Measurement of the neutron lifetime using a magneto-gravitational trap and in situ detection
Creators
Abstract
The precise value of the mean neutron lifetime, τ_n, plays an important role in nuclear and particle physics and cosmology. It is used to predict the ratio of protons to helium atoms in the primordial universe and to search for physics beyond the Standard Model of particle physics. We eliminated loss mechanisms present in previous trap experiments by levitating polarized ultracold neutrons above the surface of an asymmetric storage trap using a repulsive magnetic field gradient so that the stored neutrons do not interact with material trap walls. As a result of this approach and the use of an in situ neutron detector, the lifetime reported here [877.7 ± 0.7 (stat) +0.4/–0.2 (sys) seconds] does not require corrections larger than the quoted uncertainties.
Additional Information
© 2018 American Association for the Advancement of Science. Received 2 June 2017; accepted 13 March 2018; Published online 6 May 2018. The authors thank the staff of LANSCE for their diligent efforts to develop the diagnostics and new techniques required to provide the proton beam for this experiment. Funding: This work was supported by the Los Alamos Laboratory Directed Research and Development (LDRD) office (no. 20140568DR), the LDRD Program of Oak Ridge National Laboratory, managed by UT-Battelle (no. 8215), the National Science Foundation (nos. 130692, 1307426, 161454, 1306997, and 1553861), NIST Precision Measurement Grant, IU Center for Space Time Symmetries (IUCSS), the LANSCE Rosen Scholarship program, and U.S. DOE Low Energy Nuclear Physics (nos. DE-FG02-97ER41042 and DE-AC05-00OR22725). Competing interests: None declared. Author contributions: Experiment design was performed by R.W.P., N.B.C., C.C.-W., E.R.A., S.M.C., W.F., P.G., K.P.H., A.T.H., A.K., C.-Y.L., M.M., C.L.M., J.R., D.J.S., A.S., S.J.S., E.I.S., S.K.S., J.V., P.L.W., and A.R.Y.; experiment construction was performed by R.W.P., N.B.C., C.C.-W., E.R.A., S.M.C., S.A.C., X.D., A.T.H., C.-Y.L., S.W.T.M., M.M., C.L.M., J.D.O., D.J.S., A.S., J.V., B.V., W.W., T.L.W., A.R.Y., and B.A.Z.; detector research and development was performed by R.W.P., C.C.-W., E.R.A., D.E.F., M.A.H., M.M., C.L.M., J.D.O., J.R., D.J.S., E.I.S., and Z.W.; data acquisition was performed by R.W.P., N.B.C., C.C.-W., E.R.A., L.J.B., S.M.C., E.B.D., E.M.E., D.E.F., P.G., K.P.H., A.T.H., A.K., C.-Y.L., M.M., C.L.M., J.D.O., D.J.S., A.S., S.J.S., S.K.S., Z.T., P.L.W., W.W., H.L.W., J.W.W., A.R.Y., and B.A.Z.; and data analysis was performed by R.W.P., N.B.C., C.C.-W., E.R.A., S.M.C., A.T.H., C.-Y.L., C.L.M., D.J.S., and S.J.S. Data and materials availability: The data shown in this paper are available as part of the supplementary materials. The raw data that underlie these results are curated at Los Alamos National Laboratory and are available upon request from the corresponding author.Attached Files
Supplemental Material - aan8895-Pattie-SM.pdf
Supplemental Material - aan8895_Pattie_SM_Data-File-S1.zip
Files
aan8895-Pattie-SM.pdf
Additional details
Identifiers
- Eprint ID
- 86241
- Resolver ID
- CaltechAUTHORS:20180507-100740959
Funding
- Los Alamos National Laboratory
- 20140568DR
- Oak Ridge National Laboratory
- 8215
- NSF
- PHY-130692
- NSF
- PHY-1307426
- NSF
- PHY-161454
- NSF
- PHY-1306997
- NSF
- PHY-1553861
- National Institute of Standards and Technology (NIST)
- IU Center for Space Time Symmetries
- Department of Energy (DOE)
- DE-FG02-97ER41042
- Department of Energy (DOE)
- DE-AC05-00OR22725
Dates
- Created
-
2018-05-07Created from EPrint's datestamp field
- Updated
-
2021-11-15Created from EPrint's last_modified field
Caltech Custom Metadata
- Caltech groups
- Kellogg Radiation Laboratory