Hadron production in relativistic nuclear collisions: thermal hadron source or hadronizing quark-gluon plasma?

Measured hadron yields from relativistic nuclear collisions can be equally well understood in two physically distinct models, namely a static thermal hadronic source vs. a time-dependent, nonequilibrium hadronization off a quark-gluon plasma droplet. Due to the time-dependent particle evaporation off the hadronic surface in the latter approach the hadron ratios change (by factors of less than or similar to <5) in time. Final particle yields reflect time averages over the actual thermodynamic properties of the system at a certain stage of the evolution. Calculated hadron, strangelet and (anti-)cluster yields as well as freeze-out times are presented for different systems. Due to strangeness distillation the system moves rapidly out of the T, mu(q) plane into the mu(s)-sector. Strangeness to baryon ratios f(s) = 1 - 2 prevail during a considerable fraction (50%) of the time evolution (i.e. Lambda-droplets or even Xi(-)-droplets form the system at the late stage: The possibility of observing this time evolution via two-particle correlations is discussed). The observed hadron ratios require T-x approximate to 160 MeV and B-1/4 greater than or similar to 200 MeV. If the present model is fit to the extrapolated hadron yields, metastable hypermatter can only be produced with a probability p < 10(-8) for A greater than or equal to 4.