Transverse flow of nuclear matter in collisions of heavy nuclei at intermediate energies

The Quantum Molecular Dynamics Model (IQMD) is used to investigate the orig in of the collective transverse velocity observed in heavy ion experiments. We find that there are three contributions to this effect: initial-final s tate correlations, potential interactions and collisions. For a given nucle ar equation of state (eos) the increase of the transverse velocity with inc reasing beam energy is caused by the potential part. For a given beam energ y the collective transverse velocity is independent of the nuclear eos but the relative contributions of potential and collisions differ. In view of t he importance of the potential interactions between the nucleons it is not evident that the similarity of the radial Velocities measured for fragments at beam energies below 1 A GeV and that for mesons at beam energies above 2 A GeV is more than accidental. (C) 2001 Elsevier Science B.V, All rights reserved.