Browsing by Author "Xu, Y. P."
Now showing 1 - 2 of 2
Results Per Page
Sort Options
- First Measurement of the Neutron beta Asymmetry with Ultracold NeutronsPattie, R. W.; Anaya, J.; Back, H. O.; Boissevain, J. G.; Bowles, T. J.; Broussard, L. J.; Carr, Rachel E.; Clark, D. J.; Currie, S.; Du, S.; Filippone, B. W.; Geltenbort, P.; Garcia, A.; Hawari, A.; Hickerson, K. P.; Hill, R.; Hino, M.; Hoedl, S. A.; Hogan, G. E.; Holley, A. T.; Ito, T. M.; Kawai, T.; Kirch, K.; Kitagaki, S.; Lamoreaux, S. K.; Liu, C. Y.; Liu, J.; Makela, M.; Mammei, R. R.; Martin, J. W.; Melconian, D.; Meier, N.; Mendenhall, M. P.; Morris, C. L.; Mortensen, R.; Pichlmaier, A.; Pitt, M. L.; Plaster, B.; Ramsey, J. C.; Rios, R.; Sabourov, K.; Sallaska, A. L.; Saunders, A.; Schmid, R.; Seestrom, S. J.; Servicky, C.; Sjue, S. K. L.; Smith, D.; Sondheim, W. E.; Tatar, E.; Teasdale, W.; Terai, C.; Tipton, B.; Utsuro, M.; Vogelaar, R. Bruce; Wehring, B. W.; Xu, Y. P.; Young, A. R.; Yuan, J.; Ucna Collaboration (American Physical Society, 2009-01-09)We report the first measurement of an angular correlation parameter in neutron beta decay using polarized ultracold neutrons (UCN). We utilize UCN with energies below about 200 neV, which we guide and store for similar to 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 x 2 pi solenoidal spectrometer. We determine a value for the beta-asymmetry parameter A(0) = -0.1138 +/- 0.0046 +/- 0.0021.
- Measurement of the neutron beta-asymmetry parameter A(0) with ultracold neutronsPlaster, B.; Rios, R.; Back, H. O.; Bowles, T. J.; Broussard, L. J.; Carr, Rachel E.; Clayton, S.; Currie, S.; Filippone, B. W.; Garcia, A.; Geltenbort, P.; Hickerson, K. P.; Hoagland, J.; Hogan, G. E.; Hona, B.; Holley, A. T.; Ito, T. M.; Liu, C. Y.; Liu, J.; Makela, M.; Mammei, R. R.; Martin, J. W.; Melconian, D.; Mendenhall, M. P.; Morris, C. L.; Mortensen, R.; Pattie, R. W.; Galvan, A. P.; Pitt, M. L.; Ramsey, J. C.; Russell, R.; Saunders, A.; Schmid, R.; Seestrom, S. J.; Sjue, S.; Sondheim, W. E.; Tatar, E.; Tipton, B.; Vogelaar, R. Bruce; VornDick, B.; Wrede, C.; Xu, Y. P.; Yan, H.; Young, A. R.; Yuan, J.; Ucna Collaboration (American Physical Society, 2012-11-12)We present a detailed report of a measurement of the neutron beta-asymmetry parameter A(0), the parity-violating angular correlation between the neutron spin and the decay electron momentum, performed with polarized ultracold neutrons (UCN). UCN were extracted from a pulsed spallation solid deuterium source and polarized via transport through a 7-T magnetic field. The polarized UCN were then transported through an adiabatic-fast-passage spin-flipper field region, prior to storage in a cylindrical decay volume situated within a 1-T 2 x 2 pi solenoidal spectrometer. The asymmetry was extracted from measurements of the decay electrons in multiwire proportional chamber and plastic scintillator detector packages located on both ends of the spectrometer. From an analysis of data acquired during runs in 2008 and 2009, we report A(0) = -0.11966 +/- 0.00089(-0.00140)(+0.00123), from lambda = g(A)/g(V) = -1.27590 +/- 0.00239(-0.00377)(+0.00331). Complete details of the analysis are presented.