Frauenfelder, H.; Borone, R.; Von Goeler, E.; Levine, N.; Lewis, H.R.; Peacock, R.N.; Rossi, A.; de Pasquali, G.; Parity and the Polarization of Electrons from 60Co
Phys. Rev. 106 (1957) 386;
R. N. Cahn and G. Goldhaber, The Experimental Foundations of Particle Physics, Cambridge Univ. Press (1991) 178.
Lee and Yang (Phys. Rev. 104 (1956) 254) recently proposed that parity may not be conserved in weak interactions and suggested various experiments to verify their hypothesis. Two of the experiments have since been performed with positive result - the asymmetry of the electron emission from aligned nuclei and polarization of muons. In a second paper, Lee and Yang discuss a two-component theory of the neutrino and consider some more experimental tests. Among these, they list the measurement
of momentum and polarization of electrons emitted in beta decay. If parity is not conserved, the electrons should be longitudinally polarized. For tensor and scalar interaction, the degree of polarization is simply equal to (v/c). We have found this polarization in the case of 60Co.
Related references See also T. D. Lee and C. N. Yang, Phys. Rev. 104 (1956) 254;
C. S. Wu et al., Phys. Rev. 105 (1957) 1413;
N. Sherman, Phys. Rev. 103 (1956) 1601;
R. L. Garwin, L. M. Lederman, and M. Weinrich, Phys. Rev. 105 (1957) 1415;
H. A. Tolhoek, Rev. of Mod. Phys. 28 (1956) 277;
J. I. Friedman and V. L. Telegdi, Phys. Rev. 105 (1957) 1681;
60Co ee X
Further confirmation of spatial parity nonconservation in beta decays.