Determination of the CP violating weak phase $γ$ from the Decays $B \to D π$

Abstract

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 $B^- \rightarrow D^0 π^- \rightarrow f π^-$ and $B^- \rightarrow \bar D^0 π^- \rightarrow f π^-$ decays, where $f$ are final states such as $K^+ π^-$, $K^+ ρ^-$, $K ππ$, {\it etc.} We also study the experimental feasibility of our new method. With 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.