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HK: Fachverband Physik der Hadronen und Kerne
HK 18: Structure and Dynamics of Nuclei III
HK 18.7: Vortrag
Dienstag, 27. Februar 2018, 15:45–16:00, HZO 70
Investigation of isovector valence-shell excitations in nuclei around the N = 82 shell closure — •Ralph Kern1, Robert Stegmann1, Georgi Rainovski2, Norbert Pietralla1, Liam Gaffney3, Kalin Gladnishki2, Vasil Karayonchev4, Pär-Anders Söderström1, Pietro Spagnoletti5, Andreas Vogt4, Nigel Warr4, Andree Welker3, Volker Werner1, Johannes Wiederhold1, and Radostina Zidarova2 — 1Technische Universität Darmstadt — 2University of Sofia — 3CERN — 4Universität zu Köln — 5University of the West of Scotland
In near-spherical nuclei, the two most fundamental quadrupole-collective excitations can be understood as a mixture of the collective 2+ proton and 2+ neutron excitations: the fully symmetric 21+ state and the so-called mixed-symmetric 21,ms+ state. Based on the evolution of these states in the N = 80 isotonic chain, it has been suggested that the properties of the mixed-symmetry states are sensitive to the underlying subshell structure. In particular, the observed fragmentation of the 21,ms+ of 138Ce has been explained as due to the absence of a mechanism dubbed shell stabilization. In order to examine further the effect of shell stabilization of the MSSs, it is necessary to identify and study the properties of these states in the next heavy N = 80 isotones beyond Z = 58: 140Nd and 142Sm. This Coulomb excitation experiment was performend at the RIB facility ISOLDE at CERN using the MINIBALL HPGe-array. Preliminary results from the experiment will be shown.
Supported by the BMBF under Grant No. 05P15RDCIA.