Bulletin of the American Physical Society
APS April Meeting 2022
Volume 67, Number 6
Saturday–Tuesday, April 9–12, 2022; New York
Session X12: Ultrarelativistic HeavyIon CollisionsRecordings Available

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Sponsoring Units: DNP Chair: Raghav Kunnawalkam Elayavalli, Yale University Room: Shubert 
Tuesday, April 12, 2022 10:45AM  10:57AM 
X12.00001: Heavy quarkonium dynamics at nexttoleading order in the binding energy over temperature Ajaharul Islam, Nora Brambilla, Miguel A Escobedo, Michael Strickland, Anurag Tiwari, Antonio Vairo, Peter V Griend We present a systematic method for solving the Lindblad equation for heavyquarkonium dynamics in the quarkgluon plasma which accounts for corrections that are nexttoleading order (NLO) in the ratio of the binding energy of the state and the temperature. The method used relies on mapping the threedimensional Lindblad evolution to the solution of the onedimensional Schrodinger evolution with stochastically sampled quantum jumps. We demonstrate how to achieve this dimensional reduction by writing the NLO complex Hamiltonian and jump operators in the spherical basis in which the operators act only on the radial part of the wave function. As result, one can implement the quantum trajectories method to solve the NLO Lindblad equation. Using the resulting NLO framework we can more reliably extend the calculation of heavyquarkonium suppression to lower temperatures than is possible with the LO formalism. 
Tuesday, April 12, 2022 10:57AM  11:09AM 
X12.00002: Quantify phenomenological effects of causality constraints in the hydrodynamic description of relativistic heavyion collisions Cheng Chiu, Chun Shen We study theoretical uncertainties in the hydrodynamic description of relativistic heavyion collisions by examining the full nonlinear causality conditions [1] and quantifying their effects on flow observables [2]. The causality conditions impose physical constraints on the maximum allowed values of inverse Reynolds numbers during the hydrodynamic evolution. We develop a new numerical scheme to impose the necessary and sufficient causality conditions on individual fluid cells during the evolution. We find that the necessary causality condition can effectively stabilize eventbyevent hydrodynamic simulations with large pressure gradients. Performing systematic simulations with and without the necessary and sufficient causality conditions, we quantify their effects on flow observables in p+Au and Au+Au collisions at the top RHIC energy and p+Pb and Pb+Pb collisions at LHC. Their impacts on the global Bayesian extraction of the QGP transport properties will be discussed. 
Tuesday, April 12, 2022 11:09AM  11:21AM 
X12.00003: Probing earlytime longitudinal dynamics with the Λ hyperon's spin polarization in relativistic heavyion collisions Sahr A Alzhrani, Chun Shen, Sangwook Ryu, Vahidin Jupic We present a systematic study of the hyperon global polarization's sensitivity to the collision systems' initial longitudinal flow velocity using 3+1D hydrodynamic simulations [1]. By explicitly imposing local energymomentum conservation when mapping the initial collision geometry to macroscopic hydrodynamic fields, the evolution of systems' orbital angular momentum (OAM) and fluid vorticity are studied. We find that a simultaneous description of the Λ hyperons' global polarization and the slope of pion's directed flow can strongly constrain the size of longitudinal flow at the beginning of hydrodynamic evolution. We constrain the initial longitudinal flow size and the fraction of orbital angular momentum in the produced QGP fluid as a function of collision energy with the STAR measurements in the RHIC Beam Energy Scan program. We examine the effects of the new thermal shear gradients on the hyperon's polarization. The gradients of µB/T can change the ordering between Λ's and Λ's polarization. Finally, we extend calculations to eventbyevent simulations for the isobar, Cu+Au, Au+Au, and U+U collisions at the top RHIC energies and study the systemsize dependence of novel correlations among hyperons polarization and charge hadrons' averaged transverse momentum and anisotropic flow coefficients. Measuring these correlations will verify the OAMvorticitypolarization paradigm in heavyion collisions. 
Tuesday, April 12, 2022 11:21AM  11:33AM 
X12.00004: Production of π, K, and proton(antiproton) in d+Au collisions at √S_{NN }= 19.6, 39, and 62.4 GeV Chuan Sun, Shengli Huang Measurements of identified particles in d+Au collisions will provide fundamental information for understanding cold nuclear matter effects on particle production, such as Cronin enhancement, nuclear shadowing, and gluon saturation. It will also be helpful to study particle production mechanisms in the hot QGP droplet. 
Tuesday, April 12, 2022 11:33AM  11:45AM 
X12.00005: The mean lifetimes of light nuclei and selfconsistency of the statistical hadronization model Boris Gelman The statistical hadronization model (SHM) describes the yields of hadrons and nuclei in heavy ion collisions. SHM parametrizes the data in terms of a small number of universal parameters such as the chemical freezeout temperature and chemical potentials. SHM achieves a remarkable phenomenological success over nine orders of magnitude in the hadron masses and several orders of magnitude in the energy of the colliding ions. In this talk, I will discuss the consistency of the assumptions underlying SHM by focusing on the yield of light nuclei whose binding energies are much lower than the chemical freezeout temperature predicted by the model. The statistical hadronization model can be used to derive the bounds on the mean lifetimes of the light nuclei in a thermally equilibrated hadronic gas. The analysis shows that these lifetime bounds are badly violated at the chemical freezeout temperature predicted by SHM. 
Tuesday, April 12, 2022 11:45AM  11:57AM 
X12.00006: QCD equation of state at finite density with a critical point from an alternative expansion scheme. Micheal KAHANGIRWE, Jamie M Karthein, Pierre V Moreau, Damien Price, Olga Soloveva, Jorg AICHELIN, Steffen A Bass, Elena Bratkovskaya, Claudia Ratti In Ref. [1], results for the QCD equation of state from the lattice Taylor expansion were combined with the 3D Ising model critical behavior, to build a family of equations of state which match the first principle results and contain a critical point in the expected universality class for QCD. This family of equations of state was limited to chemical potentials 0 ≤ μ_{B} ≤ 450 MeV, due to the limitations of the Taylor expansion. In Ref. [2], an alternative expansion scheme was introduced, for extrapolating the lattice QCD equation of state to finite chemical potential. In this research, we combine these two approaches to obtain a family of equations of state in the range 0 ≤ μ_{B} ≤ 700 MeV and 30 MeV ≤ T ≤ 800 MeV, that match the lattice QCD results at small density and contain a 3DIsing model critical point. With these new equations of state, we substantially extend the coverage of the QCD phase diagram. 
Tuesday, April 12, 2022 11:57AM  12:09PM 
X12.00007: Equilibrium and Dynamical Properties of Hot and Dense QuarkGluon matter from Holographic Black Holes Joaquin J Grefa, Jorge Noronha, Jacquelyn NoronhaHostler, Israel Portillo Vazquez, Claudia Ratti, Romulo Rougemont By using gravity/gauge correspondence, we employ an EinsteinMaxwellDilaton model to compute the equilibrium and outofequilibrium properties of a hot and baryon rich strongly coupled quarkgluon plasma. The family of 5dimensional holographic black holes, which are constrained to mimic the lattice QCD equation of state at zero density, is used to investigate the temperature and baryon chemical potential dependence of the equation of state [1]. We also obtained the baryon charge transport coefficients, the bulk and shear viscosities as well as the drag force and langevin diffusion coefficients associated with heavy quark jet propagation and the jet quenching parameter of light quarks in the baryon dense plasma, with a particular focus on the behavior of these observables on top of the critical end point and the line of first order phase transition predicted by the model. 
Tuesday, April 12, 2022 12:09PM  12:21PM 
X12.00008: Quantifying the uncertainty on the location of the holographic critical point Michael Trujillo, Joaquin J Grefa, Claudia Ratti, Israel Portillo Vazquez, Jorge Noronha, Jacquelyn NoronhaHostler, Mauricio T Hippert, Romulo Rougemont In Quantum Chromodynamics (QCD), we study the behavior of strongly interacting matter made up of quarks and gluons. The transition between the confined and lowenergy phase called hadron gas and the deconfined and hot quark gluon plasma phase is a smooth crossover at vanishing density. However, it has been conjectured the crossover must evolve into a line of first order phase transition with a critical end point. By using an EinsteinMaxwellDilaton (EMD) model, fixed to reproduce the LatticeQCD equation of state at vanishing chemical potential, we predict the location of a critical end point in the phase diagram. Two free functions in the EMD model are fixed to reproduce the lattice equation of state, a scalar dilation potential V(φ), and another corresponding to the coupling between the Maxwell and dilation fields, f(φ). By modifying these free functions, we study a possible change in the predicted location of the critical point in the phase diagram. 
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