Competition betweenβ +- andβ −-decays from the transitional nucleus74As

A theoretical study of theβ ⁺- andβ ^?-decays of the⁷⁴As nucleus is performed. Both non-relativistic and relativistic formfactor coefficients are calculated in the framework of the asymmetric rotor model with admixtures of two quasiparticles for transitional nuclei. The induced interactions are shown to have small contributions to the values of the formfactor coefficients in this case. The theoretical results for the principal observables are in good agreement with the experimental data in the case of the beta decays to the 2⁺ final states. The failure in describing the beta observables corresponding to the transitions to the ground states points to the existence of a more complex structure of the 0⁺-states in the daughter nuclei⁷⁴Se and⁷⁴Ge.