Bottomonium suppression and flow in heavy-ion collisions

Michael Strickland

doi:10.1051/epjconf/202225904001

Abstract

The strong suppression of bottomonia production in ultra-relativistic heavy-ion collisions is a smoking gun for the creation of a deconfined quarkgluon plasma (QGP). In this proceedings contribution, I review recent work that aims to provide a more comprehensive and systematic understanding of bottomonium dynamics in the QGP through the use of pNRQCD and an open quantum systems approach. This approach allows one to evolve the heavyquarkonium reduced density matrix, taking into account non-unitary effective Hamiltonian evolution of the wave-function and quantum jumps between different angular momentum and color states. In the case of a strong coupled QGP in which Ebind ≪ T, mD ≪ 1=a0, the corresponding evolution equation is Markovian and can therefore be mapped to a Lindblad evolution equation. To solve the resulting Lindblad equation, we make use of a stochastic unraveling called the quantum trajectories algorithm and couple the non-abelian quantum evolution to a realistic 3+1D viscous hydrodynamical background. Using a large number of Monte-Carlo sampled bottomonium trajectories, we make predictions for bottomonium RAA and elliptic flow as a function of centrality and transverse momentum and compare to data collected by the ALICE, ATLAS, and CMS collaborations.

Highlights

Bottomonium states that propagate through a deconfined quark-gluon plasma (QGP) are suppressed due to both Debye-screening, which modifies the real part of the heavy-quark potential, and in-medium transitions/breakup, which are encoded in the imaginary part of the heavy-quark potential
In recent years there have significant advances in our understanding of heavy-quark bound state dynamics in the QGP stemming from a combination of potential non-relativistic QCD and open quantum systems (OQS) [1–4]
Using potential non-relativistic QCD (pNRQCD) and OQS, in Refs. [1, 2] the authors obtained a set of master equations for heavy quarkonium in a strongly coupled QGP

Summary

Introduction

Bottomonium states that propagate through a deconfined quark-gluon plasma (QGP) are suppressed due to both Debye-screening, which modifies the real part of the heavy-quark potential, and in-medium transitions/breakup, which are encoded in the imaginary part of the heavy-quark potential. In recent years there have significant advances in our understanding of heavy-quark bound state dynamics in the QGP stemming from a combination of potential non-relativistic QCD (pNRQCD) and open quantum systems (OQS) [1–4]. In this effective field theory treatment one relies on a separation scales between the inverse size of the bound states 1/ r , the effective temperature of the system T , and the binding energy of the states E. The dynamical equation which governs the evolution of the heavy quarkonium reduced density matrix is of Lindblad form [1, 2]

Methods

Results

Conclusion