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arXiv · hep-ph/0110078

Isospin Breaking in B -> K^* gamma Decays

Alexander L. Kagan·Matthias Neubert
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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.

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Alexander L. Kagan, Matthias Neubert. 2002-06-12. Isospin Breaking in B -> K^* gamma Decays. https://doi.org/10.1016/s0370-2693(02)02100-7

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