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

Abstract

We investigate the possible occurrence of the highly-elongated shapes near the yrast line in ${}^{40}$Ca and ${}^{41}$Ca at high spins on the basis of the nuclear energy-density functional method. Not only the superdeformed (SD) yrast configuration but 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 the hyperdeformation (HD) beyond $J\simeq 25\hslash$ in ${}^{40}$Ca. We find that the change of triaxiality in response to rotation plays a decisive role for 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 ${}^{41}$Ca, one of which ($\alpha =+1/2$) undergoes crossings with the HD band while the other ($\alpha =-1/2$) shows the smooth evolution from the collective rotation at low spins to the non-collective rotation with oblate shape at the termination.

References in corpus (16)

• Nuclear energy density optimization: Large deformations
• Isovector splitting of nucleon effective masses, ab-initio benchmarks and extended stability criteria for Skyrme energy functionals
• Broyden's Method in Nuclear Structure Calculations
• Beyond-mean-field-model analysis of low-spin normal-deformed and superdeformed collective states of S32, Ar36, Ar38 and Ca40
• Coexistence of spherical states with deformed and superdeformed bands in doubly magic 40-Ca; A shell model challenge
• Axially deformed solution of the Skyrme-Hartree-Fock-Bogolyubov equations using the transformed harmonic oscillator basis (III) hfbtho (v3.00): a new version of the program
• Solution of the Skyrme-Hartree-Fock-Bogolyubov equations in the Cartesian deformed harmonic-oscillator basis. (VIII) hfodd (v2.73y): a new version of the program
• The tensor part of the Skyrme energy density functional. III. Time-odd terms at high spin
• Cranked Skyrme-Hartree-Fock calculation for superdeformed and hyperdeformed rotational bands in N=Z nuclei from 32S to 48Cr
• From superdeformation to extreme deformation and clusterization in the N~Z nuclei of the A~40 mass region
• Error Analysis in Nuclear Density Functional Theory
• Clustering and Triaxial Deformations of ${}^{40}$Ca
• Superdeformation in Asymmetric N$>$Z Nucleus ${}^{40}$Ar
• Mixed Representation RPA Calculation for Octupole Excitations on Superdeformed Sates in the 40Ca and Neutron-Rich Sulfur Regions
• Superdeformation and clustering in ${}^{40}$Ca studied with Antisymmetrized Molecular Dynamics
• High-spin structure in ${}^{40}$K

Cited by in corpus (3)

• Cranked Skyrme-Hartree-Fock-Bogoliubov approach for a mean-field description of nuclear rotations near the drip line
• Super- and hyper-deformation in ${}^{60}$Zn, ${}^{62}$Zn, and ${}^{64}$Ge at high spins
• Multiphonon structure of high-spin states in ${}^{40}$Ca, ${}^{90}$Zr, and ${}^{208}$Pb