Doubly-heavy tetraquarks

TL;DR

This study uses the chiral quark model and complex scaling to investigate low-lying doubly-heavy tetraquark states, identifying potential bound and resonance states across various configurations and quantum numbers.

Contribution

It provides a detailed dynamical analysis of doubly-heavy tetraquarks considering multiple configurations and quantum numbers, revealing possible bound and resonance states.

Findings

Bound states for doubly-charm and doubly-bottom tetraquarks with specific quantum numbers.

Loosely bound states in charm-bottom tetraquarks with certain quantum numbers.

Compact structures are possible in diquark-antidiquark configurations, especially in bottom-heavy tetraquarks.

Abstract

In the framework of the chiral quark model along with complex scaling range, we perform a dynamical study on the low-lying $S$-wave doubly-heavy tetraquark states ($QQ\bar{q}\bar{q}$, $Q=c, b$ and $q=u, d$) with an accurate computing approach, Gaussian expansion method. The meson-meson and diquark-antidiquark configurations within all possible color structures for spin-parity quantum numbers $J^P=0^+$, $1^+$ and $2^+$, and in the $0$ and $1$ isospin sectors are considered. Possible tightly bound and narrow resonance states are obtained for doubly-charm and doubly-bottom tetraquarks with $IJ^P=01^+$, and these exotic states are also obtained in charm-bottom tetraquarks with $00^+$ and $01^+$ quantum numbers. Only loosely bound state is found in charm-bottom tetraquarks of $02^+$ states. All of these bound states within meson-meson configurations are loosely bound whether in color-singlet channels or coupling to hidden-color ones. However compact structures are available in diquark-antidiquark channels except for charm-bottom tetraquarks in $02^+$ states.