2019/02/28 by H. E. Swanson, C. D. Bass, T. D. Bass +16 · 8 citations
Physics and Astronomy · #Amplitude #Atomic and Subatomic Physics Research #Neutron #Nuclear physics research studies #Parity (physics) #Quantum Chromodynamics and Particle Interactions #Rotation (mathematics) #Spin (aerodynamics) #Systematic error #Weak measurement #nucl-ex
paper · pdf · doi:10.1103/physrevc.100.015204
published in Physical Review C 100(1) (American Institute of Physics) · 15 pages, 7 figures
openalex created_date 2019/03/02 · openalex publication_date 2019/07/16 · arxiv created 2019/07/22 · arxiv updated 2019/07/24 · openalex updated_date 2026/08/06
Neutron spin rotation is expected from quark-quark weak interactions in the standard model, which induce weak interactions among nucleons that violate parity. We present the results from an experiment searching for the effect of parity violation via the spin rotation of polarized neutrons in a liquid 4He medium. The value for the neutron spin rotation angle per unit length in 4He, d\ensuremathφ/dz=[+2.1\ifmmode±\else\textpm\fi8.3(stat.)\phantom\rule0.16em0ex_\ensuremath-0.2+2.9(sys.)]\ifmmode×\else\texttimes\fi10^\ensuremath-7 rad/m, is consistent with zero. The result agrees with the best current theoretical estimates of the size of nucleon-nucleon weak amplitudes from other experiments and with the expectations from recent theoretical approaches to weak nucleon-nucleon interactions. In this paper we review the theoretical status of parity violation in the \stackrelPn+4He system and discuss details of the data analysis leading to the quoted result. Analysis tools are presented that quantify systematic uncertainties in this measurement and that are expected to be essential for future measurements.