par Leoni, Silvia;Fornal, B.;Marginean, N.;Sferrazza, Michele ;Tsunoda, Yusuke;Otsuka, Takaharu;Bocchi, G.;Crespi, Fabio Celso Luigi;Bracco, Angela;Aydin, Salih;Boromiza, M;Bucurescu, D;Cieplicka-Oryńczak, N.;Costache, C;Calinescu, S.;Florea, N;Ghita, D.G;Glodariu, T.;Ionescu, A;Iskra, L.W;Krzysiek, M;Marginean, R;Mihai, C;Mihai, R.E;Mitu, A.;Negret, Alexandru;Nita, C.R;Olacel, A;Oprea, A;Pascu, S;Petkov, P;Petrone, C.;Porzio, Giovanni;Serban, A;Sotty, C;Stan, L;Stiru, I;Stroe, L;Suvaila, R;Toma, S;Turturica, A;Ujeniuc, S;Ur, C.A.
Référence Physical review letters, 118, 16, 162502
Publication Publié, 2017-04
Référence Physical review letters, 118, 16, 162502
Publication Publié, 2017-04
Article révisé par les pairs
Résumé : | A search for shape isomers in the Ni66 nucleus was performed, following old suggestions of various mean-field models and recent ones, based on state-of-the-art Monte Carlo shell model (MCSM), all considering Ni66 as the lightest nuclear system with shape isomerism. By employing the two-neutron transfer reaction induced by an O18 beam on a Ni64 target, at the sub-Coulomb barrier energy of 39 MeV, all three lowest-excited 0+ states in Ni66 were populated and their γ decay was observed by γ-coincidence technique. The 0+ states lifetimes were assessed with the plunger method, yielding for the 02+, 03+, and 04+ decay to the 21+ state the B(E2) values of 4.3, 0.1, and 0.2 Weisskopf units (W.u.), respectively. MCSM calculations correctly predict the existence of all three excited 0+ states, pointing to the oblate, spherical, and prolate nature of the consecutive excitations. In addition, they account for the hindrance of the E2 decay from the prolate 04+ to the spherical 21+ state, although overestimating its value. This result makes Ni66 a unique nuclear system, apart from U236,238, in which a retarded γ transition from a 0+ deformed state to a spherical configuration is observed, resembling a shape-isomerlike behavior. |