Photon Production : a Signature of Quark-Gluon Plasma Formationin Relativistic Nuclear Collisions

Considering the influence of latent heat, the photon spectra from the quark-gluon plasma (QGP) and from the hadronic background are calculated. A “full stopping scenario” which assumes a spherical nuclear fireball expanding in a 3+1 dimensional flamework is addressed to solve the relativistic hydrodynamic equations. Our results show that at large transverse momenta, say p_r≥ 4 - 5 GeV/c, one may probably expect to distinguish the photons originating in QGP from in the hadronic background. According to the measured total spectrum authors pose a graphical method to diagnose if QGP exists.