Analysis of unique beta transitions

Abstract

The Heidelberg group measurements 1) of unique forbidden transitions have been analysed. It has been found that experimental shape factors can be reproduced only with the induced pseudoscalar form factor d < 0, and/or with the induced G-non-conserving tensor form factor b > 0. In the former case they contradict Daniel's results 3) for 0 − → 0 + transitions, whereas in the latter they are in disagreement with other known analyses of μ-meson capture, allowed and forbidden transitions 4–8). The conclusion appears to be independent of limited variations of nuclear matrix element ratios. A complete theoretical expression for the shape factor and details of the analysis are presented.