Searching for new physics with B→Kπ decays

We propose a method to quantify the Standard Model uncertainty in B→Kπ decays using the experimental data, assuming that power counting provides a reasonable estimate of the subleading terms in the 1/mb expansion. Using this method, we show that present B→Kπ data are compatible with the Standard Model. We analyze the pattern of subleading terms required to reproduce the B→Kπ data and argue that anomalously large subleading terms are not needed. Finally, we find that SKSπ0 is fairly insensitive to hadronic uncertainties and obtain the Standard Model estimate SKSπ0=0.74±0.04.