München 2006 – wissenschaftliches Programm

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HK: Physik der Hadronen und Kerne

HK 42: Kernphysik/Spektroskopie

HK 42.4: Vortrag

Donnerstag, 23. März 2006, 15:15–15:30, C

Test of the critical point symmetry X(5) in case of ¹⁷⁶Os with absolute transition probabilities — •B. Melon¹, A. Dewald¹, O. Möller¹, Th. Pissulla¹, C. Fransen¹, A. Linnemann¹, J. Jolie¹, K.O. Zell¹, P. Petkov², D.R. Napoli³, C. Rusu³, D. Bazzacco⁴, C.A. Ur⁴, and R. Menegazzo⁴ — ¹Institut für Kernphysik, Universität zu Köln, Köln, Germany — ²Bulg. Acad. of Sciences, Inst. for Nucl. Res. and Nucl. Ener., Sofia, Bulgaria — ³INFN, Laboratori Nazionali di Legnaro, Italy — ⁴Dipartimento di Fisica dell’Universita‘ and INFN Sezione Padova, Padova, Italy

It has been shown that the energy spectrum and the experimental transition probabilities of ¹⁷⁸Os can be very well described in the framework of the critical point symmetry X(5)[1]. ¹⁷⁸Os is the first example of an X(5) like nucleus in a mass region different to A = 150 where the first X(5) like nuclei were identified. Based on the energy spectrum, also ¹⁷⁶Os was found to be a good X(5) candidate. Therefore we performed a lifetime measurement with the Köln coincidence plunger device and the GASP spectrometer at the Laboratori Nazionali di Legnaro using the ¹⁵²Sm(²⁹Si,5n)¹⁷⁶Os reaction at E(²⁹Si) = 145 MeV to allow for a more a stringent test of the X(5) predictions including absolute transition probabilities. The obtained results will be presented and will be compared to the calculated values in the framework of the X(5) model, the Interacting Boson Model (IBM) and the General Collective Model (GCM).

[1] A. Dewald et al., J.Phys.(London) G31, S1427 (2005)