Charmonium, $B_c$ and X(3872) Transport at the LHC

TL;DR

This paper uses a kinetic-rate equation approach to study the production and transport of various quarkonium states, including X(3872), in heavy-ion collisions at the LHC, comparing results with experimental data.

Contribution

It introduces a comprehensive kinetic-rate model incorporating temperature-dependent equilibrium limits and reaction rates, including different internal structure scenarios for X(3872).

Findings

Model reproduces experimental yields of quarkonia.

Different X(3872) structure scenarios affect transport predictions.

Reaction rates depend on quark masses and binding energies.

Abstract

We deploy a kinetic-rate equation to evaluate the transport of $J/\psi$, $\psi(2S)$, $B_c$ and X(3872) in ultra-relativistic heavy-ion collisions and compare their production yields to experimental data from the Large Hadron Collider. The rate equation has two main transport parameters, i.e., the equilibrium limit and reaction rate for each state. The temperature-dependent equilibrium limits include charm- and bottom-quark fugacities based on their initial production. The reaction rates for charmonia, bottomonia and $B_c$ rely on charm- and bottom-quark masses as well as binding energies from a thermodynamic $T$-matrix approach. For the X(3872) particle, its internal structure information is encoded in reaction rates and initial conditions in the hadronic phase via two different scenarios: a loosely bound hadronic molecule vs. a compact diquark-antidiquark tetraquark.