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.
| Original language | English |
|---|---|
| Article number | 066 |
| Journal | Proceedings of Science |
| Volume | 472 |
| DOIs | |
| State | Published - Jun 27 2025 |
| Event | 20th International Workshop on Polarized Source, Targets, and Polarimetry, PSTP 2024 - Newport News, United States Duration: Sep 22 2024 → Sep 27 2024 |
Funding
We acknowledge the support from the National Science Foundation (in particular from awards 2111363, 2209484, 2209590, 2412782, 2412846), Department of Energy Nuclear Physics (NP) (in particular from awards DE-FG02-03ER41258, DE-FG02-97ER41042, DE-SC0014622 and DE-SC0019309), the University of Virginia, Arizona State University, the Natural Sciences and Engineering Research Council of Canada, and Triangle University Nuclear Laboratory.