Vector-axialvector mixing from a chiral effective field theory at finite temperature

TL;DR

This paper investigates how vector and axialvector mesons mix in a hot medium near the chiral phase transition, revealing modifications in spectral functions and meson couplings using a chiral effective field theory framework.

Contribution

It introduces a detailed analysis of vector-axialvector mixing at finite temperature within a generalized hidden local symmetry model, highlighting the behavior of meson spectral functions and couplings near the critical point.

Findings

Vector spectral function is reduced around the rho meson mass.

Spectral function is enhanced around the a1 meson mass.

Coupling strength of a1 to rho and pi vanishes at the critical temperature.

Abstract

We study the vector-axialvector mixing in a hot medium and its evolution toward the chiral phase transition using different symmetry restoration scenarios based on the generalized hidden local symmetry framework. We show that the presence of the $a_1$ meson reduces the vector spectral function around $\rho$ meson mass and enhances it around $a_1$ meson mass. The coupling strength of $a_1$ to $\rho$ and $\pi$ vanishes at the critical temperature due to the degenerate $\rho$-$a_1$ masses. This feature holds rigorously in the chiral limit and still stays intact to good approximation for the physical pion mass.