Anisotropic flows and the shear viscosity of the QGP within an event-by-event massive parton transport approach

Abstract

We have developed an event-by-event relativistic kinetic transport approach to study the build up of the anisotropic flows v_{n}(p_T) for a system at fixed eta /s(T). The partonic approach describe the evolution of massless partons which imply epsilon =3p as Equation of State (EoS). We extend previous studies to finite partonic masses tuned to simulate a system that expand with an EoS close to the recent lQCD results. We study the role of EoS and the effect of eta /s(T) ratio on the build up of v_n(p_T) up to n=5 for two beam energies: RHIC energies at sqrt{s}=200 GeV and LHC energies at sqrt{s}=2.76 TeV. We find that for the two beam energies considered the suppression of the v_n(p_T) due to the viscosity of the medium have different contributions coming from the cross over or QGP phase. We shows that in ultra-central collisions (0–0.2%) the v_n(p_T) have a stronger sensitivity to the T dependence of eta /s that increases with the order of the harmonic n. Finally, we discuss the results for the integrated flow harmonics langle v_{n} rangle in ultra-central collisions pointing-out how the relative strength of langle v_{n} rangle depend on the colliding energies as well as on the freeze-out dynamics.