Hard Photon Productions out of Equilibrium
The production rate of hard photons from a QCD plasma out of equilibrium is worked out. A simple scenario is used to describe the departure from equilibrium in the case of a quark gluon plasma locally thermalized and away from chemical equilibrium. The space time inhomogeneities of the medium are supposed to be described by a ``macroscopic'' variable varying on scales larger than $1/gT$. The calculation is performed to leading order in $g$ for a hard photon with energy $E_{\gamma} \gg T$. Within the closed time path formalism, using the hard thermal loop framework, it is shown that dynamical screening provides a finite rate in the same way as in equilibrium.
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