High-energy nuclear collisions: evolution of the compressed zone

On the basis of a relativistic intranuclear cascade model which reproduces the bulk of experimental data, the space and time evolution of the compressed zone formed in head-on collisions of two nuclei is investigated. The maximum compressions achieved turn out to be not very different from those following from hydrodynamic estimations. The shape of the spatial distribution of the compressed zone is not that of a classical Mach cone. The existence of a rarefied zone resulting in an effect of the 'dead-water' type is found. The characteristics of pions emerging from collisions of nuclei at relativistic energies are discussed.