Scalar leptoquarks and the rareBmeson decays

We study some rare decays of $B$ mesons involving the quark-level transition $b\to q{l}^{+}{l}^{-}(q=d,s)$ in the scalar leptoquark model. We constrain the leptoquark parameter space using the recently measured branching ratios of $B_{s,d}\to {\mu }^{+}{\mu }^{-}$ processes. Using such parameters, we obtain the branching ratios, direct $CP$-violation parameters, and isospin asymmetries in the $B\to K{\mu }^{+}{\mu }^{-}$ and $B\to \pi {\mu }^{+}{\mu }^{-}$ processes. We also obtain the branching ratios for some lepton-flavor-violating decays $B\to l_i^{+}{l}_j^{-}$. We find that the various anomalies associated with the isospin asymmetries of the $B\to K{\mu }^{+}{\mu }^{-}$ process can be explained in the scalar leptoquark model.