Effects of EoS in viscous hydro + cascade model for the RHIC Beam Energy Scan

Abstract

A state-of-the-art 3+1 dimensional cascade + viscous hydro + cascade model vHLLE+UrQMD has been applied to heavy ion collisions in RHIC Beam Energy Scan range sNN=7.7,…,200 GeV. Based on comparison to available experimental data it was estimated that an effective value of shear viscosity over entropy density ratio η/s in hydrodynamic stage has to decrease from η/s=0.2 to 0.08 as collision energy increases from sNN=7.7 to 39 GeV, and to stay at η/s=0.08 for 39≤s≤200 GeV.In this work we show how an equation of state with first order phase transition affects the hydrodynamic evolution at those collision energies and changes the results of the model as compared to “default scenario” with a crossover type EoS from chiral model.