Restoration of singlet axial symmetry at finite temperature

TL;DR

This paper proposes a modification to the Witten-Veneziano relation at high temperature, indicating the restoration of U(1)A symmetry and the Goldstone nature of eta prime, to explain RHIC data on eta prime multiplicity.

Contribution

It introduces a minimal modification to the Witten-Veneziano relation at high temperature to account for eta prime mass reduction and symmetry restoration.

Findings

Significant eta prime mass drop at high temperature.

Restoration of U(1)A symmetry.

Goldstone character of eta prime preserved.

Abstract

To accomodate recent RHIC data on eta prime multiplicity, we propose a minimal modification of the Witten-Veneziano relation at high temperature. This renders a significant drop of eta prime mass at high temperature signaling a restoration of the U(1)A, and the Goldstone character of etaprime.