Naslov
Pseudospin Symmetry and Microscopic Origin of Shape Coexistence in the Ni78 Region: A Hint from Lifetime Measurements

Autori
Delafosse, C. ; Verney, D. ; Marević, P. ; Gottardo, A. ; Michelagnoli, C. ; Lemasson, A. ; Goasduff, A. ; Ljungvall, J. ; Clément, E. ; Korichi, A. ; De Angelis, G. ; Andreoiu, C. ; Babo, M. ; Boso, A. ; Didierjean, F. ; Dudouet, J. ; Franchoo, S. ; Gadea, A. ; Georgiev, G. ; Ibrahim, F. ; Jacquot, B. ; Konstantinopoulos, T. ; Lenzi, S. M. ; Maquart, G. ; Matea, I. ; Mengoni, D. ; Napoli, D. R. ; Nikšić, T. ; Olivier, L. ; Pérez-Vidal, R. M. ; Portail, C. ; Recchia, F. ; Redon, N. ; Siciliano, M. ; Stefan, I. ; Stezowski, O. ; Vretenar, D. ; Zielinska, M. ; Barrientos, D. ; Benzoni, G. ; Birkenbach, B. ; Boston, A. J. ; Boston, H. C. ; Cederwall, B. ; Charles, L. ; Ciemala, M. ; Collado, J. ; Cullen, D. M. ; Désesquelles, P. ; de France, G. ; Domingo- Pardo, C. ; Eberth, J. ; González, V. ; Harkness- Brennan, L. J. ; Hess, H. ; Judson, D. S. ; Jungclaus, A. ; Korten, W. ; Lefevre, A. ; Legruel, F. ; Menegazzo, R. ; Million, B. ; Nyberg, J. ; Quintana, B. ; Ralet, D. ; Reiter, P. ; Saillant, F. ; Sanchis, E. ; Theisen, Ch. ; Valiente Dobon, J. J.

Izvornik
Physical Review Letters (0031-9007) 121 (2018), 19; 192502, 7

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
pseudospin symmetry ; nuclear energy density functionals

Sažetak
Lifetime measurements of excited states of the light N=52 isotones 88Kr, 86Se, and 84Ge have been performed, using the recoil distance Doppler shift method and VAMOS and AGATA spectrometers for particle identification and gamma spectroscopy, respectively. The reduced electric quadrupole transition probabilities B(E2 ; 2+→0+) and B(E2 ; 4+→2+) were obtained for the first time for the hard-to-reach 84Ge. While the B(E2 ; 2+→0+) values of 88Kr, 86Se saturate the maximum quadrupole collectivity offered by the natural valence (3s, 2d, 1g7/2, 1h11/2) space of an inert 78Ni core, the value obtained for 84Ge largely exceeds it, suggesting that shape coexistence phenomena, previously reported at N≲49, extend beyond N=50. The onset of collectivity at Z=32 is understood as due to a pseudo-SU(3) organization of the proton single-particle sequence reflecting a clear manifestation of pseudospin symmetry. It is realized that the latter provides actually reliable guidance for understanding the observed proton and neutron single particle structure in the whole medium-mass region, from Ni to Sn, pointing towards the important role of the isovector-vector ρ field in shell-structure evolution.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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