Rapidity correlations test stochastic hydrodynamics

TL;DR

This paper proposes using rapidity-dependent transverse momentum correlations to measure key parameters like isotropization time and shear viscosity in stochastic hydrodynamics, providing a new experimental approach.

Contribution

It introduces methods to compute correlations in second order dissipative hydrodynamics with noise, linking measurements to fundamental hydrodynamic parameters.

Findings

Current data suggest $ au_{c} / u \u2248 10

Methods enable precise determination of isotropization time

Framework connects experimental correlations to hydrodynamic properties

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.