Meson Spectral Functions at finite Temperature

TL;DR

This paper applies the Maximum Entropy Method to reconstruct meson spectral functions at finite temperature, analyzing the effects of smearing techniques and comparing results with standard fits, revealing deviations from free spectral functions above T_c.

Contribution

It demonstrates the use of Bayesian methods for spectral reconstruction at finite temperature and investigates the impact of smearing on spectral shape in lattice QCD calculations.

Findings

Spectral functions differ from free spectral functions above T_c.

Maximum Entropy Method effectively reconstructs spectral functions at finite temperature.

Smearing techniques influence the spectral shape and are analyzed in the study.

Abstract

The Maximum Entropy Method provides a Bayesian approach to reconstruct the spectral functions from discrete points in Euclidean time. The applicability of the approach at finite temperature is probed with the thermal meson correlation function. Furthermore the influence of fuzzing/smearing techniques on the spectral shape is investigated. We present first results for meson spectral functions at several temperatures below and above $T_c$. The correlation functions were obtained from quenched calculations with Clover fermions on large isotropic lattices of the size $(24-64)^3 \times 16$. We compare the resulting pole masses with the ones obtained from standard 2-exponential fits of spatial and temporal correlation functions at finite temperature and in the vacuum. The deviation of the meson spectral functions from free spectral functions is examined above the critical temperature.