Identification of the g{sub (9/2)} proton and neutron band crossing in the N=Z nucleus {sup 76}Sr

Journal Article · Mon Jan 15 04:00:00 EST 2007 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.75.011302· OSTI ID:20990924

Davies, P J; Wadsworth, R; Jenkins, D G; Johnston-Theasby, F L; Joshi, P ^[1]; Afanasjev, A V ^[2]; Andreoiu, C ^[3]; Austin, R A. E. ^[4]; Carpenter, M P; Greene, J; Moore, F; Mukherjee, G; Seweryniak, D ^[5]; Dashdorj, D ^[6]; Freeman, S J ^[7]; Garrett, P E ^[3]; Goergen, A ^[8]; Macchiavelli, A O; Ward, D ^[9]; Reviol, W ^[10]

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1. Department of Physics, University of York, Heslington, York YO10 5DD (United Kingdom)
2. Department of Physics and Astronomy, Mississippi State University, Mississippi 39762 (United States)
3. Department of Physics, University of Guelph, Guelph, Ontario N1G 2W1 (Canada)
4. Department Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4K1 (Canada)
5. Physics Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States)
6. North Carolina State University, Rayleigh, North Carolina 27695 (United States)
7. Physics Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA (United States)
8. CE Saclay, Daphnia/SphN, F-91191 Gif-sur-Yvette Cedex France (France)
9. Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
10. Department of Chemistry, Washington University, St. Louis, Missouri 63130 (United States)

High-spin states in {sup 76}Sr 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{sub (9/2)} protons and neutrons, to a tentative spin of 24({Dirac_h}/2{pi}). 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{sub (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.

• OSTI ID: 20990924
• Journal Information: Physical Review. C, Nuclear Physics, Journal Name: Physical Review. C, Nuclear Physics Journal Issue: 1 Vol. 75; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
HIGH SPIN STATES
MEAN-FIELD THEORY
MOMENT OF INERTIA
NEUTRONS
PROTONS
RELATIVISTIC RANGE
SPIN
STRONTIUM 76