Comparison of the π+ and π? elastic scattering from 12C over the πN (3,3) resonance region

Pion-carbon scattering was measured for both π⁺ and π^? at 162 and 226 MeV. The significant differences observed between the π⁺ and π^? elastic cross sections in the diffraction minima are shown to be of opposite sign below and above the πN (3,3) resonance. In addition, differences between the π⁺ and π^? cross sections are also observed at 162 MeV at backward angles.