Using Baryonic Charge Balance Functions to Resolve Questions about the Baryo-Chemistry of the QGP

TL;DR

This paper uses charge balance functions of protons and antiprotons to quantify baryon annihilation during the hadronic stage of heavy-ion collisions, improving the understanding of initial baryo-chemistry and early-stage charge correlations.

Contribution

It introduces a method to analyze charge balance functions to better understand baryon annihilation effects and extract initial baryo-chemistry in heavy-ion collisions.

Findings

Charge balance functions clarify the extent of baryon annihilation.

Enhanced accuracy in determining initial baryo-chemistry.

Improved interpretation of charge-balance correlations for early-stage chemistry.

Abstract

Baryon annihilations during the hadronic stage of heavy-ion collisions affects final-state baryon and antibaryon yields and final-state correlations of baryons and antibaryons. Understanding annihilation is important for addressing questions about the chemistry at the beginning of the hadronic stage, and for interpreting charge-balance correlations involving baryons. Here, charge balance functions, using protons and antiprotons binned by relative momentum, rapidity and azimuthal angle, are shown to clarify the amount of annihilation in the hadronic stage. This enables a more accurate extraction of the baryo-chemistry at the beginning of the hadronic stage. Understanding annihilation is also crucial if charge balance correlations are to be used to infer the chemistry of the earliest stages of a heavy-ion collision. Calculations are presented based on microscopic simulations of the hadronic stage coupled to a hydrodynamic description of the earlier stage, along with a detailed modeling of correlations of protons and antiprotons, known as charge-balance functions.