Bulletin of the American Physical Society
5th Joint Meeting of the APS Division of Nuclear Physics and the Physical Society of Japan
Volume 63, Number 12
Tuesday–Saturday, October 23–27, 2018; Waikoloa, Hawaii
Session FD: Electroweak Experiment and Theory
9:00 AM–11:30 AM,
Friday, October 26, 2018
Hilton Room: Kohala 3
Chair: Dinko Pocanic, University of Virginia
Abstract ID: BAPS.2018.HAW.FD.1
Abstract: FD.00001 : Measurement of systematic effects in the UCNτ experiment*
9:00 AM–9:15 AM
Eric Michael Fries
Eric Michael Fries
There have been various measurements of the free neutron lifetime (τn) using either cold neutron beams, or ultracold neutrons (UCN) stored in a trap. There is a ∼4σ discrepancy in measured lifetimes between the two methods. The UCNτ experiment at Los Alamos Neutron Science Center uses an asymmetric magneto-gravitational trap to store UCN, and counts the UCN remaining in the trap after various holding times to measure τn. Analysis of our 2016-2017 data established a current limit for our systematic uncertainty of +0.4/-0.2 s. Some systematic effects that can change the measured τn are depolarization and microphonic heating of trapped UCN, insufficient cleaning of UCN with energies above the trapping potential, and phase space evolution of UCN during storage. The effect of depolarization is measured by changing the strength of the magnetic holding field, the effects of heating and insufficient cleaning are measured by detecting high-energy UCN, and the effect of phase space evolution is measured by comparing the time distributions of UCN after different holding times. We will present details of how these systematic uncertainties are measured and projections of how they will be better constrained.
*Special thanks to DoE, NSF, LANL LDRD, and LANSCE.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2018.HAW.FD.1
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