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The role of seniority-zero states in nuclear level densities

Åberg, Sven LU ; Carlsson, Gillis LU ; Dossing, Th. and Moller, P. (2015) In Nuclear Physics, Section A 941. p.97-120
Abstract
At low excitation energies seniority-zero states dominate the level density of K = 0 bands in deformed even even nuclei, while they play no role at higher excitation energies. We describe the level densities in a Fermi-gas model as well as in a combinatorial level-density model and compare to detailed experimental data for some rare-earth nuclei. An explanation is provided for recent observations of an odd even staggering in the spin-distribution function as an effect of r-symmetry of wave functions for deformed nuclei. The structure of 0(+) states in deformed nuclei is discussed in the model and compared to data, stressing the role of the seniority quantum number. The Fermi-gas model is utilized to obtain an overview of the odd even... (More)
At low excitation energies seniority-zero states dominate the level density of K = 0 bands in deformed even even nuclei, while they play no role at higher excitation energies. We describe the level densities in a Fermi-gas model as well as in a combinatorial level-density model and compare to detailed experimental data for some rare-earth nuclei. An explanation is provided for recent observations of an odd even staggering in the spin-distribution function as an effect of r-symmetry of wave functions for deformed nuclei. The structure of 0(+) states in deformed nuclei is discussed in the model and compared to data, stressing the role of the seniority quantum number. The Fermi-gas model is utilized to obtain an overview of the odd even staggering phenomenon in other mass regions. Odd even staggering in spherical nuclei, appearing in open-shell nuclei, is briefly discussed as caused by fermion exchange symmetry. (C) 2015 Elsevier B.V. All rights reserved. (Less)
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author
; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Level-density, Seniority-zero states, Spin-distribution, 0(+)-states
in
Nuclear Physics, Section A
volume
941
pages
97 - 120
publisher
Elsevier
external identifiers
  • wos:000360515100008
  • scopus:84935010919
ISSN
0375-9474
DOI
10.1016/j.nuclphysa.2015.05.009
language
English
LU publication?
yes
additional info
The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Mathematical Physics (Faculty of Technology) (011040002)
id
2479b69f-f2f4-4682-81b5-5d45de85912f (old id 8077589)
date added to LUP
2016-04-01 13:09:58
date last changed
2022-04-13 23:40:40
@article{2479b69f-f2f4-4682-81b5-5d45de85912f,
  abstract     = {{At low excitation energies seniority-zero states dominate the level density of K = 0 bands in deformed even even nuclei, while they play no role at higher excitation energies. We describe the level densities in a Fermi-gas model as well as in a combinatorial level-density model and compare to detailed experimental data for some rare-earth nuclei. An explanation is provided for recent observations of an odd even staggering in the spin-distribution function as an effect of r-symmetry of wave functions for deformed nuclei. The structure of 0(+) states in deformed nuclei is discussed in the model and compared to data, stressing the role of the seniority quantum number. The Fermi-gas model is utilized to obtain an overview of the odd even staggering phenomenon in other mass regions. Odd even staggering in spherical nuclei, appearing in open-shell nuclei, is briefly discussed as caused by fermion exchange symmetry. (C) 2015 Elsevier B.V. All rights reserved.}},
  author       = {{Åberg, Sven and Carlsson, Gillis and Dossing, Th. and Moller, P.}},
  issn         = {{0375-9474}},
  keywords     = {{Level-density; Seniority-zero states; Spin-distribution; 0(+)-states}},
  language     = {{eng}},
  pages        = {{97--120}},
  publisher    = {{Elsevier}},
  series       = {{Nuclear Physics, Section A}},
  title        = {{The role of seniority-zero states in nuclear level densities}},
  url          = {{http://dx.doi.org/10.1016/j.nuclphysa.2015.05.009}},
  doi          = {{10.1016/j.nuclphysa.2015.05.009}},
  volume       = {{941}},
  year         = {{2015}},
}