The role of induced interactions in nuclear beta transitions

Using the decoupling model for odd-odd-mass nuclei, extended to include in addition the possibility of strong coupling, the beta-decay observables for the ¹⁷⁰Tm 1^- to 2⁺ and 1^- to 0⁺ beta branches are calculated. The same branches are studied for the isotopes ¹⁸⁶Re and ¹⁸⁸Re using the decoupling model for odd-odd-mass transitional nuclei. The authors find that their theoretical results are in satisfactory agreement with experiment for the nuclei ¹⁷⁰Tm and ¹⁸⁸Re only if small induced terms are considered in the axial current in addition to the weak magnetism term in the vector current. However, these small effects are very difficult to estimate rigorously.