Identification of the g9/2 proton and neutron band crossing in the N = Z nucleus 76Sr

P. J. Davies, A. V. Afanasjev, R. Wadsworth, C. Andreoiu, R. A. E. Austin, M. P. Carpenter, D. Dashdorj, S. J. Freeman, P. E. Garrett, A. Gorgen, J. Greene, D. G. Jenkins, F. L. Johnston-Theasby, P. Joshi, A. O. Macchiavelli, F. Moore, G. Mukherjee, W. Reviol, D. Sarantites, D. SeweryniakM. B. Smith, C. E. Svensson, J. J. Valiente-Dobon, D. Ward

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High-spin states in Sr-76 have been studied using Gammasphere plus Microball detector arrays. The known yrast band has been extended beyond the first band crossing, which involves the simultaneous alignment of pairs of g(9/2) protons and neutrons, to a tentative spin of 24h. The data are compared with the results of cranked relativistic mean-field (CRMF) and cranked relativistic Hartree-Bogoliubov (CRHB) calculations. The properties of the band, including the g(9/2) proton/neutron band crossing frequency and moments of inertia, are found to be well reproduced by the CRHB calculations. Furthermore, the unpaired CRMF calculations show quite good agreement with the data beyond the band crossing region, indicating that pairing is weak at these frequencies. The high spin results suggest that there is little evidence for an isoscalar (t=0) np pair field. Moreover, a systematic study of the band crossings in even-even N=Z nuclei for the first time reveals that there is no evidence to support the existence of the Coulomb antipairing effect caused by the Coulomb exchange term.

Original languageEnglish
Article number011302
Pages (from-to)-
Number of pages5
JournalPhysical Review C
Issue number1
Publication statusPublished - Jan 2007


  • N=Z

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