QUASI-GAUSSIAN FIXED-POINTS AND FACTORIAL CUMULANTS IN NUCLEAR MULTIFRAGMENTATION

We re-analyze the conditions for the phenomenon of intermittency (self -similar fluctuations) to occur in models of multifragmentation. Analy zing two different mechanisms, the bond-percolation and the ERW (Elatt ari, Richert and Wagner) statistical fragmentation models, we point ou t a common quasi-Gaussian shape of the total multiplicity distribution in the critical range. The fixed-point property is also observed for the multiplicity of the second bin. Fluctuations are studied using sca led factorial cumulants instead of scaled factorial moments. The secon d-order cumulant displays the intermittency signal while higher order cumulants are equal to zero, revealing a large information redundancy in scaled factorial moments. A practical criterion is proposed to iden tify the Gaussian feature of light-fragment production, distinguishing between a self-similarity mechanism (ERW) and the superposition of in dependent sources (percolation). (C) 1997 Elsevier Science B.V.