Probing the Phase Boundary between Hadronic Matter and the   Quark-Gluon-Plasma in Relativistic Heavy Ion Collisions
  We discuss recent data on particle production with emphasis on the degree of thermal and chemical equilibration achieved. The data are interpreted in terms of a resonance gas model. The phase boundary constructed between the resonance gas and the quark-gluon plasma is shown to be very close to the deduced parameters characterizing the hadronic fireball at freeze-out. 
P. Braun-Munzinger and J. Stachel