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 dphi/dz = (5.8 +/- 8.7(stat) +/- 1.3(sys))E-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 dphi/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 effect measurements, and (3) expanding the Monte-Carlo simulation to study systematic effects from neutron scattering and magnetic fields.

Author

• Gan, Kangfei

Language

• en

Keyword

• Helium
• Simulation
• Spin rotation
• Weak interaction
• Parity-Violation
• Neutron

Date created

• 2011

Type of Work

• Dissertation

License

• All rights reserved

Rights statement

• In Copyright

GW Unit

• Physics

Degree

• Ph.D.

Advisor

• Opper, Allena K

Committee Member(s)

• Griesshammer, Harald W
• Feldman, Gerald
• Haberzettl, Helmut
• Briscoe, William
• Beise, Elizabeth J

Persistent URL

•  https://scholarspace.library.gwu.edu/etd/rx913q01t