Measurement of the neutrino asymmetry in the beta decay of laser-cooled, polarized K-37 Academic Article uri icon


  • A measurement of the neutrino asymmetry is presented which represents the first search for new physics using polarized radioactive atoms initially cooled and confined in a magneto-optical trap. Optical pumping and photoionization techniques are used to generate and measure, in situ, a highly spin-polarized (96.5 (0.8) %) sample of the short-lived +-emitter 37K. The angular distribution of neutrinos from this polarized decay, inferred from the daughter recoil asymmetry, is used to search for a hypothetical V + A current in the weak interaction. We find the asymmetry parameter to be B = - 0.755 0.020 (stat) 0.013 (syst), in agreement with the standard model's purely V - A interaction. 2007 Elsevier B.V. All rights reserved.

published proceedings


author list (cited authors)

  • Melconian, D., Behr, J. A., Ashery, D., Aviv, O., Bricault, P. G., Dombsky, M., ... Vollrath, I.

citation count

  • 49

complete list of authors

  • Melconian, D||Behr, JA||Ashery, D||Aviv, O||Bricault, PG||Dombsky, M||Fostner, S||Gorelov, A||Gu, S||Hanemaayer, V||Jackson, KP||Pearson, MR||Vollrath, I

publication date

  • June 2007