Theoretical analysis for the apparent discrepancy between [formula omitted] and pp data in charged particle forward–backward multiplicity correlations

Yu-Liang Yan,Bao-Guo Dong,Dai-Mei Zhou,Xiao-Mei Li,Ben-Hao Sa

doi:10.1016/j.physletb.2008.01.048

Yu-Liang Yan, Bao-Guo Dong + Show 3 more

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https://doi.org/10.1016/j.physletb.2008.01.048

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Abstract

The strength of charged particle forward–backward multiplicity correlation in p¯+p and p+p collisions at s=200GeV is studied by PYTHIA 6.4 and compared to the UA5 and STAR data correspondingly. It is turned out that a factor of 3–4 apparent discrepancy between UA5 and STAR data can be attributed to the differences in detector acceptances and observing bin interval in both experiments. A mixed event method is introduced and used to calculate the statistical correlation strength and the dynamical correlation strengths stemming from the charge conservation, four-momentum conservation, and decay, respectively. It seems that the statistical correlation is much larger than dynamical one and the charge conservation, four-momentum conservation and decay may account for most part of the dynamical correlation. In addition, we have also calculated the correlation strength by fitting the charged particle multiplicity distribution from PYTHIA to the Negative Binomial Distribution and found that the result agrees well with the correlation strength calculated by mixed events.

Highlights

The strength of charged particle forward-backward multiplicity correlation in p + p and p + p collisions at √s=200 GeV is studied by PYTHIA 6.4 and compared to the UA5 and STAR data correspondingly
Fluctuations and correlations are important observables investigating the properties of thermodynamic system and are critical tools revealing the mechanism of particle production and the formation of quark-gluonplasma in relativistic heavy ion collisions [1, 2]
Several thermodynamic quantities and the produced particle distributions show varying fluctuation patterns when system undergoes phase transition. Such as the large energy density fluctuation is expected in the first order phase transition and a second order phase transition may relate to a divergence in specific heat

Summary

Introduction

The strength of charged particle forward-backward multiplicity correlation in p + p and p + p collisions at √s=200 GeV is studied by PYTHIA 6.4 and compared to the UA5 and STAR data correspondingly. We fit the particle multiplicity distribution from PYTHIA to the Negative Binomial Distribution (NBD) and calculate the strength of charged particle forward-backward multiplicity correlation which agrees well with the one calculated by mixed events.

Results

Conclusion