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

The Multi-Phase Transport model (AMPT) is used to investigate the longitudinal broadening of the transverse momentum two-particle correlator $C_2(\mathrm{\Delta }\eta ,\mathrm{\Delta }\phi )$, and its utility to extract the specific shear viscosity, $\eta \mathrm{/}s$, of the quark-gluon plasma formed in ultra-relativistic heavy ion collisions. The results from these model studies indicate that the longitudinal broadening of $C_2(\mathrm{\Delta }\eta ,\mathrm{\Delta }\phi )$ is sensitive to the magnitude of $\eta \mathrm{/}s$. 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.