QCD factorization for B → ππ decays: Strong phases and CP violation in the heavy quark limit

We show that, in the heavy quark limit, the hadronic matrix elements that enter B meson decays into two light mesons can be computed from first principles, including “nonfactorizable” strong interaction corrections, and expressed in terms of form factors and meson light-cone distribution amplitudes. The conventional factorization result follows in the limit when both power corrections in 1/m_b and radiative corrections in α_s are neglected. We compute the order- α_s corrections to the decays B_d → π⁺π^-, B_d → π⁰π⁰, and B⁺ → π⁺π⁰ in the heavy quark limit and briefly discuss the phenomenological implications for the branching ratios, strong phases and CP violation.