PARAMETRIZATION OF THERMAL PHOTON-EMISSION RATES FROM MESONIC MATTER

Photons have long been considered as a probe of the dynamics of high energy nuclear collisions. Here we present simple analytical expressions which parametrize the thermal production rates of photons for the processes pi-pi --> rho-gamma, pi-rho --> pi-gamma, and rho --> pi-pi-gamma which are occuring in hot mesonic matter. These parametrizations are good for photon energies greater than 150 MeV and for temperatures between 100 and 200 MeV. They can be used in various thermal and hydrodynamical models of heavy ion collisions.