Shen Chun, Schenke Björn, Zhao Wenbin
Department of Physics and Astronomy, Wayne State University, Detroit, Michigan 48201, USA.
RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973, USA.
Phys Rev Lett. 2024 Feb 16;132(7):072301. doi: 10.1103/PhysRevLett.132.072301.
This work presents the first Bayesian inference study of the (3+1)D dynamics of relativistic heavy-ion collisions and quark-gluon plasma viscosities using an event-by-event (3+1)D hydrodynamics+hadronic transport theoretical framework and data from the Relativistic Heavy Ion Collider Beam energy scan program. Robust constraints on initial state nuclear stopping and the baryon chemical potential-dependent shear viscosity of the produced quantum chromodynamic (QCD) matter are obtained. The specific bulk viscosity of the QCD matter is found to exhibit a preferred maximum around sqrt[s_{NN}]=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 for net baryon chemical potential μ_{B}∼0.2(0.4) GeV.
这项工作首次使用逐事件的(3+1)维流体动力学+强子输运理论框架以及相对论重离子对撞机束流能量扫描计划的数据，对相对论重离子碰撞的(3+1)维动力学和夸克-胶子等离子体粘性进行了贝叶斯推断研究。获得了对初始状态核阻止以及所产生的量子色动力学(QCD)物质的依赖于重子化学势的剪切粘性的有力约束。发现QCD物质的比体粘性在(\sqrt[s_{NN}]=19.6) GeV附近呈现出一个偏好的最大值。对于净重子化学势(\mu_{B}\sim0.2(0.4)) GeV，该结果允许相对于所采用的基于格点QCD的状态方程，对声速的降低(和/或增加)进行另一种解释。
