Centrality dependence of elliptic flow and QGP viscosity

TL;DR

This paper analyzes PHENIX data on elliptic flow in Au+Au collisions using Israel-Stewart hydrodynamics, revealing that the QGP viscosity varies with collision centrality, being higher in peripheral collisions.

Contribution

It provides a detailed analysis of how QGP viscosity depends on collision centrality using second-order hydrodynamics and recent experimental data.

Findings

Viscosity to entropy ratio ($\,\eta/s$) ranges from 0 to 0.17 across centralities.

More viscous fluid behavior is observed in peripheral collisions.

Hydrodynamic modeling aligns with experimental elliptic flow data.

Abstract

In the Israel-Stewart's theory of second order hydrodynamics, we have analysed the recent PHENIX data on charged particles elliptic flow in Au+Au collisions. PHENIX data demand more viscous fluid in peripheral collisions than in central collisions. Over a broad range of collision centrality (0-10%- 50-60%), viscosity to entropy ratio ($\eta/s$) varies between 0-0.17.