Perturbative QCD Calculations of Elliptic Flow and Shear Viscosity in Au+Au Collisions at $\sqrt{s_{NN}}=200$ GeV

TL;DR

This paper uses perturbative QCD calculations within a parton cascade model to estimate elliptic flow and shear viscosity in Au+Au collisions at 200 GeV, finding results consistent with experimental data and theoretical bounds.

Contribution

It provides a novel perturbative QCD-based approach to compute elliptic flow and shear viscosity in heavy-ion collisions, aligning with experimental observations.

Findings

Gluon plasma generates large elliptic flow $v_2$ consistent with measurements.

Calculated $ ext{eta}/s$ values are close to the lower bound from AdS/CFT conjecture.

Standard pQCD yields $ ext{eta}/s$ around 0.08-0.15.

Abstract

The elliptic flow $v_2$ and the ratio of the shear viscosity over the entropy density, $\eta/s$, of gluon matter are calculated from the perturbative QCD (pQCD) based parton cascade Boltzmann approach of multiparton scatterings. For Au+Au collisions at $\sqrt{s}=200$A GeV the gluon plasma generates large $v_2$ values measured at the BNL Relativistic Heavy Ion Collider. Standard pQCD yields $\eta/s\approx 0.08-0.15$ as small as the lower bound found from the anti-de Sitter/conformal field theory conjecture.