Charge Balance Functions for Heavy-Ion Collisions at LHC Energies

TL;DR

This paper investigates charge balance functions in heavy-ion collisions at LHC energies to understand quark-gluon plasma properties, comparing detailed theoretical models with experimental data to analyze charge correlation evolution.

Contribution

It introduces a detailed theoretical model for charge correlations evolution and proposes a ratio of balance functions to isolate diffusion effects in quark-gluon plasma.

Findings

Model agrees with preliminary ALICE data

Charge correlations evolve during the collision

Diffusivity constraints are improved

Abstract

Heavy-ion collisions at the LHC provide the conditions to investigate regions of quark-gluon plasma that reach higher temperatures and that persist for longer periods of time compared to collisions at the Relativistic Heavy Ion Collider. This extended duration allows correlations from charge conservation to better separate during the quark-gluon plasma phase, and thus be better distinguished from correlations that develop during the hadron phase or during hadronization. In this study charge balance functions binned by relative rapidity and azimuthal angle and indexed by species are considered. A detailed theoretical model that evolves charge correlations throughout the entirety of an event is compared to preliminary results from the ALICE Collaboration. The comparison with experiment provides insight into the evolution of the chemistry and diffusivity during the collision. A ratio of balance functions is proposed to better isolate the effects of diffusion and thus better constrain the diffusivity.