2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/82784The present status of theoretical expectations of studies of single photons from relativistic heavy ion collisions is discussed. It is argued that the upper limit of single photon radiation from S+Au collisions at CERN SPS obtained by the WA80 collaboration perhaps rules out any reasonable description of the collision process which does not involve a phase transition to quark gluon plasma. Predictions for single photons from the quark-matter likely to be created in collision of two lead nuclei at RHIC and LHC energies are given with a proper accounting of chemical equilibration and transverse expansion. Finally, it is pointed out that, contrary to the popular belief of a quadrilateral dependence of electromagnetic radiations ($N_γ$) from such collisions on the number of charged particles ($N_{ch})$, we may only have $N_γ\propto N_{ch}^{1.2}$.Invited Talk given at Third International Conference on Physics and Astrophysics of Quark Gluon Plasma, Jaipur, India, March 1997Nuclear Theorytext