β decay study of ¹⁶⁸Hf and a test of new geometrical models

Excited low-spin, nonyrast states of ¹⁶⁸Hf were populated in β⁺/ε decay and studied through γ-ray spectroscopy to assess the nature of low-lying K^π=0⁺,2⁺ intrinsic excitations. Coincidence data provided improved measurements of the decay properties of the low-lying states, and γ-γ angular correlation measurements yielded spin assignments for several levels as well as E2/M1 mixing ratios. The resulting level scheme of ¹⁶⁸Hf is compared with the predictions of new simple geometrical models, including the confined beta soft model and the Davidson potential. It is found that the predictions for most observables are similar for all the models and in agreement with the data on ¹⁶⁸Hf. However, large differences exist in the predictions for the excited K=0⁺ sequence, with the Davidson potential best reproducing the data in ¹⁶⁸Hf.