Non-Conservation of Parity
As mentioned before, experiments with polarized nuclei demonstrate unmistakably that parity is not conserved. The fact that electrons and positrons emitted in beta-decay possess a high degree of longitudinal polarization provides a new tool for the determination of the fundamental beta-interaction. If the 2-state theory with lepton conservation is assumed, the experimental result that positrons are right-polarized implies that positrons are always emitted together with vR-neutrinos. This would mean that the beta-interaction is A and V.
The experimental situation on this question is in confusion. First, most experiments seem to agree on the interaction being S or V plus A or T. This follows from the absence of Fierz interference terms (plus the assumption of time-reversal invariance). The detailed distinction between S or V and T or A is made by electron-neutrino correlation experiments which have nothing to do with violation of parity as such. Experiments with argon-35 seem to show V, experiments with helium-6 show T; neon -19 and neutron data are compatible with either (S,T) or (V,A) combinations. It would appear that if the helium-6 experiments x stay firm, the 2-state theory with lepton conservation will have to be abandoned, notwithstanding its success.
The experimental situation on this question is in confusion. First, most experiments seem to agree on the interaction being S or V plus A or T. This follows from the absence of Fierz interference terms (plus the assumption of time-reversal invariance). The detailed distinction between S or V and T or A is made by electron-neutrino correlation experiments which have nothing to do with violation of parity as such. Experiments with argon-35 seem to show V, experiments with helium-6 show T; neon -19 and neutron data are compatible with either (S,T) or (V,A) combinations. It would appear that if the helium-6 experiments x stay firm, the 2-state theory with lepton conservation will have to be abandoned, notwithstanding its success.