Form factors for semileptonic, nonleptonic, and rare B(Bs) meson decays

We provide new values for the model parameters of the covariant constituent quark model (with built-in infrared confinement) in the meson sector by a fit to the leptonic decay constants and a number of electromagnetic decays. We then evaluate, in a parameter-free way, the form factors of the B(B_s)→P(V) transitions in the full kinematical region of momentum transfer. As an application of our results, we calculate the widths of the nonleptonic B_s decays into D_s^-D_s⁺, D_s^*-D_s⁺+D_s^-D_s^*+, and D_s^*-D_s^*+. These modes give the largest contribution to ΔΓ for the B_s-B¯_s system. We also treat the nonleptonic decay B_s→J/ψϕ. Although this mode is color-suppressed, this decay has important implications for the search of possible CP-violating new-physics effects in B_s-B¯_s mixing.