학술논문
Improved limits on Fierz Interference using asymmetry measurements from the UCNA experiment
Document Type
Working Paper
Author
Sun, Xuan; Adamek, E.; Allgeier, B.; Bagdasarova, Y.; Berguno, D. B.; Blatnik, M.; Bowles, T. J.; Broussard, L. J.; Brown, M. A. -P.; Carr, R.; Clayton, S.; Cude-Woods, C.; Currie, S.; Dees, E. B.; Ding, X.; Filippone, B. W.; García, A.; Geltenbort, P.; Hasan, S.; Hickerson, K. P.; Hoagland, J.; Hong, R.; Holley, A. T.; Ito, T. M.; Knecht, A.; Liu, C. -Y.; Liu, J.; Makela, M.; Mammei, R.; Martin, J. W.; Melconian, D.; Mendenhall, M. P.; Moore, S. D.; Morris, C. L.; Nepal, S.; Nouri, N.; Pattie Jr., R. W.; Galván, A. Pérez; Phillips II, D. G.; Picker, R.; Pitt, M. L.; Plaster, B.; Salvat, D. J.; Saunders, A.; Sharapov, E. I.; Sjue, S.; Slutsky, S.; Sondheim, W.; Swank, C.; Tatar, E.; Vogelaar, R. B.; VornDick, B.; Wang, Z.; Wei, W.; Wexler, J. W.; Womack, T.; Wrede, C.; Young, A. R.; Zeck, B. A.
Source
Phys. Rev. C 101, 035503 (2020)
Subject
Language
Abstract
The Ultracold Neutron Asymmetry (UCNA) experiment was designed to measure the $\beta$-decay asymmetry parameter, $A_0$, for free neutron decay. In the experiment, polarized ultracold neutrons are transported into a decay trap, and their $\beta$-decay electrons are detected with $\approx 4\pi$ acceptance into two detector packages which provide position and energy reconstruction. The experiment also has sensitivity to $b_{n}$, the Fierz interference term in the neutron $\beta$-decay rate. In this work, we determine $b_{n}$ from the energy dependence of $A_0$ 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 $b_{n}$ measurement using the weighted average of our asymmetry dataset fits, to obtain $b_{n} = 0.066 \pm 0.041_{\text{stat}} \pm 0.024_{\text{syst}}$ which corresponds to a limit of $-0.012 < b_{n} < 0.144$ at the 90% confidence level.
Comment: 6 pages, 3 figures. Submission to PRC
Comment: 6 pages, 3 figures. Submission to PRC