PUB - Publikationen an der Universität Bielefeld

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 similar to 1.1T(c) similar to 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.