Neutron excitations across the N = 86 superdeformed shell gap

Abstract Based on data obtained with the Eurogam spectrometer, a systematic investigation of superdeformed bands built on single neutron excitations across the N = 86 shell gap has been carried out for gadolinium, terbium, and dysprosium isotopes with 85 ≤ N ≤ 87. In each nucleus, pairs of bands corresponding to degenerate signature partners have been observed. The effective alignment is constant and close to zero for many of the bands, in agreement with cranked shell model calculations for the [402]5/2 and [514]9/2 orbitals. Several bands exhibit non-zero alignments, indicating in some cases the influence of pairing correlations even at high spin and in other cases the occupancy of the [521]3/2 orbital.