Analysis of the semileptonic $B_c\to D_s^*\mu^+ \mu^-$ decay mode in the effective field theory approach

TL;DR

This paper investigates the semileptonic decay $B_c o D_s^*\, ext{mu}^+ ext{mu}^-$ using effective field theory, providing predictions for observables and exploring potential new physics effects in light of existing anomalies.

Contribution

It offers a comprehensive analysis of $B_c o D_s^*\, ext{mu}^+ ext{mu}^-$ decay within EFT, including a global fit to data and predictions for observables under Standard Model and new physics scenarios.

Findings

Predicted branching ratio and asymmetries for $B_c o D_s^*\, ext{mu}^+ ext{mu}^-$.

Identified potential deviations from Standard Model in observables.

Provided theoretical estimates to guide future experimental searches.

Abstract

Discrepancies have been noted between experimental measurements and Standard Model predictions for various observables related to the $B\to(K, K^*,\phi) ll$ processes. Recently, the Belle-II Collaboration observed a $2.8\sigma$ deviation from Standard Model predictions in the branching ratio of the $B \to K \nu_l \bar{\nu_l}$ decay mode. In this context, we investigate the exclusive semileptonic $B_c\to D_s^{*}\mu^+ \mu^-$ decay mode, mediated by $b\to s$ quark level transition, using Effective Field Theory formalism. We perform a global fit to the new parameters using existing experimental data on $b \to s \mu^+ \mu^-$. We then estimate the branching ratio and other observables such as forward-backward asymmetry, lepton polarisation asymmetry, and the lepton non-universality parameter of the $B_c\to D_s^{(*)}\mu^+ \mu^-$ process. Although this process has not yet been detected experimentally, we offer predictions and discuss the observables for $B_c\to D_s^{*}\mu^+ \mu^-$ in both the Standard Model and potential new physics scenarios.