Berlin 2005 – wissenschaftliches Programm
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HK: Physik der Hadronen und Kerne
HK 3: Kernphysik/Spektroskopie
HK 3.2: Vortrag
Freitag, 4. März 2005, 14:30–14:45, TU MA004
Test of the critical point symmetry X(5) in the A=180 mass region — •O. Möller1, A. Dewald1, B. Melon1, P. Petkov1,2, A. Fitzler1, K. Jessen1, J. Jolie1, C. Ur3, M. Axiotis3, and C. Rusu3 — 1Institut für Kernphysik, Universität zu Köln, Deutschland — 2Institute for Nuclear Research and Nuclear Energy, Sofia, Bulgaria — 3INFN, Laboratori Nazionali di Legnaro, Legnaro, Italy
The investigation of nuclear phase transition phenomena is one of the
new and very challenging topics in nuclear structure physics.
Recently N=90 nuclei became of special interest as testing ground for
the new dynamic symmetry at the critical point of shape phase
transition from axially deformed to spherical nuclei, called X(5) [1]. Based on the energy spectra and relative transition probabilities the even 176−180Os nuclei can be considered to be very promising X(5) candidates in a new mass region. In order to perform stringent tests
for these Os nuclei, experimental data on absolute transition
probabilities are needed. Therefore we performed different experiments:
We measured lifetimes of the 21+-states at the Köln FN-Tandem facility using the electronic timing technique. Lifetimes of higher lying states in 178Os were measured in a RDDS coincidence experiment with the GASP spectrometer and the Köln
plunger device.
The excellent agreement of our present results with the X(5) predictions encouraged us to continue this project, further experiments on this topic are scheduled.
[1] F. Iachello, Phys. Rev. Lett. 87, 52502 (2001)
Supported by the BMBF project no. 06K-167 and under the EU Programme contract no.HPRI–CT-1999-00083.