Polarization and Dip-Bump Structure inπ−pCharge-Exchange Scattering

We show that the new ${\pi }^{-}p$ charge-exchange polarization and differential cross-section data at large angles can be explained in terms of a simple model which includes a $\rho$ Regge pole plus a background term which one may interpret as either a secondary pole or a cut. We show that the rise after the dip is primarily due to the background term and not the spin-flip Regge term recovering from $\alpha$ passing through zero near $t=-0.6\mathrm{}$ ${\mathrm{GeV}}^2$. We discuss the effect of this insight on dip systematics.