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HK: Fachverband Hadronen und Kerne
HK 58: Nuclear Structure and Dynamics I
HK 58.4: Vortrag
Mittwoch, 18. März 2009, 17:30–17:45, H-ZO 40
Low-spin excitations in 98Ru — •Désirée Radeck, Michael Albers, Christian Bernards, Christoph Fransen, Jan Jolie, and Dennis Mücher — Institut für Kernphysik, Universität zu Köln
In the context of collectivity in the A=100 mass region N=52 isotones were investigated in detail and phonon excitations - especially the mixed-symmetry (MS) states - were identified. In order to investigate how states with this MS character evolve with increasing valence neutron number N=54 isotones were studied. While in 96Mo the one-phonon MS state 21,ms+ was identified [1], 98Ru shows a breakdown of vibrational structure above the two-phonon triplet and no candidate for the 21,ms+ state was assigned [2]. The recently investigated N=54 isotone 100Pd was explained well with an Uπν(5) fit within the IBM-2. Furthermore, a candidate for the one-phonon MS 21,ms+ state was determined [3]. To do further investigations on the N=54 isotone 98Ru - in particular regarding the breakdown of vibrational symmetry and the one-phonon MS excitation - an experiment was performed at the Cologne Tandem Accelerator using the HORUS spectrometer. The nuclei were populated by the reaction 97Mo(3He,2n)98Ru. By analysing the coincidence and γγ angular correlation data the level scheme was extended and clarified by determining spins, multipole mixing ratios and branching ratios. The low-energy excitations of positive parity will be discussed and compared to theoretical expectations. The results will be compared with those for other N=54 isotones. [1] S.R. Lesher et al., Phys. Rev. C 75, 2007. [2] R.B. Cakirli et al., Phys. Rev. C 70, 2004. [3] D. Radeck et al., submitted. Supported by DFG, grant Jo 391/3-2.