Model study of the energy dependence of the correlation between anisotropic flow and the mean transverse momentum in Au+Au collisions

Abstract

A hybrid model that employs the hadron-string transport model UrQMD and the (3+1)D relativistic viscous hydrodynamic code vHLLE, is used to investigate the beam energy dependence of the correlation coefficient ρ(v 2 2 , [pT ]) between the average transverse momentum [pT ] of hadrons emitted in an event and the square of the anisotropic flow coefficient v 2 2 . For Au+Au collisions, the model predicts characteristic patterns for the energy and event-shape dependence of the variances for [pT ] and v 2 n (Var([pT ]) and Var(v 2 2 )), and the covariance of v 2 n and [pT ] (cov(v 2 2 , [pT ])), consistent with the attenuation effects of the specific shear viscosity η/s. In contrast, ρ(v 2 2 , [pT ]) is predicted to be insensitive to the beam energy but sensitive to the initial-state geometry of the collisions. These observations suggest that a precise set of measurements for Var ([pT ]), Var(v 2 2 ), cov(v 2 2 , [pT ]) and ρ(v 2 2 , [pT ]) as a function of beam-energy and event-shape, could aid precision extraction of the temperature and baryon chemical-potential dependence of η/s from the wealth of Au+Au data obtained in the RHIC beam energy scan.