Vector mesons at finite temperature and QCD sum rules

TL;DR

This paper derives finite energy sum rules for vector and axial-vector currents at finite temperature to analyze the spectral behavior of rho and a1 mesons and explore chiral symmetry restoration.

Contribution

It introduces finite energy sum rules in a thermal medium for vector and axial-vector currents, including finite widths, to study meson spectral behavior at nonzero temperature.

Findings

Differences between vector and axial-vector channels are characterized.

The approach incorporates the chiral-symmetry-breaking scale into the sum rules.

The spectral behavior of rho and a1 mesons is constrained at finite temperature.

Abstract

Finite energy sum rules for vector and axial-vector currents are derived in a thermal medium to provide constraints for the spectral behavior of rho and a1 mesons at nonvanishing temperature and hence to study the tendency toward chiral symmetry restoration. The parity-mixing ansatz for the rho and a1 spectra, including finite widths, is investigated as a function of temperature. Characteristic differences between vector and axial-vector channels are discussed with regard to the implementation of the chiral-symmetry-breaking scale, 4pi times the pion decay constant, in the sum rule approach.