Multiplicities in ultrarelativistic proton-(anti)proton collisions and negative binomial distribution fits

TL;DR

This study tests whether charged-particle multiplicities in proton-(anti)proton collisions follow a negative binomial distribution, finding that the hypothesis is rejected for ALICE-LHC data but accepted for UA5 data, highlighting discrepancies between datasets.

Contribution

The paper applies likelihood ratio tests to evaluate the negative binomial distribution hypothesis for multiplicity data at different energies, revealing dataset-dependent differences.

Findings

Negative binomial hypothesis rejected for ALICE-LHC data

Hypothesis accepted for UA5 data

Discrepancies explained by potential experimental or methodological factors

Abstract

Likelihood ratio tests are performed for the hypothesis that charged-particle multiplicities measured in proton-(anti)proton collisions at $\sqrt{s}$ = 0.9 and 2.36 TeV are distributed according to the negative binomial form. Results indicate that the hypothesis should be rejected in the all cases of ALICE-LHC measurements in the limited pseudo-rapidity windows, whereas should be accepted in the corresponding cases of UA5 data. Possible explanations of that and of the disagreement with the least-squares fitting method are given.