Rapidity Correlation Structure in Nuclear Collisions

TL;DR

This paper proposes a method to extract key transport coefficients like shear viscosity and isotropization time from rapidity-dependent transverse momentum correlations in nuclear collisions, using second order hydrodynamics with noise.

Contribution

It introduces a novel approach to determine the isotropization time and shear viscosity from correlation measurements in heavy-ion collisions.

Findings

Current data suggest $ au_/ u \u2248 10$

Methods for computing correlations with dissipative hydrodynamics are formulated

Targeted measurements can refine the precision of these parameters

Abstract

We show that measurements of the rapidity dependence of transverse momentum correlations can be used to determine the characteristic time $\tau_\pi$ that dictates the rate of isotropization of the stress energy tensor, as well as the shear viscosity $\nu = \eta/sT$. We formulate methods for computing these correlations using second order dissipative hydrodynamics with noise. Current data are consistent with $\tau_\pi/\nu \sim 10$, but targeted measurements can improve this precision.