PHOTON RADIATION FROM EXPANDING GLUON-RICH PLASMA

Photon production in expanding gluon plasma with an initially small ad mixture of quarks is considered. Photons are created in the lowest ord er (in alpha(s)) processes that involve quarks. Chemical equilibration of quarks is governed by rate equations based on the lowest order (in alpha(s)) processes gg reversible arrow <q(q)over bar>. Expansion slo ws down quark production. A drastic reduction of intermediate-energy p hotons in relation to standard-local equilibrium estimates is obtained if the initial quark admixture is 20% below the chemical-saturation d ensity. Higher initial temperatures increase significantly the yield o f high-energy photons and overcompensate this reduction.