NUCLEAR-MATTER EXPANSION PARAMETERS FROM THE MEASUREMENT OF DIFFERENTIAL MULTIPLICITIES FOR LAMBDA-PRODUCTION IN CENTRAL AU+AU COLLISIONS AT AGS

The double differential multiplicities and rapidity distributions for Lambda hyperon production in central Au + Au interactions at AGS in th e range of rapidities from 1.7 to 3.2 GeV and the range of transverse kinetic energies from 0.0 to 0.7 GeV are parametrized in terms of the Blast Wave approximation. The longitudinal and transverse radial expan sion parameters and the mean temperature of Lambda hyperons after the freeze-out of the nuclear matter are presented. The predictions of the RQMD model with and without mean field potentials are compared to our data. Both variants of RQMD are parameterized in terms of the Blast W ave model and the results of such parameterizations are compared to th e experimental ones. It is found that inclusion of the repulsive mean field potentials in RQMD is essential to account for the strong expans ion observed in the data. (C) 1998 Published by Elsevier Science B.V.