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

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.