Dynamical aspects of multifragmentation

The decay channel of excited nuclear matter into multiple complex fragments is still not thoroughly understood. Different scenarios are discussed, for example, the role of sequential decay of multiple binary breakups. Condensation processes in an expanded nucleus are reviewed. The latter is especially interesting due to its link to a nuclear liquid-gas phase transition. More recently it was proposed that the fragmentation process could be introduced by shape instabilities arising from surface fluctuations. To understand the decay mechanism it is very important to get an estimate of the size of the decaying source and the relative emission time of the heavy fragments. The different breakup scenarios are expected to leave characteristic signatures in kinematic fragment-fragment correlations. Since the multifragment decay produces heavy fragments, the repulsive long-range Coulomb force is expected to play a dominant role. In the following the authors present kinematic correlations between three heavy projectile fragments that were produced in Au induced relativistic heavy-ion collisions and compare them with three-body Coulomb trajectory calculations. The experimental results presented here emerge from an experiment that was performed at the ALADIN spectrometer at SIS in 1990. C, Al, Cu and Pb targets with an interaction probability of 3% were bombarded with a 600 MeV per nucleon Au beam