# Production of exotic tetraquarks $QQ\bar{q}\bar{q}$ in heavy-ion collisions at the LHC

## TL;DR

This paper models the production of exotic tetraquarks in heavy-ion collisions at the LHC, finding lower yields than previous estimates but highlighting potential for future discovery due to chiral symmetry effects.

## Contribution

It provides a detailed coalescence model using realistic four-body wave functions to estimate tetraquark production yields in heavy-ion collisions.

## Key findings

- Production yields are an order of magnitude smaller than previous estimates.
- Partial chiral symmetry restoration enhances tetraquark stability and production.
- Potential for discovering exotic tetraquarks in upcoming LHC experiments.

## Abstract

We investigate the production of exotic tetraquarks, $QQ\bar{q}\bar{q} \equiv T_{QQ}$ ($Q=c$ or $b$ and $q=u$ or $d$), in relativistic heavy-ion collisions using the quark coalescence model. The $T_{QQ}$ yield is given by the overlap of the density matrix of the constituents in the emission source with the Wigner function of the produced tetraquark. The tetraquark wave function is obtained from exact solutions of the four-body problem using realistic constituent models. The production yields are typically one order of magnitude smaller than previous estimations based on simplified wave functions for the tetraquarks. We also evaluate the consequences of the partial restoration of chiral symmetry at the hadronization temperature on the coalescence probability. Such effects, in addition to increasing the stability of the tetraquarks, lead to an enhancement of the production yields, pointing towards an excellent discovery potential in forthcoming experiments. We discuss further consequences of our findings for the search of exotic tetraquarks in central Pb+Pb collisions at the LHC.