Weak decays of $B_s$ meson in self-consistent covariant light-front approach

Abstract

We present a comprehensive study of weak transition form factors and decay observables of the $B_s$ meson in transitions to pseudoscalar ($P$) and vector ($V$) mesons. The $B_s \to P(V)$ form factors are calculated using the self-consistent covariant light-front quark model, with a model-independent $z$-series expansion calibrated to lattice QCD and phenomenological inputs for quark masses and $\beta$ parameters. This enables reliable $q^2$-resolved predictions across the full kinematic range. Based on these form factors, we predict branching ratios and angular observables, including forward-backward asymmetries, polarization fractions, and leptonic convexity parameters for semileptonic decays. Nonleptonic two-body decay rates for $B_s \to PP$ and $B_s \to PV$ modes are also computed within the standard factorization framework using the same dynamical input. Comparisons with results from lattice QCD, light-cone sum rules, and other approaches are presented, highlighting both theoretical consistency and persistent tensions with experiment.