Investigation of the tetraquark states $Qq\bar{Q} \bar{q}$ in the improved chromomagnetic interaction model

TL;DR

This paper predicts the mass spectra and decay channels of $Qqar{Q}ar{q}$ tetraquark states using an improved chromomagnetic interaction model, explaining recent experimental observations and suggesting future search strategies.

Contribution

The study provides a systematic analysis of $Qqar{Q}ar{q}$ tetraquark states with detailed mass predictions and decay channels, incorporating angular momentum and $ ext{C}$-parity considerations, and offers explanations for recent experimental findings.

Findings

Predicted mass spectra align with observed hidden-charm tetraquarks.

Low-lying states have large overlaps with $Qar Q$ and $qar q$ meson bases.

Suggested search channels involve $Qar Q$ and $qar q$ mesons.

Abstract

In the framework of the improved chromomagnetic interaction model, we complete a systematic study of the $S$-wave tetraquark states $Qq\bar{Q}\bar{q}$ ($Q=c,b$, and $q=u,d,s$) with different quantum numbers, $J^{PC}=0^{+(+)}$, $1^{+(\pm)}$, and $2^{+(+)}$. The mass spectra of tetraquark states are predicted and the possible decay channels are analyzed by considering both the angular momentum and $\mathcal{C}$-parity conservation. The recently observed hidden-charm tetraquark states with strangeness, such as $Z_{cs}(3985)^-$, $X(3960)$, and $Z_{cs}(4220)^+$, can be well explained in our model. Besides, based on the wave function of each tetraquark state, we find that the low-lying states of each $Qq\bar{Q}\bar{q}$ configuration have a large overlap to the $Q\bar Q$ and $q\bar q$ meson basis, instead of $Q\bar q$ and $q\bar Q$ meson basis. This indicates one can search these tetraquark states in future experiments via the channel of $Q\bar Q$ and $q\bar q$ mesons.