First measurement of the neutron beta asymmetry with ultracold neutrons.
Phys Rev Lett
; 102(1): 012301, 2009 Jan 09.
Article
de En
| MEDLINE
| ID: mdl-19257182
ABSTRACT
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 approximately 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 2x2pi solenoidal spectrometer. We determine a value for the beta-asymmetry parameter A_{0}=-0.1138+/-0.0046+/-0.0021.
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Collection:
01-internacional
Base de données:
MEDLINE
Langue:
En
Journal:
Phys Rev Lett
Année:
2009
Type de document:
Article
Pays d'affiliation:
États-Unis d'Amérique