Abstract
Precision measurements of free-neutron β decay have been used to precisely constrain our understanding of the weak interaction. However, the neutron Fierz interference term bn, which is particularly sensitive to beyond-standard-model tensor currents at the TeV scale, has thus far eluded measurement. Here we report the first direct constraints on this term, finding bn=0.067±0.005stat-0.061+0.090sys, consistent with the standard model. The uncertainty is dominated by absolute energy reconstruction and the linearity of the β spectrometer energy response.
Original language | English |
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Article number | 042501 |
Journal | Physical Review C |
Volume | 96 |
Issue number | 4 |
DOIs | |
State | Published - Oct 30 2017 |
Funding
This work is supported in part by the US Department of Energy, Office of Nuclear Physics (DE-FG02-08ER41557, DE-SC0014622, DE-FG02-97ER41042) and the National Science Foundation (Grants No. NSF-0653222, No. NSF-0700491, No. NSF-0855538, No. NSF-1002814, No. NSF-1005233, No. NSF-1205977, No. NSF-1306997, No. NSF-1307426, No. 1506459, and No. NSF-1615153). We gratefully acknowledge the support of the LDRD program (20110043DR), and the LANSCE and AOT divisions of the Los Alamos National Laboratory.