On Statistical Mechanics Developments of Clan Concept in Multiparticle Production

Abstract

Clan concept has been introduced in multiparticle dynamics in order to interpret the wide occurrence of negative binomial (NB) regularity in n-charged particle multiplicity distributions (MDs) in various high energy collisions. The centrality of clan concept led to the attempt to justify its occurrence within a statistical model of clan formation and evolution. In this framework all thermodynamical potentials have been explicitly calculated in terms of NB parameters. Interestingly it was found that NB parameter k corresponds to the one particle canonical partition function. The goal of this paper is to explore a possible temperature and volume dependence of parameter k in various classes of events in high energy hadron-hadron collisions. It is shown that the existence of a phase transition at parton level from the ideal clan gas associated to the semihard component with k>1 to the ideal clan gas of the hard component with k<1 implies a discontinuity in the average number of particles at hadron level.