Chemical nonequilibrium and deconfinement in 200A GeV sulphur induced reactions

We interpret hadronic particle abundances produced in S-Au/W/Pb 200A GeV reactions in terms of the final state hadronic phase space model and determine by a data fit of the chemical hadron freeze-out parameters. Allowing for the flavor abundance nonequilibrium a highly significant fit to experimental particle abundance data emerges, which supports the possibility of strangeness distillation. We find under different strategies stable values for freeze-out temperature T-f=143+/-3 MeV, baryochemical potential mu(B)=173 +/-6 MeV, ratio of strangeness (gamma(s)) and light quark (gamma(q)) phase space occupancies gamma(s)/gamma(q)=0.60+/-0.02, and gamma(q)=1.22+/-0.05 without accounting for collective expansion (radial flow). When introducing flow effects which allow a consistent description of the transverse mass particle spectra, yielding \(v) over right arrow(c)\ = 0.49 +/- 0.01 c, we find gamma(s)/gamma(q)= 0.69 +/- 0.03, gamma(q) = 1.41 +/- 0.08. The strange quark fugacity is fitted at lambda(s) = 1.00+/- 0.02 suggesting chemical freeze-out directly from the deconfined phase. [S0556-2813(99)01402-8].