Minimal Unified Resolution to $R_{K^{(*)}}$ and $R(D^{(*)})$ Anomalies with Lepton Mixing

It is a challenging task to explain, in terms of a simple and compelling new physics scenario, the intriguing discrepancies between the standard model expectations and the data for the neutral-current observables $R_K$ and $R_{K^{*}}$, as well as the charged-current observables $R(D)$ and $R(D^{*})$. We show that this can be achieved in an effective theory with only two unknown parameters. In addition, this class of models predicts some interesting signatures in the context of both $B$ decays as well as high-energy collisions.

Figure 1

The light and dark blue regions denote 95% and 99% C.L. bands, respectively, around the best-fit points. The red shaded region is allowed by bounds from $\mathrm{BR}(B^{+}\to K^{+}{\mu }^{-}{\tau }^{+})$.

Figure 2

The fit for $A_2=4A_1/5$, with the bands around the best-fit points corresponding to 95% and 99% C.L. Also shown are the $1\sigma$ bands from $R_{K^{(*)}}$ and $R(D)$ and the 95% upper limits from $B_s\to \tau \tau$ and $B^{+}\to K^{+}{\mu }^{-}{\tau }^{+}$.