Decay modes of the scalar exotic meson Tbs ;u ¯d ¯ -

We investigate the semileptonic decay of the scalar tetraquark T_b^{s ;u ¯d ¯ -} to final state T_c^{s ;u ¯ d ¯ 0}l ν_{¯ l} , which proceeds due to the weak transition b →c l ν_{¯ l} . For these purposes, we calculate the spectroscopic parameters of the final-state scalar tetraquark T_c^{s ;u ¯ d ¯ 0} . In calculations we use the QCD sum rule method by taking into account the quark, gluon, and mixed condensates up to dimension 10. The mass of the T_c^{s ;u ¯ d ¯ 0} obtained in the present work (2878 ±128 ) MeV indicates that it is unstable against the strong interactions, and can decay to the mesons D⁰K^{¯ 0} and D⁺K^-. Partial widths of these S -wave modes as well as the full width of the tetraquark T_c^{s ;u ¯ d ¯ 0} are found by means of the QCD light-cone sum rule method and technical tools of the soft-meson approximation. The partial widths of the main semileptonic processes T_b^{s ;u ¯ d ¯ -}→T_c^{s ;u ¯ d ¯ 0}l ν_{¯ l} , l =e , μ , and τ are computed by employing the weak form factors G₁(q²) and G₂(q²) , which are extracted from the QCD three-point sum rules. We also trace back the weak transformations of the stable tetraquark T_b^{b ;u ¯ d ¯ -} to conventional mesons. The obtained results for the full width Γ_full=(3.28 ±0.60 )×10^-10 MeV and mean lifetime τ =2.0 1_-0.31^+0.44 ps of T_b^{s ;u ¯ d ¯ -} , as well as predictions for decay channels of the tetraquark T_b^{b ;u ¯d ¯ -} can be used in experimental studies of these exotic states.