Collective effects and multifragmentation in heavy-ion collisions at intermediate energies within a hybrid model

Central and semi-central Au + Au collisions at 150 and 250 A ·MeV are investigated in the framework of a hybrid model with dynamical and statistical components. Starting from the BUU approach and ansatz for the Wigner function is made which describes thermal and collective motion of the nucleons and models the transition from the one-source to the two-source behavior. Anisotropic flow energies and temperatures as well as angular momenta are extracted. Nucleonic flow and pre-equilibrium emission reduce considerably the excitation energy of the matter. The cluster formation is described by the Copenhagen multifragmentation model. Charge spectra, energy spectra and two-particle correlations of the fragments are reproduced. Agreement with experiment can be improved by assuming a reduced transverse flow.