Strangeness Production and Color Deconfinement

The relative multiplicities for hadron production in different high energy\ncollisions are in general well described by an ideal gas of all hadronic\nresonances, except that under certain conditions, strange particle rates are\nsystematically reduced. We show that the suppression factor gamma_s, accounting\nfor reduced strange particle rates in pp, pA and AA collisions at different\ncollision energies, becomes a universal function when expressed in terms of the\ninitial entropy density s_0 or the initial temperature T of the produced\nthermal medium. It is found that gamma_s increases from about 0.5 to 1.0 in a\nnarrow temperature range around the quark-hadron transition temperature T_c =\n160 MeV. Strangeness suppression thus disappears with the onset of color\ndeconfinement; subsequently, full equilibrium resonance gas behavior is\nattained.