Double-heavy tetraquarks with strangeness in the chiral quark model

TL;DR

This study investigates double-heavy strange tetraquarks using the chiral quark model, identifying a bound state for $bbar{u}ar{s}$ and discovering resonant states, contributing to understanding exotic hadrons in particle physics.

Contribution

It introduces a comprehensive analysis of $QQar{q}ar{s}$ tetraquarks considering multiple structural pictures and identifies specific bound and resonant states, advancing theoretical predictions in this area.

Findings

Only $bbar{u}ar{s}$ with $J^P=1^+$ is bound, with 3.5 MeV binding energy.

Resonant states are found for double-heavy strange tetraquarks.

The study supports the existence of exotic tetraquark states in the chiral quark model.

Abstract

Recently, some progresses have been made on the double-heavy tetraquarks in the experiments, such as $T_{cc}$ reported by LHCb Collaboration, and $X_{cc\bar{s}\bar{s}}$ reported by the Belle Collaboration. Coming on the heels of our previous work about $T_{cc}$ and $T_{bb}$, we present a study on the bound states and the resonant states of its companions $QQ\bar{q}\bar{s}$ ($Q=c,b; q=u, s$) tetraquarks with strange flavor in the chiral quark model. Two pictures, one with meson-meson picture, another with diquark-antidiquark picture and their couplings are considered in our calculations. Isospin violation is neglected herein. Our numerical analysis indicates that only the state $bb\bar{u}\bar{s}$ with $\frac{1}{2}(1^+)$ is bound, with the binding energy 3.5 MeV. Besides, we also find some resonant states for the double-heavy strange tetraquarks with the real scaling method.