Abstract
The Ultracold Neutron Asymmetry (UCNA) experiment was designed to measure the β-decay asymmetry parameter, A0, for free neutron decay. In the experiment, polarized ultracold neutrons are transported into a decay trap, and their β-decay electrons are detected with ≈4π acceptance into two detector packages which provide position and energy reconstruction. The experiment also has sensitivity to bn, the Fierz interference term in the neutron β-decay rate. In this work, we determine bn from the energy dependence of A0 using the data taken during the UCNA 2011-2013 run. In addition, we present the same type of analysis using the earlier 2010 A dataset. Motivated by improved statistics and comparable systematic errors compared to the 2010 data-taking run, we present a new bn measurement using the weighted average of our asymmetry dataset fits, to obtain bn=0.066±0.041stat±0.024syst which corresponds to a limit of -0.012<bn<0.144 at the 90% confidence level.
| Original language | English |
|---|---|
| Article number | 035503 |
| Journal | Physical Review C |
| Volume | 101 |
| Issue number | 3 |
| DOIs | |
| State | Published - Mar 2020 |
Bibliographical note
Publisher Copyright:© 2020 American Physical Society.
Funding
This work is supported in part by the U.S. Department of Energy, Office of Nuclear Physics (DE-FG02-08ER41557, DE-SC0014622, DE-FG02-97ER41042) and the National Science Foundation (1002814, 1005233, 1205977, 1306997, 1307426, 1506459, 1615153, 1812340, and 1914133). Furthermore, we gratefully acknowledge the support of the LDRD program (20110043DR), and the help of those at the Accelerator Operations and Technology division at Los Alamos National Laboratory.
| Funders | Funder number |
|---|---|
| U.S. Department of Energy Chinese Academy of Sciences Guangzhou Municipal Science and Technology Project Oak Ridge National Laboratory Extreme Science and Engineering Discovery Environment National Science Foundation National Energy Research Scientific Computing Center National Natural Science Foundation of China | 1506459, 1205977, 1615153, 1914133, 1005233, 1306997, 1307426, 1812340, 1002814 |
| U.S. Department of Energy Chinese Academy of Sciences Guangzhou Municipal Science and Technology Project Oak Ridge National Laboratory Extreme Science and Engineering Discovery Environment National Science Foundation National Energy Research Scientific Computing Center National Natural Science Foundation of China | |
| U.S. Department of Energy Oak Ridge National Laboratory U.S. Department of Energy National Science Foundation National Energy Research Scientific Computing Center | |
| Horia Hulubei National Institute for Physics and Nuclear Engineering | DE-FG02-08ER41557, DE-FG02-97ER41042, DE-SC0014622 |
| Horia Hulubei National Institute for Physics and Nuclear Engineering | |
| Laboratory Directed Research and Development | 20110043DR |
| Laboratory Directed Research and Development | |
| Los Alamos National Laboratory |
ASJC Scopus subject areas
- Nuclear and High Energy Physics