Decay modes of the scalar exotic meson Tbs;(u)over-bar(d)over-bar(-)

Abstract

We investigate the semileptonic decay of the scalar tetraquark T-bs;(u) over bar(d) over bar(-) to final state T(cs;(u) over bar(d) over bar)l (nu) over bar (0)(l), which proceeds due to the weak transition b -> cl (nu) over bar (l). For these purposes, we calculate the spectroscopic parameters of the final-state scalar tetraquark T-cs;(u) over bar(d) over bar 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-cs;(u) over bar(d) over bar 0 obtained in the present work (2878 +/- 128) MeV indicates that it is unstable against the strong interactions, and can decay to the mesons D-0(K) over bar (0) and D+K- Partial widths of these S-wave modes as well as the full width of the tetraquark T-cs;(u) over bar(d) over bar 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-bs;(u) over bar(d) over bar(-) -> T(cs;(u) over bar(d) over bar)l (nu) over bar (0)(l), l = e, mu, and tau are computed by employing the weak form factors G(1)(q(2)) and G(2) (q(2)), which are extracted from the QCD three-point sum rules. We also trace back the weak transformations of the stable tetraquark T-bb;(u) over bar(d) over bar(-) to conventional mesons. The obtained results for the full width Gamma(full) = (3.28 +/- 0.60) x 10(-10) MeV and mean lifetime tau = 2.01(-031)(+0.44) ps of T-bs;(u) over bar(d) over bar(-), as well as predictions for decay channels of the tetraquark T-bb;(u) over bar(d) over bar(-) can be used in experimental studies of these exotic states.