Probing electroweak physics using B -> XM decays in the endpoint region

TL;DR

This paper uses soft-collinear effective theory to analyze semi-inclusive B -> XM decays near the endpoint, providing insights into electroweak physics, CP asymmetries, and potential new physics effects with fewer hadronic uncertainties.

Contribution

It introduces a leading-order effective theory framework for semi-inclusive B decays near the endpoint, including eta and eta' mesons, reducing hadronic uncertainties and probing nonperturbative effects and new physics.

Findings

Predicted branching ratios and CP asymmetries depend on fewer parameters.

Comparison with BaBar data suggests an enhanced charming penguin.

Decays serve as a powerful probe of electroweak and nonperturbative effects.

Abstract

Using soft-collinear effective theory we describe at leading order in 1/m_b all the semi-inclusive hadronic B -> XM decays near the endpoint, where an energetic light meson M recoils against an inclusive jet X. We also include the decays involving eta, eta' mesons that receive additional contributions from gluonic operators. The predicted branching ratios and CP asymmetries depend on fewer hadronic parameters than the corresponding two-body B decays. This makes semi-inclusive hadronic B -> XM decays a powerful probe of the potential nonperturbative nature of charming penguins as well as a useful probe of new physics effects in electroweak flavor changing transitions. A comparison with B -> KX data from BaBar points to an enhanced charming penguin, albeit with large experimental errors.