Charged-Particle Multiplicity in Proton-Proton Collisions

TL;DR

This paper reviews measurements and theoretical concepts of charged-particle multiplicity in proton-proton collisions across a wide energy range, discussing scaling laws, distribution models, and predictions for LHC energies.

Contribution

It provides a comprehensive review of experimental data, theoretical models, and future predictions for charged-particle multiplicities in proton-proton collisions.

Findings

Multiplicity distributions follow negative binomial models.

Energy dependence shows similarities between p+p and e+e- collisions.

Predictions for LHC energies are summarized and compared.

Abstract

This article summarizes and critically reviews measurements of charged-particle multiplicity distributions and pseudorapidity densities in p+p(pbar) collisions between sqrt(s) = 23.6 GeV and sqrt(s) = 1.8 TeV. Related theoretical concepts are briefly introduced. Moments of multiplicity distributions are presented as a function of sqrt(s). Feynman scaling, KNO scaling, as well as the description of multiplicity distributions with a single negative binomial distribution and with combinations of two or more negative binomial distributions are discussed. Moreover, similarities between the energy dependence of charged-particle multiplicities in p+p(pbar) and e+e- collisions are studied. Finally, various predictions for pseudorapidity densities, average multiplicities in full phase space, and multiplicity distributions of charged particles in p+p(pbar) collisions at the LHC energies of sqrt(s) = 7 TeV, 10 TeV, and 14 TeV are summarized and compared.