Exclusive and Inclusive Decays of the Bc Meson in the Light-Front ISGW Model

الأصل · EN

We investigate the total decay rate of the (ground state) Bc meson within the framework of the relativistic constituent quark model formulated on the light-front (LF). The exclusive semileptonic (SL) and nonleptonic (NL) beauty and charm decays of the Bc meson are described through vector and axial hadronic form factors, which are calculated in terms of the overlap of the parent and daughter LF wave functions. The latters are derived via the Hamiltonian LF formalism using as input the update version of the ISGW model. The inclusive SL and NL partial rates are calculated within a convolution approach inspired by the partonic model and involving the same Bc wave function which is used for evaluation of the exclusive modes. We predict the partial rates for 74 exclusive SL and NL channels and 43 inclusive partial rates corresponding to the underlying b→ c and c→ s quark decays. Based on our approach we find Γb(Bc)= 0.52 ± 0.02 ps⁻¹, Γᶜ(Bc)= 0.98 ± 0.07 ps⁻¹, where the theoretical uncertainty is dominated by the uncertainty in the choice of the threshold values at which the hadron continuum starts. For the Bc lifetime we obtain τBc= 0.63 ± 0.02 ps in a good agreement with the prediction obtained using the nonrelativistic operator product expansion. We also predict decay rates for many specific weak transitions of Bc. In particular, for the branching fractions of the B+c → J/ψμ+νμ, Bc+→ J/ψπ+ and Bc+ → J/ψ+X decays we obtain 1.7%, 0.1 % and 13.2%, respectively.