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

TL;DR

This paper provides a detailed analysis of $B_s$ meson weak decays using a covariant light-front model, offering predictions for form factors, decay rates, and angular observables across the full kinematic range, with comparisons to other methods.

Contribution

It introduces a self-consistent covariant light-front approach for $B_s$ decay form factors, calibrated with lattice QCD and phenomenological inputs, enabling comprehensive decay predictions.

Findings

Form factors consistent with lattice QCD and sum rules.

Predicted branching ratios and angular observables for semileptonic decays.

Identified tensions between theoretical predictions and experimental data.

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.