A leptoquark model to accommodate $R_K^{\exp }<R_K^{\mathrm{SM}}$ and $R_{K^{\ast }}^{\exp }<R_{K^{\ast }}^{\mathrm{SM}}$

Abstract

We show that a modification of the model with a low energy scalar leptoquark state carrying hypercharge $Y=7/6$ allows to accommodate both $R_K<1$ and $R_{K^{\ast }}<1$, through loop effects, consistent with recent observations made at LHCb. We describe details of the model, compute the relevant Wilson coefficient and, after discussing a number of constraints, we examine the phenomenological consequences of the model. The bounds on the lepton flavor violating decay rates, induced by this model, include $\mathcal{B}(Z\to \mu \tau )\lesssim \mathcal{O}(10^{-7})$, and $\mathcal{B}(B\to K\mu \tau )\lesssim \mathcal{O}(10^{-9})$. We also comment on the interpretation of the bounds on the leptoquark mass obtained from the direct searches at LHC.

Comments: 18 pages, 7 figures (published version)