Final Neutron Lifetime Results from UCNτ and Status of the Follow-on UCNτ+ Experiment
ORAL
Abstract
The UCNτ collaboration recently completed measurement of the free neutron lifetime τn by loading ultracold neutrons (UCN) through a trapdoor into a magnetic plus gravitational trapping potential and utilizing a novel in situ detector to count surviving UCN after a variable holding time. We will present this result, which achieved a record relative precision of 0.03%. Combined with measurements of the β-asymmetry, this new result provides for the first time a test of CKM unitarity that is directly competitive with nuclear decay experiments. The completed analysis demonstrated that the experiment is still operating in a statistics-limited regime, and a follow-on experiment, called UCNτ+, aims to increase the number of trapped UCN by a factor of five to ten by loading via an "elevator" configuration. The current status of that effort will also be presented.
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Publication: Musedinovic et al. (UCNτ Collaboration), "Measurement of the Free Neutron Lifetime in a Magneto-Gravitational Trap with In Situ Detection," e-Print: 2409.05560 [nucl-ex] (Sep 9, 2024)<br>Gonzalez et al. (UCNτ Collaboration), "Improved neutron lifetime measurement with UCNτ," Phys.Rev.Lett. 127 (2021) 16, 162501<br>Pattie et al. (UCNτ Collaboration), "Measurement of the neutron lifetime using a magneto-gravitational trap and in situ detection," Science Vol 360, Issue 6389, pp. 627-632 (6 May 2018)
Presenters
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Steven M Clayton
Los Alamos National Laboratory, Los Alamos National Laboratory (LANL)
Authors
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Steven M Clayton
Los Alamos National Laboratory, Los Alamos National Laboratory (LANL)