Precision Measurement of the Asymmetry in Spin-Polarized ^{37}K Decay.
Overview
Research
Identity
Additional Document Info
Other
View All
Overview
abstract
Using Triumf's neutral atom trap, Trinat, for nuclear decay, we have measured the asymmetry with respect to the initial nuclear spin in ^{37}K to be A_{}=-0.5707(13)_{syst}(13)_{stat}(5)_{pol}, a 0.3% measurement. This is the best relative accuracy of any -asymmetry measurement in a nucleus or the neutron, and is in agreement with the standard model prediction -0.5706(7). We compare constraints on physics beyond the standard model with other -decay measurements, and improve the value of V_{ud} measured in this mirror nucleus by a factor of 4.