Inelastic scattering ofπ+andπ−mesons fromHe3andHe4at energies of 350, 400, and 475 MeV

The momentum distributions of pions inelastically scattered from ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ and ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ were measured for incident energies of 350, 400, and 475 MeV. Pions were detected in a magnetic spectrometer at scattering angles of 60°, 90°, and 120°. The spectra show quasifree scattering from single nucleons along with a substantial component of lower momentum pions. The results are compared to a simple impulse approximation model, which accounts for the principal features of the data, but does not reproduce the low momentum tail even with the inclusion of multiple scattering.