PHOTON PRODUCTION IN AN EXPANDING AND CHEMICALLY EQUILIBRATING GLUON-ENRICHED PLASMA

Photon production in a longitudinally and transversely expanding gluon plasma with initially little quark admixture is considered. Chemical equilibration of quarks and gluons is followed by rate equations. The yields of hard photons with E greater-than-or-equal-to 2 GeV are insen sitive to chemical equilibration and depend mainly on the initial ther malized state. Medium-energy photons with E approximately 1 GeV are mo re frequently produced in case of faster equilibration, despite of fas ter cooling. For an assumed' fast equilibration we follow the evolutio n of matter through mixed and hadron phases. The transverse momentum k ick, due to transverse expansion, of photons from hadron matter is sho wn to be reduced for an equation of state with reduced latent heat. Th e photon yield in the region E > 1 GeV from deconfined matter dominate s for conditions, estimated to be achieved at RHIC, in case of a weakl y first-order confinement transition.