Köln 2004 – wissenschaftliches Programm
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HK: Physik der Hadronen und Kerne
HK 16: Nuclear Structure/Spectroscopy II
HK 16.7: Vortrag
Dienstag, 9. März 2004, 17:30–17:45, A
First observation of the scissors mode decay to the γ-band in a well-deformed nucleus ∗ — •V. Werner1, N. Pietralla2, M.W. Ahmed3, P. von Brentano1, C. Fransen1, H. von Garrel4, U. Kneissl4, C. Kohstall4, A. Linnemann1, S. Müller5, H.H. Pitz4, D. Savran5, M. Scheck4, F. Stedile4, A. Tonchev3, S. Walter4, H.R. Weller3, and Y. Wu3 — 1Institut für Kernphysik, Universität zu Köln — 2SUNY, Stony Brook, NY — 3FELL, Dept. of Physics, Duke University, Durham, NC — 4Institut für Strahlenphysik, Universität Stuttgart — 5Institut für Kernphysik, TU Darmstadt
Various experiments on 164Dy in the 80’s and 90’s left ambiguities in the placement of some γ-transitions. Todays improved NRF setup in Stuttgart allowed a reinvestigation with increased sensitivity. γ-rays were observed in an experiment above the energy threshold of about 3 MeV of the scissors mode, while the corresponding lines were missing when tuning the maximum energy of the incident photons just below that energy. Another experiment was performed at the new NRF setup [1] at the FELL at Duke University using an almost monochromatic and totally polarized photon beam. The polarization allowed firm parity assignments, and the well-defined energy ensured that one of the mentioned γ-rays stems from a so far only presumed level at 3.1 MeV. While the ground state decay of that level is unexpectedly weak, the observation backs a placement of so far unobserved decays of the scissors mode to the γ-band. Transition strengths are in agreement with IBM predictions.
[1] N. Pietralla et al., Phys. Rev. Lett. 88 (2002) 012502. ∗ supported by the DFG under Br799/11-1, Kn153/31-2, and Pi 393/1-2.