SIGNALS OF THE LIQUID GAS-PHASE TRANSITION IN THE FRAGMENTATION OF HOT NUCLEI - FINITE-SIZE SCALING

The distributions of fragments produced in events involving the multifragmentation of hot nuclei are compared with the cluster distributions predicted by a bond percolation model on a finite lattice. The nuclear events are generated by a microcanonical Metropolis sampling method. This comparison makes it possible within the model to separate the events due to the nuclear liquid-gas phase transition from the "hot fission" events. The latter events correspond to a phenomenon that is peculiar to the nuclear case and that reflects the role of the long-range Coulomb force. Finite-size scaling methods are used to analyze the percolation and nuclear liquid-gas phase transitions and to determine the appropriate critical exponents. The influence of the Coulomb force on the critical behaviour of the nuclear liquid-gas phase transition is discussed.