Charmless weak $B_s$ decays in the relativistic quark model

The form factors of the weak $B_s$ transitions to ground-state and orbitally excited strange mesons are calculated in the framework of the QCD-motivated relativistic quark model based on the quasipotential approach. These form factors are expressed through the overlap integrals of meson wave functions found in their mass spectrum evaluations. The momentum dependence of the form factors is determined in the whole accessible kinematical range without any additional assumptions and extrapolations. Relativistic effects, including the wave function transformation from rest to a moving reference frame as well as the contributions of the intermediate negative-energy states, are consistently taken into account. The calculated form factors are used for the evaluation of the charmless semileptonic decay rates and two-body nonleptonic $B_s$ decays in the factorization approximation. The obtained results are confronted with previous predictions and available experimental data.