Observation of strongly deformed shapes in 154-152Dy nuclei at medium temperatures☆

Abstract The γ-decay of the giant dipole resonance (GDR) built on excited states of 154-152 Dy nuclei is studied. The selection of GDR decay from high spin states leading to specific exit channels was made possible by triggering on high spin isomers. The deduced energy splitting of the GDR implies large deformations ( |β|≌0.4–0.5 ). The resonance widths of the components are comparable to those of the GDR built on the ground state indicating small shape fluctuations.