Deviations from the standard model prediction have been reported in various semileptonic $B$ decays mediated via $b\to c$ charged-current interactions. In this context, we analyze corresponding semileptonic baryon decays ${\mathrm{\Xi }}_b\to {\mathrm{\Xi }}_c\tau \nu$ using the helicity formalism. We report numerical results on various observables such as the decay rate, ratio of branching ratios, lepton-side forward-backward asymmetry, longitudinal polarization fraction of the charged lepton, and the convexity parameter for this decay mode using results from the relativistic quark model. We also provide an estimate of the new physics effect on these observables under various new physics scenarios.

• Received 27 January 2018

DOI:https://doi.org/10.1103/PhysRevD.97.073004

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP³.

Published by the American Physical Society