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Large Direct CP Violation in B^0 -> pi^+ pi^- and an Enhanced Branching Ratio for B^0 -> pi^0 pi^0

S. Barshay·L. M. Sehgal·J. van Leusen
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Abstract

Recent measurements of B^0 -> pi pi decays reveal two features that are in conflict with conventional calculations: the channel B^0 (Bbar^0) -> pi^+ pi^- shows a large direct CP-violating asymmetry, and the channel B^0 (B^0) -> pi^0 pi^0 has an unexpectedly high branching ratio. We show that both features can be understood in terms of strong-interaction mixing of pi pi and D Dbar channels in the isospin-zero state, an effect that is important because of the large experimentally observed ratio Gamma(B^0 / Bbar^0 -> D^+ D^-) / Gamma (B^0 / Bbar^0 -> pi^+ pi^-) approx. 50. Our dynamical model correlates the branching ratios and the CP-violating parameters C and S, for the decays B^0 (Bbar^0) -> pi^+ pi^-, B^0 (Bbar^0) -> pi^0 pi^0, B^0 (Bbar^0) -> D^+ D^- and B^0 (Bbar^0) -> D^0 Dbar^0.

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S. Barshay, L. M. Sehgal, J. van Leusen. 2004-04-07. Large Direct CP Violation in B^0 -> pi^+ pi^- and an Enhanced Branching Ratio for B^0 -> pi^0 pi^0. https://doi.org/10.1016/j.physletb.2004.04.014

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