New shape minimum in Yb 160 : Evidence for a triaxial, strongly deformed band

A high-spin rotational band was observed in the N=90 nucleus Yb-160 with moment of inertia and decay characteristics very similar to recently discovered sequences in Er-157,Er-158. These latter structures were discussed in terms of strongly deformed triaxial bands. Detailed cranked Nilsson-Strutinsky calculations were performed that predict that well-deformed triaxial structures are also expected at high spin in Yb-160. Within this interpretation the observed discontinuity in the dynamic moment of inertia around h omega=0.40-0.45 MeV can be explained as a crossing between i(13/2) neutron levels.