Seniority-two valence-shell building blocks of the octupole phonon

Fuente: arXiv
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Main Authors: Scheck, M., Chapman, R., Mashtakov, K., Meeten, R., Sassarini, P. L., Spagnoletti, P.
Format: Preprint
Published: 2025
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author Scheck, M.
Chapman, R.
Mashtakov, K.
Meeten, R.
Sassarini, P. L.
Spagnoletti, P.
author_facet Scheck, M.
Chapman, R.
Mashtakov, K.
Meeten, R.
Sassarini, P. L.
Spagnoletti, P.
contents The relative ordering of $J^-$ levels of multiplets resulting from two-body excitations, which include a $J^π=3^-$ state that can contribute to the octupole phonon, are investigated in a simplistic shell-model approach. To calculate the relative level ordering, harmonic oscillator wavefunctions and a residual $δ$ interaction are used. The simplistic approach confirms for the particle-particle channel, the often stated preference of the $Δj=3, Δl =3$ subshell combination over the $Δj=3, Δl =1$ subshell combination through an enhanced energy gain. Furthermore, it is shown that, in the particle-hole channel, the gain is less pronounced for the $Δj=3, Δl =3$ subshell configuration. In combination with the overall structure of an oscillator shell, these results explain the comparatively low excitation energy for 3$^-_1$ excitations observed for the octupole-soft proton and neutron numbers predicted by various models.
format Preprint
id arxiv_https___arxiv_org_abs_2505_16515
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Seniority-two valence-shell building blocks of the octupole phonon
Scheck, M.
Chapman, R.
Mashtakov, K.
Meeten, R.
Sassarini, P. L.
Spagnoletti, P.
Nuclear Theory
Nuclear Experiment
The relative ordering of $J^-$ levels of multiplets resulting from two-body excitations, which include a $J^π=3^-$ state that can contribute to the octupole phonon, are investigated in a simplistic shell-model approach. To calculate the relative level ordering, harmonic oscillator wavefunctions and a residual $δ$ interaction are used. The simplistic approach confirms for the particle-particle channel, the often stated preference of the $Δj=3, Δl =3$ subshell combination over the $Δj=3, Δl =1$ subshell combination through an enhanced energy gain. Furthermore, it is shown that, in the particle-hole channel, the gain is less pronounced for the $Δj=3, Δl =3$ subshell configuration. In combination with the overall structure of an oscillator shell, these results explain the comparatively low excitation energy for 3$^-_1$ excitations observed for the octupole-soft proton and neutron numbers predicted by various models.
title Seniority-two valence-shell building blocks of the octupole phonon
topic Nuclear Theory
Nuclear Experiment
url https://arxiv.org/abs/2505.16515