Photon production in S + Au nuclear collisions at SPS energies

Abstract A modified hydrodynamical “tube” model is applied to study hard thermal photon production from the quark-gluon plasma (QGP) and hot hadronic matter in central S + Au nuclear collisions at SPS energies. Resonance production and the jump of the sound velocity at the phase transition between hadronic phase and QGP is taken into account. Hard direct photon emission is also investigated with the consideration of nuclear shadowing effect on structure function of quarks and gluons. The predicted photon yield does not contradict the experimental data obtained by the WA80 Collaboration.