The intrinsic nuclear shapes deviating from a sphere not only manifest themselves in nuclear collective states but also play important roles in determining nuclear potential energy surfaces (PES's) and fission barriers. In order to describe microscopically and self-consistently nuclear shapes and PES's with as many shape degrees of freedom as possible included, we developed multidimensionally constrained covariant density functional theories (MDC-CDFTs). In MDC-CDFTs, the axial symmetry and the reflection symmetry are both broken and all deformations characterized by beta(lambda mu) with even mu are considered. We have used the MDC-CDFTs to study PES's and fission barriers of actinides, the non-axial octupole Y-32 correlations in N = 150 isotones and shapes of hypernuclei. In this Review we will give briefly the formalism of MDC-CDFTs and present the applications to normal nuclei.

http://iopscience.iop.org/article/10.1088/0031-8949/91/6/063008/pdf

Multidimensionally constrained covariant density functional theories-nuclear shapes and potential energy surfaces

Nuclear chiral doublet bands data tables

Specific features and symmetries for magnetic and chiral bands in nuclei

https://repository.kulib.kyoto-u.ac.jp/dspace/bitstream/2433/232694/1/j.physletb.2018.06.030.pdf

Multiple chiral doublets in four-j shells particle rotor model: Five possible chiral doublets in 60136Nd76

https://iopscience.iop.org/article/10.1088/1402-4896/aa800e/pdf

Nuclear chirality, a model and the data

The nature of the chiral candidate bands in $^{106}\mathrm{Ag}$, one of only two known examples of candidates which actually cross, is investigated experimentally and theoretically. Lifetimes have been determined for these bands in $^{106}\mathrm{Ag}$ using the Doppler-shift attenuation method with the $\ensuremath{\gamma}$-detector array AFRODITE. The level scheme of $^{106}\mathrm{Ag}$ has been extended, and three negative-parity bands have been observed to high spins. Configurations were assigned to the negative-parity bands based on a quasiparticle alignment analysis and on configuration-fixed constrained relativistic mean field calculations. The excitation energies, $B(M1)$ and $B(E2)$ values, as well as $B(M1)/B(E2)$ ratios have been compared with results of particle-rotor model calculations. From the investigations, it is concluded that the three close-lying negative-parity bands are a two-quasiparticle high-$K$ band and a pair of four-quasiparticle bands. The proposal that the two lowest-lying bands are chiral partners has not been confirmed.

Resolution of Chiral Conundrum in Ag106 : Doppler-Shift Lifetime Investigation

A brief survey of results of studies of nuclear chirality in the mass 80 and 190 region at iThemba LABS is given, before looking at the case of 106Ag in detail. Here, the crossing of a pair of candidate chiral bands is re-interpreted as the crossing of a prolate band by an aligned four-quasiparticle band.

Studies of chirality in the mass 80, 100 and 190 regions

Combining the new spectroscopy results of 144Tb and previous spectroscopy studies of neighboring nuclei, a systematic investigation on the low-lying spectra in N = 78 ~ 80 isotones is performed. Good systematics have been found for the coupling patterns which couple the odd nucleon(s), such as πh11/2, , to the 2+, 4+, 6+ and 3- core excitations. It is found that the relative excitation energies of the states formed by coupling h11/2 proton(s) to the 2+, 4+ core excitations are pushed up, in contrast with those formed by coupling h11/2 neutron hole(s) to the 2+, 4+ core excitations, which are pulled down. According to the systematics, the interpretation that the 17/2+ states observed in 141Sm and 143Gd are the fully aligned member of coupling the odd h11/2 neutron hole to the octupole 3- core excitation, is explored to the isotones 145Dy, 142Eu, and 144Tb.

P. W. Zhao

Papers

Resolution of Chiral Conundrum in Ag106 : Doppler-Shift Lifetime Investigation

Studies of chirality in the mass 80, 100 and 190 regions

Systematics on the low-lying spectra in N = 78 ~ 80 isotones