William Cummings

Asymmetries for elastic scattering ofπ±from polarized3He atΔresonance energies

Asymmetries A{sub y} for {pi}{sup +} and {pi}{sup {minus}} elastic scattering from polarized {sup 3}He were measured at incident energies passing through the {pi} nucleon P{sub 33}, or {Delta}(1232), resonance. The data were taken at the Clinton P. Anderson Meson Physics Facility using the high-energy pion channel P{sup 3} and a large acceptance spectrometer to detect the scattered pions. The polarized {sup 3}He target, originally developed at TRIUMF, was modified for these experiments by the addition of diode lasers. Completely unexpected negative asymmetries were observed at and below the resonance in {pi}{sup +} scattering near 50{degree}{endash}60{degree}, which cannot be reproduced by multiple scattering theory and Faddeev wave functions. A hybrid model, which adds a {Delta}-neutron spin-spin interaction term to the conventional calculations, provides a good description of the {pi}{sup +} data. For {pi}{sup {minus}} scattering this term predicts a negligible effect on A{sub y} and the data do not show the anomalous A{sub y} seen with {pi}{sup +}. {copyright} {ital 1997} {ital The American Physical Society}

Asymmetries for elastic scattering of pi+- from polarized He-3 at Delta resonance energies

Asymmetries A{sub y} for {pi}{sup +} and {pi}{sup {minus}} elastic scattering from polarized {sup 3}He were measured at incident energies passing through the {pi} nucleon P{sub 33}, or {Delta}(1232), resonance. The data were taken at the Clinton P. Anderson Meson Physics Facility using the high-energy pion channel P{sup 3} and a large acceptance spectrometer to detect the scattered pions. The polarized {sup 3}He target, originally developed at TRIUMF, was modified for these experiments by the addition of diode lasers. Completely unexpected negative asymmetries were observed at and below the resonance in {pi}{sup +} scattering near 50{degree}{endash}60{degree}, which cannot be reproduced by multiple scattering theory and Faddeev wave functions. A hybrid model, which adds a {Delta}-neutron spin-spin interaction term to the conventional calculations, provides a good description of the {pi}{sup +} data. For {pi}{sup {minus}} scattering this term predicts a negligible effect on A{sub y} and the data do not show the anomalous A{sub y} seen with {pi}{sup +}. {copyright} {ital 1997} {ital The American Physical Society}

Asymmetries for elastic scattering of {pi}{sup {plus_minus}} from polarized {sup 3}He at {Delta} resonance energies

Asymmetries A{sub y} for {pi}{sup +} and {pi}{sup {minus}} elastic scattering from polarized {sup 3}He were measured at incident energies passing through the {pi} nucleon P{sub 33}, or {Delta}(1232), resonance. The data were taken at the Clinton P. Anderson Meson Physics Facility using the high-energy pion channel P{sup 3} and a large acceptance spectrometer to detect the scattered pions. The polarized {sup 3}He target, originally developed at TRIUMF, was modified for these experiments by the addition of diode lasers. Completely unexpected negative asymmetries were observed at and below the resonance in {pi}{sup +} scattering near 50{degree}{endash}60{degree}, which cannot be reproduced by multiple scattering theory and Faddeev wave functions. A hybrid model, which adds a {Delta}-neutron spin-spin interaction term to the conventional calculations, provides a good description of the {pi}{sup +} data. For {pi}{sup {minus}} scattering this term predicts a negligible effect on A{sub y} and the data do not show the anomalous A{sub y} seen with {pi}{sup +}. {copyright} {ital 1997} {ital The American Physical Society}