Enhancement of CP violation in B± → Ki± D0 by resonant effects

Resonance width effects in charged B decays to neutral D mesons and excited kaon states Ki around 1400 MeV are shown to lead to large calculable final state phases. CP asymmetries are defined for any charged B decay to three pseudoscalar mesons involving intermediate overlapping resonance states. Asymmetries up to about 10% are found in B+ → Ki+ D0 → (Kπ)+ D0. Decay distributions can be used to determine the weak phase γ of the Cabibbo-Kobayashi-Maskawa (CKM) matrix. No separation of the contributions from individual resonances is required.