U_A(1) Symmetry Restoration from an In-Medium eta' Mass Reduction in sqrt(s(NN)) = 200 GeV Au+Au Collisions

TL;DR

This study investigates the potential restoration of U_A(1) symmetry in hot, dense matter created in high-energy Au+Au collisions by analyzing pion correlations, revealing a significant in-medium eta' mass reduction.

Contribution

It provides evidence for a substantial in-medium eta' mass reduction, supporting U_A(1) symmetry restoration in heavy-ion collisions at RHIC.

Findings

At least 200 MeV eta' mass reduction needed

Supports U_A(1) symmetry restoration hypothesis

Analysis combines PHENIX and STAR data

Abstract

A reduction of the mass of the eta'(958) meson may signal restoration of the U_A(1) symmetry in a hot and dense hadronic matter, corresponding to the return of the 9th, "prodigal" Goldstone boson. We report on an analysis of a combined PHENIX and STAR data set on the intercept parameter of the two-pion Bose-Einstein correlation functions, as measuremed in sqrt(s(NN)) = 200 GeV Au + Au collisions at RHIC. To describe this combined PHENIX and STAR dataset, an in-medium eta' mass reduction of at least 200 MeV is needed, at the 99.9 % confidence level in a broad model class of resonance abundances.