$R_2$ as a single leptoquark solution to $R_{D^{(\ast )}}$ and $R_{K^{(\ast )}}$

Abstract

We show that, up to plausible uncertainties in BR$(B_c\to \tau \nu )$, the $R_2$ leptoquark can simultaneously explain the observation of anomalies in $R_{K^{(\ast )}}$ and $R_{D^{(\ast )}}$ without requiring large couplings. The former is achieved via a small coupling to first generation leptons which boosts the decay rate $\Gamma (\bar{B}\to {\bar{K}}^{(\ast )}{e}^{+}{e}^{-})$. Finally we motivate a neutrino mass model that includes the $S_3$ leptoquark which can alleviate a mild tension with the most conservative limits on BR$(B_c\to \tau \nu )$.

Comments: 24 pages, 4 figures; matches version published in PRD