Photon emission from quark-gluon plasma out of equilibrium

TL;DR

This paper develops a new theoretical framework to analyze photon emission from an out-of-equilibrium quark-gluon plasma, incorporating coherence effects and viscous corrections for the first time.

Contribution

It introduces an integral equation for photon production in non-equilibrium QGP, including Landau-Pomeranchuk-Migdal effects and viscous corrections, advancing the understanding of electromagnetic emissions.

Findings

Derived an integral equation for photon emission in out-of-equilibrium QGP.

Included coherence effects like LPM in the out-of-equilibrium context.

Simplified the model for isotropic viscous plasmas with three key parameters.

Abstract

The photon emission from a non-equilibrium quark-gluon plasma (QGP) is analyzed. We derive an integral equation that describes photon production through quark-antiquark annihilation and quark bremsstrahlung. It includes coherence between different scattering sites, also known as the Landau-Pomeranchuk-Migdal effect. These leading-order processes are studied for the first time together in an out-of-equilibrium field theoretical treatment that enables the inclusion of viscous corrections to the calculation of electromagnetic emission rates. In the special case of an isotropic, viscous, plasma the integral equation only depends on three constants which capture the non-equilibrium nature of the medium.