Simulation of heavy quarkonium equilibration in the quark-gluon plasma

TL;DR

This paper models how heavy quarkonium reaches equilibrium in a quark-gluon plasma using a combined transport approach, revealing timescales and mechanisms relevant to heavy-ion collision experiments.

Contribution

It introduces a coupled Langevin and Boltzmann simulation framework for heavy quarkonium in QGP, incorporating higher-order dissociation and regeneration processes.

Findings

Equilibration time is comparable to QGP lifetime in LHC collisions.

The interplay between open and hidden heavy sectors influences equilibration.

The model supports statistical hadronization as a valid description of charmonium production.

Abstract

We simulate the heavy quarkonium equilibration through transport in a static and homogeneous quark-gluon plasma (QGP) box within the semi-classical Boltzmann approach incorporating both the leading-order and next-to-leading-order dissociation and regeneration reactions. The scattering amplitudes involved are taken from perturbative computations based on effective color-electric dipole coupling of the heavy quarkonium with thermal gluons. By coupling the Langevin simulation of single heavy quark diffusion and the Boltzmann transport of the heavy quarkonium in a real-time fashion, we demonstrate how the kinetic and chemical equilibrium of heavy quarkonium with single heavy quarks in the medium is achieved in terms of both the bound state's yields and momentum distributions. The pertinent equilibration time turns out to be comparable to the lifetime of the QGP created in the most central heavy-ion collisions at the LHC energies. The role of the intricate interplay between the open and hidden heavy sector in the process of equilibration is highlighted. This work provides a dynamical way of understanding the phenomenological success of statistical hadronization model for charmonium production in relativistic heavy-ion collisions, and also paves the way for realistic phenomenological applications to heavy quarkonium transport.