Theoretical Constraints for Observation of Superdeformed Bands in the Mass-60 Region

The lightest superdeformed nuclei of the mass-60 region are described using the Projected Shell Model. In contrast to the heaviest superdeformed nuclei where a coherent motion of nucleons often dominates the physics, it is found that alignment of $g_{9/2}$ proton and neutron pairs determines the high spin behavior for superdeformed rotational bands in this mass region. It is predicted that, due to the systematics of shell fillings along the even--even Zn isotopic chain, observation of a regular superdeformed yrast band sequence will be unlikely for certain nuclei in this mass region.