0 On the hadron production from the quark – gluon plasma phase in ultra – relativistic heavy – ion collisions

We describe the quark gluon plasma (QGP) as a thermalized quark–gluon system, the thermalized QGP phase of QCD. The hadronization of the thermalized QGP phase is given in a way resembling a simple coalescence model. The input parameters of the approach are the spatial volumes of the hadronization. We introduce three dimensionless parameters CM , CB and CB̄ related to the spatial volumes of the production of low–lying mesons (M), baryons (B) and antibaryons (B̄). We show that at the temperature T = 175MeV our predictions for the ratios of multiplicities agree good with the presently available set of hadron ratios measured for various experiments given by NA44, NA49, NA50 and WA97 Collaborations on Pb+Pb collisions at 158GeV/nucleon, NA35 Collaboration on S+S collisions and NA38 Collaboration on O+U and S+U collisions at 200GeV/nucleon. PACS numbers: 25.75.–q, 12.38.Mh, 24.85.+p E–mail: [email protected], State Technical University, Department of Nuclear Physics, 195251 St. Petersburg, Russian Federation E–mail: [email protected], Tel.: +43–1–58801–14261, Fax: +43–1–58801–14299 Participation within the Scientific Student Program of the Department of Nuclear Physics in State Technical University of St. Petersburg, Russian Federation State Technical University, Department of Nuclear Physics, 195251 St. Petersburg, Russian Federation E–mail: [email protected], St. Petersburg Institute for Nuclear Research, Gatchina, Russian Federation Permanent Address: State Technical University, Department of Nuclear Physics, 195251 St. Petersburg, Russian Federation