Model-independent information on gamma from B^+- -> pi K Decays

TL;DR

This paper discusses how measurements of B^+- -> pi K decays can provide largely model-independent insights into the weak phase gamma, with strategies to minimize uncertainties and explore new physics.

Contribution

It introduces methods to extract gamma from B^+- -> pi K decays with reduced theoretical uncertainties, considering hadronic effects and symmetry violations.

Findings

Bounds on gamma can be obtained with small theoretical uncertainties.

Hadronic uncertainties are limited to nonfactorizable, power-suppressed contributions.

B^+- -> pi K decays have potential to probe physics beyond the Standard Model.

Abstract

Measurements of the rates for the hadronic decays B^+- -> pi K can be used to derive information on the weak phase gamma=arg(V_ub^*) in a largely model-independent way. Hadronic uncertainties can be reduced to the level of nonfactorizable contributions to the decay amplitudes that are power-suppressed in Lambda/m_b and, in addition, either violate SU(3) flavor symmetry or are doubly Cabibbo suppressed. Various strategies to obtain bounds on gamma and to extract its value with small theoretical uncertainty are described. The potential of B^+- -> pi K decays for probing physics beyond the Standard Model is also discussed.