학술논문
First direct lifetime measurement of the 2+1 state in 72,74Zn: new evidence for shape transition between N = 40 and N = 42 close to Z = 28
Document Type
Working Paper
Author
Niikura, M.; Mouginot, B.; Franchoo, S.; Matea, I.; Stefan, I.; Verney, D.; Azaiez, F.; Assie, M.; Bednarczyk, P.; Borcea, C.; Burger, A.; Burgunder, G.; Buta, A.; Càceres, L.; Clément, 2 E.; Coquard, L.; de Angelis, G.; de France, G.; Santos, F. de Oliveira; Dewald, A.; Dijon, A.; Dombradi, Z.; Fiori, E.; Fransen, C.; Friessner, G.; Gaudefroy, L.; Georgiev, G.; Grévy, S.; Hackstein, M.; Harakeh, M. N.; Ibrahim, F.; Kamalou, O.; Kmiecik, M.; Lozeva, R.; Maj, A.; Mihai, C.; Möller, O.; Myalski, S.; Negoita, F.; Pantelica, D.; Perrot, L.; Pissulla, Th.; Rotaru, F.; Rother, W.; Scarpaci, J. A.; Stodel, C.; Thomas, J. C.; Ujic, P.
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Abstract
We report here the first direct lifetime measurement of the 2+1 state in 72,74Zn. The neutron-rich beam was produced by in-flight fragmentation of 76Ge at the Grand Acc\'el\'erateur National d'Ions Lourds and separated with the LISE spectrometer. The 2+1 state was excited by inelastic scattering and knock-out reaction on a CD2 target and its lifetime was measured by the recoil-distance Dopplershift method with the K\"oln plunger device combined with the EXOGAM detectors. The lifetimes of the 2+1 states in 72,74Zn were determined to be 17.9(18) and 27.0(24) ps, which correspond to reduced transition probabilities B(E2; 2+1 \rightarrow 0+) = 385(39) and 370(33) e2fm4, respectively. These values support the idea of a systematic maximum of collectivity at N = 42 for Zn, Ge and Se nuclei. In addition, the available systematics in the neighboring nuclei point towards a transition from a spherical oscillator at N = 40 to complete {\gamma}-softness at N = 42.
Comment: 10 pages, 13 figures; accepted for publication in Phys. Rev. C
Comment: 10 pages, 13 figures; accepted for publication in Phys. Rev. C