Early signal of emerging nuclear collectivity in neutron-rich ${}^{129}$Sb

Abstract

Radioactive ${}^{129}$Sb, which can be treated as a proton plus semi-magic ${}^{128}$Sn core within the particle-core coupling scheme, was studied by Coulomb excitation. Reduced electric quadrupole transition probabilities, $B(E2)$, for the $2^{+}$ $\times$ $\pi g_{7/2}$ multiplet members and candidate $\pi d_{5/2}$ state were measured. The results indicate that the total electric quadrupole strength of ${}^{129}$Sb is a factor of 1.39(11) larger than the ${}^{128}$Sn core, which is in stark contrast to the expectations of the empirically successful particle-core coupling scheme. Shell-model calculations performed with two different sets of nucleon-nucleon interactions suggest that this enhanced collectivity is due to constructive quadrupole coherence in the wavefunctions stemming from the proton-neutron residual interactions, where adding one nucleon to a core near a double-shell closure can have a pronounced effect. The enhanced electric quadrupole strength is an early signal of the emerging nuclear collectivity that becomes dominant away from the shell closure.

arXiv commentAccepted, Physical Review Letters

References in corpus (8)

• The Shell Model as Unified View of Nuclear Structure
• Tables of E2 Transition Probabilities from the first $2^{+}$ States in Even-Even Nuclei
• The magic nature of 132Sn explored through the single-particle states of 133Sn
• Magnetic moments of the 2${}_1^{+}$ states around ${}^{132}$Sn
• Calculation of Gamow-Teller and Two-Neutrino Double-Beta Decay Properties for 130Te and 136Xe with a realistic nucleon-nucleon potential
• Change of nuclear configurations in the neutrinoless double-$\beta$ decay of ${}^{130}$Te $\to$ ${}^{130}$Xe and ${}^{136}$Xe $\to$ ${}^{136}$Ba
• Emerging collectivity from the nuclear structure of ${}^{132}$Xe: Inelastic neutron scattering studies and shell-model calculations
• Effective field theory for vibrations in odd-mass nuclei

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• Exploring laser-driven neutron sources for neutron capture cascades and the production of neutron-rich isotopes
• Coulomb excitation of ${}^{124}$Te: Emerging collectivity and persisting seniority structure in the $6_1^{+}$ level
• Shape polarization in the tin isotopes near $N=60$ from precision $g$-factor measurements on short-lived $11/2^{-}$ isomers
• Lifetimes and Transition Probabilities in $N=76^{130}Xe$
• Isolated one-phonon mixed-symmetry 2+ state of the radioactive neutron-rich nuclide 132Te
• Relation between E2 transitions in even--even and odd-mass nuclei