Viscous Hydrodynamic Evolution with Non-Boost Invariant Flow for the Color Glass Condensate

TL;DR

This paper develops a viscous hydrodynamic model with non-boost invariant flow to better understand the evolution of the color glass condensate in heavy ion collisions, addressing discrepancies in multiplicity predictions at the LHC.

Contribution

It introduces a full second-order viscous hydrodynamic model for longitudinal expansion that accounts for non-boost invariant flow, improving the description of CGC evolution.

Findings

Viscous hydrodynamics deforms rapidity distributions during evolution.

Entropy production and flux significantly affect the distributions.

Results highlight the importance of non-boost invariant flow in CGC modeling.

Abstract

The Large Hadron Collider (LHC) experiments have revealed that the predictions of the color glass condensate (CGC) tend to underestimate the multiplicity at mid-rapidity. We develop and estimate a full second-order viscous hydrodynamic model for the longitudinal expansion to find that the CGC rapidity distributions are visibly deformed during the hydrodynamic stage due to the interplay between the entropy production and the entropy flux to forward rapidity. The results indicate the importance of viscous hydrodynamic evolution with non-boost invariant flow for understanding the CGC in terms of the heavy ion collisions.