Nonperturbative Charming Penguin Contributions to Isospin Asymmetries in Radiative B decays

TL;DR

This paper uses Soft-Collinear Effective Theory to calculate isospin asymmetries in radiative B decays, highlighting the significant impact of nonperturbative charming penguins on these asymmetries and related observables.

Contribution

It introduces the inclusion of nonperturbative charming penguin contributions in theoretical predictions of isospin asymmetries in B decays, improving agreement with experimental data.

Findings

NPCP can significantly increase isospin asymmetries in B -> V gamma decays.

Without NPCP, predicted asymmetries are only a few percent or less.

NPCP affects branching ratios and CP asymmetries in B^  V^  gamma decays.

Abstract

Recent experimental data on the radiative decays B -> V gamma, where V is a light vector meson, find small isospin violation in B -> K^* gamma while isospin asymmetries in B -> rho gamma are of order 20%, with large uncertainties. Using Soft-Collinear Effective Theory, we calculate isospin asymmetries in these radiative B decays up to O(1/m_b), also including O(v alpha_s) contributions from nonperturbative charming penguins (NPCP). In the absence of NPCP contributions, the theoretical predictions for the asymmetries are a few percent or less. Including the NPCP can significantly increase the isospin asymmetries for both B -> V gamma modes. We also consider the effect of the NPCP on the branching ratio and CP asymmetries in B^\pm -> V^\pm gamma.