Precision Measurement of the Asymmetry in Spin-Polarized ^{37}K Decay. Academic Article uri icon


  • 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.

published proceedings

  • Phys Rev Lett

author list (cited authors)

  • Fenker, B., Gorelov, A., Melconian, D., Behr, J. A., Anholm, M., Ashery, D., ... Warner, C. L.

publication date

  • January 1, 2018 11:11 AM