Fully-heavy tetraquarks in strongly interacting medium

TL;DR

This paper investigates the properties and production of fully-heavy tetraquarks in hot and dense environments, providing insights into their masses, wave functions, and yields in high-energy nuclear collisions.

Contribution

It introduces a method to calculate tetraquark properties at finite temperature and models their production in heavy-ion collisions using the coalescence mechanism.

Findings

Tetraquarks are above meson-meson thresholds in vacuum.

The exotic state X(6900) may be a ccar car c tetraquark.

Production yield of ccar car c is significantly enhanced in heavy-ion collisions.

Abstract

We study the properties of fully-heavy tetraquarks at finite temperature and their production in high-energy nuclear collisions. We obtain the masses and wave functions of the exotic hadron states $cc\bar c\bar c$ and $bb\bar b\bar b$ by solving the four-body Schr\"odinger equation in vacuum and strongly interacting matter. In vacuum, the tetraquarks are above the corresponding meson-meson mass threshold, and the newly observed exotic state $X(6900)$ might be a $cc\bar c\bar c$ state with quantum number $J^{PC}=0^{++}$ or $1^{+-}$. In hot medium, the temperature dependence of the tetraquark masses and the dissociation temperatures are calculated. Taking the wave function at finite temperature, we construct the Wigner function for the tetraquark states and calculate, with coalescence mechanism, the production yield and transverse momentum distribution of $cc\bar c\bar c$ in heavy-ion collisions at LHC energy. In comparison with nucleon-nucleon collisions, the yield per binary collision is significantly enhanced.