The current data on backward $\pi N$ scattering cross sections and polarization, including CERN-I.P.N. Orsay-Oxford measurements, are analyzed using complex Regge poles. Good fits are obtained with complex $N_{\alpha }$, $N_{\gamma }$, and ${\Delta }_{\delta }$ trajectories. There are no MacDowell partners and each trajectory produces the usual baryon spectrum at positive $u$.

• Received 15 July 1974

DOI:https://doi.org/10.1103/PhysRevD.10.3095