Influence of band interaction on the spin prediction of superdeformed rotational bands

The influence of band interaction on the spin predictions and the J ?(2) pattern of superdeformed (SD) bands are investigated. To make a reliable spin prediction using the best-fit method, the transitions with significant band mixing should be excluded from the least-squares fitting. Spin predictions for 15 SD bands in the A ~150 region are made. In particular, the spin of the lowest level of the first discovered high-spin SD band 152 Dy(1) is predicted to be I 0 = 26. A two-band mixing model is used to describe the irregular behaviour of J ?(2) with angular momentum. Two types of J ?(2) patterns are discussed. For the band-crossing case, the J ?(2) pattern in the band-crossing region is of a V (or inverse-V) type, which has been observed in both the A ~190 and 150 regions. For the band-mixing case characterized by a relatively weak band interaction, the J ?(2) pattern in the band-mixing region is of a W (or inverse-W) type, which was observed only in some SD bands in the A ~150 region.