Résumé du preprint Irfu-08-98
| Irfu-08-98 |
|---|
| 0_gs^+ -> 2_1^+ Transition Strength in 106Sn and 108Sn |
| A. Ekstrom, J. Cederkall, C. Fahlander, M. Hjorth-Jensen, F. Ames, P.A. Butler, T. Davinson, J. Eberth, F. Fincke, A. Gorgen, M. Gorska, D. Habs, A.M. Hurst, M. Huyse, O. Ivanov, J. Iwanicki, O. Kester, U. Koster, B.A. Marsh, J. Mierzejewski, P. Reiter, H. Scheit, D. Schwalm, S. Siem, G. Sletten, I. Stefanescu, G.M. Tveten, J. Van de Walle, P. Van Duppen, D. Voulot, N. Warr, D. Weisshaar, F. Wenander, M. Zielinska |
| The reduced transition probabilities, $B(E2;0_{gs}^+ \\rightarrow 2_1^+)$, have been measured in the radioactive isotopes $^{106,108}$Sn using subbarrier Coulomb excitation at the REX-ISOLDE facility at CERN. Deexcitation $\\gamma$ rays were detected by the highly segmented MINIBALL Ge-detector array. The results, $B(E2;0_{gs}^+ \\rightarrow 2_1^+) = 0.222(19) e^2b^2$ for $^{108}$Sn and $B(E2;0_{gs}^+ \\rightarrow 2_1^+) = 0.195(39) e^2b^2$ for $^{106}$Sn were determined relative to a stable $^{58}$Ni target. The resulting $B(E2)$ values are ~30% larger than the shell-model predictions and deviate from the generalized seniority model. This experimental result may point towards a weakening of the N=Z=50 shell closure. |