Polarized 3He(e,e'n) Asymmetries in Three Orthogonal Measurements

Abstract

Asymmetry measurements were conducted in Jefferson Lab's experimental Hall A through electron scattering from a polarized ${}^3$He target in the quasi-elastic ${}^3\mathrm{He}(e,e^{\prime }n)$ reaction. Measurements were made with the target polarized in the longitudinal direction with respect to the incoming electrons ($A_L$), in a transverse direction that was orthogonal to the beam-line and parallel to the q-vector ($A_T$), and in a vertical direction that was orthogonal to both the beam-line and the q-vector ($A_y^0$). The experiment measured $A_y^0$ at four-momentum transfer squared (Q${}^2$) of 0.127 (GeV/$c$)${}^2$, 0.456 (GeV/$c$)${}^2$, and 0.953 (GeV/$c$)${}^2$. The $A_T$ and $A_L$ asymmetries were both measured at Q${}^2$ of 0.505 (GeV/$c$)${}^2$ and 0.953 (GeV/$c$)${}^2$. This is the first time that three orthogonal asymmetries have been measured simultaneously. Results from this experiment are compared with the plane wave impulse approximation (PWIA) and Faddeev calculations. These results provide important tests of models that use ${}^3$He as an effective neutron target and show that the PWIA holds above Q${}^2$ of 0.953 (GeV/$c{)}^2$.

127 pages, 74 figures