RESILIENCE OF NUCLEAR-MATTER IN LIGHT-ION INDUCED REACTIONS

Cavitation and heating of the target nucleus in the first instances of He-3-induced collisions in the GeV/nucleon range are investigated in an intranuclear cascade model for the formation of this structure and a stochastic one-body dynamics calculation to study its evolution. The hard collisions having essentially ceased when the structure is fully developed, the latter model is particularly suited to study the possi ble breakup of the system. It is shown, however, that the target recov ers a spherical shape rather rapidly, and has thus a good chance to de cay by standard evaporation, justifying the use of a cascade + evapora tion model to analyze the data. It is also shown that the system has t o be much more modified to break up into pieces instead of recovering a compact shape: in these reactions, it is thus expected that nuclear matter is resilient to shape deformation and thermal excitation. Argum ents are given to explain that expansion of the system, not important in these reactions, is required to overcome this resilience.