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Onset of intruder ground state in exotic Na isotopes and evolution of the N=20 shell gap

Yutaka Utsuno·Takaharu Otsuka·Thomas Glasmacher·Takahiro Mizusaki·Michio Honma
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Abstract

The onset of intruder ground states in Na isotopes is investigated by comparing experimental data and shell-model calculations. This onset is one of the consequences of the disappearance of the N=20 magic structure, and the Na isotopes are shown to play a special role in clarifying the change of this magic structure. Both the electromagnetic moments and the energy levels clearly indicate an onset of ground state intruder configurations at neutron number N=19 already, which arises only with a narrow N=20 shell gap in Na isotopes resulting from the spin-isospin dependence of the nucleon-nucleon interaction (as compared to a wider gap in stable nuclei like 40Ca). It is shown why the previous report based on the mass led to a wrong conclusion.

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Yutaka Utsuno, Takaharu Otsuka, Thomas Glasmacher, Takahiro Mizusaki, Michio Honma. 2004-07-23. Onset of intruder ground state in exotic Na isotopes and evolution of the N=20 shell gap. https://doi.org/10.1103/physrevc.70.044307

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