From Sequential Processes to Multifragmentation in Proton Reactions with Gold

The distribution of relative angles between the intermediate mass fragments has been measured and analyzed for thermal multifragmentation in p + Au collisions at 2.1, 3.6 and 8.1 GeV. The analysis has been done on an event by event basis. The multibody Coulomb trajectory calculations of all charged particles have been performed starting with the initial break-up conditions given by the combined model with the revised intranuclear cascade (INC) followed by the statistical multifragmentation model. The measured correlation function was compared with the calculated one to find the actual time scale of the intermediate mass fragment (IMF) emission. It found transition from sequential evaporation for p(2.1 GeV) + Au to simultaneous multibody decay of a hot and expanded nuclear system in case of p(8.1 GeV) + Au.