Quarkonium Polarization Kinetic Equation from Open Quantum Systems and Effective Field Theories

TL;DR

This paper derives a kinetic equation for the spin-dependent in-medium dynamics of quarkonia using open quantum systems and effective field theories, providing a framework to understand polarization phenomena in quark-gluon plasmas.

Contribution

It introduces a gauge-invariant kinetic equation incorporating chromomagnetic field correlators for polarized quarkonia, extending previous spin-independent models.

Findings

Derived the Boltzmann transport equation with polarization dependence.

Connected the Lindblad equation to chromomagnetic field correlators.

Applicable to both weakly and strongly coupled quark-gluon plasmas.

Abstract

Recent measurements of polarization phenomena in relativistic heavy ion collisions have aroused a great interest in understanding dynamical spin evolution of the QCD matter. In particular, the spin alignment signature of $J/\psi$ has been recently observed in Pb-Pb collisions at LHC, which may infer nontrivial spin transport of quarkonia in quark gluon plasmas. Motivated by this, we study the spin-dependent in-medium dynamics of quarkonia by using the potential nonrelativistic QCD (pNRQCD) and the open quantum system framework. By applying the Markovian approximation and Wigner transformation, we systematically derive the Boltzmann transport equation for vector quarkonia with polarization dependence in the quantum optical limit. As opposed to the previous study for the spin-independent case where the collision terms depend on chromoelectric correlators, the new kinetic equation incorporates gauge invariant correlators of chromomagnetic fields that determine the recombination and dissociation terms with polarization dependence at the order we are working in the multipole expansion. In the quantum Brownian motion limit, the Lindblad equation with new transport coefficients defined in terms of the chromomagnetic field correlators have also been derived. Our formalism is generic and valid for both weakly-coupled and strongly-coupled quark gluon plasmas. It may be further applied to study spin alignment of vector quarkonia in heavy ion collisions.