A new long distance contribution to $B^{\pm }\to K^{\pm }/{\pi }^{\pm }{\ell }^{+}\ell -$ decays

Abstract

We have identified a missing long-distance (one-photon exchange) contribution to the $B^{\pm }\to K^{\pm }/{\pi }^{\pm }{\ell }^{+}{\ell }^{-}$ decays. Although it does not help to explain the anomaly measured by the LHCb Coll. in the ratio $R_K=\mathcal{B}(B^{\pm }\to K^{\pm }{\mu }^{+}{\mu }^{-})/\mathcal{B}(B^{\pm }\to K^{\pm }{e}^{+}{e}^{-})\sim 0.75$ (2.6 $\sigma$ deviation with respect to $R_K=1+\mathcal{O}(10^{-4})$ in the Standard Model), it provides a sizable contribution to the branching ratio of the $B^{\pm }\to {\pi }^{\pm }{\ell }^{+}{\ell }^{-}$ decays. The new decay mechanism gives rise to a measurable CP asymmetry, which is of order 1\% in both channels. These predictions can be tested in forthcoming LHCb measurements.

Comments: Rencontres de Moriond QCD 2015 Proceedings, 3 figures, 4 pages