Complementarity of the constraints on New Physics from B_s -> mu+ mu- and from B -> K l+l- decays

TL;DR

This paper explores how combining experimental data from B_s -> mu+ mu- and B -> K l+l- decays provides model-independent constraints on new physics, emphasizing the role of asymmetry measurements.

Contribution

It demonstrates the complementarity of decay channels in constraining Wilson coefficients and highlights the importance of asymmetry measurements for identifying new physics sectors.

Findings

Combined bounds improve constraints on Wilson coefficients.

Transverse asymmetries help identify new physics phases.

Forward-backward asymmetry measurements are crucial at high q^2.

Abstract

We discuss the advantages of combining the experimental bound on Br(B_s -> mu+ mu-) and the measured Br(B -> K l+l-) to get the model independent constraints on physics beyond the Standard Model. Since the two decays give complementary information, one can study not only the absolute values of the Wilson coefficients that are zero in the Standard Model, but also their phases. To identify the sector in which the new physics might appear, information about the shapes of the transverse asymmetries in B -> K* l+l- at low q^2's can be particularly useful. We also emphasize the importance of measuring the forward-backward asymmetry in B -> K l+l- decay at large q^2's.