OCT
26
Today
Special Nuclear Theory/RIKEN seminar
"A new relativistic viscous hydrodynamics code for high-energy heavy-ion collisions"
Presented by Chihi Nonaka, Nagoya University, Japan
11 am, Small Seminar Room, Bldg. 510
Wednesday, October 26, 2016, 11:00 am
Hosted by: ''Chun Shen''
Relativistic hydrodynamic simulations play a key role in exploring the QGP bulk property and the QCD phase transition from analyses of high-energy heavy-ion collisions at RHIC and LHC. From the intensive study based on relativistic viscous hydrodynamic models with event-by-event initial fluctuations, we can extract detailed information of the bulk feature of the QGP such as transport coefficients and the QCD equations of states. In the quantitative analyses of the QGP property, high-precision numerical treatment on the hydrodynamic calculation is important. Recently, we developed a new 3+1 dimensional relativistic viscous hydrodynamics code in Cartesian coordinates. In the algorithm, we use a Riemann solver based on the two-shock approximation which is stable under existence of large shock waves. We extend the algorithm in Cartesian coordinates to that in Milne coordinates so that we can efficiently apply it to the analyses of relativistic heavy-ion collisions. We check the correctness of the numerical algorithm by comparing numerical calculations and analytical solutions in various problems for ideal and viscous fluids. The new numerical scheme is stable even with small numerical viscosity, which is very important to discuss the physical viscosities at RHIC and LHC.
OCT
27
Thursday
RIKEN Lunch Seminar
"Hybrid approach to relativistic heavy-ion collisions at the RHIC BES energies"
Presented by Chun Shen, BNL
12:30 pm, Building 510, Room 2-160
Thursday, October 27, 2016, 12:30 pm
Hosted by: '''Hiroshi Oki'''
Using a hybrid (viscous hydrodynamics + hadronic cascade) framework, we model the bulk dynamics of relativistic heavy-ion collisions at the RHIC BES collision energies, including the effects from non-zero net baryon current and its dissipative diffusion during the evolution. The framework is in full 3+1 dimension which allows us to study the non-trivial longitudinal structure and dynamics of the collision systems, for example, the baryon stopping/transport. The collision energy dependence of hadronic chemistry, identified particle spectra, anisotropic flows, and HBT radii is studied from 200 GeV to 19.6 GeV. Effects of breaking boost-invariance, net-baryon current, and its related diffusion on hadronic observables will be addressed. Finally, flow prediction for recent d+Au collisions at the BES energies will be presented within the same framework.
NOV
4
Friday
Nuclear Physics & RIKEN Theory Seminar
"Glue spin from lattice QCD"
Presented by Yi-Bo Yang, University of Kentucky
2 pm, Small Seminar Room, Bldg. 510
Friday, November 4, 2016, 2:00 pm
Hosted by: ''Heikki Mantysaari''
: I will present the result of the glue spin in proton from the lattice QCD simulation, and also the renormalization and matching issues. The lattice calculation is carried out with valence overlap fermions on 2+1 flavor DWF gauge configurations on four lattice spacings and four volumes including an ensemble with physical values for the quark masses. The glue spin $S_G$ in the $\overline{\text{MS}}$ scheme is obtained with the 1-loop perturbative matching. I will also discuss the generic strategy and possible difficulties of calculating the glue helicity on the lattice, from the large momentum effective theory to the lattice simulations.
NOV
8
Tuesday
Physics Colloquium
"Skyrmions and Nuclei"
Presented by Nick Manton
3:30 pm, Large Seminar Room, Bldg. 510
Tuesday, November 8, 2016, 3:30 pm
Hosted by: 'Robert Pisarski'
Nuclear forces are mediated by pions. As pions are light compared to nucleons and other mesons, they are treated as approximate Goldstone bosons in an effective field theory (EFT) with spontaneously broken SO(4) chiral symmetry. Generically, the nonlinear field equations of EFT have topological soliton solutions called Skyrmions, which we identify as the intrinsic structures of nucleons or larger nuclei. The quantum states of the unit-winding, spherical Skyrmion represent protons and neutrons with spin half. Skyrmions of many higher winding numbers are also known, having beautiful symmetries, and sometimes showing alpha-particle or other clustering. The classical solutions have definite location, orientation, and pion field orientation, so we quantize the collective coordinates to obtain states with definite momentum, spin and isospin. A Skyrmion's symmetry restricts its allowed spin/isospin combinations (Finkelstein—Rubinstein constraints). The recent inclusion of vibrational degrees of freedom has helped to create a reasonable model for Oxygen-16 and its excited states.
NOV
29
Tuesday
Physics Colloquium
"Isolated quantum systems in extreme conditions: From heavy-ion collisions to ultracold quantum gases"
Presented by Juergen Berges, University of Heidelberg
3:30 pm, Large Seminar Room, Bldg. 510
Tuesday, November 29, 2016, 3:30 pm
Hosted by: ''Rob Pisarski''
Isolated quantum systems in extreme conditions can exhibit characteristic common properties despite dramatic differences in key parameters such as temperature, density, field strength and others. The existence of universal regimes, where even quantitative agreements between seemingly disparate physical systems can be observed, drives a remarkable convergence of research activities across traditional lines of specialization. I will describe the concerted research efforts by the recently established Heidelberg Collaborative Research Center ISOQUANT in collaboration with BNL and discuss recent developments concerning the thermalization dynamics of non-Abelian plasmas and ultracold atoms.