Weak Decays of Stable Doubly Heavy Tetraquark States

TL;DR

This paper predicts the spectra and decay modes of stable doubly heavy tetraquarks, providing guidance for experimental searches at LHCb and Belle II, based on recent discoveries and SU(3) symmetry analysis.

Contribution

It introduces a theoretical framework for predicting the spectra and decay channels of stable doubly heavy tetraquarks using the Sakharov-Zeldovich formula and SU(3) symmetry.

Findings

$T^+_{cc\bar{u}\bar{d}}$ is 16MeV below $DD^*$ threshold

$T^-_{bb\bar{u}\bar{d}}$ is 73MeV below $BB^*$ threshold

Identifies promising decay channels for experimental detection

Abstract

In the light of the recent discovery of the $\Xi^{++}_{cc}$ by LHCb collaboration, we study the stable doubly heavy tetraquarks. These states are compact exotic hadrons which can be approximated as the diquark-anti-diquark correlations. In the flavor SU(3) symmetry, they form an SU(3) triplet or anti-sextet. The spectra of the stable doubly heavy tetraquark states are predicted by Sakharov-Zeldovich formula. We find that the $T^+_{cc\bar{u}\bar{d}}({\bf 3})$ is about 16MeV below the $DD^*$ threshold, while $T^{-}_{bb\bar{u}\bar{d}}({\bf 3})$ is about 73MeV below the $BB^*$ threshold. We then study the semileptonic and nonleptonic weak decays of the stable doubly heavy tetraquark states. The decay amplitudes are parametrized in terms of SU(3)-irreducible amplitudes. Ratios between decay widths of different channels are also derived. At the end, we collect the Cabibbo allowed two-body and three-body decay channels, which are most promising to search for the stable doubly heavy tetraquark states at LHCb and Belle II experiments.