Power Corrections in Charmless Nonleptonic B-Decays: Annihilation is Factorizable and Real

TL;DR

This paper demonstrates that leading annihilation contributions in charmless nonleptonic B-decays are factorizable and real, significantly reducing the expected strong phases and aligning with observed decay amplitudes.

Contribution

It proves that the dominant annihilation amplitudes are real and factorizable at leading order, clarifying the nature of power corrections in B-decays using soft-collinear effective theory.

Findings

Leading annihilation amplitudes are real and factorizable.

Incalculable strong phases are suppressed unless certain expansions break down.

Annihilation accounts for approximately 11-15% of measured penguin amplitudes.

Abstract

We classify LambdaQCD/mb power corrections to nonleptonic B-> M1 M2 decays, where M1 and M2 are charmless non-isosinglet mesons. Using recent developments in soft-collinear effective theory, we prove that the leading contributions to annihilation amplitudes of O[alphas(mb) LambdaQCD/mb] are real. The leading annihilation amplitudes depend on twist-2 and twist-3 three parton distributions. A complex nonperturbative parameter from annihilation first appears at O[alphas^2(sqrt{Lambda mb}) LambdaQCD/mb]. ``Chirally enhanced'' contributions are also factorizable and real at lowest order. Thus, incalculable strong phases are suppressed in annihilation amplitudes, unless the alphas(sqrt{Lambda mb}) expansion breaks down. Modeling the distribution functions, we find that (11 +- 9)% and (15 +- 11)% of the absolute value of the measured B-> K- pi+ and B-> K- K0 penguin amplitudes come from annihilation. This is consistent with the expected size of power corrections.