A Parity-Violating Spin Rotation Measurement of Transversely Polarized Cold Neutrons Through a Liquid Helium Target

The nucleon-nucleon (NN) weak interaction is one of the more poorly understood areas of the Standard Model. A quantitative description of the NN interaction is needed to describe weak interaction phenomenon in atomic, nuclear, and hadronic systems. This Ph.D. dissertation is based on a high precision measurement of the parity-violating (PV) spin rotation for transversely polarized cold neutrons passing through a liquid 4He target, which will support a quantitative interpretation of the NN weak interaction. The PV rotation angle was measured to be dø/dz = (5.8±8.7(stat)±1.3( sys))×10-7 rad/m. This result is the most precise PV spin rotation measurement to date and the uncertainty is smaller than current estimates of the range of possible values of dø/dz in the n-4He system. My contribution to the experiment includes (1) constructing a feedback system for active shielding of magnetic fields, (2) taking and analyzing data for both production and systematic e®ect measurements, and (3) expanding the Monte-Carlo simulation to study systematic effects from neutron scattering and magnetic fields