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Title: Improved limits on Fierz interference using asymmetry measurements from the Ultracold Neutron Asymmetry (UCNA) experiment

Journal Article · · Physical Review C

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. Furthermore, 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.

Research Organization:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Nuclear Physics (NP); USDOE Laboratory Directed Research and Development (LDRD) Program; National Science Foundation (NSF)
Contributing Organization:
UCNA Collaboration
Grant/Contract Number:
AC05-00OR22725; FG02-08ER41557; SC0014622; FG02-97ER41042; 20110043DR; 1002814; 1005233; 1205977; 1306997; 1307426; 1506459; 1615153; 1812340; 1914133
OSTI ID:
1820879
Alternate ID(s):
OSTI ID: 1604864
Journal Information:
Physical Review C, Vol. 101, Issue 3; ISSN 2469-9985
Publisher:
American Physical Society (APS)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 14 works
Citation information provided by
Web of Science

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