Köln 2004 – scientific programme

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PV: Plenarvorträge

PV VII

PV VII: Plenary Talk

Tuesday, March 9, 2004, 09:30–10:00, P

Wobbling excitations in Nuclei - Proof of Stable Triaxiality^* — •A. Neußer, P. Bringel, H. Hübel, N. Nenoff, A.K. Singh, and G. Schönwaßer — Helmholtz-Institut für Strahlen- und Kernphysik, Univ. Bonn, Germany

The existence of nuclei with stable triaxial deformation has been predicted theoretically for a long time. However, triaxiality is difficult to prove experimentally and up to recently only ambiguous indications existed. A unique fingerprint for triaxiality is the ’wobbling mode’ which has been predicted more than 25 years ago [1]. Wobbling introduces a series of rotational bands with increasing wobbling phonon number and a characteristic pattern of γ-ray transitions between them.

The first evidence for wobbling excitations was obtained recently in experiments with the EUROBALL spectrometer. In several Lu and Hf nuclei superdeformed bands have been observed for which theory predicts a pronounced triaxiality. In the odd-A isotopes ^161−167Lu families of bands are identified that show the behaviour expected for wobbling. The experimental results are reviewed and the wobbling interpretation, based on particle-rotor calculations in which an odd proton is coupled to a triaxial core, is presented.

[1] A. Bohr and B.R. Mottelson, Nuclear Structure, Volume II, Benjamin, New York (1975) ^*supported by BMBF and EU