Masses of doubly heavy tetraquarks $T_{QQ^\prime}$ in a relativized quark model

TL;DR

This paper systematically investigates the mass spectra of doubly heavy tetraquarks using a relativized quark model, predicting a potentially stable state with specific quantum numbers that could guide future experiments.

Contribution

It introduces a comprehensive relativized quark model calculation for doubly heavy tetraquarks, identifying a stable $bb ar u ar d$ state with unique properties.

Findings

The $bb ar u ar d$ state is 54 MeV below relevant thresholds.

This state is predicted to be stable against strong and electromagnetic decays.

The tetraquark is a compact structure with a large hidden color component.

Abstract

In the present work, the mass spectra of doubly heavy tetraquarks $T_{QQ^\prime}$ are systematically investigated in a relativized quark model. The four-body systems including the Coulomb potential, confining potential, spin-spin interactions, and relativistic corrections are solved within the variational method. Our results suggest that the $IJ^P=01^+$ $bb \bar u \bar d$ state is 54 MeV below the relevant $\bar B \bar B$ and $\bar B \bar B^*$ thresholds, which indicates that both strong and electromagnetic decays are forbidden, and thus this state can be a stable one. Its large hidden color component and small root mean square radius demonstrate that it is a compact tetraquark rather than a loosely bound molecule or point-like diquark-antidiquark structure. Our predictions of the doubly heavy tetraquarks may provide valuable information for future experimental searches.