Relativistic heavy ion collisions and the nuclear equation of state

Central collisions between heavy nuclei in the relativistic regime have been systematically investigated at the Bevalac in Berkeley by a joint GSI-LBL-collaboration during the last years with 4π-detector devices, the LBL-Streamer Chamber and the GSI-Plastic Ball. These investigations have provided strong evidence for the compression of nuclear matter by a factor of up to 4. Moreover they have shown a collective flow of nuclear matter as predicted by hydrodynamical models. Many features of the space-time development of these reactions have been investigated and compared with theoretical predictions. The analysis of recent results give evidence for a rather stiff equation of state in contrast to considerations from astrophysical models for neutron star formation.