Searching For New Physics With B to K pi Decays

TL;DR

The paper introduces a method to assess Standard Model uncertainties in B to K pi decays using experimental data, demonstrating current data compatibility with the Standard Model and providing a robust estimate for S(KS pi0).

Contribution

It presents a novel approach to quantify theoretical uncertainties in B to K pi decays based on experimental data and power counting, without requiring large subleading terms.

Findings

Current B to K pi data are compatible with the Standard Model.

Large subleading terms are not necessary to fit the data.

The estimate for S(KS pi0) is 0.74 ± 0.04, insensitive to hadronic uncertainties.

Abstract

We propose a method to quantify the Standard Model uncertainty in B to K pi 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 to K pi data are compatible with the Standard Model. We analyze the pattern of subleading terms required to reproduce the B to K pi data and argue that anomalously large subleading terms are not needed. Finally, we find that S(KS pi0) is fairly insensitive to hadronic uncertainties and obtain the Standard Model estimate S(KS pi0)=0.74 +- 0.04.