Selfconsistent evaluation of charm and charmonium in the quark-gluon plasma

Abstract

A selfconsistent calculation of heavy-quark (HQ) and quarkonium properties in the quark-gluon plasma (QGP) is conducted to quantify flavor transport and color screening in the medium. The main tool is a thermodynamic T-matrix approach to compute HQ and quarkonium spectral functions in both scattering and bound-state regimes. The T-matrix, in turn, is employed to calculate HQ selfenergies which are implemented into spectral functions beyond the quasiparticle approximation. Charmonium spectral functions are used to evaluate Eulcidean-time correlation functions, which are compared to results from thermal lattice QCD. The comparisons are performed in various hadronic channels, including zero-mode contributions consistently accounting for finite charm-quark width effects. The zero modes are closely related to the charm-quark number susceptibility, which is also compared to existing lattice ‘data’. Both the susceptibility and the heavy-light quark T-matrix are applied to calculate the thermal charm-quark relaxation rate, or, equivalently, the charm diffusion constant in the QGP. Implications of our findings in the HQ sector for the viscosity-to-entropy-density ratio of the QGP are briefly discussed.