M. A. Espy

Analyzing powers for the π − p → → π 0 n reaction across the Δ ( 1232 ) resonance

High quality analyzing powers for the {pi}{sup {minus}}{rvec p}{r_arrow}{pi}{sup 0}n reaction have been obtained with a polarized proton target over a broad angular range at incident kinetic energies of 98.1, 138.8, 165.9, and 214.4 MeV. This experiment nearly doubled the existing {pi}N single-charge-exchange database for energies ranging from 10 to 230 MeV, with 36 new analyzing powers. The Neutral Meson Spectrometer was used to detect the outgoing neutral pions. The data are well described by recent phase-shift analyses. When combined with high-precision and accurate cross section data at the same energies, the data can provide a good test of the degree of isospin breaking in the region of the {Delta}(1232) resonance. They will also be helpful for constraining the evaluation of the pion-nucleon {sigma} term from the scattering amplitudes. {copyright} {ital 1999} {ital The American Physical Society}High quality analyzing powers for the

Asymmetries for elastic scattering ofπ±from polarized3He atΔresonance energies

{\ensuremath{\pi}}^{\ensuremath{-}}\stackrel{\ensuremath{\rightarrow}}{p}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}n

The 4He(p, n)4Li∗ reaction at 100 and 200 MeV: Implications for the mass-four system and for astrophysics

reaction have been obtained with a polarized proton target over a broad angular range at incident kinetic energies of 98.1, 138.8, 165.9, and 214.4 MeV. This experiment nearly doubled the existing

Study of the 3,4He(p↘,n) reactions at Tp=100 and 200 MeV

\ensuremath{\pi}N

Pion double charge exchange onO16atTπ=300–500 MeV

single-charge-exchange database for energies ranging from 10 to 230 MeV, with 36 new analyzing powers. The Neutral Meson Spectrometer was used to detect the outgoing neutral pions. The data are well described by recent phase-shift analyses. When combined with high-precision and accurate cross section data at the same energies, the data can provide a good test of the degree of isospin breaking in the region of the

Pion double charge exchange on [sup 16]O at [ital T][sub [pi]]=300--500 MeV

\ensuremath{\Delta}(1232)

Pion double charge exchange on O 16 at T π =300–500 MeV

resonance. They will also be helpful for constraining the evaluation of the pion-nucleon

Search for an eta bound state in pion double charge exchange on 18O.

\ensuremath{\sigma}

Asymmetries for elastic scattering of pi + from polarized 3He and the Delta -neutron spin-spin interaction.

term from the scattering amplitudes.

The 4He(p, n)4Li∗ reaction at 100 and 200 MeV: Implications for the mass-four system and for astrophysics [Phys. Lett. B 368 (1996) 39]

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}