Selected Citation

Electron-Neutrino Angular Correlation in the Positron Decay of Argon35

Authors(s):W. B. Herrmannsfeldt, D. R. Maxson, P. Stahelin, and J. S. Allen Publication:Physical Review Letters Publication Date:July 15, 1957 Publisher: American Physical Society Citation:PhysRev.107.2 Link:

The positron-neutrino angular correlation coefficient has been measured for the decay of A35. Since this decay occurs mainly through the Fermi matrix element, The correlation should be sensitive to the ratio of the two Fermi coupling constants. Two different experiments have been carried. out, and in each case, the results have shown that the vector interaction is dominant.

In view of this rather unexpected result,a review of the existing data on the angular correlation coefficient of the positron emitter Ne19 may be interesting. For comparison with the A35 results, the experimental values and the theoretical limits of X for Ne19 are plotted in the lower half of Fig. 2. It is evident, that in the case of Ne19, the experimental values of A. are in agreement with either the S, T or A, V combination of interactions. However, the accurate measurements of Rustad and Ruby show that X=+0.34&0.13 for the He6 decay which indicates that the tensor interaction is dominant in this transition. Thus, there is an apparent inconsistency between the experiments on the negatron decay of He6 and the positron decays of Ne19 and A35.