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HK: Fachverband Physik der Hadronen und Kerne

HK 5: Structure and Dynamics of Nuclei I

HK 5.4: Vortrag

Montag, 18. März 2019, 15:00–15:15, HS 14

Enhanced quadrupole and octupole strength in doubly-magic ¹³²Sn — D. Rosiak, •M. Seidlitz, and P. Reiter for the IS551 Miniball and HIE-ISOLDE collaboration — Institut für Kernphysik, Universität zu Köln

The first 2⁺ and 3⁻ states of the doubly-magic nucleus ¹³²Sn were populated via safe Coulomb excitation at HIE-ISOLDE, CERN, employing the highly-efficient MINIBALL array. ¹³²Sn ions with a beam energy of 5.49 MeV/nucleon were impinged on a ²⁰⁶Pb target. De-exciting γ rays from the low-lying excited states of the target and the projectile were recorded in coincidence with scattered particles. Reduced E1, E2, and E3 transition strengths were determined. A locally enhanced B(E2; 0_g.s.⁺ → 2₁⁺) strength at doubly-magic ¹³²Sn is found and confronted with the microscopic description of the structure of the respective states within different theoretical approaches. The results provide crucial information on cross-shell configurations which were determined for the first time within state-of-the-art shell-model (LSSM, MCSM) and mean-field calculations (RPA). The presented results of experiment and theory can be considered to be the first direct verification of the sphericity and double-magicity of ¹³²Sn.
Supported by the German BMBF (Contract No. 05P15PKCIA, 05P18PKCIA, and Verbundprojekt No. 05P2015) and by European Union’s Horizon 2020 programm (Grant Agreement No. 654002).