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 ($\delta \approx \pi \mathrm{/}2$). 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.