Bulletin of the American Physical Society
2021 Fall Meeting of the APS Division of Nuclear Physics
Volume 66, Number 8
Monday–Thursday, October 11–14, 2021; Virtual; Eastern Daylight Time
Session LH: Theory Developments in Heavy Ion Collisions |
Hide Abstracts |
Chair: Derek Teaney, Stony Brook University Room: Whittier |
Wednesday, October 13, 2021 2:00PM - 2:12PM |
LH.00001: Simulating heavy-ion collisions at finite baryon densities Aritra De, Joseph I Kapusta, Thomas P Welle, Mayank Singh We present results from our new framework simulating heavy-ion collisions at non-zero baryon densities. We dynamically initialize the system using a LEXUS [1] inspired 3D Monte-Carlo initialization model. Our initial-state model parameters are constrained by nucleon-nucleon collision data. We use the hydrodynamic package MUSIC [2] to solve the hydrodynamic equations and perform the Cooper-Frye procedure. We used departure func- tions derived from the quasiparticle theory [3] of transport coefficients for hadronic matter at non-zero baryon density. We employ a crossover equation of state which connects the equations of state of an excluded volume hadron resonance gas with that of perturbative QCD [4]. |
Wednesday, October 13, 2021 2:12PM - 2:24PM |
LH.00002: Fluctuations of conserved charges beyond the ideal HRG model Jamie M Karthein, Volker Koch, Claudia Ratti, Volodymyr Vovchenko We investigate extensions of the Hadron Resonance Gas (HRG) Model beyond the ideal case by implementing both attractive and repulsive additions to the model. When considering additional states exceeding those measured with high confidence by the Particle Data Group, additive corrections to the overall pressure in the HRG model are imposed. On the other hand, we also apply excluded-volume corrections, which ensure there is no overlap of baryons by turning on repulsive (anti)baryon-(anti)baryon interactions. We see that these two extensions are complementary and focus on the agreement with first-principles lattice QCD results on fluctuations of conserved charges. We note that these results are interesting for heavy-ion-collision systems at both the LHC and RHIC. In particular, we find interesting ratios of susceptibilities that are sensitive to one correction and not the other. This allows us to constrain the excluded volume and particle spectrum effects separately. Additionally, we see that strangeness susceptibilities indicate a smaller excluded volume for hyperons than non-strange baryons. |
Wednesday, October 13, 2021 2:24PM - 2:36PM |
LH.00003: A lattice-based equation of state to study the matter at the Bean Energy Scan. Pierre V Moreau, Olga Soloveva, Taesoo Song, Elena Bratkovskaya, Steffen A Bass We construct a novel equation of state (EoS) describing QCD (Quantum Chromodynamic) matter at finite temperature and baryon B, electric Q and strangeness S chemical potentials by utilizing the alternate expansion scheme from the lattice QCD results [Phys.Rev.Lett. 126 (2021) 23, 232001]. This procedure allows to reliably estimate the baryon and strangeness densities at larger values of the baryon chemical potential μB in comparison to the usual Taylor expansion in terms of susceptibilities. We use the latter only to incorporate the μQ and μS dependence into thermodynamic quantities, which is sufficient for studying the matter as produced in relativistic heavy-ion collisions. We then smoothly match this lattice-based EoS at high temperature with the thermodynamics of the Hadron-Resonance Gas (HRG) model at low temperature. Finally we employ this newly constructed EoS to illustrate the trajectories of the matter produced at the Beam Energy Scan (BES) program by coarse-graining the Parton-Hadron-String Dynamics (PHSD) transport approach which consistently describes the whole non-equilibrium dynamics of heavy-ion collisions, from the early nucleon hard scatterings, to the partonic phase based on the Dynamical QuasiParticle Model (DQPM), and up to the final hadron rescatterings. |
Wednesday, October 13, 2021 2:36PM - 2:48PM |
LH.00004: Bayesian analysis of strong and weakly coupled pre-hydrodynamic stage using the Trajectum heavy ion code Govert Nijs, Wilke van der Schee In Bayesian analyses, the pre-hydrodynamic stage is usually modeled by free streaming of massless particles, implicitly assuming vanishing coupling. In this work, we present an AdS/CFT inspired model for the pre-hydrodynamic stage, which is therefore strongly coupled. Furthermore, we interpolate between both models using a parameter. This allows us to confront both models with data, whereby the interpolating parameter can teach us which model describes experimental data best. |
Wednesday, October 13, 2021 2:48PM - 3:00PM |
LH.00005: The η/s - q^/T3 Relation at Next-to-Leading Order Berndt Mueller The Majumder-Müller-Wang relation [1] between the specific shear viscosity η/s and the dimensionless jet quenching parameter q^/T3 in perturbative QCD is obtained at next-to-leading order in the QCD coupling constant. It is shown that the relation changes only modestly, although both transport coefficients independently are subject to large modifications at the NLO level. This finding confirms that the relationship is robust. |
Wednesday, October 13, 2021 3:00PM - 3:12PM |
LH.00006: Electromagnetic probes of strongly magnetized quark-gluon plasma Igor A Shovkovy, Xinyang Wang The polarization effects of a strongly magnetized quark-gluon plasma are studied at finite temperature and nonzero baryon chemical potential. It is found that a background magnetic field can have a strong effect on the photon and dilepton emission rates. It affects not only the total rate but also the angular dependence. In particular, the Landau-level quantization leads to a nontrivial momentum dependence of the photon ellipticity coefficient on transverse momentum. It is proposed that the anisotropy of the photon and dilepton emission may serve as indirect measurements of the magnetic field. |
Wednesday, October 13, 2021 3:12PM - 3:24PM |
LH.00007: Chiral Cherenkov radiation in Quark Gluon Plasma and other chiral media Kirill Tuchin Chiral Cherenkov radiation is a particular type of radiation emitted by a charged fermion traversing chiral medium. Its most remarkable features—the resonant behavior at a certain emission angle and the circular polarization of the spectrum—depend on the parameters of the chiral anomaly in a particular material or matter. Chiral Cherenkov radiation can be used to investigate the chiral anomaly in such diverse media as the quark-gluon plasma, Weyl semimetals, and axionic dark matter. Unlike the Cherenkov radiation, the chiral Cherenkov radiation gives a major contribution to the particle collisional energy loss. I discuss both quantum and classical aspects of the chiral Cherenkov radiation and its phenomenological applications. |
Wednesday, October 13, 2021 3:24PM - 3:36PM |
LH.00008: Challenges in Solving Chiral Hydrodynamics Jorge Noronha, Enrico Speranza We show that the widely known theory of ideal chiral hydrodynamics, as derived from chiral kinetic theory, is acausal and its initial-value problem is ill-posed. Having an ill-posed initial-value problem means that the solution of the partial differential equations does not exist or is not unique, which implies that the system cannot be solved and numerical simulations cannot be performed. Therefore, such theory cannot be used to determine how the chiral anomaly affects the hydrodynamic evolution of the quark-gluon plasma formed in ultrarelativistic heavy-ion collisions. We also demonstrate that the standard first-order theory of viscous chiral hydrodynamics is acausal. We show that these fundamental issues can be cured by using different definitions (frames) for the hydrodynamic fields. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700