Direct Evidence for Octupole Deformation in ^{146}Ba and the Origin of Large E1 Moment Variations in Reflection-Asymmetric Nuclei

Phys Rev Lett. 2017 Apr 14;118(15):152504. doi: 10.1103/PhysRevLett.118.152504. Epub 2017 Apr 12.

Abstract

Despite the more than 1 order of magnitude difference between the measured dipole moments in ^{144}Ba and ^{146}Ba, the octupole correlations in ^{146}Ba are found to be as strong as those in ^{144}Ba with a similarly large value of B(E3;3^{-}→0^{+}) determined as 48(+21-29) W.u. The new results not only establish unambiguously the presence of a region of octupole deformation centered on these neutron-rich Ba isotopes, but also manifest the dependence of the electric dipole moments on the occupancy of different neutron orbitals in nuclei with enhanced octupole strength, as revealed by fully microscopic calculations.