Effective Restoration of the U_A(1) symmetry in the SU(3) linear sigma model

TL;DR

This paper investigates the restoration of U_A(1) symmetry in the SU(3) linear sigma model at finite temperatures, highlighting observable signals in heavy-ion collisions related to meson mass spectrum changes.

Contribution

It demonstrates how the disappearance of the chiral anomaly affects meson masses and proposes experimental signals for detecting chiral phase transitions.

Findings

Enhanced eta/pi0 ratio in collisions

Suppressed a0 in K+K- spectrum

Appearance of scalar kappa meson peak

Abstract

The effective restoration of the chiral U(A)(1) symmetry in strong interactions is studied using the linear chiral SU(3)xSU(3) model at finite temperatures. We find that the disappearance of the chiral anomaly causes a considerable change in the meson mass spectrum. We propose several signals for detecting this chiral phase in ultrarelativistic heavy-ion collisions: The eta/pi0 ratio is enhanced by an order of magnitude, the a0 is suppressed in the K+K- mass spectrum, and the scalar kappa meson appears as a peak just below the K*(892) in the invariant piK mass spectrum.