- By:
- Baessler, Stefan F; Broussard, Leah J; Gonzalez, Francisco M; Mueller, Paul E; Penttila, Seppo I; Saunders, Alexander ; Schreyer, Wolfgang S
- Journal Name:
- PoS - Proceedings of Science
- Page Number:
- 66
- Volume:
- 472
- Publication Date:
- July 17, 2025
- View DOI Listing:
- https://doi.org/10.22323/1.472.0066
Abstract
The Nab and pNAB collaborations are conducting a program of studies of free neutron beta decay, with the primary goal of testing the unitarity of the Cabbibo-Kobayashi-Maskawa matrix that describes quark mixing due to the weak interaction. For this purpose, a large, novel electromagnetic spectrometer, the Nab spectrometer, has been designed, built, and placed in use to determine the correlation coefficients in unpolarized neutron beta decay: "a", the neutrino-electron correlation coefficient; and "b", the Fierz term. The subject of this paper is pNAB, the second phase of the program, that will deploy the same spectrometer with a polarized neutron beam to determine "A", the beta asymmetry; and "B", the neutrino asymmetry coefficients. A focus of this paper will be on the strategies to provide a high and precisely known neutron beam polarization.
