proposed as an alternative to the currently used toxic and corrosive alkanolamine solutions. Experimental gas sorption studies of MOFs usually focus on gas isotherms measurements that, while providing the necessary information on the overall gas uptake and framework behavior upon gas loading, yield limited information on the mechanism of the gas adsorption. Molecular level understanding of gas adsorption in MOFs is an important problem and the most detailed structural models necessary to elucidate the adsorbate-adsorbent interaction can be obtained with the crystallographic techniques. This talk will present the recent exciting discoveries of CO2 and hydrocarbon adsorption in MOFs. In contrast to current trends in the design of MOFs, we discovered the unique mechanism responsible for a high CO2/N2 adsorption selectivity in a Ca-based MOF: Ca(sdb), (sdb: 4,4'-sulfonyldibenzoate), even in the presence of water in the gas stream. Single crystal XRD (SCXRD) experiments of gas loaded samples revealed that the v-shaped linker provides a "pi-pocket" formed by two phenyl rings, and that CO2 locate between the rings, resulting in a high heat of adsorption. To determine the gas adsorption performance in situ in the presence of water, we used differential scanning calorimetry technique (XRD-DSC) that allows for measuring enthalpy while collecting X-ray diffraction patterns, to evaluate the structural response during the gas adsorption. The XRD-DSC technique and single crystal diffraction were further used to evaluate the CO2 adsorption in a Cd-analog of Ca(sdb), hydrocarbon adsorption in two Ca-based MOFs and gate opening mechanism in a Mn-based MOF. The knowledge acquired can promote the directed synthetic search for novel

  159. Physics Colloquium

    "Neutrinos and friends in the past and present universe"

    Presented by Alex Kusenko, UCLA

    Tuesday, April 21, 2015, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Morgan May

    Neutrinos play a role in various aspects of cosmology, including production of light elements, and the rate of expansion of the universe. Furthermore, the neutrino masses imply the likely existence of right-handed neutrinos, which can exist in the form of dark matter, and which can explain the matterantimatter asymmetry of the universe. I will discuss the many faces ordinary and hypothetical neutrinos in cosmology.

  160. Center for Data-Driven Discovery C3D

    "Computing Intensive Problems in Cosmology"

    Presented by Anze Slosar

    Tuesday, April 21, 2015, 2 pm
    John Dunn Seminar Room, Bldg. 463

    Hosted by: Robert Harrison

    Cosmology is a branch of physics that studies the whole universe as a single physical system. Computing intensive methods are used throughout, both for data analysis and for theoretical modeling. The computational difficulties are in most cases due to existence of gravitational force which is important at all scales. This makes problems fundamentally different from problems in particle physics where each collision event can be considered to be statistically independent. In simulations, it is necessary to take into account the force contribution of any particle to any other and in data analysis the correlations between any two measurements. I will overview problems, solutions and current limitations. Time permitting, I will describe more technical aspects of the code we are developing to analyze data from the spectroscopic datasets.

  161. Condensed-Matter Physics & Materials Science Seminar

    "Competing Superexchange Interactions in Double Perovskite Osmates"

    Presented by Ryan Morrow, Ohio State University

    Monday, April 20, 2015, 1:30 pm
    ISB Bldg. 734, Conf. Rm. 201 (upstairs)

    Hosted by: Simon Billinge/Emil Bozin

    Double perovskites, A2BB'O6, containing mixed transition metal ions have exhibited numerous desirable properties such as colossal magnetoresistance, half metallic transport, and high temperature ferrimagnetism. However, a predictive understanding of the superexchange mechanisms which control the magnetism of these materials when they are insulating and B is 3d transition metal and B' is a 4d or 5d transition metal has remained elusive. In this work, a number of insulating double perovskite osmates, A2BOsO6 (A=Sr,Ca,La; B=Cr,Fe,Co,Ni) have been chosen and studied using magnetometry, specific heat, XMCD, and neutron powder diffraction techniques in order to systematically probe the effects of electronic configuration and bonding geometry on the magnetic ground state. It is concluded that the magnetic properties of these materials are controlled by a competition between short range B��'O��'Os and long range superexchange interactions which are sensitive to bonding geometry resulting in tunability of the magnetic ground state.

  162. Nuclear Physics & RIKEN Theory Seminar

    "Consistency of Perfect Fluidity and Jet Quenching in semi-Quark-Gluon Monopole Plasmas"

    Presented by Jiechen Xu, Columbia University

    Friday, April 17, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

    Abstract: We utilize a new framework, CUJET3.0, to deduce the energy and temperature dependence of jet transport parameter, q^(E>10GeV,T), from a combined analysis of available data on nuclear modification factor and azimuthal asymmetries from RHIC/BNL and LHC/CERN on high energy nuclear collisions. Extending a previous perturbative-QCD based jet energy loss model (known as CUJET2.0) with (2+1)D viscous hydrodynamic bulk evolution, this new framework includes three novel features of nonperturbative physics origin: (1) the Polyakov loop suppression of color-electric scattering (aka "semi-QGP" of Pisarski et al) and (2) the enhancement of jet scattering due to emergent magnetic monopoles near Tc (aka "magnetic scenario" of Liao and Shuryak) and (3) thermodynamic properties constrained by lattice QCD data. CUJET3.0 reduces to v2.0 at high temperatures T>400 MeV, but greatly enhances q^ near the QCD deconfinement transition temperature range. This enhancement accounts well for the observed elliptic harmonics of jets with pT>10 GeV. Extrapolating our data-constrained q^ down to thermal energy scales, E∼2 GeV, we find for the first time a remarkable consistency between high energy jet quenching and bulk perfect fluidity with η/s∼T3/q^∼0.1 near Tc.

  163. Particle Physics Seminar

    "Cosmology with Strong Gravitational Lenses"

    Presented by Phil Marshall, SLAC National Accelerator Laboratory

    Thursday, April 16, 2015, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Anze Slosar

    Strong gravitational lenses have become an important astronomical tool: they allow us to make accurate measurements of galaxy masses, they provide a magnified view of the distant universe, and they allow us to constrain cosmological parameters. In particular, the time delays in multiply-imaged quasar systems enable measurements of distance in the Universe each with around 5% precision. I will present our recent measurement of time delay distance in two galaxy-scale lens systems. For us to realize the potential of this cosmological probe, we need to increase the size of our lens sample, and continue to improve the accuracy of its analysis. I will discuss the potential of LSST to provide a sample of several hundred lensed quasars with well-measured time delays that would enable competitive and complementary constraints on Dark Energy, and describe our ongoing investigations of how to find lenses, infer their time delays and model their mass distributions accurately, and account for weak lensing effects from external mass structures.

  164. RIKEN Lunch Seminar

    "Jarzynski-type equalities in gambling: role of information in capital growth"

    Presented by Yuji Hirono, Stony Brook

    Thursday, April 16, 2015, 12:30 pm
    Building 510 Room 2-160

    Hosted by: Tomomi Ishikawa

  165. High-Energy Physics & RIKEN Theory Seminar

    "CKM physics with lattice QCD"

    Presented by Aida El-Khadra, University of Illinois at Urbana-Champaign

    Wednesday, April 15, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Chris Kelly

  166. Nuclear Theory/RIKEN seminar

    "Hydrodynamics Beyond the Gradient Expansion: Resurgence and Resummation"

    Presented by Michael Heller, Perimeter Institute

    Friday, April 10, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

    Consistent formulations of relativistic viscous hydrodynamics involve short lived modes, leading to asymptotic rather than convergent gradient expansions. In this talk I will consider the Mueller-Israel-Stewart theory applied to a longitudinally expanding quark-gluon plasma system and identify hydrodynamics as a universal attractor without invoking the gradient expansion. I will give strong evidence for the existence of this attractor and then show that it can be recovered from the divergent gradient expansion by Borel summation. This requires careful accounting for the short-lived modes which leads to an intricate mathematical structure known from the theory of resurgence.

  167. HET/RIKEN seminar

    "Radiation from the Dark Sector"

    Presented by Tongyan Lin, University of Chicago

    Wednesday, April 8, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Chien-Yi Chen

  168. Physics Colloquium

    "The Proton and the Future of Particle Physics"

    Presented by Richard Hill, Univ. Chicago

    Tuesday, April 7, 2015, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Peter Petreczky

    The venerable proton continues to play a central role in fundamental particle physics. Neutrinos scatter from protons in neutrino oscillation experiments, Weakly Interacting Massive Particles (WIMPs) are expected to scatter from protons in dark matter searches, and electrons or muons are bound by protons in precision atomic spectroscopy. Our understanding of the proton is an obstacle to the success of next generation experiments hoping to discover CP violation in the lepton sector and determine the neutrino mass hierarchy, discover the particle nature of dark matter, or reveal new interactions such as those that violate lepton universality. In this talk I present (i) an overview of the current state of knowledge in the neutrino sector, and theoretical advances that will determine a crucial missing ingredient in the predicted signal process of neutrino-nucleus scattering at a Long Baseline Neutrino Facility (ii) the first complete calculation of the scattering cross section of a proton on a static electroweak source, which determines WIMP-nucleus scattering rates at underground direct detection experiments and (iii) the status of the proton radius puzzle, whose most "mundane" resolution requires a 5 standard deviation shift in the value of the Rydberg constant. I describe how each of these problems has spurred the development of powerful new methods in effective quantum field theory.

  169. Condensed-Matter Physics & Materials Science Seminar

    "2-dimensional Superconductivity at the LaAlO3/SrTiO3 Interface"

    Presented by Jean-Marc Triscone, DQMP, University of Geneva, Switzerland

    Tuesday, April 7, 2015, 1:30 pm
    ISB Bldg. 734, Conf. Rm. 201 (upstairs)

    Hosted by: Ivan Bozovic

    The interface between LaAlO3 and SrTiO3, two good band insulators, which was found in 2004 to be conducting [1], and, in some doping range, superconducting with a maximum critical temperature of about 200 mK [2] is attracting of lot of attention. The electronic structure of the system displays signatures of confinement and of the d-character of the carriers. This electron liquid has a thickness of a few nanometers at low temperatures and a low electronic density. Being naturally sandwiched between two insulators, it is ideal for performing electric field effect experiments that allow the carrier density to be tuned and the phase diagram of the system to be determined [3]. I will discuss in this presentation superconductivity, the phase diagram of the system and the link with bulk doped SrTiO3, spin orbit [4], and an approach that allows superconducting coupling between different gases to be studied. I will also discuss recent thermopower measurements that allow access to localized electronic states [5]. [1] A. Ohtomo, H. Y. Hwang, Nature 427, 423 (2004). [2] N. Reyren, S. Thiel, A. D. Caviglia, L. Fitting Kourkoutis, G. Hammerl, C. Richter, C. W. Schneider, T. Kopp, A.-S. Ruetschi, D. Jaccard, M. Gabay, D. A. Muller, J.-M. Triscone and J. Mannhart, Science 317, 1196 (2007). [3] A. Caviglia, S. Gariglio, N. Reyren, D. Jaccard, T. Schneider, M. Gabay, S. Thiel, G. Hammerl, J. Mannhart, and J.-M. Triscone, Nature 456, 624 (2008). [4] A.D. Caviglia, M. Gabay, S. Gariglio, N. Reyren, C. Cancellieri, and J.-M. Triscone, Physical Review 104, 126803 (2010). [5] I. Pallecchi, F. Telesio, D. Li, A. Fête, S. Gariglio, J.-M. Triscone, A. Filippetti, P. Delugas, V. Fiorentini, and D. Marré, to appear in Nature Communications.

  170. Nuclear Physics Seminar

    "New Studies of Elastic Nucleon Form Factors"

    Presented by Dr. Seamus Riordan, Stony Brook University

    Tuesday, April 7, 2015, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: Jin Huang

    The electromagnetic form factors of the nucleon provide experimental access to the underlying charge and magnetic moment distributions arranged by the strong nuclear force. These form factors provide excellent testing grounds for QCD and QCD-inspired models and are fundamentally important in understanding non-perturbative strong force physics. By studying them over a broad range of momentum transfers, they provide insight into the underlying mechanisms relevant to the generation of nucleon structure. At low Q2 there is presently a controversy regarding the charge radius measurements of the proton. At high Q2, scaling of the form factors are presently being studied in the context of a transition from soft QCD interactions. In this talk I will provide an overview of our present experimental of elastic nucleon form factors, review their context within current theoretical models, discuss upcoming future measurements at Jefferson Lab, in particular the Super Bigbite program.

  171. C-AD Accelerator Physics Seminar

    ""Solid-State Laser Engineering for Inertial Confinement Fusion Laser Systems Applications""

    Presented by Dr. Andrey Okishev

    Friday, April 3, 2015, 4 pm
    Bldg 911B., Large Conf.Rm., Rm. A202

    "Solid-state laser concepts for ICF laser system applications including master oscillator, regenerative amplifier, OPO, and fiber-based front-end are discussed. Applications for the ICF laser system front-end, laser temporal diagnostics testing, laser damage testing, ASE suppression for OPCPA pump, energetic picosecond pulse generation without mode locking, cryogenic target layering, complex multi-FM pulses generation are described."

  172. Nuclear Theory/RIKEN seminar

    "Gravitational collapse, holography and hydrodynamics in extreme conditions"

    Presented by Paul Chesler, Harvard University

    Friday, April 3, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Soeren Schlichting

    A remarkable observation from RHIC and the LHC is that the quark-gluon plasma produced in heavy-ion collisions behaves as a strongly coupled and nearly ideal liquid. Data also suggests that the debris produced by proton-nucleus collisions can also behave as a liquid. Understanding the dynamics responsible for the rapid equilibration of such tiny droplets is an outstanding problem. In recent years holography has emerged as a powerful tool to study non-equilibrium phenomena, mapping challenging quantum dynamics onto the classical dynamics of gravitational fields in one higher dimension. In the dual gravitational description the process of quark-gluon plasma formation and equilibration maps onto the process of gravitational collapse and black hole formation. I will describe how one can apply techniques and lessons learned from numerical relativity to holography and present recent work on holographic models of high energy collisions and the applicability of hydrodynamics to tiny droplets of quark-gluon plasma.

  173. Particle Physics Seminar

    "Measurement of the pion polarizability at COMPASS"

    Presented by Jan Friedrich, Technische Universität München, Germany

    Friday, April 3, 2015, 10 am
    Small Seminar Room, Bldg. 510

    Hosted by: Ketevi A. Assamagan

    For more than a decade, the COMPASS experiment at the CERN Super Proton Synchrotron has been tackling the measurement of the electromagnetic polarizability of the charged pion, which describes the stiffness of the pion against deformation in electromagnetic fields. Previous experiments date back to the 1980's in Serpukhov (Russia), where the Primakoff method to study charged-pion interactions with quasi-real photons was first employed. Later also other techniques in photon-nucleon and photon-photon collisions were carried out at different machines. The COMPASS measurement demonstrates that the charged-pion polarizability is significantly smaller than the previous dedicated measurements, roughly by a factor two, with the smallest uncertainties realized so far. The pion polarisability is of fundamental interest in the low-energy sector of quantum chromodynamics. It is directly linked to the quark-gluon substructure and its dynamics in the lightest bound system of strong interaction.

  174. Particle Physics Seminar

    "Neutrino Oscillations with IceCube"

    Presented by Tyce DeYoung, Michigan State University

    Thursday, April 2, 2015, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Elizabeth Worcester

    The IceCube Neutrino Observatory is the world's largest neutrino detector. Although designed to detect TeV " PeV scale neutrinos from astrophysical accelerators, IceCube's DeepCore infill array permits searches for dark matter and measurements of neutrino oscillations in the 10-100 GeV range. The most recent measurements of muon neutrino disappearance with IceCube DeepCore will be presented, and prospects for future neutrino physics measurements with IceCube and the proposed PINGU array will be discussed

  175. RIKEN Lunch Seminar

    "Spin-Orbit Coupling in an Unpolarized Heavy Nucleus"

    Presented by Matt Sievert, BNL

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

    Hosted by: Daniel Pitonyak

    The next-generation Electron-Ion Collider (EIC) will make high precision measurements of spin-dependent observables at high energies on nuclear targets. This unique nuclear physics laboratory will bring together access to the multitude of spin-spin and spin-orbit structures which can exist in hadronic targets, and the high color-charge densities which generate the most intense gluon fields permitted by quantum mechanics. The interplay between those two features gives rise to new physical mechanisms which translate these spin-orbit structures into the observed cross-sections, and it makes these mechanisms amenable to first-principles calculation. In this talk, I will discuss the spin-orbit structure of quarks within an unpolarized heavy nucleus in the quasi-classical approximation. The possibility of polarized nucleons with orbital motion inside the unpolarized nucleus generates nontrivial mixing between the spin-orbit structures of the nucleons, and the corresponding structures in the nucleus. This generic feature of a dense quasi-classical system leads to direct predictions testable at an EIC, and in principle allows direct access to the orbital angular momentum in the nucleus.

  176. HET/RIKEN Seminar

    "A Global Approach to Top-quark FCNCs"

    Presented by Gauthier Durieux, Cornell University

    Wednesday, April 1, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Chien-Yi Chen

  177. Physics Colloquium

    "Hot Jupiters: astrophysical laboratories for extreme weather"

    Presented by Rosalba Perna, Stony Brook University

    Tuesday, March 31, 2015, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Peter Petreczky

    Hot Jupiters, a class of exoplanets orbiting in the proximity of their parent stars, are subjected to a strong irradiating flux that governs their radiative and dynamical properties. It is a regime which is not observed in the giant planets of our solar system. In this talk, I will describe current efforts to understand their radiative and dynamical properties, characterize their atmospheres by means of a variety of techniques, study the interaction of their fast, weakly ionized winds with the planetary magnetic field, and shed light on an evolutionary puzzle known as the problem of inflated radii.

  178. Nuclear Physics Seminar

    "Molten salt: towards the next generation of nuclear energy"

    Presented by Dr. Ondrej Chvala, University of Tennessee

    Tuesday, March 31, 2015, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: Jin Huang

    Current nuclear powerplants use almost exclusively highly pressurized water as reactor coolant and heat transfer medium. This limits their operation to relatively low temperatures. Molten alkali-halide salts allow low pressure operation at high temperatures, improving thermal efficiency and operational safety. The talk will cover the history of molten salt reactor development, reasons for the renewed interest, and focus on recent developments of molten salt nuclear technologies in the U.S. and abroad.

  179. C-AD Accelerator Physics Seminar

    "High-Power Fiber Lasers for Cornell Energy Recovery LINAC"

    Presented by Dr. Zhi Zhao, Cornell University

    Monday, March 30, 2015, 4 pm
    Bldg 911B, Large Conf. Rm. Rm.A202

    Hosted by: John Skaritka

    "In this talk, I will present a description of high-power fiber lasers and beam shaping systems that have been used to achieve low emittance and record high beam current in the Cornell energy recovery LINAC injector. Design, limitation, as well as power scaling of fiber lasers for the future accelerators will be discussed. "

  180. Condensed-Matter Physics & Materials Science Seminar

    "Printed nanocomposite capacitors for power conversion applications, and solution processed methods for producing ferroic complex oxide nanoparticles"

    Presented by Stephen O'Brien, Department of Chemistry, The City college of New York, New York, NY 10031, Energy Institute, City University of New York, NY 10031

    Monday, March 30, 2015, 11 am
    Conference Room, Building 480

    Hosted by: Yimei Zhu

    I will give an overview of the metacapacitors project, an ARPA-E sponsored project that aims to improve efficiency, functionality and form factor of off-line power converters suitable for LED solid-state lighting, with a view to developing an attractive technology platform for load management and power conversion across a broad range of applications. Based on integrated switched-capacitor (SC) topologies, the project adopts an integrated approach from materials to devices to circuits. We designed capacitors based on high-dielectric nanocrystals, that can be prepared using high throughput microfabrication/nanotechnology techniques, ink deposition and multilayering. The capacitor dielectric, a nanocomposite composed of (Ba,Sr)TiO3 nanocrystals in polyfurfuryl alcohol (BST/PFA, _ > 20 , 100Hz - 1 MHz , loss < 0:01 , 20 kHz ), targets a high volumetric capacitance density and ripple current capability. The capacitors were board-integrated with a custom hybrid-switched-capacitor resonant (HSCR) DC-DC converter, tested and demonstrated to operate with high efficiency. The methodology for preparing the capacitor dielectric films relies on a novel method to prepare complex oxides, followed by evaporatively driven self-assembly into thin films. I'll review rational synthetic design, multigram scaling, and dispersion formulation design, as well as recent advances in the synthesis and characterization of novel multiferroic and ferroelectric complex oxides. STEPHEN O'BRIEN is an Associate Professor of Chemistry at City College New York and a member of the CUNY Energy Institute. He holds appointments on the Doctoral Faculty of the CUNY Graduate Center and Grove School of Engineering. Steve is a researcher in nanomaterials synthesis, properties and structural characterization: nanoparticle synthesis and self-assembly into superlattices, transition metal oxide nanomaterials, high k dielectrics/memory materials. He is published in over

  181. C-AD Accelerator Physics Seminar

    ""Spin Dynamics Modeling in the AGS Based on a Stepwise Ray-Tracing Method""

    Presented by Yann Dutheil, BNL

    Friday, March 27, 2015, 4 pm
    Bldg 911B, Large Conf. Rm. Rm. A202

    "The AGS provides a polarized proton beam to RHIC. The beam is accelerated in the AGS from Gγ = 4.5 to Gγ = 45.5 and the polarization transmission is critical to the RHIC spin program. In the recent years, various systems were implemented to improve the AGS polarization transmission. These upgrades include the double partial snakes configuration and the tune jumps system. However, 100 % polarization transmission through the AGS acceleration cycle is not yet reached. Understanding the sources of depolarization in the AGS is critical to improve the AGS polarized proton performances. The complexity of beam and spin dynamics, which is in part due to the specialized Siberian snake magnets, drove a strong interest for original methods of simulations. For that, the Zgoubi code, capable of direct particle and spin tracking through field maps, was used to model the AGS. The Zgoubi model of the AGS will be introduced and recent results obtained through multiturn tracking will be shown. Selected example will highlight the relevance of the Zgoubi simulations to improve the polarization transmission in the AGS."

  182. Particle Physics Seminar

    "Nue appearance analysis in NOvA"

    Presented by Jianming Bian, University of Minnesota

    Thursday, March 26, 2015, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Elizabeth Worcester

    The NOvA experiment is a long base-line accelerator based neutrino oscillation experiment. It uses the upgraded NuMI beam from Fermilab and measures electron neutrino appearance and muon neutrino disappearance at its far detector in Ash River, Minnesota. Goals of the experiment include measurements of theta13, mass hierarchy and the CP violating phase. NOvA has begun to take neutrino data and first neutrino candidates are observed in its far detector. This talk provides an introduction to the scientific reach of the experiment, the detector construction and the nue appearance analysis, as well as the first data in near and far detectors.

  183. C-AD Accelerator Physics Seminar

    ""Beam-Beam Effects and Landau Damping in the LHC and HL-LHC""

    Presented by Claudia Tambasco, CERN, Italy

    Thursday, March 26, 2015, 2 pm
    Bldg 911B, Large Conf. Rm. Rm. A202

    Hosted by: Wolfram Fischer

    "The Large Hadron Collider (LHC) at CERN is a high-energy circular hadron collider designed to provide a maximum center of mass energy of 14 TeV and a peak luminosity of L = 1e34-1e35 cmâˆ'2 sâˆ'1 . The LHC 2012 RUN has shown strong coherent transverse instabilities developing at top energy (4TeV) which where causing large particle losses and in many cases also beam dumps. Coherent modes driven by the machine impedance are normally Landau damped by the use of octupole magnets which are regularly powered to ensure enough detuning with amplitude. Also beam-beam effects contribute to the detuning with amplitude and they could therefore increase or decrease the Landau damping range of frequencies depending on the spread obtained from the octupoles. The interplay between impedance, Landau octupoles and beam-beam interactions defines the stability limits of the accelerator that can be evaluated by the so called stability diagrams. In the tune spread analysis there is no information on possible mechanisms which modify the particle distribution, second fundamental ingredient of the Landau damping. Therefore it is fundamental to explore experimentally, through Beam Transfer Function measurements, and with simulations the effects of different distributions to the stability diagrams. The High Luminosity Large Hadron Collider (HL-LHC) projects aims to extend the LHC discovery potential and it is designed to operate with beams of much higher brightness resulting in much stronger beam-beam interactions. Landau damping properties for this scenario are also presented."

  184. HET/RIKEN seminar

    "Flavored Dark Matter with Weak Scale Mediators"

    Presented by Can Kilic, The University of Texas, Austin

    Wednesday, March 25, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Chien-Yi Chen

    All matter in the Standard Model appears in three generations, with an intricate flavor structure the origin of which is not well understood. This motivates the question whether distinct phenomenological features arise if dark matter (DM) also has a non-trivial flavor structure. In this talk I will review the experimental signatures of this scenario. In the case of lepton-flavored DM, I will argue that the generation of a lepton asymmetry at a high energy scale can also produce a DM asymmetry, which can strongly affect the sensitivity of direct detection experiments, and I will present novel signatures that can appear at colliders and in indirect detection experiments. I will also review the case of top quark-flavored DM with a distinct collider phenomenology including final states of top pairs and missing energy as well the possibility of displaced decays.

  185. Physics Colloquium

    "Discoveries that changed the world: 1932 - 1942 - James Chadwick & Lise Meitner"

    Presented by Gerard Lander, EITU - Karlsruhe

    Tuesday, March 24, 2015, 11 am
    Large Seminar Room, Bldg. 510

    Hosted by: Doon Gibbs

    From the discovery of the neutron (1932) to the first demonstration of controlled fission (1942) was just ten years; a period that took physics from an occupation of a small number of eccentric gentlemen and (even fewer) ladies to something of concern to, and funding decisions of, Governments all over the world. The shadows of those tumultuous years are still with us, for better or worse. This talk will recount those ten years through the lives of James Chadwick (1891-1974) and Lise Meitner (1878-1968), contemporaries who played pivotal roles in the events, even though, partly because of their retiring personalities, they are often over-shadowed by "larger" figures.

  186. Joint NT/RIKEN Seminar

    "Flow-like behavior in small systems — Multi-parton interactions and color reconnection effects at the LHC"

    Presented by Antonio Ortiz Velasquez, National Autonomous University of Mexico

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

    Hosted by: Soeren Schlichting

    Collectivity in high multiplicity pp and p-Pb collisions is the most unexpected discovery at the LHC, its origin is still an open question. In heavy ion collisions, collectivity is attributed to final state effects due to the presence of a hot and dense QCD medium, and it is well described by viscous hydrodynamical calculations with fluctuating initial state geometries. Surprisingly, calculations which employ hydrodynamics reproduce qualitatively well the features of p-Pb data, but, the applicability of hydro in small systems faces conceptual problems. This is not the case of other approaches which do not require a medium to be formed and also are able to reproduce qualitatively well some features of data. In this talk it will be shown that multi-parton interactions and color reconnection (CR) produce flow-like effects in high multiplicity pp collisions. A study of the transverse momentum (pT) distribution of identified hadrons as a function of the event multiplicity will be presented. This comprises studies of the average pT vs hadron mass and number of constituent quarks, and a pT differential study using the Boltzmann-Gibbs Blast-Wave model. A comparison between hydro and color reconnection calculations will be presented. In this context, the results from the same study using LHC data (pp, p-Pb and Pb-Pb collisions) will be discussed.

  187. Condensed-Matter Physics & Materials Science Seminar

    "Graphene on Ir(111), adsorption and intercalation of Cs and Eu atoms"

    Presented by Predrag Lazic, Rudjer Boskovic Institute, Croatia

    Thursday, March 19, 2015, 1:30 pm
    ISB Bldg. 734, Conf. Rm. 201 (upstairs)

    Hosted by: Tonica Valla

    Experimental and theoretical study of Cs and Eu atoms adsorption on graphene on Ir(111) will be presented [1,2]. Graphene on Ir(111) surface is an interesting system because graphene has almost pristine electronic structure in it due to its weak bonding character to iridum surface. The bonding is almost exclusively of the van der Waals type. However adding Cs or Eu atoms graphene gets doped and and nature of binding changes - especially in the case when the atoms intercalate. Density Functional Theory calculations with standard semilocal functionals (GGA) - fail to reproduce experimental findings even qualitatively. Only when the newly developed nonlocal correlation functional is used (vdW-DF) which includes van der Waals interactions, are the calculations in agreement with experiment, revelaing the mechanism of graphene delamination and relamination which is crucial for intercalation and trapping of atoms under the graphene. [1] M. Petrovic et al., Nat. Commun. 4, 2772 (2013). [2] S. Schumacher et al., Nano Lett. 13, 5013 (2013).

  188. HET/RIKEN seminar

    "Spontaneous CP violation and the strong CP problem"

    Presented by Luca Vecchi, University of Maryland

    Wednesday, March 18, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Chien-Yi Chen

  189. RIKEN BNL

    "The title of my talk is "How Jets and Two-Particle Correlations Impact Our Understanding of the Quark Gluon Plasma"

    Presented by Megan Connors, Yale University

    Wednesday, March 18, 2015, 2 pm
    Building 510 Room 2-160

    Hosted by: Samuel Aronson

    Relativistic heavy ion collisions can reproduce the conditions necessary to form a hot and dense medium known as the Quark Gluon Plasma (QGP), the state of the universe immediately following the Big Bang, in which quarks and gluons are deconfined. Results from experiments at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC), which study the properties of the QGP, will be presented. This seminar will focus on two particle correlations and jet physics results in Pb-Pb and Au-Au collisions at the LHC and RHIC respectively and the prospects for such measurements at the proposed sPHENIX detector. In addition, the implications of using p-p or p-A systems as a reference for these A-A measurements will be discussed. Jets are the result of a hard scattering, which occurs early in the collision process, and probe how partons interact and lose energy in the medium. Two particle correlations are used to study jet physics and energy loss, as well as the underlying event. The interplay between the two is important for understanding how high momentum particles lose energy and for finding where that lost energy goes. To quantify the influence of the QGP on these measurements, it is important to have a good baseline measurement. A-A measurements are typically compared to expectations based on p-p collisions. Recent results from p-A collisions are used to quantify cold nuclear matter effects not captured in p-p collisions. However, p-A measurements have proven to be interesting in their own unexpected way which has implications for physics measurements at the future Electron Ion Collider.

  190. Physics Colloquium

    "Measuring Dark Matter and Dark Energy with Gravitational Lensing"

    Presented by Erin Sheldon, BNL

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

    Hosted by: Morgan May

    Gravitational lensing is the bending of light as it passes massive bodies. The amount of deflection is directly related to the mass of the lensing body and the geometrical configuration of the lens-source system. Typical lens configurations involve a distant background galaxy lensed by a much closer foreground galaxy, or cluster of galaxies. The lensing effect can be used to infer the mass of the lens, both luminous and dark matter. Lensing, as a purely geometrical phenomenon has become the most important way to measure the distribution of dark matter in the universe. I will discuss measurements I have made of the dark matter distribution in galaxies and clusters of galaxies using the lensing phenomenon. These measurements, the most precise to date, are consistent with the predictions of the cold dark matter model. Dark energy has accelerated the expansion of the universe at late times, and thus alters the relationship between the observed redshift of galaxies and their true distance from us. Lensing is sensitive to this redshift-distance relationship, and thus dark energy, since the amount of light deflection depends on the relative distances of lens and source. I will discuss the Dark Energy Survey (DES), a survey of the southern sky, now ending our second year of data taking. DES surveys larger volumes of the universe, and probes farther back in time than previous lensing surveys. With DES we will establish lensing as a competitive method to study dark energy. I will discuss preliminary results from DES using galaxy clusters as lenses and distant background galaxies as sources. I will end with a discussion of the new Large Synoptic Survey Telescope (LSST) survey, of which BNL is a member. LSST is a successor of DES, now entering the construction phase. With LSST we will bring lensing to maturity as a probe of dark energy.

  191. Nuclear Physics Seminar

    "Recent development of quarkonium production in p+p and p+A collisions"

    Presented by Yan-Qing Ma, University of Maryland

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

    Hosted by: Oleg Eyser

    Although the next-to-leading order NRQCD calculation can solve many puzzles of heavy quarkonium production phenomena, it can neither describe data at very high nor very low transverse momentum (pT) region. At very high pT region, a double parton fragmentation formalism was proposed recently, which can systematically reorganize the expansion and resum large logarithms; while at very low pT region, a NRQCD+CGC framework was proposed to take into account the intrinsic transverse momentum and gluon saturation effects. I will talk about these theories and their application on p+p and p+A collisions from RHIC to LHC.

  192. Particle Physics Seminar

    "Search for Direct Top Squarks"

    Presented by Walter Hopkins, University of Oregon

    Monday, March 16, 2015, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Ketevi Assamagan

    The results of a search for direct pair production of the scalar partner to the top quark using an integrated luminosity of 20/fb of proton-proton collision data at 8 TeV, recorded with the ATLAS detector at the LHC, are reported. The top squark is assumed to decay via stop -> top+LSP where LSP denotes the lightest neutralino in supersymmetric models. The search targets a fully hadronic final state in events with four or more jets and large missing transverse momentum. No significant excess over the Standard Model background prediction is observed, and exclusion limits are reported in terms of the top squark and LSP masses. In addition to the current results, prospects and plans for stop searches in the LHC Run 2 will be discussed.

  193. Physics Colloquium

    "DOUBLE BETA DECAY AND NEUTRINO MASSES"

    Presented by Francesco Iachello, Yale University

    Tuesday, March 10, 2015, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Peter Petreczky

    The question of whether or not neutrinos are Majorana particles and, if so, what is their average mass remains one of the most fundamental problems in physics today. The average neutrino mass can be obtained from neutrinoless double beta decay. The inverse half-life for this process is given by the product of a phase space factor (PSF), a nuclear matrix element (NME) and whatever physics there is beyond the standard model. In this talk, the theory of double beta decay, both with and without the emission of neutrinos, will be reviewed, and recent calculations of the PSF and NME will be presented. From these and from experimental limits on the half-life of neutrinoless double beta decay, one can extract limits on the neutrino mass, both for the exchange of light (mνá1keV) and heavy (mνà1GeV) neutrinos. Current limits will be discussed. Finally, the question of how many neutrino species there are will be briefly addressed, including the possibility of sterile neutrinos with masses in the intermediate range keV-GeV.

  194. Sustainable Energy Technologies Seminar

    "Surfactant Free Synthesis of Plasmonic Nanoparticles and Their Application in Optical Detection of Explosives and Ions"

    Presented by Devika Sil, Temple University, Philadelphia

    Tuesday, March 10, 2015, 2 pm
    ISB 734 2nd Floor Seminar Room 201

    Hosted by: Matthew Eisaman

    The localized surface plasmon resonance (LSPR), arising due to the collective oscillation of free electrons in metal nanoparticles, is a sensitive probe of the nanostructure and its surrounding dielectric medium. Synthetic strategies for developing surfactant free nanoparticles providing direct access to the metallic surface that harvest the localized surface plasmons will be discussed first followed by the applications. It is well known that the hot carriers generated as a result of plasmonic excitation can participate and catalyze chemical reactions. One such reaction is the dissociation of hydrogen. By the virtue of plasmonic excitation, an inert metal like Au can become reactive enough to support the dissociation of hydrogen at room temperature, thereby making it possible to optically detect this explosive gas.1 The mechanism of sensing is still not well understood. However, a potential hypothesis is that the dissociation of hydrogen may lead to the formation of a metastable gold hydride with optical properties distinct from the initial Au nanostructures, causing a reversible increase in transmission and blue shift in LSPR. It will also be shown that by tracking the LSPR of bare Au nanoparticles grown on a substrate, the adsorption of halide ions on Au can be detected exclusively. The shift in LSPR frequency is attributed to changes in electron density rather than the morphology of the nanostructures, which is often the case.

  195. HET/RIKEN Seminar

    "The Galactic Center Gamma-ray Excess: Have We Started to See Dark Matter"

    Presented by Samuel McDermott, Stony Brook University

    Wednesday, March 4, 2015, 2 pm
    Building 510 SSR

    Hosted by: Sally Dawson

  196. C-AD Accelerator Physics Seminar

    "Polarization Aperture Response for 250 GeV Ramps"

    Presented by Dr. Vahid Ranjbad, BNL

    Friday, February 27, 2015, 4 pm
    Bldg 911B, Large Conf. Rm., Rm A202

    "Through direct and lattice independent tracking we show how the polarization aperture can be greatly expanded by modifying the 453-nu intrinsic spin resonance next to the main 393+nu resonance. We also explore the conjecture that the structure of the aperture is related to the area of the parametric resonance regions based on the new formulation for the T-BMT equation (given in my recent PRSTAB paper http://journals.aps.org/prstab/pdf/10.110/PhysRevSTAB.18.014001) and how this might explain some of the apparent structure in the polarization profile measurements."

  197. HET/BNL Lunch Time Talk

    "Primordial non-Gaussianity is a crucial probe of inflationary physics"

    Presented by Anze Slosar, BNL

    Friday, February 27, 2015, 12 pm
    Building 510 Room 2-160

    Hosted by: Amarjit Soni

  198. Particle Physics Seminar

    "The ATLAS H-ZZ(*)-4l decay channel"

    Presented by Kalliopi Iordanidou, Columbia University, Nevis Laboratories

    Friday, February 27, 2015, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: Ketevi A. Assamagan

    The H->ZZ(*)4l decay channel is the experimentally cleanest signature for the Higgs boson production at the LHC (CERN). The selection of the candidates, the data driven background estimation methods and the property measurements of the Higgs boson are presented using the ATLAS Run-I data. Prospect expectations are explored for the High Luminosity LHC (HL-LHC) scenario.

  199. Particle Physics Seminar

    "Coherent Charged Pion Production in ArgoNeuT"

    Presented by Tingjun Yang, Fermilab

    Thursday, February 26, 2015, 3 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Elizabeth Worcester

    I will present the first cross section measurements for charged current coherent pion production by neutrinos and antineutrinos on argon. These measurements are performed using the ArgoNeuT detector exposed to the NuMI beam at Fermilab. The results are in a good agreement with the theoretical predictions from GENIE and NuWro.

  200. Special Nuclear Physics/HEP Seminar

    "Nuclear parton distributions in theory"

    Presented by Adam Freese, Florida International University, Miami, FL

    Thursday, February 26, 2015, 10 am
    Building 510 Room 2-160

    Hosted by: Thomas Ulrich

    Quantum chromodynamics has been extremely successful in describing a multitude of high-energy experiments with aid from the use of universal parton distribution functions. PDFs for the free proton are fairly well-constrained by experiment, but nuclear PDFs require elaboration. Three ingredients are necessary to obtain a nuclear PDF theoretically: (1) an account of the nuclear momentum distribution that includes the latest results regarding short range correlations; (2) a model of how nucleons immersed in the nuclear medium are modified at a quark-gluon level; and (3) the application of QCD evolution to connect the low momentum resolution scales at which the first two ingredients are obtained to the high momentum transfer scales relevant to the LHC and the EIC. These three ingredients will be described in detail, and an example of their application to proton-nucleus collisions at LHC energies will be provided.

  201. High-Energy Physics & RIKEN Theory Seminar

    "The Search for Relic Neutrinos"

    Presented by Mariangela Lisanti, Princeton

    Wednesday, February 25, 2015, 2 pm
    Small Seminar Room, Bldg. 510

    Hosted by: Sally Dawson

  202. Physics Workshop

    "Brain Circulation Workshop"

    Wednesday, February 25, 2015, 9 am
    Large Seminar Room, Bldg. 510

    Hosted by: Rob Pisarski

    This is the third workshop for a visiting program between the Japanese Society for the Promotion of Science and the Nuclear, Lattice Gauge, and High Energy Theory groups at Brookhaven. The grant, termed a Brain circulation program, is between Dr. Tetsuo Hatsuda, Chief Scientist at RIKEN, and his colleagues from RIKEN, Kyoto University, and Tsukuba University, and is designed to allow young scientists to visit BNL. In this workshop young scientists from both Japan and BNL will discuss their work.

  203. Nuclear Physics Seminar

    "Understanding flow fluctuations with Principal Components"

    Presented by Derek Teaney, Stony Brook University

    Tuesday, February 24, 2015, 11 am
    Small Seminar Room, Bldg. 510

    Hosted by: Jiangyong Jia

    We perform a Principal Component Analysis (PCA) of $v_3(p_T)$ in event-by-event hydrodynamic simulations of Pb+Pb collisions at the LHC. The PCA procedure identifies two dominant contributions to the two particle correlation function, which together capture 99.9\% of the squared variance. We find that the subleading flow (which is the largest source of flow factorization breaking in hydrodynamics) is predominantly a response to the radial excitations of a third-order eccentricity. We present a systematic study of the hydrodynamic response to these radial excitations in 2+1D viscous hydrodynamics. Finally, we construct a good geometrical predictor for the orientation angle and magnitude of the leading and subleading flows using two Fourier modes of the initial geometry.

  204. Condensed-Matter Physics & Materials Science Seminar

    "Non-equilibrium electronic structure and ultrafast dynamics of solid materials"

    Presented by Uwe Bovensiepen, Univ. Duisburg-Essen, Germany

    Friday, February 20, 2015, 1:30 pm
    ISB, Bldg. 734, Conf. Rm. 201 (upstairs)

    Hosted by: Jonathan Rameau

    Optical excitations in solid materials decay typically on femto- to picosecond time scales due to interactions which lead to a redistribution of the excess energy among the electronic, the lattice, and the spin subsystem, before final dissipation. We perform pump-probe experiments in order to analyze these excitations and the action they generate through their relaxation directly in the time domain. In this talk time- and angle-resolved photoemission (tr-ARPES) results which probe the excited state with energy and momentum sensitivity on complex materials like charge density wave compounds [1] and high temperature superconductors [2,3] will be discussed. In the prototype charge density wave material RTe3 (R=Ho, Tb, Dy) we obtained a momentum dependent analysis of the time dependent gap function (k,t) which sheds lights on the amplitude mode and the interaction responsible for the charge density wave formation. In the iron based superconductor material BaFe2As2 the optical excitation induces oscillations in the chemical potential linked to the coherent A1g phonon which modulates the pnictogen height and electronic correlations. In the cuprates pump-induced changes are observed below and above Tc. We obtained evidence for considerable photo-doping effects based on transient changes in the Fermi momentum kF upon optical excitation. Remarkably, the observed changes follow predictions based on chemical doping, which suggests time- and angle-resolved photoemission as a novel method to differentially probe the Fermi surface of complex materials. [1] L. Rettig, J.-H. Chu, I. R. Fisher, U. Bovensiepen, M. Wolf, Faraday Discuss. 171, 1 (2014). [2] J. Rameau, S. Freutel, L. Rettig, I. Avigo, M. Ligges, Y. Yoshida, H. Eisaki, J. Schneeloch, R. D. Zhong, Z. J. Xu, G. D. Gu, P. D. Johnson, U. Bovensiepen, Phys. Rev. B 89, 115115 (2014). [3] L. X. Yang, G. Rohde, T. Rohwer, A. Stange, K. Hanff, C

  205. Condensed-Matter Physics & Materials Science Seminar

    "Electronic phase separation and magnetic phase behavior in the Ru-doped spin-orbit Mott insulator Sr3Ir2O7"

    Presented by Chetan Dhital, Oak Ridge National Laboratory

    Wednesday, February 18, 2015, 11 am
    ISB Bldg. 734, Conf. Rm. 201 (upstairs)

    Hosted by: Mark Dean

    Recent theoretical and experimental studies have predicted a very interesting electronic phase diagram in 5d iridate system arising due to interplay of spin orbit interaction and the electronic correlation. Spin-orbit Mott phase is one such electronic phase realized in Ruddelsden-Popper (RP) series [Srn+1IrnO3n+1] oxides. Sr3Ir2O7 (n=2) and Sr2IrO4 (n=1) are two representative candidates of this series. Although their ground state properties are studied to some extent, very little is known regarding how the properties of their antiferromagnetic, insulating, parent states evolve upon carrier substitution. One way of experiencing the strength and relevance of electronic correlation in any condensed matter system is by doping charge carriers. The presence of electronic correlations in the host system determines the fate of the dopant and hence stabilizes a new electronic/magnetic ground state. I will discuss about importance of electronic correlations in one such doped system Sr3 (Ir1-xRux) 2O7 using combined neutron scattering, electric transport and magnetization techniques. Our findings demonstrate that correlation effects felt by carriers introduced within in a 5d Mott phase remain robust enough to drive electron localization, a key ingredient in emergent phenomena such as high temperature superconductivity and enhanced ferroic behavior. References: [1]. Dhital, Chetan, et al. "Spin ordering and electronic texture in the bilayer iridate Sr3Ir2O7." Physical Review B 86.10 (2012): 100401. [2]. Dhital, Chetan, et al. "Neutron scattering study of correlated phase behavior in Sr2IrO4." Physical Review B 87.14 (2013): 144405. [3]. Dhital, Chetan, et al. " Carrier localization and electronic phase separation in a doped spin-orbit-driven Mott phase in Sr3 (Ir1â€"xRux) 2O7 (Nature communications,2014)

  206. RIKEN/BNL Lunch Time Talk

    "Bose-Einstein Condensation, Isotropization, and Thermalization in Overpopulated Systems"

    Presented by Jinfeng Liao, Indiana University / RBRC

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

    Hosted by: Tomomi Ishikawa

    We discuss recent progress, using the kinetic theory framework, in understanding the non-equilibrium evolution of overpopulated systems that resemble the glasma during the early stage of heavy ion collisions. We analyze a number of important factors that influence the course of thermalization in such systems, and in particular their consequences for the nontrivial dynamics driving Bose-Einstein Condensation as well as the isotropization. We discuss recent progress, using the kinetic theory framework, in understanding the non-equilibrium evolution of overpopulated systems that resemble the glasma during the early stage of heavy ion collisions. We analyze a number of important factors that influence the course of thermalization in such systems, and in particular their consequences for the nontrivial dynamics driving Bose-Einstein Condensation as well as the isotropization.

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