Comparison of results from a 2+1D relativistic viscous hydrodynamic model to elliptic and hexadecapole flow of charged hadrons measured in Au-Au collisions at $\sqrt{s_{ m {NN}}}$ = 200 GeV

摘要

Simulated results from a 2+1D relativistic viscous hydrodynamic model havebeen compared to the experimental data on the centrality dependence ofinvariant yield, elliptic flow ($v_{2}$), and hexadecapole flow ($v_{4}$) as afunction of transverse momentum ($p_{T}$) of charged hadrons in Au-Aucollisions at $\sqrt{s_{\rm {NN}}}$ = 200 GeV. Results from two types ofinitial transverse energy density profile, one based on the Glauber model andother based on Color-Glass-Condensate (CGC) are presented. We observe nodifference in the simulated results on the invariant yield of charged hadronsfor the calculations with different initial conditions. The comparison to theexperimental data on invariant yield of charged hadrons supports a shearviscosity to entropy density ratio ($\eta/s$) between 0 to 0.12 for the 0-10%to 40-50% collision centralities. The simulated $v_{2}(p_{T})$ is found to behigher for a fluid with CGC based initial condition compared to Glauber basedinitial condition for a given collision centrality. Consequently the Glauberbased calculations when compared to the experimental data requires a lowervalue of $\eta/s$ relative to CGC based calculations. In addition, a centralitydependence of the estimated $\eta/s$ is observed from the $v_{2}(p_{T})$ study.The $v_{4}(p_{T})$ for the collision centralities 0-10% to 40-50% supports a$\eta/s$ value between 0 - 0.08 for a CGC based initial condition. Whilesimulated results using the Glauber based initial condition for the ideal fluidevolution under estimates the $v_{4}(p_{T})$ for collision centralities 0-10%to 30-40%.