Tagging of eta' decay products to analyze chiral restoration

TL;DR

This paper proposes a method to identify pions from eta' decays to study chiral U_A(1) symmetry restoration, showing that eta' mass reduction enhances two-pion correlations in various collision systems.

Contribution

A novel kinematical cut technique to select eta' decay pions, applicable across multiple collision systems and energies, aiding in chiral symmetry restoration studies.

Findings

Method effectively identifies eta' decay pions in simulations.

Mass decrease of eta' boson influences two-pion correlation functions.

Technique is versatile across different collision environments.

Abstract

In case of chiral U_A(1) symmetry restoration the mass of the eta' boson (the ninth, would-be Goldstone boson) is decreased, thus its production cross section is heavily enhanced. The eta' decays (through one of its decay channels) into five pions. These pions will not be correlated in terms of Bose-Einsten correlations, thus the production enhancement changes the strength of two-pion correlation functions at low momentum. Preliminary results strongly support the mass decrease of the eta' boson. In this paper we propose a method to select pions coming from eta' decays. We investigate the efficiency of the proposed kinematical cut in several collision systems and energies with several simulators. We prove that our method can be used in all investigeted collision systems.