Statistical fragmentation of Au projectiles at E/A=600 MeV

The mean multiplicity of intermediate mass fragments (IMF) MIMF produced by fragmentation of Au projectiles interacting with targets of C, Al, Cu, and Pb at an incident energy of E/A=600 MeV is compared to predictions of statistical multifragmentation and sequential evaporation models. The initial conditions for the calculations were provided by Boltzmann-Uehling-Uhlenbeck simulations. In the high excitation energy regime where the IMF multiplicity reaches its maximum the observed universal correlation between MIMF and the total charge Zbound of projectile fragments with charges Z2 cannot be reproduced by a sequential evaporation code. In this regime the data are better described by statistical decay calculations which assume the formation of an expanded nuclear system and a rather fast breakup.