Phenomenological Model for π--PElastic Scattering near Resonances

A study is made to determine whether the observed forward diffraction peak and the backward bump in the pi /sup -/-p elastic scattering cross sections, at energies on the order of 1 Bev, can be explained in terms of the second and third pi -nucleon resonances and the T = J = 1 pi - pi resonance. It is concluded that a weak coupling is required, in order to produce a reasonable cross-section magnitude; that the model proposed reproduces the backward bump; that nonresonant amplitudes must be taken into account in the diffraction peak; and that the polarization of the recoil proton should be about 50%. (T.F.H.)