$A_y^0$ Measurement from Quasi-Elastic $^3\mbox{He}^\uparrow(e,e'n)$ Scattering at Jefferson Lab

Due to the lack of free neutron targets, studies of the structure of the neutron are typically made by scattering electrons from either $^2$H or $^3$He targets. In order to extract useful neutron information from a $^3$He target, one must first understand how the neutron in a $^3$He system differs from a free neutron by taking into account nuclear effects such as final state interactions and meson exchange currents. The target single spin asymmetry $A_y^0$ is an ideal probe of such effects, as any deviation from zero indicates effects beyond plane wave impulse approximation. When nuclear effects within the $^3$He wave function are taken into account, calculations show that this asymmetry can become large ($>50\%$). New measurements of the target single spin asymmetry $A_y^0$ were made at Jefferson Lab using the quasi-elastic $^3\mathrm{He}^{\uparrow}(e,e'n)$ reaction. The measured asymmetry decreases by over two orders of magnitude, from $>70\%$ at $Q^2=0.1$ (GeV/$c)^2$ to nearly zero at $Q^2=1$ (GeV$/c)^2$, providing evidence of the dominance and fall-off of nuclear effects when studying neutron structure by electron scattering from $^3$He. Details of the measurement will be presented.