# The mutable nature of particle-core excitations with spin in the one-valence-proton nucleus $^{133}$Sb

Abstract : The gamma-ray decay of excited states of the one-valence-proton nucleus 133Sb has been studied using cold-neutron induced fission of 235U and 241Pu targets, during the EXILL campaign at the ILL reactor in Grenoble. By using a highly efficient HPGe array, coincidences between gamma-rays prompt with the fission event and those delayed up to several tens of microseconds were investigated, allowing to observe, for the first time, high-spin excited states above the 16.6 micros isomer. Lifetimes analysis, performed by fast-timing techniques with LaBr3(Ce) scintillators, reveals a difference of almost two orders of magnitude in B(M1) strength for transitions between positive-parity medium-spin yrast states. The data are interpreted by a newly developed microscopic model which takes into account couplings between core excitations (both collective and non-collective) of the doubly magic nucleus 132Sn and the valence proton, using the Skyrme effective interaction in a consistent way. The results point to a fast change in the nature of particle-core excitations with increasing spin.
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Journal articles
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http://hal.in2p3.fr/in2p3-01294282
Contributor : Michel Lion <>
Submitted on : Tuesday, March 29, 2016 - 8:47:17 AM
Last modification on : Thursday, February 7, 2019 - 3:19:56 PM

### Citation

G. Bocchi, S. Leoni, B. Fornal, G. Colo, P.F. Bortignon, et al.. The mutable nature of particle-core excitations with spin in the one-valence-proton nucleus $^{133}$Sb. Physics Letters B, Elsevier, 2016, 760, pp.273-278. ⟨10.1016/j.physletb.2016.06.065⟩. ⟨in2p3-01294282⟩

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