Measurements of asymmetries of pion single charge exchanage on polarized He-3

Asymmetries, A_y, for the (π^- π⁰) reaction on polarized ³He were measured using a pion beam at LAMPF. The π⁰'s were detected with the new Neutral Meson Spectrometer (NMS) in coincidence with the recoiling tritons. The recoil triton detector (RTD) consisted of scintillation-counter telescopes and a wire chamber that measured energy loss and direction of emission, respectively. The polarized gaseous ³He target developed at TRUMF was modified and run with two diode lasers. Polarizations were typically 50%. The A_y taken at T_pi = 200 MeV between 60 and 105 degrees were found to be strongly angle-dependent. The results were compared with the DWIA theoretical calculation. The scattering amplitudes were analyzed using current cross section and asymmetry data. It was found the spin-dependent amplitudes do not agree with from DWIA calculation. The S/sp/prime and D states of ³He give significant contributions to the spin- dependent amplitude at the Δ resonance energy due to the SS/sp/prime and SD overlap.