Asymmetries in 100 MeV π+/π--3 rvec He elastic scattering

We have measured cross sections and analyzing powers for π+ and π- elastic scattering from a polarized 3He target at Tπ=100 MeV. Measurements have been made over an angular range of 60 degree to 110 degree which extends over the region of the cross section minimum where spin effects in π-nucleus scattering are predicted to be largest. This is evident from the large value of Ay observed in π+ scattering from 3He near θlab=80 degree. The Ay data for both π+ and π- scattering are qualitatively reproduced by a schematic PWIA model; however, agreement with the data is significantly improved when a full nonlocal DWIA reaction model employing realistic three-body wave functions is used. The asymmetry in π--3He scattering resembles the asymmetry for π- scattering from a free neutron near the cross section minimum and is about half that for π+ scattering