Estimation of shear viscosity based on transverse momentum correlations

TL;DR

This paper investigates how transverse momentum correlations in heavy ion collisions can be used to estimate the shear viscosity-to-entropy ratio of the created matter, providing preliminary experimental insights.

Contribution

It introduces a comparison of two correlation functions as novel observables for studying shear viscosity in heavy ion collisions.

Findings

Preliminary measurements of transverse momentum correlations at RHIC.

Comparison of inclusive and differential correlation functions.

Potential for these observables to inform shear viscosity estimates.

Abstract

Event anisotropy measurements at RHIC suggest the strongly interacting matter created in heavy ion collisions flows with very little shear viscosity. Precise determination of "shear viscosity-to-entropy" ratio is currently a subject of extensive study. We present preliminary results of measurements of the evolution of transverse momentum correlation function with collision centrality of $Au +Au$ interactions at $\sqrt{s_{NN}}$ = 200 GeV. We compare two differential correlation functions, namely {\it inclusive} and a differential version of the correlation measure $\tilde C$ introduced by Gavin ${\it et. al.}$. These observables can be used for the experimental study of the shear viscosity per unit entropy.