Possible Manifestations of Oblate Shapes at High Spin in the Yrast Region ofA=160−180Nuclei

Abstract

The possible manifestations of an oblate-shape region at high spin in $A=160\ensuremath{-}180$ nuclei are considered. We focus attention on the fact that rotational band phenomena indeed can exist in nuclei with oblate shapes. From estimates of transition energies, the yrast cascade there could consist largely of low-energy, alternating $M1$ transitions within bands and $E2$ transitions between bands. If the recently found stretched-dipole transitions are confirmed as $M1$, these results may be an indication for the existence of oblate shapes at high spin.