Strong Phases in the Decays B to D Pi

The observed strong phase difference of 30^{o} between I=(3/2) and I=(1/2) final states for the decay B to D Pi is analyzed in terms of rescattering like D^{∗}Pi to D Pi, etc. It is concluded that for the decay B^{o}to D^{+} Pi^{-} the strong phase is only about 10^{o}. Implications for the determination of sin(2 Beta + gamma) are discussed.Comment: 4 pages (includes 1 reference page