Quadrupole Moments of Collective Structures up to Spin $\sim$ $65\hslash$ in ${}^{157}$Er and ${}^{158}$Er: A Challenge for Understanding Triaxiality in Nuclei

Abstract

The transition quadrupole moments, $Q_{\mathrm{t}}$, of four weakly populated collective bands up to spin $\sim$ $65\hslash$ in ${}^{157,158}$Er have been measured to be $\sim 11\mathrm{eb}$ demonstrating that these sequences are associated with large deformations. However, the data are inconsistent with calculated values from cranked Nilsson-Strutinsky calculations that predict the lowest energy triaxial shape to be associated with rotation about the short principal axis. The data appear to favor either a stable triaxial shape rotating about the intermediate axis or, alternatively, a triaxial shape with larger deformation rotating about the short axis. These new results challenge the present understanding of triaxiality in nuclei.

6 pages, 5 figures, Phys. Lett. B, in press

References in corpus (5)

• Parametrizations of triaxial deformation and E2 transitions of the wobbling band
• Evidence for particle-hole excitations in the triaxial strongly-deformed well of ^{163}Tm
• Additivity of effective quadrupole moments and angular momentum alignments in the A~130 nuclei
• Lifetime measurements of Triaxial Strongly Deformed bands in ${}^{163}$Tm
• Exotic Collective Excitations at High Spin: Triaxial Rotation and Octupole Condensation

Cited by in corpus (6)

• Interpretation of the large-deformation high spin bands in selected A=158-168 nuclei
• Self-consistent tilted-axis-cranking study of triaxial strongly deformed bands in ${}^{158}$Er at ultrahigh spin
• Microscopic description of rotation: From ground states to the extremes of ultra-high spin
• Description of 158Er at ultrahigh spin in nuclear density functional theory
• Kerman-Onishi conditions in self-consistent tilted-axis-cranking mean-field calculations
• Interpretation of normal-deformed bands in 167Lu