# Pre-Equilibrium Stage and Phase Transition of Quark Matter Probed by Photon Interferometry

## TL;DR

This paper investigates photon production in heavy-ion collisions, revealing how photon correlations can signal the quark-gluon plasma phase transition by combining advanced models that include pre-equilibrium effects.

## Contribution

It introduces a novel approach integrating the Parton-Cascade-Model with 3D hydrodynamics to account for pre-equilibrium effects in photon emission analysis.

## Key findings

- Photon correlation width decreases sharply below 1.5 GeV transverse momentum.
- Pre-equilibrium effects significantly influence photon spectra.
- Photon interferometry can serve as a signature of the deconfinement phase transition.

## Abstract

We study single- and double-inclusive spectra of thermal photons, produced in heavy-ion collisions at $\sqrt{s}=200$ AGeV within a realistic space-time framework which combines the Parton-Cascade-Model and 3-dimensional hydrodynamics (HYLANDER). This allows also for the first time to take into account pre-equilibrium effects for photon production. A rapid decrease in the width of the correlation function as the photon transverse momentum drops below $\sim 1.5$ GeV is a signature of the deconfinement phase transition.