The longitudinal polarization of positrons emitted along and opposite to the nuclear spin direction has been measured in the decay of polarized N-12. The results are consistent with the Standard Model prediction. In manifest left-right symmetric models this measurement provides a lower bound of 310 GeV/c(2) at 90% CL on the mass of a possible right-handed gauge boson contributing to the electroweak interaction. In generalized versions of this model our measurement provides constraints complementary to those set by high-energy experiments. (C) 2001 Elsevier Science B.V. All rights reserved.
Thomas, E. ; Prieels, René ; Allet, M. ; Bodek, K. ; Camps, J. ; et. al. Positron polarization in the decay of polarized N-12: a precision test of the Standard Model. In: Nuclear Physics, Section A, Vol. 694, no. 3-4, p. 559-589 (2001)