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First measurement of the neutron β asymmetry with ultracold neutrons

Pattie, R. W., Jr. and Anaya, J. and Back, H. O. and Boissevain, J. G. and Bowles, T. J. and Broussard, L. J. and Carr, R. and Clark, D. J. and Currie, S. and Du, S. and Filippone, B. W. and Geltenbort, P. and García, A. and Hawari, A. and Hickerson, K. P. and Hill, R. and Hino, M. and Hoedl, S. A. and Hogan, G. E. and Holley, A. T. and Ito, T. M. and Kawai, T. and Kirch, K. and Kitagaki, S. and Lamoreaux, S. K. and Liu, C.-Y. and Liu, J. and Makela, M. and Mammei, R. R. and Martin, J. W. and Melconian, D. and Meier, N. and Mendenhall, M. P. and Morris, C. L. and Mortensen, R. and Pichlmaier, A. and Pitt, M. L. and Plaster, B. and Ramsey, J. C. and Rios, R. and Sabourov, K. and Sallaska, A. L. and Saunders, A. and Schmid, R. and Seestrom, S. and Servicky, C. and Sjue, S. K. L. and Smith, D. and Sondheim, W. E. and Tatar, E. and Teasdale, W. and Terai, C. and Tipton, B. and Utsuro, M. and Vogelaar, R. B. and Wehring, B. W. and Xu, Y. P. and Young, A. R. and Yuan, J. (2009) First measurement of the neutron β asymmetry with ultracold neutrons. Physical Review Letters, 102 (1). 012301. ISSN 0031-9007.

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We report the first measurement of an angular correlation parameter in neutron β decay using polarized ultracold neutrons (UCN). We utilize UCN with energies below about 200 neV, which we guide and store for ~30 s in a Cu decay volume. The interaction of the neutron magnetic dipole moment with a static 7 T field external to the decay volume provides a 420 neV potential energy barrier to the spin state parallel to the field, polarizing the UCN before they pass through an adiabatic fast passage spin flipper and enter a decay volume, situated within a 1 T field in a 2×2π solenoidal spectrometer. We determine a value for the β-asymmetry parameter A_0=-0.1138±0.0046±0.0021.

Item Type:Article
Related URLs:
URLURL TypeDescription
Filippone, B. W.0000-0002-2618-2688
Hickerson, K. P.0000-0001-7647-119X
Ito, T. M.0000-0003-3494-6796
Morris, C. L.0000-0003-2141-0255
Additional Information:© 2009 The American Physical Society. Received 17 September 2008; published 5 January 2009. This work was supported in part by the Department of Energy, National Science Foundation, and Los Alamos National Laboratory LDRD. We acknowledge helpful discussions with A. P. Serebrov. PACS numbers: 14.20.Dh, 12.15.Ff, 12.15.Hh, 23.40.Bw.
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Department of EnergyUNSPECIFIED
Los Alamos National LaboratoryUNSPECIFIED
Issue or Number:1
Record Number:CaltechAUTHORS:20090805-094145827
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:14811
Deposited By: Tony Diaz
Deposited On:06 Aug 2009 22:58
Last Modified:09 Mar 2020 13:19

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