Isospin Breaking in B -> K^* gamma Decays
Abstract
A calculation of the leading isospin-breaking contributions to the B -> K^* gamma decay amplitudes based on the QCD factorization approach is presented. They arise at order Lambda/m_b in the heavy-quark expansion and are due to annihilation contributions from 4-quark operators, the chromo-magnetic dipole operator, and charm penguins. In the Standard Model the decay rate for B^0 -> K^{*0} gamma is predicted to be about 10-20 % larger than that for B^- -> K^{*-} gamma. Isospin-breaking effects are a sensitive probe of the penguin sector of the effective weak Hamiltonian. New Physics models in which the hierarchy of B -> K^* gamma decay rates is either flipped or greatly enhanced could be ruled out with more precise data.
Cite
@article{arxiv.hep-ph/0110078,
title = {Isospin Breaking in B -> K^* gamma Decays},
author = {Alexander L. Kagan and Matthias Neubert},
journal= {arXiv preprint arXiv:hep-ph/0110078},
year = {2014}
}
Comments
11 pages, 2 figures. Extended version to appear in Physics Letters B. Includes an additional section with a discussion of New Physics effects