Thermal quarkonium physics in the pseudoscalar channel

TL;DR

This study compares perturbative spectral functions with lattice data for pseudoscalar quarkonium correlators at finite temperature, finding no resonance peaks needed for charmonium but a broadened resonance for bottomonium.

Contribution

It constructs a thermal spectral function incorporating resummed effects and compares it with lattice data, providing insights into quarkonium behavior at high temperatures.

Findings

No resonance peaks needed for charmonium at T ≥ 1.1Tc

Good description of bottomonium with a thermally broadened resonance

Modest differences possibly due to non-perturbative effects

Abstract

The pseudoscalar correlator is an ideal lattice probe for thermal modifications to quarkonium spectra, given that it is not compromised by a contribution from a large transport peak. We construct a perturbative spectral function incorporating resummed thermal effects around the threshold and vacuum asymptotics above the threshold, and compare the corresponding imaginary-time correlators with continuum-extrapolated lattice data for quenched SU(3) at several temperatures. Modest differences are observed, which may originate from non-perturbative mass shifts or renormalization factors, however no resonance peaks are needed for describing the quenched lattice data for charmonium at and above T ~ 1.1Tc ~ 350 MeV. For comparison, in the bottomonium case a good description of the lattice data is obtained with a spectral function containing a single thermally broadened resonance peak.