# The Glasma, Photons and the Implications of Anisotropy

## TL;DR

This paper models the early-stage Glasma in heavy ion collisions, deriving photon production rates that reveal geometric scaling and are affected by anisotropy and delayed thermalization, impacting photon flow.

## Contribution

It introduces distribution functions for quarks and gluons in the Glasma and analyzes their impact on photon emission, highlighting effects of anisotropy and delayed equilibration.

## Key findings

- Photon rates follow geometric scaling with saturation momenta.
- Photon distributions from the Glasma are steeper than in thermalized plasma.
- Delayed equilibration and anisotropy lead to slower expansion and increased photon emission times.

## Abstract

We introduce distribution functions for quarks and gluons in the Glasma and discuss how they satisfy various relationships of statistical physics. We use these distributions to compute photon production in the early stages of heavy ion collisions. Photon rates satisfy geometric scaling, that is, the emission rate per unit area scales as a function of the saturation momenta divided by the transverse momentum of the photon. Photon distributions from the Glasma are steeper than those computed in the Thermalized Quark Gluon Plasma (TQGP). Both the delayed equilibration of the Glasma and a possible anisotropy in the pressure lead to slower expansion and mean times of photon emission of fixed energy are increased. This delayed emission might allow for larger photon elliptic flow.