Interpretation of Experiments on the Beta Decay ofEu152

Abstract

The 1483-kev beta decay of ${\mathrm{Eu}}^{152}$ has previously been interpreted in terms of the "modified $B_{\mathrm{ij}}$" approximation. This decay has been reconsidered using more complete theoretical expressions and including the recent determination of the beta-circularly polarized gamma correlation along with the beta-gamma directional correlation and the beta spectral shape. The data indicate that the nuclear matrix element parameter ${\zeta }_1$ lies between 0.5 and 1. For some suitable sets of matrix element parameters the quantities $u$ and $x$ are small in qualitative agreement with the "modified $B_{\mathrm{ij}}$" approximation. However, other suitable sets of matrix element parameters may be found which are in disagreement with the approximation. The method of analysis described here is generally applicable to first forbidden beta decays with spin change 1 and the results from various types of experiments may be incorporated.