Rotation-induced shape transitions in Dy nuclei |
| |
Authors: | H. Emling E. Grosse R. Kulessa D. Schwalm H.J. Wollersheim |
| |
Affiliation: | Gesellschaft für Schwerionenforschung, D-6100 Darmstadt, Germany |
| |
Abstract: | Lifetimes of states with spins up to 30? have been measured in the nuclei 156Dy, 157Dy, and ll58Dy using the recoil-distance technique together with inverse reactions of the type . The applied method, which benefited from the high velocities of the fusion residues as well as from improvements of the recoil-distance technique, allowed us to determine lifetimes and feeding times down to 0.1 ps. Below the first backbending the resultant B(E2) values in the ground-state band of 156, 158Dy increase faster with increasing rotational frequency than expected for rigid rotors, reaching values similar to those observed for the well-deformed neutron-rich Dy isotopes. In contrast to this, the E2-transition probabilities between high-spin states are clearly retarded. The retardation gradually evolves from the rotation alignment of nucléons and indicates deformation changes most likely towards a triaxial shape. From the analysis of the side-feeding times of the high-spin yrast states it could be furthermore deduced that the E2 component of the preyrast γ-decay stems from transitions along highly collective bands. |
| |
Keywords: | Nuclear reactions |
本文献已被 ScienceDirect 等数据库收录! |
|