Jet-photons from an anisotropic {\em Quark-Gluon-Plasma}

TL;DR

This paper investigates how pre-equilibrium momentum-space anisotropy in the Quark-Gluon Plasma affects jet conversion photon production, showing significant modifications in photon distributions and comparing results with experimental data.

Contribution

It introduces a phenomenological model for anisotropic evolution of the Quark-Gluon Plasma and analyzes its impact on jet conversion photon yields, highlighting the importance of anisotropy in photon production.

Findings

Pre-equilibrium anisotropy significantly modifies photon $p_T$ distributions.

Fixed initial condition anisotropy enhances photon yields, while fixed final multiplicity suppresses them.

Model results align with PHENIX data for isotropization time around 1.5 fm/c.

Abstract

We calculate the $p_T$ distributions of jet conversion photons from {\em Quark Gluon Plasma} with pre-equilibrium momentum-space anisotropy. A phenomenological model has been used for the time evolution of hard momentum scale $p_{\rm hard}(\tau)$ and anisotropy parameter $\xi(\tau)$. As a result of pre-equilibrium momentum-space anisotropy, we find significant modification of the jet conversion photon $p_T$ distribution. For example, with {\em fixed initial condition} (FIC) pre-equilibrium anisotropy, we predict significant enhancement of the jet-photon $p_T$ distribution in the entire region, whereas for pre-equilibrium anisotropy with {\em fixed final multiplicity} (FFM), suppression of the jet conversion photons $p_T$ distribution is observed. The results with FFM (as it is the most realistic situation) have been compared with high $p_T$ PHENIX photon data. It is found that the data is reproduced well if the isotropization time lies within $1.5$ fm/c.