Final State Interaction Phases in $ B \to K \pi$ Decay Amplitudes
  A simple Regge pole model for $K\pi$ scattering explains the large $e^{i \delta}$ between isospin amplitudes which is observed at the D meson mass ($\delta \approx \pi/2$). It predicts $\delta \approx 14^{\circ}- 20^{\circ}$ at the B mass. Implications for ($B \to K \pi$) decays and extensions of the model to other two-body decay channels are briefly discussed. 
D.Delepine, J.-M.Gerard, J.Pestieau and J.Weyers