Alberto Giovannini

Negative binomial multiplicity distributions in high energy hadron collisions

AbstractThis paper concerns the results recently obtained by the UA5 Collaboration on charged particle multiplicity distributions at the CERN

Common origin of the shoulder in multiplicity distributions and of oscillations in the factorial cumulants to factorial moments ratio

p\bar p

Superposition effect and clan structure in forward-backward multiplicity correlations

collider

Hierarchical structure of correlation functions for single jets

(\sqrt s = 540 GeV)

Multiplicity distributions in a thermodynamical model of hadron production ine + e − collisions

and their comparison with lower energy data [1, 2]. Our aim is to interpret in general terms the experimental finding that the distributions are of negative binomial (NB) form both for total multiplicities and in finite pseudorapidity intervals. This can be understood in terms of partial stimulated emission of bosons, or of a simple form of cascade process, or (more artificially) with both mechanisms. The cascade interpretation appears to be the most attractive. It leads to a new concept of clustering, the empirical data imply unexpected properties for the clusters, and a novel type of high energy asymptotics seems to emerge. We briefly discuss the relation with QCD-based models for hadron production and the case ofe+e− annihilation.

Virtuality evolution and rapidity structure of a simplified parton shower

Abstract It is shown that the ratio of factorial cumulant moments to factorial moments for a multiplicity distribution truncated in the tail reveals oscillations in sign similar to those observed in experimental data. It is suggested that this effect be taken into account in the analysis of data in order to obtain correct physical information on the multiplicity distributions.