New results from high-spin experiments at Gammasphere

To date, a wealth of superdeformed (SD) bands have been observed in the A ∼130, A ∼ 150, and A ∼ 190 mass regions, many of which reveal striking properties in terms of relative alignments and moments of inertia. An especially large interest has been focused on the open-quotes identicalclose quotes SD bands; pairs of SD bands in different nuclei that have been found to have transition energies simply related to other SD bands. The physical mechanism behind these features is not understood. However, different interpretations involving occupation of deformation driving open-quotes intruderclose quotes orbitals, pseudospin symmetry, and the alignment of pseudo intrinsic spins have been proposed. Following the discoveries of the SD bands in the A ∼ 190 region, a large number of dipole bands persisting up to high spin have been observed. The character of these bands is still under dispute but the favored interpretation is collective high-K bands at an oblate shape. Recently a number of experiments aimed at studying superdeformed and collective oblate nuclear states at high spin have been carried out at the Lawrence Berkeley Laboratory 88-inch cyclotron facility. Results from these experiments are reviewed