$\bar{B}\to D^{\ast }{\ell }^{-}{\bar{\nu }}_{\ell }$ Decays: Angular Distributions and New Physics

Abstract

At the present time, there are hints of new physics (NP) in several observables involving $b\to c{\ell }^{-}{\bar{\nu }}_{\ell }$ decays. In this talk, I describe measurable angular distributions for $\bar{B}\to D^{\ast }{\mu }^{-}{\bar{\nu }}_{\mu }$ and $\bar{B}\to D^{\ast }{\tau }^{-}(\to {\pi }^{-}{\nu }_{\tau }){\bar{\nu }}_{\tau }$ decays, including the most general NP contributions. These angular distributions contain enough information to pin down the Lorentz structure of the NP, which will help to identify it. They also have the ability to reveal the presence of non-SMEFT (non-decoupling) NP.

Comments: 7 pages, 3 figures. Talk given at the 11th International Workshop on the CKM Unitarity Triangle (CKM2021), 22-26 November 2021, The University of Melbourne, Australia