HEAVY-ION COLLISIONS AND THE DENSITY-DEPENDENCE OF THE LOCAL MEAN-FIELD

We study the effect of the density dependence of the scalar and the ve ctor part of the nucleonic self-energy in relativistic quantum molecul ar dynamics (RQMD) on observables like the transversal flow and the ra pidity distribution. Linear and non-linear density dependences of the mean field are studied, The latter case can either be restricted to th e scalar part of the mean field or be taken into account in both the s calar and vector parts. The mean field is determined from a non-linear extension of the Walecka model or from the Brueckner-Hartree-Fock G-m atrix with the Reid soft-core potential. The transversal flow is very sensitive to these different approaches. In particular, a linear scali ng of the flow with the effective mass of the considered models is obs erved. For the reaction Ar + KCI at 1.8 GeV/nucleon a comparison with the data is given.