Quarkonium states in an anisotropic QCD plasma

TL;DR

This paper investigates how anisotropy in a hot QCD plasma affects quarkonium states, revealing that viscosity and expansion influence binding strength and induce polarization of P-wave states.

Contribution

It provides a novel analysis of quarkonium in anisotropic QCD plasmas, including a model for the potential and numerical solutions showing effects of viscosity and anisotropy.

Findings

Quarkonium binding increases with viscosity and expansion rate.

Anisotropy causes polarization of P-wave states.

Potential modeled with short-distance Coulomb and long-distance string components.

Abstract

We consider quarkonium in a hot QCD plasma which, due to expansion and non-zero viscosity, exhibits a local anisotropy in momentum space. At short distances the heavy-quark potential is known at tree level from the hard-thermal loop resummed gluon propagator in anisotropic perturbative QCD. The potential at long distances is modeled as a QCD string which is screened at the same scale as the Coulomb field. At asymptotic separation the potential energy is non-zero and inversely proportional to the temperature. We obtain numerical solutions of the three-dimensional Schroedinger equation for this potential. We find that quarkonium binding is stronger at non-vanishing viscosity and expansion rate, and that the anisotropy leads to polarization of the P-wave states.