Effect of centrality bin width corrections on two-particle number and transverse momentum differential correlation functions

TL;DR

This paper introduces a correction technique for two-particle correlation functions in heavy-ion collisions to account for centrality bin width effects, improving measurement precision.

Contribution

A novel correction method for centrality bin width effects in two-particle correlation functions in heavy-ion collision experiments.

Findings

The correction technique achieves better than 1% precision in simulations.

It effectively reduces centrality bin width dependence in correlation measurements.

Validated with Pb-Pb collision simulations using HIJING and UrQMD models.

Abstract

Two-particle number and transverse momentum differential correlation functions are powerful tools for unveiling the detailed dynamics and particle production mechanisms involved in relativistic heavy-ion collisions. Measurements of transverse momentum correlators $P_2$ and $G_2$, in particular, provide added information not readily accessible with better known number correlation functions $R_2$. However, it is found that the $R_2$ and $G_2$ correlators are somewhat sensitive to the details of the experimental procedure used to measure them. They exhibit, in particular, a dependence on the collision centrality bin width, which may have a rather detrimental impact on their physical interpretation. A technique to correct these correlators for collision centrality bin-width averaging is presented. The technique is based on the hypothesis that the shape of single- and pair- probability densities vary slower with collision centrality than the corresponding integrated yields. The technique is tested with Pb-Pb simulations based on the HIJING and ultrarelativistic quantum molecular dynamics models and shown to enable a precision better than 1% for particles in the kinematic range $0.2 \leq p_{\rm T} \leq 2.0$ GeV/$c$.