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HK: Hadronen und Kerne

HK 7: Nuclear Moments

HK 7.6: Vortrag

Montag, 16. März 1998, 15:30–15:45, E

Test of shell model calculations for ⁵⁰Cr with measured magnetic moments of the first excited 2⁺ -and 4⁺ -states⁺ — •R. Ernst¹, K.-H. Speidel¹, A. Gohla¹, U. Grabowy¹, B. Heller¹, J. Gerber², P. Maier-Komor³, G. Jakob⁴, G. Kumbartzki⁴, N. Benczer-Koller⁴, and L. Zamick⁴ — ¹Institut f"ur Strahlen- und Kernphysik, Univ. Bonn, Nußallee 14-16, D-53115 Bonn — ²Institut de Recherches Subatomique, F-67037 Strasbourg, France — ³Phys. Dept. TU M"unchen, D-85748 Garching — ⁴Dept. of Phys., Rutgers Univ., USA

Large-scale shell model calculations predict for the yrast states of ⁵⁰Cr [1], with excitation of neutrons and protons in the fp-shell, g-factors such as g(2⁺)=0.54, g(4⁺)=0.76,  g(6⁺)=0.74 etc. which are in severe conflict with experimental data [2] yielding the same value for all states. The discrepancy has been attributed to more collectivity than described by the model. We have performed new measurements focussing on the 2⁺– and 4⁺-states for which theory predicts a striking increase of the g-factor. Coulomb excitation of 120 MeV ⁵⁰Cr beam ions from the Munich tandem accelerator was accomplished with a carbon target. For the measurement of the magnetic moments the transient field technique with Gd as host was applied. The results are compared with those of former measurements and model predictions

[1] L. Zamick, D.C. Zheng, Phys. Rev. C54, 956 (1996)

[2] A. Pakou et al., Phys. Rev. C50, 2608 (1994) ⁺ supported by BMBF and DFG