Nature of $\gamma$-deformation in Ge and Se nuclei and the triaxial projected shell model description

Abstract

Recent experimental data have demonstrated that ${}^{76}$Ge may be a rare example of a nucleus exhibiting rigid $\gamma$-deformation in the low-spin regime. In the present work, the experimental analysis is supported by microscopic calculations using the multi-quasiparticle triaxial projected shell model (TPSM) approach. It is shown that to best describe the data of both yrast and $\gamma$-vibrational bands in ${}^{76}$Ge, a rigid-triaxial deformation parameter $\gamma \approx 30^{\circ }$ is required. TPSM calculations are discussed in conjunction with the experimental observations and also with the published results from the spherical shell model. The occurrence of a $\gamma \gamma$-band in ${}^{76}$Ge is predicted with the bandhead at an excitation energy of $\sim$ 2.5 MeV. We have also performed TPSM study for the neighboring Ge- and Se-isotopes and the distinct $\gamma$-soft feature in these nuclei is shown to result from configuration mixing of the ground-state with multi-quasiparticle states.

12 pages, 15 figures, To appear in Phys. Rev. C

References in corpus (4)

• Energy density functional study of nuclear matrix elements for neutrinoless $\beta \beta$ decay
• Triaxial projected shell model study of gamma-vibrational bands in even-even Er isotopes
• Triaxiality and shape coexistence in Germanium isotopes
• gamma-vibrational states in superheavy nuclei

Cited by in corpus (15)

• Systematic study of nuclear matrix elements in neutrinoless double-beta decay with a beyond mean-field covariant density functional theory
• A microscopic benchmark-study of triaxiality in low-lying states of 76Kr
• Evidence for rigid triaxial deformation in ${}^{76}$Ge from a model-independent analysis
• Skyrme-Hartree-Fock-Bogoliubov mass models on a 3D Mesh: Effect of triaxial shape
• Microscopic nuclear structure models and methods : Chiral symmetry, Wobbling motion and $\gamma -$bands
• The Low-Energy Quadrupole Mode of Nuclei
• Quasiparticle and $\gamma$-band structures in ${}^{156}$Dy
• Unified description of rotational-, $\gamma$-, and quasiparticle-band structures in neutron-rich mass $\sim$ 110 region
• Microscopic description of triaxiality in Ru isotopes with covariant energy density functional theory
• Observation of a $\gamma$-band based on two-quasiparticle configuration in ${}^{70}$Ge
• Quasi-$\gamma$ band in ${}^{\text{114}}$Te
• Shape coexistence close to $N=50$ in the neutron-rich isotope ${}^{80}$Ge investigated by IBM-2
• Spin-dependent $\gamma$ softness or triaxiality in even-even ${}^{132-138}$Nd nuclei
• High Spin Spectroscopy and Shape Evolution in 105Cd
• Triaxial projected shell model study of $\gamma$-bands in atomic nuclei