ELASTIC-SCATTERING OF PI+ AND PI- FROM HE-4 BETWEEN 90 AND 240 MEV

In a series of experiments, differential cross sections for elastic scattering of pi+ and pi- from He-4 were measured at the Clinton P. Anderson Meson Physics Facility (LAMPF). Data were taken at incident energies between T-pi = 90 and 240 MeV using different experimental setups which covered the angular range from far forward (almost-equal-to 10-degrees) to far backward angles (almost-equal-to 170-degrees). A phase-shift analysis of the data was carried out. The experimental phase shifts are compared with values predicted by a first-order optical model program.