Quark-Gluon Plasma in Pb--Pb 158 A GeV collisions: Evidence from strange   particle abundances and the Coulomb effect
  The hadronic particle production data from relativistic nuclear Pb--Pb 158 A GeV collisions are successfully described within the chemical non-equilibrium model, provided that the analysis treats Omega and anti-Omega abundances with care. We further show that there is a subtle influence of the Coulomb potential on strange quarks in quark matter which is also seen in our data analysis, and this Coulomb effect confirms the finding made by chemical analysis in the S--Au/W/Pb 200 A GeV collisions that the hadron particle source is deconfined with respect to strange quark propagation. Physical freeze-out conditions (pressure, specific energy, entropy, and strangeness) are evaluated and considerable universality of hadron freeze-out between the two different collision systems is established. 
Jean Letessier and Johann Rafelski (LTHE-Paris 7 and Department of   Physics, University of Arizona, Tucson, AZ, 85721)