Revisiting B → K(*) v(v)over-bar decays in the Standard Model and beyond

In this letter we revisit the Standard Model predictions for B(B -> K-(*) v (v) over bar) and discuss the opportunities that open up when combining its partial decay rate with that of B -> K((*))ll . In the Standard Model a suitable ratio of these two modes can be used to extract C-9(eff), which is essential for a reliable phenomenological analysis of the B -> K((*))ll angular observables. The same ratio also proves to be more sensitive to the presence of New Physics in many plausible extensions of the Standard Model. We also suggest that the separate measurement of B(B -> K v (v) over bar) for high and for low q(2)'s can be helpful for testing the assumed shape of the vector form factor, because the lattice QCD data are obtained at high q(2)'s, whereas the low q(2) region is obtained through an extrapolation.

Automated summary

In this letter, the authors revisit the predictions of the Standard Model for B(B -> K-(*) v (v) over bar) and discuss the advantages of combining its partial decay rate with that of B -> K((*))ll. The suitable ratio of these two modes in the Standard Model can be used to determine C-9(eff), which is vital for an accurate analysis of the B -> K((*))ll angular observables. Additionally, this ratio is more sensitive to the presence of New Physics in various extensions of the Standard Model. The authors also propose separate measurements of B(B -> K v (v) over bar) at high and low q(2) regions to test the assumed shape of the vector form factor.