A theoretical study of the beta decay transitions 0− → 2+ and 0− → 0+ of the Ho166 nucleus

The theoretical beta decay observables are compared with the experimental values for the 0^? → 2⁺ and 0^? → 2⁺ transitions. By considering a Ho¹⁶⁶ ground state configuration infered from (d, p) reaction experiments, and using all the matrix elements, satisfactory results are obtained for the 0^? → 2⁺ transition. For the 0^? → 2⁺ transition an important cancellation effect has been found which determines the failure of the ξ approximation and an energy dependent spectrum shape.