γ-tunneling calculations for the decays of the K isomers in the Hf, W, Os region

Recent studies of the high-K isomers in the Hf, W, Os region have uncovered the existence of direct branches to the low-K rotational bands with unexpectedly large transition probabilities. The measured hindrance factors have called the validity of the K quantum number into question. In order to give a new insight to this problem, we have performed systematic calculations of the M1 and E2 partial life times of the K isomers by using a simple tunneling model in which the γ degree of freedom is taken into account. Many of the observed partial life times are reproduced by the model, but some data remain completely off the calculations. This requires further studies of the spin-orientation degree of freedom. (orig.)