A model investigation of the longitudinal broadening of the transverse momentum two-particle correlator

TL;DR

This study uses the AMPT model to explore how the longitudinal broadening of the transverse momentum two-particle correlator can be used to estimate the shear viscosity to entropy ratio of quark-gluon plasma in heavy ion collisions.

Contribution

It demonstrates that the longitudinal broadening of the correlator is sensitive to shear viscosity and discusses conditions for reliable extraction of this property.

Findings

Longitudinal broadening correlator is sensitive to $/s$.

Suppression of self-correlations is necessary for accurate measurements.

Model results support using correlator broadening to estimate shear viscosity.

Abstract

The Multi-Phase Transport model (AMPT) is used to investigate the longitudinal broadening of the transverse momentum two-particle correlator $C_{2}\left(\Delta\eta,\Delta\varphi\right)$, and its utility to extract the specific shear viscosity, $\eta/s$, of the quark-gluon plasma formed in ultra-relativistic heavy ion collisions. The results from these model studies indicate that the longitudinal broadening of $C_{2}\left(\Delta\eta,\Delta\varphi\right)$ is sensitive to the magnitude of $\eta/s$. However, reliable extraction of the longitudinal broadening of the correlator requires the suppression of possible self-correlations associated with the definition of the collision centrality.