Branching ratios in sequential statistical multifragmentation

The energy dependence of the probability of producing n fragments follows a characteristic statistical law. Experimental intermediate-mass-fragment multiplicity distributions are shown to be binomial at all excitation energies. From these distributions a single binary event probability can be extracted that has the thermal dependence p = exp[-B/T]. Thus, it is inferred that multifragmentation is a sequence of thermal binary events. The increase of p with excitation energy implies a corresponding contraction of the time-scale and explains recently observed fragment-fragment and fragment-spectator Coulomb correlations. (author). 22 refs., 5 figs