Quarkonium suppression in heavy-ion collisions: an open quantum system approach

TL;DR

This paper models the evolution of heavy-quarkonium states in a quark-gluon plasma using open quantum systems, providing predictions for their suppression patterns relevant to heavy-ion collision experiments.

Contribution

It introduces a novel open quantum system framework for quarkonium evolution, incorporating dissociation and recombination effects with minimal non-perturbative parameters.

Findings

Predicted suppression patterns for $0(1S)$ and $0(2S)$ states.

Formulated Lindblad equations for quarkonium density matrices.

Quantified effects of thermal mass shifts and widths.

Abstract

We address the evolution of heavy-quarkonium states in an expanding quark-gluon plasma by implementing effective field theory techniques in the framework of open quantum systems. In this setting we compute the nuclear modification factors for quarkonia that are $S$-wave Coulombic bound states in a strongly-coupled quark-gluon plasma. The calculation is performed at an accuracy that is leading-order in the heavy-quark density expansion and next-to-leading order in the multipole expansion. The quarkonium density-matrix evolution equations can be written in the Lindblad form, and, hence, they account for both dissociation and recombination. Thermal mass shifts, thermal widths and the Lindblad equation itself depend on only two non-perturbative parameters: the heavy-quark momentum diffusion coefficient and its dispersive counterpart. Finally, by numerically solving the Lindblad equation, we provide results for the $\Upsilon(1S)$ and $\Upsilon(2S)$ suppression.