INTERFERENCE TERMS AND SYMMETRY PRINCIPLES IN THE THEORY OF BETA DECAY WITH MIXED INVARIANTS

In the theory of allowed 3-decay 1) 3), with the aid of an arbitrary linear mixture of invariants (1 = scalar, 2 = vector, 3 = tensor, 4 = axial vector, 5 = pseudo-scalar), one finds in the spectrum a factor [Equation 1] where the upper sign pertains to positive and the lower to negative β-decay. A factor like (1), but with 2 instead of (2y/E) is found in the probability of allowed K-capture. These factors are generally used to discuss the existence of the interference terms (from form of spectrum, and from ratio of the probabilities of K-capture and β⁺ emission) and the relative magnitude of Fermi-terms and Gamow-Teller-terms.