$\bar{B}\to D^{(\ast )}\ell \bar{X}$ decays in effective field theory with massive right-handed neutrinos

Abstract

We calculate the complete differential decay distributions for the $B$ meson decays, $\bar{B}\to D^{(\ast )}\ell \bar{X}$, to a massive right-handed (RH) neutrino in the low-energy effective field theory (LEFT) framework. We find that a massive RH neutrino does not introduce any new angular structures compared to the massless case, but can cause significant distortions in angular observables. We study the phenomenology of low-energy four-fermion operators permitted by the standard model effective field theory (SMEFT) extended with RH neutrinos (SMNEFT). We show that to explain the positive value of the difference in forward-backward asymmetries, $\Delta A_{\text{FB}}\equiv A_{\text{FB}}^{\mu }-A_{\text{FB}}^e$, tentatively inferred from Belle data, the RH neutrino must be massive. We also make predictions for $q^2$ dependent angular observables to motivate future measurements.

12 pages, 4 figures, 3 tables. Version to appear as a Letter in PRD

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Cited by in corpus (4)

• When Energy Goes Missing: New Physics in $b\to s\nu \nu$ with Sterile Neutrinos
• Right-handed interactions in puzzling $B$-decays
• Implications for the $\Delta A_{FB}$ anomaly in ${\bar{B}}^0\to D^{\ast +}{\ell }^{-}\bar{\nu }$ using a new Monte Carlo Event Generator
• Status of G2HDM with right handed neutrino coupling in the light of $b\to c\tau \nu$ anomalies