IMF-IMF correlations 3–4-fragment correlations reveal details of the breaking process

Abstract

The existence of the Coulomb hole in the IMF-IMF correlation function indicates the breakdown of independent sequential emission of an expanded or nonexpanded source. The Berlin multifragmentation model allows to predict any many-fragment correlation with sufficient statistical accuracy and to trace it back to a few parameters describing the freeze-out configuration: At fixed freeze-out volume the width of the Coulomb hole at low relative velocities is found to be independent of the fragmentation mode. This opens the possibility to determine the size of the freeze-out. For low excitation energies a bump is seen at lower relative velocities in the correlation function. This rise is interpreted as a signal of a very asymmetric hot fission. The reason for the bump is the presence of a very large fragment besides intermediate-mass fragments in multifragmentation events. We analysed the events from different multifragmentation modes. Especially correlation functions for fragmentation events with two very large fragments in addition to an IMF pair may contain information on whether the emission process is simultaneous and statistical, or if not, whether the decay is occurring first by evaporation of smaller particles and then by fission of the rest, or in the opposite way.