Parity violation in polarized cold neutron capture

Author

Robert Stephen Mahurin, University of Tennessee

Date of Award

5-2009

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Physics

Major Professor

Geoffrey L. Greene

Abstract

The longitudinal asymmetry in photons emitted during radiative neutron-proton capture depends cleanly on the neutral current contribution to the weak nucleonnucleon interaction. The NPDGamma experiment is an eort to measure this asymmetry with precision ten parts per billion, which is 10% of its range of predicted values. In 2006 the NPDGamma collaboration acquired its rst production dataset at the Los Alamos Neutron Science Center. A pulsed beam of polarized slow neutrons is incident on a 16 L parahydrogen target; capture photons are observed in current mode in a cylindrical array of CsI scintillators. In this initial experiment, roughly 730 hours running with 50-55% neutron polarization, we set a new upper limit of 210 parts per billion for the size of the NPDGamma asymmetry, a modest improvement over the existing limit. In the next stage of the experiment this limit will be greatly reduced with the increased neutron ux at the Spallation Neutron Source.

Recommended Citation

Mahurin, Robert Stephen, "Parity violation in polarized cold neutron capture. " PhD diss., University of Tennessee, 2009.
https://trace.tennessee.edu/utk_graddiss/6040