Search for QGP and thermal freeze-out of strange hadrons

After reviewing the observables of QGP we perform an analysis of m ⊥ spectra of strange hadrons measured as function of centrality in 156 A GeV Pb-Pb interactions. We show that there is a good agreement between the chemical and thermal freeze-out conditions, providing additional evidence for the formation and sudden disintegration of a supercooled QGP fireball.