Quark charge balance function and hadronization effects in relativistic heavy ion collisions

TL;DR

This study analyzes the charge balance function in high-energy heavy ion collisions, examining how hadronization and resonance decays influence charge correlations and their invariance properties.

Contribution

It introduces a detailed calculation of charge balance functions before and after hadronization, highlighting the effects of quark combination and resonance decays on these functions.

Findings

Hadronization slightly increases the width of charge balance functions.

Balance functions maintain boost invariance and scaling in rapidity space despite hadronization.

Resonance decays significantly affect the width but not the invariance properties.

Abstract

We calculate the charge balance function of the bulk quark system before hadronization and those for the directly produced and the final hadron system in high energy heavy ion collisions. We use the covariance coefficient to describe the strength of the correlation between the momentum of the quark and that of the anti-quark if they are produced in a pair and fix the parameter by comparing the results for hadrons with the available data. We study the hadronization effects and decay contributions by comparing the results for hadrons with those for the bulk quark system. Our results show that while hadronization via quark combination mechanism slightly increases the width of the charge balance functions, it preserves the main features of these functions such as the longitudinal boost invariance and scaling properties in rapidity space. The influence from resonance decays on the width of the balance function is more significant but it does not destroy its boost invariance and scaling properties in rapidity space either. The balance functions in azimuthal direction are also presented.