Semileptonic and nonleptonic decays of the axial-vector tetraquark Tbb;(u)over-bar(d)over-bar-

The semileptonic and nonleptonic decays of the double-beauty axial-vector tetraquark T-bb;(u) over bar(d) over bar(-) to a state (T) over tilde (0)(bc;(u) over bar(d) over bar) (hereafter T-bb(-) and (T) over tilde (0)(bc), respectively) are investigated in the context of the QCD sum rule method. The final-state tetraquark (T) over tilde (0)(bc) is treated as an axial-vector particle built of a heavy axial-vector diquark b(T)gamma C-mu(c) and light scalar antidiquark (u) over barC(gamma 5)(d) over bar (T). Its spectroscopic parameters are calculated using the two-points sum rules by taking into account contributions of quark, gluon and mixed condensates up to dimension 10. We study the dominant semileptonic T-bb(-) -> (T) over tilde (0)(bc)l (nu) over bar (l) and nonleptonic decays T-bb(-) -> (T) over tilde M-0(bc), where M is one of the pseudoscalar mesons pi(-), K-, D- and Ds(-). The partial widths of these processes are computed in terms of weak form factors G(i)(q(2)), i = 1, 2, 3, 4, extracted by employing the QCD three-point sum rule approach. Predictions obtained for partial widths of considered decays are used to improve accuracy of theoretical predictions for full width and lifetime of the tetraquark T-bb(-), which are important for experimental exploration of this exotic meson.

Automated summary

In this study, the semileptonic and nonleptonic decays of the double-beauty axial-vector tetraquark T-bb are investigated using the QCD sum rule method. The spectroscopic parameters of the final-state tetraquark are calculated, and the partial widths of the dominant decays are computed in terms of weak form factors. The predictions obtained for the partial widths of the decays are used to improve the theoretical accuracy of the full width and lifetime of the tetraquark T-bb, which are crucial for experimental exploration.