A detailed analysis of possible new-physics effects in semileptonic decays $B_s \to D_s^{(*)}\tau\bar{\nu}$

TL;DR

This paper investigates potential new physics effects in semileptonic $B_s$ decays to $D_s^{(*)} auar{ u}$, using a covariant quark model to predict observables and constrain new physics operators based on recent data.

Contribution

It introduces a comprehensive analysis of new-physics operators in $B_s$ decays, with form factors calculated in a covariant quark model and constraints derived from experimental data.

Findings

Constraints on new physics Wilson coefficients established.

Predictions for observables in $B_s o D_s^{(*)} auar{ u}$ decays provided.

Potential signals for new physics identified for future experiments.

Abstract

We study the semileptonic decays $B_s \to D_s^{(*)}\tau\bar{\nu}$ as a promising probe for new physics (NP) beyond the standard model (SM). The extension of the SM is done through the introduction of four-fermion operators beyond the $V-A$ structure with the corresponding Wilson coefficients characterizing their contribution. The constraints on these coefficients are obtained from recent experimental data. Form factors describing hadron transitions are calculated in our covariant quark model with infrared confinement. Theoretical predictions for the full set of observables in these channels are provided. We analyze possible NP effects to be tested in future experiments.