Signature dependent triaxiality for shape evolution from superdeformation in rapidly rotating 40^{40}Ca and 41^{41}Ca

Mar 12, 2020
17 pages
Published in:
  • PTEP 2020 (2020) 6, 063
  • Published: Jun 1, 2020
e-Print:
Report number:
  • KUNS-2800

Citations per year

2020202120222023132
Abstract: (Oxford University Press)
We investigate the possible occurrence of highly elongated shapes near the yrast line in |40^{40}|Ca and |41^{41}|Ca at high spins on the basis of the nuclear energy-density functional method. Both the superdeformed (SD) yrast configuration and the yrare configurations on top of the SD band are described by solving the cranked Skyme–Kohn–Sham equation in the three-dimensional coordinate space representation. It is suggested that some of the excited SD bands undergo band crossings and develop to hyperdeformation (HD) beyond |J25J \simeq 25 \hbar| in |40^{40}|Ca. We find that the change of triaxiality in response to rotation plays a decisive role in the shape evolution towards HD, and that this is governed by the signature quantum number of the last occupied orbital at low spins. This mechanism can be verified in an experimental observation of the positive-parity SD yrast signature-partner bands in |41^{41}|Ca, one of which (⁠|α=+1/2\alpha=+1/2|⁠) undergoes crossings with the HD band, while the other (⁠|α=1/2\alpha=-1/2|⁠) shows smooth evolution from collective rotation at low spins to non-collective rotation with an oblate shape at termination.
  • D13 Stable and unstable nuclei