Off-equilibrium corrections to energy and conserved charge densities in the relativistic fluid in heavy-ion collisions

TL;DR

This paper explores how off-equilibrium dissipative corrections to energy and charge densities affect relativistic hydrodynamics in heavy-ion collisions, revealing potential observable modifications in particle spectra and flow.

Contribution

It formulates causal dissipative hydrodynamics including off-equilibrium corrections and analyzes their impact on heavy-ion collision observables.

Findings

Particle spectra are visibly modified by off-equilibrium corrections.

Elliptic flow shows noticeable changes due to dissipative effects.

The relation between hydrodynamic stability and transport coefficients is discussed.

Abstract

Dissipative processes in relativistic fluids are known to be important in the analyses of the hot QCD matter created in high-energy heavy-ion collisions. In this work, I consider dissipative corrections to energy and conserved charge densities, which are conventionally assumed to be vanishing but could be finite. Causal dissipative hydrodynamics is formulated in the presence of those dissipative currents. The relation between hydrodynamic stability and transport coefficients is discussed. I then study their phenomenological consequences on the observables of heavy-ion collisions in numerical simulations. It is shown that particle spectra and elliptic flow can be visibly modified.