Thermometric signals of quark-gluon plasma

Abstract

It is shown that the ratio of the production rates ( μ +μ − γ ) and ( π 0± μ +μ − ) are suitable thermometric signals for detection of a possible phase transition from the hadronic world to a quark-gluon plasma; saturation of the ratio ( μ +μ − γ ) is a signal of the phase transition most suitably picked up in the high M T ~ p T regime, while the ratio ( π 0± μ +μ −μ − ) as a function of M T changes over from the hadronic world to a quark-gluon plasma with a clear decrease in the slope. Possible methods to test the validity of thermodynamic equilibrium are also explored.