Implications of the $R_K$ and $R_{K^*}$ anomalies

Abstract

We discuss the implications of the recently reported $R_K$ and $R_{K^*}$ anomalies, the lepton flavor non-universality in the $B\to K\ell^+\ell^-$ and $B\to K^*\ell^+\ell^-$. Using two sets of hadronic inputs of form factors, we perform a fit of the new physics to the $R_K$ and $R_{K^*}$ data, and significant new physics contributions are found. We suggest to study the lepton flavor universality in a number of related rare $B, B_s, B_c$ and $\Lambda_b$ decay channels, and in particular we give the predictions for the $\mu$-to-$e$ ratios of decay widths with different polarizations of the final state particles, and of the $b\to d\ell^+\ell^-$ processes which are presumably more sensitive to the structure of the underlying new physics. With the new physics contributions embedded in Wilson coefficients, we present theoretical predictions for lepton flavor non-universality in these processes.