1. Kr369660 –Low- Z Boundary of the Island of Deformation at N=60
- Author
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J. Dudouet, A. Lemasson, G. Duchêne, M. Rejmund, E. Clément, C. Michelagnoli, F. Didierjean, A. Korichi, G. Maquart, O. Stezowski, C. Lizarazo, R. M. Pérez-Vidal, C. Andreoiu, G. de Angelis, A. Astier, C. Delafosse, I. Deloncle, Z. Dombradi, G. de France, A. Gadea, A. Gottardo, B. Jacquot, P. Jones, T. Konstantinopoulos, I. Kuti, F. Le Blanc, S. M. Lenzi, G. Li, R. Lozeva, B. Million, D. R. Napoli, A. Navin, C. M. Petrache, N. Pietralla, D. Ralet, M. Ramdhane, N. Redon, C. Schmitt, D. Sohler, D. Verney, D. Barrientos, B. Birkenbach, I. Burrows, L. Charles, J. Collado, D. M. Cullen, P. Désesquelles, C. Domingo Pardo, V. González, L. Harkness-Brennan, H. Hess, D. S. Judson, M. Karolak, W. Korten, M. Labiche, J. Ljungvall, R. Menegazzo, D. Mengoni, A. Pullia, F. Recchia, P. Reiter, M. D. Salsac, E. Sanchis, Ch. Theisen, J. J. Valiente-Dobón, and M. Zielińska more...
- Subjects
Physics ,Proton ,010308 nuclear & particles physics ,Fission ,General Physics and Astronomy ,01 natural sciences ,Atomic orbital ,Excited state ,Neutron number ,0103 physical sciences ,Quadrupole ,Atomic number ,Atomic physics ,Nuclear Experiment ,010306 general physics ,Spectroscopy - Abstract
Prompt γ-ray spectroscopy of the neutron-rich $^{96}$Kr, produced in transfer- and fusion-induced fission reactions, has been performed using the combination of the Advanced Gamma Tracking Array and the VAMOS++ spectrometer. A second excited state, assigned to $J^π$ = $4^+$, is observed for the first time, and a previously reported level energy of the first 2+ excited state is confirmed. The measured energy ratio R4/2 = E($4^+$)/E($2^+$) = 2.12(1) indicates that this nucleus does not show a well-developed collectivity contrary to that seen in heavier N = 60 isotones. This new measurement highlights an abrupt transition of the degree of collectivity as a function of the proton number at Z = 36, of similar amplitude to that observed at N = 60 at higher Z values. A possible reason for this abrupt transition could be related to the insufficient proton excitations in the g9/2, d5/2, and s1/2 orbitals to generate strong quadrupole correlations or to the coexistence of competing different shapes. An unexpected continuous decrease of R4/2 as a function of the neutron number up to N = 60 is also evidenced. This measurement establishes the Kr isotopic chain as the low-Z boundary of the island of deformation for N = 60 isotones. A comparison with available theoretical predictions using different beyond mean-field approaches shows that these models fail to reproduce the abrupt transitions at N = 60 and Z = 36. more...
- Published
- 2017
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