The moments methods for the analysis of the charged particles distributions in nucleus-nucleus collisions at high energies

A convolution between the Poisson distribution and binomial distribution is supposed to describe the multiplicity distribution. One considers the superposition of the uncorrelated emission of particles with the emission during the flow of the central-participant-region, as well as the influence of the spectator regions. A second approach uses two different distribution functions for the two regions, fp and fs ; the multiplicity distribution of the charged particles emitted in an event is given by the sum of the two 'regional' distributions. For the two approaches the noncentral and central moments are calculated, as well as the skewness and kurtosis parameters. The calculations are compared with the experimental results for 15 nucleus-nucleus collisions at energies between 0.8 and 13.6 GeV/A. Significant contributions of the spectator region and of the flow is observed. A good agreement with other observations is obtained. (Author)