Coupling constants neutral weak

The reaction affords two products, an oxolane Pi and an oxetane P2, which exhibit a mirror-image relationship of their CIDNP patterns. The three most strongly polarized signals, of Hi, H7, and H7, with intensity ratios of about —2 to + 3 to +3.5, have been shown in the figure all the other protons are also polarized, but more weakly. The observed pattern is found to be in excellent agreement with the relative proton hyperfine coupling constants of the neutral benzosemiquinone radical and of the tert-butoxybicyclo[2.2.1]heptenyl radical, which were tested as model compounds for the two radical moieties.The biradical BRi is thus the source of the polarizations. It is formed in a triplet state, its singlet exit channel produces the oxolane Pi, and its triplet exit channel the oxetane P2. 

If one adopts a model-independent approach to the weak neutral current interaction, the atomic experiments supply certain information about the coupling constants not provided by high-energy experiments. Atomic experiments are necessary, as we will now show, in order to set stringent limits on the neutral current parameters and test theories (including, but not restricted to Weinberg-Salam) that predict values of these parameters. 

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