Nucleon knockout from polarized 3He by polarized protons at 290 MeV.

Abstract

The $^{3}\ensuremath{\rightarrow}$(p\ensuremath{\rightarrow},2p) and $^{3}\ensuremath{\rightarrow}$(p\ensuremath{\rightarrow},pn) knockout reactions were observed in quasielastic kinematics at 290 MeV. Spin observables ${\mathit{A}}_{\mathit{n}0}$, ${\mathit{A}}_{0\mathit{n}}$, and ${\mathit{A}}_{\mathit{n}\mathit{n}}$ were obtained for both reactions. Calculations using the plane wave impulse approximation (PWIA) and the free nucleon-nucleon scattering amplitudes were performed and compared with the data. The proton knockout data are in qualitative agreement with the calculations which predict ${\mathit{A}}_{\mathit{n}\mathit{n}}$ to be sensitive to the presence of mixed-symmetry S' components in the $^{3}\mathrm{He}$ wave function. Proton spins are expected to be exactly paired at momenta q\ensuremath{\approxeq}80 MeV/c, in agreement with the ${\mathit{A}}_{\mathit{n}\mathit{n}}$ data. Spin observables ${\mathit{A}}_{0\mathit{n}}$ and ${\mathit{A}}_{\mathit{n}\mathit{n}}$ for the $^{3}\ensuremath{\rightarrow}$(p\ensuremath{\rightarrow},pn) reaction deviate significantly from the PWIA predictions. The qualitative differences between proton and neutron knockout results may be caused by final-state interaction effects.