Tree-level new physics in $R(K^{(*)})$

Abstract

We implement the $\chi^2$ fit for $R(K^{(*)})$ with possible tree-level new physics in a model-independent parametrization. Relevant Wilson coefficients are decomposed into the new physics scale, its power, and the fermionic couplings. Constraints from the branching ratio of $B_s\to\mu^+\mu^-$ can be naturally incorporated with the scheme. For a reasonable set of the parameter ranges it is found that the new physics is less than $\sim 5~{\rm TeV}$. Some new physics models including the leptoquark, $Z'$, etc. can be embraced within our framework. We give comments on new LHCb data which are close to the standard model predictions.