Weak decays of stable doubly heavy tetraquark states

Abstract

In light of the recent discovery of the ${\mathrm{\ensuremath{\Xi}}}_{cc}^{++}$ by the LHCb Collaboration, we study the stable doubly heavy tetraquarks. These states are compact exotic hadrons which can be approximated as the diquark-antidiquark correlations. In the flavor SU(3) symmetry, they form a SU(3) triplet or antisextet. The spectra of the stable doubly heavy tetraquark states are predicted by the Sakharov-Zeldovich formula. We find that the ${T}_{bb\overline{u}\overline{d}}^{\ensuremath{-}}(\mathbf{3})$ is about 73 MeV below the $B{B}^{*}$ threshold at SET I. We then study the semileptonic and nonleptonic weak decays of the stable doubly heavy tetraquark states. The doubly heavy tetraquark decay amplitudes are parametrized in terms of flavor SU(3)-irreducible parts. 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 the LHCb and Belle II experiments.