INTERMITTENCY IN AND THE FRACTAL NATURE OF NUCLEAR FRAGMENTATION - A CRITICAL-EXAMINATION

We discuss the use of factorial moments to search for intermittency in nuclear fragmentation, and relate it to the fractal nature of the fragmenting system. We show that the horizontally scaled moments measure the deviation of the fluctuations from a poissonian distribution. The intermittency index is directly related to the anomalous or fractal dimension of the system, and its dependence on the order of the moments is different for mono- and multifractals. We calculate the moments and intermittency indices for the charge distribution from the statistical decay of an equilibrated hot nucleus, which we model by sampling the microcanonical phase space for nuclear fragmentation. The model is used to realistically study the conditions leading to the phenomenon of intermittency in heavy-ion reactions. The results are compared to those measured in 1 GeV/amu Au-197(79) on emulsion data. They indicate possible biasing of the experimental data towards events of low multiplicity. We are able to reproduce both the resolution and order scaling as given by the data while generating many more events. We show that order scaling can be related to the form of the fluctuations as well as signal intermittency.