Coherence features of the spin-aligned neutron-proton pair coupling scheme

Abstract

The seniority scheme has been shown to be extremely useful for the classification of nuclear states in semi-magic nuclei. The neutron-proton ($np$) correlation breaks the seniority symmetry in a major way. As a result, the corresponding wave function is a mixture of many components with different seniority quantum numbers. In this contribution we show that the $np$ interaction may favor a new kind of coupling in $N=Z$ nuclei, i.e., the so-called isoscalar spin-aligned $np$ pair mode. Shell model calculations reveal that the ground and low-lying yrast states of the $N=Z$ nuclei ${}^{92}$Pd and ${}^{96}$Cd may mainly be built upon such spin-aligned $np$ pairs each carrying the maximum angular momentum $J=9$ allowed by the shell $0g_{9/2}$ which is dominant in this nuclear region.

arXiv comment5 pages, 4 figues, Proceedings of the Nordic Conference on Nuclear Physics 2011. To appear in Physica Scripta T

References in corpus (6)

• Evidence for a spin-aligned neutron-proton paired phase from the level structure of ${}^{92}$Pd
• Spin-aligned neutron-proton pair mode in atomic nuclei
• Spin-aligned neutron-proton pairs in $N=Z$ nuclei
• Partial conservation of seniority in $j=9/2$ shell: Analytic and numerical studies
• Energy expressions for n=3 and 4 systems in a single-j shell
• Alternate proof of the Rowe-Rosensteel proposition and seniority conservation

Cited by in corpus (6)

• Shape coexistence in even-even nuclei: A theoretical overview
• Competition between $T$=1 and $T$=0 pairing in $pf$-shell nuclei with $N=Z$
• Minimal Theory of Isomerism -Q.Q and Other Interactions
• J=0, J=J_{max} and quadrupole pairing
• Partial conservation of seniority in semi-magic nuclei
• A critical look at the vibrational model for ^{92}Pd and comparison with ^{48}Cr