Overview
The on-line seminar series on “RHIC Beam Energy Scan: Theory and Experiment” will be held online weekly using ZOOM.The topics of this online seminar series cover broad aspects of hot and dense QCD matter, with an emphasis on physics related to RHIC beam energy scan (BES) program.
The VII-th season of the online seminar series is scheduled on every other Tuesday and the first talk will start on Oct. 10, 2023 Considering that our participants and speakers come from all parts of the world, we have selected the following time slot for the seminar: 6:00am (San Francisco), 9:00am (New York), 3:00pm (Frankfurt), 6:30pm(New Delhi), 10:00pm (Beijing), 11:00pm (Tokyo) Each talk will be one hour long, with a limited number of questions allowed during the talk, followed by an additional 30 minutes for discussion.
Organizers:
Heinz, Ulrich (OSU) heinz.9@osu.edu
Luo, Xiaofeng (CCNU) xfluo@ccnu.edu.cn
Ratti, Claudia (UH) cratti@central.uh.edu
Song, Huichao (PKU) huichaosong@pku.edu.cn
Xu, Nu (LBNL) nxu@lbl.gov
Yin, Yi (IMP) yiyin@impcas.ac.cn
Schedule
Oct. 10th
BES physics: the current status and future outlook
Helen Caines (Yale)
Abstract:
I will present the current status of analyses of the RHIC BES datasets, with a focus on those results released over the summer. I will then briefly discuss open questions and opportunities that remain to be exploited in the future.
Chair: Nu Xu (LBNL)
Oct. 24 th
Bayesian Inference the RHIC BES measurements using a full (3+1)D hybrid framework
Chun Shen (Wayne State U.)
Abstract: This talk will present the Bayesian inference approach for quantitatively characterizing the 3D dynamics of heavy-ion collisions and the Quark-Gluon Plasma (QGP) properties in the RHIC Beam Energy Scan (BES) program. To model the dynamics of the collisions from 7.7 to 200 GeV, we employ a (3+1)D dynamical initialization model coupled with the relativistic viscous hydrodynamics + hadronic cascade hybrid framework. By carrying out a joint Bayesian analysis of the RHIC BES phase I measurements for Au+Au collisions at 7.7, 19.6, and 200 GeV, we set robust constraints on initial-state nuclear stopping and the baryon chemical potential dependence of the QGP specific shear viscosity. The specific bulk viscosity of the QCD matter is found to exhibit a preferred maximum around 19.6 GeV. This result allows for the alternative interpretation of a reduction (and/or increase) of the speed of sound relative to that of the employed lattice-QCD based equation of state (EOS) for net baryon chemical potential ∼ 0.2 (0.4) GeV.
Chair: Hui-Chao Song (Peking U. )
Nov.7th
Lattice constraints on the QCD phase diagram
Owe Philipsen (Frankfurt)
Abstract: A strong fermion sign problem prohibits direct lattice simulations of QCD at finite baryon density, so that knowledge of the phase diagram is limited to small chemical potentials. On the other hand, the phase diagram is severely constrained by information about the chiral limit.
I discuss recent lattice results at vanishing density, which show the chiral phase transition for theories with Nf=2-7 degenerate massless quarks to be of 2nd order, contrary to the predictions of the seminal 1984 paper by Pisarski and Wilczek. Work in progress demonstrates that this 2nd order nature of the chiral transition does not change as a function of imaginary chemical potential, for which there is no sign problem. I discuss the emerging bounds on a possible critical endpoint in physical QCD at finite density.
Chair: Misa Stephanov (UIC)
Nov 21st
Hydrodynamics from an exact collision kernel
Gabriel Denicol (Universidade Federal Fluminense )
Abstract: We derive and investigate several hydrodynamic formalisms that emerge from a system of classical, ultra-relativistic scalar particles self-interacting via a quartic potential. The specific form of the total cross-section enables the analytical computation of all transport coefficients that appear in Navier-Stokes (NS), Bemfica-Disconzi-Noronha-Kovtun (BDNK), and second-order transient hydrodynamic theories. We solve all these formalisms in a Bjorken flow scenario and show that NS and BDNK theories display unphysical features when gradients become sufficiently large. This implies that these hydrodynamic approaches may not be suitable to describe the early stages of heavy ion collisions. We also discuss if the derived theories are causal and stable.
Chair: Dirk Rischke (Frankfurt)
Dec. 5th
Tracking the baryon number in quarks and gluons via heavy-ion collisions
Zhangbu Xu (BNL)
Abstract: Baryon number (B) is a conserved quantum number that prevents protons and stable nuclei from disintegration. This governs the visible Universe as it is today. It is conventionally assumed that the unit baryon number in a nucleon is distributed equally among its three valence quarks. Alternatively, it was proposed at the birth of the theory of the Quantum Chromodynamics (QCD) half a century ago that the baryon number is instead traced by the baryon junction, a non-perturbative Y-shaped topology of gluons that is connected to all three valence quarks. In most of the physics processes, these two scenarios are indistinguishable. Neither of these pictures have been experimentally verified. On the contrary, different experiments have demonstrated the fractional charges carried by the quarks. Relativistic heavy-ion collisions provide the necessary tools to study baryon transports in a non-perturbative way over large rapidity distance. I will present three experimental results we carried out at the Relativistic Heavy Ion Collider (RHIC) at the Brookhaven National Laboratory in the US recently to test the hypotheses using isobar and Beam Energy Scan data collected by the STAR Collaboration. I will also review the previous experimental measurements in lepton+hadron and p+p collisions relevant to this topic, and discuss what we can do in the future at RHIC, the LHC and EIC.
Chair: Li-Juan Ruan (BNL)
Code of Conduct :
The organizers are committed to making this seminar series productive and enjoyable for everyone. Creating a supportive professional environment where open and frank discussion of ideas can take place, where everyone is treated with courtesy and respect, and in which diversity and inclusion are valued is the responsibility of all the participants. We will not tolerate harassment of attendees or others involved in the conference in any form. By joining the Zoom call, you agree to follow these guidelines:
1) Behave professionally in personal interactions. Harassment and sexist, racist, or exclusionary comments or jokes are not appropriate. Harassment includes sustained disruption of talks or scientific discussions, deliberate intimidation, stalking, offensive comments related to gender identity, sexual orientation, disability, physical appearance, body size, race, nationality, or the religion or non-religion of participants.
2) Be kind to others. Do not insult or put down the speaker or the other attendees. Scientific discussion and criticism is vital and should be conducted in this spirit.
3) All communication should be appropriate for a professional audience including people of many different backgrounds.
Should a participant be asked to stop any inappropriate behavior, they are expected to comply immediately. In serious cases, they may be muted or asked to leave the meeting at the sole discretion of the organizers.
