Asymmetries for Elastic Scattering of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>π</mi></mrow><mrow><mo>+</mo></mrow></msup></mrow></math> from Polarized <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow></mrow><mrow><mn>3</mn></mrow></msup></mrow><mi mathvariant="normal">He</mi></math> and the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Δ</mi></math>-Neutron Spin-Spin Interaction

doi:10.1103/PhysRevLett.76.3667

Asymmetries for Elastic Scattering of $π^{+}$ from Polarized $^{3} He$ and the $Δ$ -Neutron Spin-Spin Interaction

M. A. Espy et al.

Phys. Rev. Lett. 76, 3667 – Published 13 May 1996

Abstract

Asymmetries for $π^{+}$ elastic scattering from polarized $^{3} He$ were measured across the $Δ$ (1232) $π$ -nucleon resonance region at incident energies $T_{π} = 142$ , 180, and 256 MeV. Large discrepancies were found between the data and calculations that use the multiple scattering formalism and Faddeev wave functions. Inclusion of a $Δ$ -neutron spin-spin interaction term in the calculations gives a greatly improved representation of the data.