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

Abstract

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.

Authors:
; ; ; ;  [1];  [2];  [3];  [4];  [5];  [6]; ; ; ; ;  [7];  [8];  [9];  [5];  [4];  [10] more »;  [11]; ;  [12];  [13] « less
  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. (Latvia)
  4. Department of Physics, University of Guelph, Guelph, Ontario N1G 2W1 (Canada)
  5. (United Kingdom)
  6. Department Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4K1 (Canada)
  7. Physics Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States)
  8. North Carolina State University, Rayleigh, North Carolina 27695 (United States)
  9. Physics Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA (United States)
  10. (Canada)
  11. CE Saclay, Daphnia/SphN, F-91191 Gif-sur-Yvette Cedex France (France)
  12. Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
  13. Department of Chemistry, Washington University, St. Louis, Missouri 63130 (United States) (and others)
Publication Date:
OSTI Identifier:
20990924
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 75; Journal Issue: 1; Other Information: DOI: 10.1103/PhysRevC.75.011302; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; HIGH SPIN STATES; MEAN-FIELD THEORY; MOMENT OF INERTIA; NEUTRONS; PROTONS; RELATIVISTIC RANGE; SPIN; STRONTIUM 76

Citation Formats

Davies, P. J., Wadsworth, R., Jenkins, D. G., Johnston-Theasby, F. L., Joshi, P., Afanasjev, A. V., Laboratory of Radiation Physics, Institute of Solid State Physics, University of Latvia, LV 2169 Salaspils, Miera str. 31, Andreoiu, C., Oliver Lodge Laboratory, University of Liverpool, Liverpool, L69 3BX, Austin, R. A. E., Carpenter, M. P., Greene, J., Moore, F., Mukherjee, G., Seweryniak, D., Dashdorj, D., Freeman, S. J., The School of Physics and Astronomy, University of Manchester, Manchester M15 9PL, Garrett, P. E., TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, V6T 2A3, Goergen, A., Macchiavelli, A. O., Ward, D., and Reviol, W. Identification of the g{sub (9/2)} proton and neutron band crossing in the N=Z nucleus {sup 76}Sr. United States: N. p., 2007. Web. doi:10.1103/PHYSREVC.75.011302.
Davies, P. J., Wadsworth, R., Jenkins, D. G., Johnston-Theasby, F. L., Joshi, P., Afanasjev, A. V., Laboratory of Radiation Physics, Institute of Solid State Physics, University of Latvia, LV 2169 Salaspils, Miera str. 31, Andreoiu, C., Oliver Lodge Laboratory, University of Liverpool, Liverpool, L69 3BX, Austin, R. A. E., Carpenter, M. P., Greene, J., Moore, F., Mukherjee, G., Seweryniak, D., Dashdorj, D., Freeman, S. J., The School of Physics and Astronomy, University of Manchester, Manchester M15 9PL, Garrett, P. E., TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, V6T 2A3, Goergen, A., Macchiavelli, A. O., Ward, D., & Reviol, W. Identification of the g{sub (9/2)} proton and neutron band crossing in the N=Z nucleus {sup 76}Sr. United States. doi:10.1103/PHYSREVC.75.011302.
Davies, P. J., Wadsworth, R., Jenkins, D. G., Johnston-Theasby, F. L., Joshi, P., Afanasjev, A. V., Laboratory of Radiation Physics, Institute of Solid State Physics, University of Latvia, LV 2169 Salaspils, Miera str. 31, Andreoiu, C., Oliver Lodge Laboratory, University of Liverpool, Liverpool, L69 3BX, Austin, R. A. E., Carpenter, M. P., Greene, J., Moore, F., Mukherjee, G., Seweryniak, D., Dashdorj, D., Freeman, S. J., The School of Physics and Astronomy, University of Manchester, Manchester M15 9PL, Garrett, P. E., TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, V6T 2A3, Goergen, A., Macchiavelli, A. O., Ward, D., and Reviol, W. Mon . "Identification of the g{sub (9/2)} proton and neutron band crossing in the N=Z nucleus {sup 76}Sr". United States. doi:10.1103/PHYSREVC.75.011302.
@article{osti_20990924,
title = {Identification of the g{sub (9/2)} proton and neutron band crossing in the N=Z nucleus {sup 76}Sr},
author = {Davies, P. J. and Wadsworth, R. and Jenkins, D. G. and Johnston-Theasby, F. L. and Joshi, P. and Afanasjev, A. V. and Laboratory of Radiation Physics, Institute of Solid State Physics, University of Latvia, LV 2169 Salaspils, Miera str. 31 and Andreoiu, C. and Oliver Lodge Laboratory, University of Liverpool, Liverpool, L69 3BX and Austin, R. A. E. and Carpenter, M. P. and Greene, J. and Moore, F. and Mukherjee, G. and Seweryniak, D. and Dashdorj, D. and Freeman, S. J. and The School of Physics and Astronomy, University of Manchester, Manchester M15 9PL and Garrett, P. E. and TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, V6T 2A3 and Goergen, A. and Macchiavelli, A. O. and Ward, D. and Reviol, W.},
abstractNote = {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.},
doi = {10.1103/PHYSREVC.75.011302},
journal = {Physical Review. C, Nuclear Physics},
number = 1,
volume = 75,
place = {United States},
year = {Mon Jan 15 00:00:00 EST 2007},
month = {Mon Jan 15 00:00:00 EST 2007}
}