Nonperturbative charming penguin contributions to isospin asymmetries in radiativeBdecays

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(nu 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-+/- -> V-+/-gamma.