Spin-Dependent Interactions and Heavy-Quark Transport in the QGP

TL;DR

This paper extends a T-matrix approach to include spin-dependent interactions in the quark-gluon plasma, refining the potential model and improving predictions for charm-quark transport relevant to heavy-ion collision experiments.

Contribution

It introduces spin-dependent relativistic corrections to the in-medium potential, enhancing the accuracy of charm-quark transport coefficient calculations in the QGP.

Findings

Vector interaction improves quarkonium mass splitting description.

Relativistic corrections increase charm-quark friction coefficients.

Results enhance phenomenology of heavy-flavor observables at RHIC and LHC.

Abstract

We extend a previously constructed T-matrix approach to the quark-gluon plasma (QGP) to include the effects of spin-dependent interactions between partons. Following earlier work within the relativistic quark model, the spin-dependent interactions figure as relativistic corrections to the Cornell potential. When applied to the vacuum spectroscopy of quarkonia, in particular their mass splittings in S- and P-wave states, the issue of the Lorentz structure of the confining potential arises. We confirm that a significant admixture of a vector interaction (to the previously assumed scalar interaction) improves the description of the experimental mass splittings. The temperature corrections to the in-medium potential are constrained by results from thermal lattice-QCD for the equation of state (EoS) and heavy-quark (HQ) free energy in a selfconsistent set-up for heavy- and light-parton spectral functions in the QGP. We then deploy the refined in-medium heavy-light T-matrix to compute the charm-quark transport coefficients in the QGP. The vector component of the confining potential, through its relativistic corrections, enhances the friction coefficient for charm quarks in the QGP over previous calculations by tens of percent at low momenta and temperatures, and more at higher momenta. Our results are promising for improving the current phenomenology of open heavy-flavor observables at Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC).