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

Abstract

We implement the ${\chi }^2$ fit for $R(K^{(\ast )})$ 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 $\sim 5\mathrm{TeV}$. Some new physics models including the leptoquark, $Z^{\prime }$, etc. can be embraced within our framework. We give comments on new LHCb data which are close to the standard model predictions.

Comments: 13 pages, 3 figures; more discussions