ASYMMETRIES FOR ELASTIC-SCATTERING OF PI(+ -) FROM POLARIZED HE-3 AT DELTA-RESONANCE ENERGIES/

Asymmetries A(y) for pi(+) and pi(-) elastic scattering from polarized He-3 were measured at incident energies passing through the pi nucleo n P-33, or Delta(1232), resonance. The data were taken at the Clinton P. Anderson Meson Physics Facility using the high-energy pion channel P-3 and a large acceptance spectrometer to detect the scattered pions. The polarized He-3 target, originally developed at TRIUMF, was modifi ed for these experiments by the addition of diode lasers. Completely u nexpected negative asymmetries were observed at and below the resonanc e in pi(+) scattering near 50 degrees-60 degrees degrees, which cannot be reproduced by multiple scattering theory and Faddeev wave function s. A hybrid model, which adds a Delta-neutron spin-spin interaction te rm to the conventional calculations, provides a good description of th e pi(+) data. For pi(-) scattering this term predicts a negligible eff ect on A(y) and the data do not show the anomalous A(y) seen with pi().