Probing the R-parity violating supersymmetric effects in the exclusive b\to c\ell^-\bar{\nu}_\ell decays

TL;DR

This paper investigates how R-parity violating supersymmetry could explain deviations in B meson decays observed by experiments, providing predictions for observables sensitive to new physics effects.

Contribution

It introduces a detailed analysis of R-parity violating SUSY effects on B decay observables, highlighting their potential to account for experimental anomalies.

Findings

Branching ratios of B_c to e and mu are sensitive to slepton exchange couplings.

Forward-backward asymmetries in B to D e decays are significantly affected by SUSY effects.

The ratio R(D*) can be enhanced within SUSY models but may not fully reach experimental lower bounds.

Abstract

Motivated by recent results from the LHCb, BABAR and Belle collaborations on B\to D^{(*)}\ell^-\bar{\nu}_\ell decays, which significantly deviate from the Standard Model and hint the possible new physics beyond the Standard Model, we probe the R-parity violating supersymmetric effects in B^-_c\to \ell^-\bar{\nu}_\ell and B\to D^{(*)}\ell^-\bar{\nu}_\ell decays. We find that (i) \mathcal{B}(B^-_c\to e^- \bar{\nu}_e) and \mathcal{B}(B^-_c\to\mu^-\bar{\nu}_\mu) are sensitive to the constrained slepton exchange couplings; (ii) the normalized forward-backward asymmetries of B\to De^-\bar{\nu}_{e} decays have been greatly affected by the constrained slepton exchange couplings, and their signs could be changed; (iii) all relevant observables in the exclusive b\to c\tau^-\bar{\nu}_\tau decays and the ratios \mathcal{R}(D^{(*)}) are sensitive to the slepton exchange coupling, \mathcal{R}(D^*) could be enhanced by the constrained slepton exchange coupling to reach each 95\% confidence level experimental range from BABAR, Belle and LHCb, but it could not reach the lower limit of the 95\% confidence level experimental average. Our results in this work could be used to probe R-parity violating effects, and will correlate with searches for direct supersymmetric signals at the running LHCb and the forthcoming Belle-II.