Axial anomaly and hadronic properties in a nuclear medium

TL;DR

This paper explores how mesonic and nucleonic properties change in a nuclear medium at finite density and temperature, revealing that the axial anomaly strength increases discontinuously at the nuclear liquid-gas transition, affecting hadronic masses and chiral symmetry restoration.

Contribution

It introduces a novel analysis of the axial anomaly's behavior at finite density using the functional renormalization group within a three-flavor linear sigma model.

Findings

Anomaly strength increases discontinuously at the liquid-gas transition.

Mesonic masses are modified due to anomaly enhancement.

Partial chiral symmetry restoration is affected by the anomaly change.

Abstract

We investigate meson and nucleon dynamics at finite baryon density and temperature by coupling the nucleon field and the omega meson to the three-flavor linear sigma model and calculate hadronic properties around the nuclear liquid-gas transition. We apply the functional renormalization group method, and find that mesonic fluctuations increase the strength of the coefficient of the $U_A(1)$ breaking determinant operator as a function of the chiral condensate. As a consequence, we find that the actual value of the anomaly increases discontinuously at the first order nuclear liquid-gas transition. We calculate how mesonic masses and partial restoration of chiral symmetry are modified due to such an effect.