arXiv subjects
Publications and source records attributed to Jan Rafelski.
We study the chemical conditions at freeze-out associated with the production of strange-particles in Si-Au collisions at 14.6 GeV A. We obtain freeze-out chemical potentials and temperature, and determine the entropy as well as the final particle abundance. We also consider in detail the alternative evolution scenarios involving the hadronic gas and the deconfined phase.
We reconsider thermal conditions of the central fireball presumed to be the source of abundantly produced strange (anti-)baryons in S -> W collisions at 200 GeV A. We show that it is possible to completely fix the freeze-out temperature of strange particles in terms of the central rapidity kaon to Lambda particle abundance ratio at fixed, high transverse mass using a non-equilibrium hadronization model and the measured quark fugacities.
We investigate here the relative abundance of strange particles produced in nuclear collisions at the SPS energies (9 GeV A in CM frame) assuming that the central reaction fireball consists of quark-gluon plasma. We show that the total strangeness yield in S-S, S-Ag and S-W reactions is compatible with this picture.
We study as function of the collision energy and stopping the thermal conditions reached in a quark-gluon plasma fireball formed in a relativistic heavy ion collision. We explore strange particle yields for the current round of Pb-Pb and Au-Au experiments.
We describe the remarkable accomplishments of the current heavy ion Pb--Pb collision experiments involving strange particle production, carried out at 158A GeV at CERN--SPS. These experimental results, together with the earlier 200A GeV S-induced reactions, imply that, at central rapidity, a novel mechanism of strangeness production arises, accompanied by excess entropy formation. We argue that: These results are consistent with the formation of a space-time localized, highly excited, dense state of matter; The freeze-out properties of strange hadrons are suggestive of the formation of a color-deconfined, thermally and nearly chemically equilibrated phase, which provides at present the only comprehensive framework to describe all experimental data; The matter fireball is undergoing a transverse expansion with nearly the velocity of sound of relativistic matter; longitudinal expansion is not in the scaling regime. We present a first analysis of the recent Pb-Pb results and discuss several alternative reaction scenarios. We evaluate quantitatively strangeness production in the deconfined quark-gluon phase and obtain yields in agreement with the experimental observations made in 200A GeV S--W and 158A GeV Pb-Pb interactions. We also present a qualitative discussion of J/Psi results consistent with our understanding of strange particle results.