Bochum 1998 – wissenschaftliches Programm

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HK: Hadronen und Kerne

HK 7: Nuclear Moments

HK 7.9: Vortrag

Montag, 16. März 1998, 16:15–16:30, E

Spectroscopic quadrupole moment of the high-K ¹⁷⁹W(35/2⁻) 5 quasi particle isomer. — •K. Vyvey, G. Neyens, S. Ternier, D.L. Balabanski, N. Coulier, S. Teughels, G. Georgiev, C. L’abbé, and R. Coussement — Instituut voor Kern- en Stralingsfysica, University of Leuven, Celestijnenlaan 200 D, B-3001 Leuven, Belgium

Recent studies have shown examples of severe violations of the K-selection rule, raising questions about the usual understanding of the K-mixing process and the structure of the K-isomeric states. The LEMS technique [1] enables us to measure the spectroscopic quadrupole moment of high-K isomers, which allows us to investigate the deformation or K-mixing. A first measurement has been performed on the ¹⁷⁹W(35/2⁻) 5 quasi particle state. An upper limit of 4 e.b has been found for the spectroscopic quadrupole moment, corresponding to an intrinsic moment Q₀ ≤ 4.7 e.b (assuming K=I). This value is considerably smaller than for the groundstate band (6.4 e.b [2]). On the other hand, if we assume Q₀ equal for the groundstate band and the 5 quasi particle state, K is found to be smaller than 16ℏ, indicating that the I=35/2 isomeric state consists out of a mixing of a K=35/2 state and a lower K state. Final experiments in order to determine the quadrupole moment of the 35/2⁻ state with increased statistics are planned by the end of November.

[1] F.Hardeman et al, Phys.Rev. C43,130(1991)

[2] P.M.Walker et al, Nucl.Phys. A568,397(1994)