Testing Mean-Field Models Near the N = Z Line: γ-ray Spectroscopy of the Tz=½ Nucleus 73Kr


Testing Mean-Field Models Near the N = Z Line: γ-ray Spectroscopy of the Tz=½ Nucleus 73Kr

Kelsall, N. S.; Fischer, S. M.; Balamuth, D. P.; Ball, G. C.; Carpenter, M. P.; Clark, R. M.; Durell, J.; Fallon, P.; Freeman, S. J.; Hausladen, P. A.; Janssens, R. V. F.; Jenkins, D. G.; Leddy, M. J.; Lister, C. J.; Macchiavelli, A. O.; Sarantites, D. G.; Schmidt, D. C.; Seweryniak, D.; Svensson, C. E.; Varley, B. J.; Vincent, S.; Wadsworth, R.; Wilson, A. N.; Afanasjev, A. V.; Frauendorf, S.; Ragnarsson, I.; Wyss, R.

Excited states in the N=Z + 1 nucleus 73Kr have been investigated using the 40Ca(36Ar,2pn) and 40Ca(40Ca,α2pn) reactions at 145 and 160 MeV, respectively. γ-rays were detected using the Gammasphere array and events were re corded in coincidence with charged-particle and neutron detectors.
The three previously observed bands were extended to high spin, and a new unfavored positive-parity band has been observed. The alignment characteristics and decay properties of the bands are all consistent with large-deformation prolate rotation, with no clear evidence for oblate bands or shape coexistence. This is quite different from neighboring 72,74Kr, indicating a strong shape-stabilizing role for the valence neutron. The experimental results are compared to extended total Routhian surface, cranked Nilsson Strutinsky, and cranked relativistic mean-field calculations. The results suggest that the paired calculations lack some important physics. Neutron-proton correlations may be the missing ingredient. There is also evidence for an unusual band crossing in the negative-parity bands, which may in dicate the presence of T = 0 pairing correlations. At high spin all the models can reproduce the experimental data.

  • Phys. Rev. C 65 (2002) 044331

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Publ.-Id: 4828