Microscopic origin of reflection-asymmetric nuclear shapes

Abstract

Background: The presence of nuclear ground states with stable reflection-asymmetric shapes is supported by rich experimental evidence. Theoretical surveys of odd-multipolarity deformations predict the existence of pear-shaped isotopes in several fairly localized regions of the nuclear landscape in the vicinity of near-lying single-particle shells with $\Delta \ell =\Delta j=3$. Purpose: We analyze the role of isoscalar, isovector, neutron-proton, neutron-neutron, and proton-proton multipole interaction energies in inducing the onset of reflection-asymmetric ground-state deformations. Methods: The calculations are performed in the framework of axial reflection-asymmetric Hartree-Fock-Bogoliubov theory using two Skyrme energy density functionals and density-dependent pairing force. Results: We show that reflection-asymmetric ground-state shapes of atomic nuclei are driven by the odd-multipolarity neutron-proton (or isoscalar) part of the nuclear interaction energy. This result is consistent with the particle-vibration picture, in which the main driver of octupole instability is the isoscalar octupole-octupole interaction giving rise to large $E3$ polarizability.

arXiv comment11 pages, 12 figures

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Cited by in corpus (6)

• Opportunities for Fundamental Physics Research with Radioactive Molecules
• Skyrme-Hartree-Fock-Bogoliubov mass models on a 3D mesh: II. Time-reversal symmetry breaking
• Generator coordinate method for nuclear octupole excitations: status and perspectives
• Interplay of quadrupole and octupole degrees of freedom in the Gd isotopes
• Radioactive Molecules as Laboratories of Fundamental Physics
• Impact of octupole deformation on the nuclear electromagnetic response