Departure from Equilibrium of the Quasi-Particle Distribution Functions in High Energy Nuclear Collisions

Abstract

In simulations of high energy heavy ion collisions that employ viscous hydrodynamics, single particle distributions are distorted from their thermal equilibrium form due to gradients in the flow velocity. These are closely related to the formulas for the shear and bulk viscosities in the quasi-particle approximation. Distorted single particle distributions are now commonly used to calculate the emission of photons and dilepton pairs, and in the late stage to calculate the conversion of a continuous fluid to individual particles. We show how distortions of the single particle distribution functions due to both shear and bulk viscous effects can be done rigorously in the quasi-particle approximation and illustrate it with the linear $\sigma$ model at finite temperature.

5 pages, 3 figures. This is the published version which takes into account comments from the referee

References in corpus (2)

• Quasi-Particle Theory of Shear and Bulk Viscosities of Hadronic Matter
• A scaling relation between proton-nucleus and nucleus-nucleus collisions

Cited by in corpus (4)

• Bayesian quantification of strongly-interacting matter with color glass condensate initial conditions
• Structure formation during phase transitions in strongly interacting matter
• Comprehensive simulation of heavy-ion collisions at non-zero baryon chemical potential
• Transport coefficients of chiral fluid dynamics using low-energy effective models