학술논문
Early signal of emerging nuclear collectivity in neutron-rich $^{129}$Sb
Document Type
Working Paper
Author
Gray, T. J.; Allmond, J. M.; Stuchbery, A. E.; Yu, C. -H.; Baktash, C.; Gargano, A.; Galindo-Uribarri, A.; Radford, D. C.; Batchelder, J. C.; Beene, J. R.; Bingham, C. R.; Coraggio, L.; Covello, A.; Danchev, M.; Gross, C. J.; Hausladen, P. A.; Itaco, N.; Krolas, W.; Liang, J. F.; Padilla-Rodal, E.; Pavan, J.; Stracener, D. W.; Varner, R. L.
Source
Physical Review Letters 124, 032502 (2020)
Subject
Language
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.
Comment: Accepted, Physical Review Letters
Comment: Accepted, Physical Review Letters