Determination of the CP-violating weak phase γ from the decays B → Dπ

We propose a new method to extract the CP-violating weak phase γ (the phase of V*_ub) in the CKM paradigm of the standard model, using B^- → D⁰π^- → fπ^- and B^- → D̄⁰π → fπ^- decays, where the f's are final states such as K⁺π^-, K⁺ρ^-, Kππ, etc. We also study the experimental feasibility of our new method. With the possibility of new phases in the CKM matrix, we re-examine some of the previously proposed methods to determine γ, and find that it would be in principle possible to identify γ and a new phase angle θ separately.