Precision measurement of the nuclear polarization in laser-cooled, optically pumped K-37 Academic Article uri icon


  • 2016 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft. We report a measurement of the nuclear polarization of laser-cooled, optically pumped 37K atoms which will allow us to precisely measure angular correlation parameters in the -decay of the same atoms. These results will be used to test the V - A framework of the weak interaction at high precision. At the Triumf neutral atom trap (Trinat), a magneto-optical trap confines and cools neutral 37K atoms and optical pumping spin-polarizes them. We monitor the nuclear polarization of the same atoms that are decaying in situ by photoionizing a small fraction of the partially polarized atoms and then use the standard optical Bloch equations to model their population distribution. We obtain an average nuclear polarization of P = 0.9913 0.0009, which is significantly more precise than previous measurements with this technique. Since our current measurement of the -asymmetry has statistical uncertainty, the polarization measurement reported here will not limit its overall uncertainty. This result also demonstrates the capability to measure the polarization to < 0.1%, allowing for a measurement of angular correlation parameters to this level of precision, which would be competitive in searches for new physics.

published proceedings


altmetric score

  • 20.5

author list (cited authors)

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

citation count

  • 6

complete list of authors

  • Fenker, B||Behr, JA||Melconian, D||Anderson, RMA||Anholm, M||Ashery, D||Behling, RS||Cohen, I||Craiciu, I||Donohue, JM||Farfan, C||Friesen, D||Gorelov, A||McNeil, J||Mehlman, M||Norton, H||Olchanski, K||Smale, S||Theriault, O||Vantyghem, AN||Warner, CL

publication date

  • July 2016