Coulomb interaction on pion production in Au+Au collisions at relativistic energies

TL;DR

This paper investigates how Coulomb interactions influence charged pion spectra in Au+Au collisions at RHIC-BES energies, revealing energy and centrality dependencies that inform about freeze-out dynamics.

Contribution

It provides a detailed analysis of Coulomb effects on pion spectra and introduces a method to extract Coulomb kick and initial pion ratios across different energies and centralities.

Findings

Coulomb kick decreases with increasing beam energy.

Larger Coulomb effects are observed in more central collisions.

Results relate Coulomb effects to kinetic freeze-out dynamics.

Abstract

Coulomb effects on charged pion transverse momentum spectra produced in Au+Au collisions at RHIC-BES energies are investigated. From these spectra the {\pi}-/{\pi}+ ratios as a function of transverse momentum are obtained and used to extract the Coulomb kick (a momentum change due to Coulomb interaction) and initial pion ratio for three different collision energies and various centrality classes. The Coulomb kick shows a decrease with the increase of beam energy and a clear centrality dependence, with larger values for the most central collisions. The results are connected with the kinetic freeze-out dynamics and discussed.