High-energy photons from quark-gluon plasma versus hot hadronic gas

摘要: Photons in the energy range of about one-half to several GeV have been proposed as a signal formation quark-gluon plasma high-energy collisions. To lowest order thermal emission rate is infrared divergent for massless quarks, but we regulate this divergence using resummation technique Braaten and Pisarski. can also be produced hadron phase. We find that dominant contribution comes from reactions $\ensuremath{\pi}\ensuremath{\pi}\ensuremath{\rightarrow}\ensuremath{\rho}\ensuremath{\gamma}$ $\ensuremath{\pi}\ensuremath{\rho}\ensuremath{\rightarrow}\ensuremath{\pi}\ensuremath{\gamma}$; decays $\ensuremath{\omega}\ensuremath{\rightarrow}\ensuremath{\pi}\ensuremath{\gamma}$ $\ensuremath{\rho}\ensuremath{\rightarrow}\ensuremath{\pi}\ensuremath{\pi}\ensuremath{\gamma}$ are significant. Comparing rates at temperature $T=200$ MeV conclude gas shines just brightly plasma.