Analyzing powers ${\mathit{A}}_{\mathit{y}}$ were measured for ${\mathrm{\pi }}^{+}$ and ${\mathrm{\pi }}^{\mathrm{-}}$ elastic scattering from polarized ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$ at energies near the ${\mathit{P}}_{33}$ resonance. At ${\mathit{T}}_{\mathrm{\pi }}$=132 MeV the values of ${\mathit{A}}_{\mathit{y}}$ are significantly different from zero for ${\mathrm{\pi }}^{\mathrm{-}}$. For ${\mathrm{\pi }}^{+}$ at 132 MeV and for both ${\mathrm{\pi }}^{\mathrm{-}}$ and ${\mathrm{\pi }}^{+}$ at all other energies, the ${\mathit{A}}_{\mathit{y}}$ are mostly consistent with zero. These data differ from the predictions of present pion-nucleus reaction theories, especially at large momentum transfers.

• Received 11 December 1990

DOI:https://doi.org/10.1103/PhysRevLett.66.1959