Probing Lepton Flavour Universality with $\hat{I}{›}_b$ decays to $\ddot{I}{„}^{+}\ddot{I}{„}^{-}$ final states

Abstract

We present a study of the rare baryonic decay $\hat{I}{›}_b\to \hat{I}›\ddot{I}{„}^{+}\ddot{I}{„}^{-}$ as a probe of new physics (NP) coupled preferentially to third-generation fermions. Within the Standard Model, we evaluate the branching ratio and the lepton-flavour-universality (LFU) ratio $R_{\hat{I}}{›}^{\ddot{I}„/\hat{I}¼}$, including both perturbative and long-distance charm contributions. We show that the LFU ratio can be predicted with an uncertainty below 10%. Possible NP effects arising from lepton non-universal dynamics are analysed within an effective field theory framework motivated by the current anomalies in $b\to c\ddot{I}„\hat{I}½$ and $b\to s\hat{I}{¼}^{+}\hat{I}{¼}^{-}$ transitions. In this context, $R_{\hat{I}}{›}^{\ddot{I}„/\hat{I}¼}$ can be enhanced by several orders of magnitude, offering a clear target for upcoming searches. The implications for the related mode $\hat{I}{›}_b\to pK\ddot{I}{„}^{+}\ddot{I}{„}^{-}$ are also briefly discussed.

17 pages, 3 figures, 4 tables

References in corpus (1)

• Measurement of the branching fraction of the $\hat{I}{›}_b^0\to J/\ddot{I}ˆ\hat{I}›$ decay and isospin asymmetry of $B\to J/\ddot{I}ˆK$ decays

Cited by in corpus (1)

• Constraints on lepton-flavor mixing with third-generation new physics