Equilibrium in nuclear multifragmentation and percolation and the behaviour of the macroscopic entropy near the phase transition

In this paper we attempt to explain the success of equilibrium statistical models in the analysis of products of small impact parameter heavy ion collisions. Our argument is based on an examination of restrictions on the space of microscopic states due to the dynamics of the collision process. We then proceed to consider the example of a simple cubic bond breaking percolation process. We show that slow convergence of certain physical observables near the phase transition is related to the fact that all partitions of the total number of sites have small probabilities (entropy maximum). We discuss the importance of similar behaviour for decay of highly excited nuclei.