Massive right-handed neutrinos in $\bar{B}\to D^{\ast }\tau \bar{X}$ decay

Abstract

We explore signatures of a massive right-handed neutrino (RHN) in angular distributions of $\bar{B}\to D^{\ast }(\to D\pi )\tau (\to \pi {\nu }_{\tau })\bar{X}$ decays, where $X$ is an invisible state. We assume the new physics is described by the standard model effective field theory extended with an RHN in the MeV-GeV mass range. We calculate for the first time the full differential distributions in terms of the visible final states, including the decay of the $\tau$ lepton. We evaluate the sensitivity of various distributions to the new physics operators.

Comments: 33 pages, 5 figures, 1 table. Version to appear in JHEP