Responsibile for the operation and physics exploitation of the PHENIX experiment at RHIC.
Responsibile for the operation and physics exploitation of the STAR experiment at RHIC.
Leads, supports, and provides for the common requirements of the RHIC spin program, particularly for polarimetry.
Conducts quantum chromodynamics and proton spin structure research.
Conducts research to understand many body aspects of QCD, including the properties of hot and dense matter as well high gluon density matter.
Studies properties of hot and dense matter using lattice QCD methods.
Provides computing services for experiments at RHIC, and the Large Synoptic Survey Telescope project.
Solving problems in observational cosmology: how to measure and constrain properties of dark matter, dark energy and the standard cosmological model.
Studies very rare processes at the Intensity Frontier.
Group members are collaborators on the LHC ATLAS experiment.
Develops physics applications software for the LHC ATLAS experiment.
Focuses on providing theoretical foundation for the search for physics beyond the standard model, including lattice QCD calculations of key quantities required for this quest.
Provides computing services for U.S. ATLAS.
BOSS studies dark energyâ€”the force thought to be responsible for the universeâ€™s accelerating expansion.
Seeks to probe the origin of the accelerating universe and uncover the nature of dark energy by measuring the 14-billion-year history of cosmic expansion.
A 3.2 gigapixel camera mounted in a ground-based telescope designed to produce the widest, densest, and most complete images of our universe ever captured.
An international collaboration working to precisely measure neutrino oscillations.
An experiment at CERN's Large Hadron Collider designed to detect particles created by proton-proton collisions.
An international collaboration studying the subtle transformations of neutrinos.
Measures low energy neutrino cross sections and investigates low energy excess events observed by the MiniBooNE experiment.
A high precision measurement of the muon's g-2 value. A deviation between theory and observed value will suggest the existence of new particles.
Experiment which directly probes the Intensity Frontier and aids research on the Energy and Cosmic frontiers with precision measurements to characterize properties of new particles.
An experiment at the Relativistic Heavy Ion Collider designed to explore quark gluon plasma.
An experiment at the Relativistic Heavy Ion Collider designed to explore quark gluon plasma.
Plans for the world's first electron-nucleus collider, also known as eRHIC, call for the addition of a 5 to 10 GeV electron ring inside the RHIC tunnel.
The Physics Department is part of Brookhaven's Nuclear & Particle Physics Directorate.
OCT
13
Tuesday
Physics Colloquium
"Random Matrices in Physics"
Presented by Hans A. Weidenmuller, Max-Planck-Institut fur Kernphysik, Heidelberg, Germany
3:30 pm, Large Seminar Room, Bldg. 510
Tuesday, October 13, 2015, 3:30 pm
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-specifc parameters suce to make predictions. In quantum physics, random matrices have similar predictive power. That approach { referred to as random-matrix theory { has found wide applica-tions in recent years, in quantum physics and beyond. The use of random matrices will be motivated, such matrices will be dened. Applications of random matri-ces 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.
OCT
9
Friday
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
11 am, Small Seminar Room, Bldg. 510
Friday, October 9, 2015, 11:00 am
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 pâŠ¥. Still, precise predictions at moderate pâŠ¥ 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.
OCT
23
Friday
Nuclear Theory/RIKEN Seminar
"Thermal photons from a modern hydrodynamical model of heavy ion collisions"
Presented by Jean-Francois Paquet, Stonybrook University
2 pm, Small Seminar Room, Bldg. 510
Friday, October 23, 2015, 2:00 pm
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.
OCT
30
Friday
Nuclear Theory/RIKEN Seminar
"Observable consequences of event-by-event fluctuations of HBT radii"
Presented by Christopher J. Plumberg, Ohio State University
2 pm, Small Seminar Room, Bldg. 510
Friday, October 30, 2015, 2:00 pm
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 Î·/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 Î·/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.
NOV
6
Friday
Nuclear Theory/RIKEN Seminar
"Massless QED in three dimensions with even number of flavors"
Presented by Rajamani Narayanan, Florida International University
2 pm, Small Seminar Room, Bldg. 510
Friday, November 6, 2015, 2:00 pm
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.
NOV
13
Friday
Nuclear Theory/RIKEN Seminar
"Linearly resummed hydrodynamics from gravity"
Presented by Yanyan Bu, Ben Gurion University of the Negev
2 pm, Small Seminar Room, Bldg. 510
Friday, November 13, 2015, 2:00 pm
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.
NOV
20
Friday
Nuclear Theory/RIKEN Seminar
"Transversity Distribution and Collins Fragmentation Functions with QCD Evolution"
Presented by Alexei Prokudin, Jefferson Lab
2 pm, Small Seminar Room, Bldg. 510
Friday, November 20, 2015, 2:00 pm
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.
DEC
4
Friday
Nuclear Theory/RIKEN Seminar
"Semi-classics, complex saddles and real path integrals"
Presented by Tin Sulejmanpasic, North Carolina State University
2 pm, Small Seminar Room, Bldg. 510
Friday, December 4, 2015, 2:00 pm
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.
OCT
22
Thursday
Particle Physics Seminar
"Light Sterile Neutrinos: An Experimental Overview"
Presented by Jonathan Link, Center for Neutrino Physics, Virginia Tech
3 pm, Small Seminar Room, Bldg. 510
Thursday, October 22, 2015, 3:00 pm
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.
NOV
5
Thursday
Particle Physics Seminar
"LAr TPC data reconstruction"
Presented by Dorota Stefan, CERN/NCBJ Warsaw Poland
3 pm, Small Seminar Room, Bldg. 510
Thursday, November 5, 2015, 3:00 pm
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.
DEC
3
Thursday
Particle Physics Seminar
"Measurements Of Cross-Section Of Charge Current Inclusive Of Antineutrino Scattering Off Nucleons Using Carbon, Iron, Lead And Scintillator At Minerva Gr 2GEV < Ev < 20GEV"
Presented by Laza Rakotondravohitra, University Of Antananarivo/Fermilab
3 pm, Small Seminar Room, Bldg. 510
Thursday, December 3, 2015, 3:00 pm
Hosted by: Ketevi Assamagan
MINERvA (Main INjector Experiment for v-A) is a neutrino scattering experiment in the NuMI high-intensity neutrino beam at the Fermi National Accelerator Laboratory. MINERvA was designed to make precision measurements of low energy neutrino and antineutrino cross sections on a variety of different materials (plastic scintillator, C, Fe, Pb, He and H2O). The experiment will provide important inputs, both in support of neutrino oscillation searches and as a pure weak probe of the nuclear medium. In this talk , we present a- preliminary results of measurements of antineutrino inclusive cross section ratios on different nuclei as a function of Bjorken x
DEC
17
Thursday
Particle Physics Seminar
"Search for Higgs Bosons produced in association with top quarks with the ATLAS detector"
Presented by Professor Vivek Jain, SUNY Albany
3 pm, Small Seminar Room, Bldg. 510
Thursday, December 17, 2015, 3:00 pm
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 tÂ¯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.