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Author(s)
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Olaizola, B (UCM, Madrid, Dept. Phys.) ; Fraile, L M (UCM, Madrid, Dept. Phys.) ; Mach, H (UCM, Madrid, Dept. Phys. ; NCBJ, Warsaw) ; Poves, A (Madrid, Autonoma U.) ; Nowacki, F (Strasbourg, IPHC) ; Aprahamian, A (Notre Dame U.) ; Briz, J A (Madrid, Inst. Estructura Materia) ; Cal-González, J (UCM, Madrid, Dept. Phys.) ; Ghiţa, D (Bucharest, IFIN-HH) ; Köster, U (Laue-Langevin Inst.) ; Kurcewicz, W (Warsaw U.) ; Lesher, S R (Notre Dame U. ; Wisconsin U., La Crosse) ; Pauwels, D (Leuven U.) ; Picado, E (UCM, Madrid, Dept. Phys. ; Heredia U.) ; Radulov, D (Leuven U.) ; Simpson, G S (LPSC, Grenoble) ; Udías, J M (UCM, Madrid, Dept. Phys.) |
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Abstract
| The lifetime of the 0$_3^+$ state in $^{66}$Ni, two neutrons below the $N=40$ subshell gap, has been measured. The transition $B(E2;0_3^+ \rightarrow 2_1^+)$ is one of the most hindered E2 transitions in the Ni isotopic chain and it implies that, unlike $^{68}$Ni, there is a spherical structure at low excitation energy. We have performed extensive shell-model calculations that correctly predict this result, obtaining a spherical 0$^+$ state at the correct energy and with an extremely low $B(E2;0_3^+ \rightarrow 2_1^+)$ value. |