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Title: Observation of γ-vibrations and alignments built on non-ground-state configurations in ¹⁵⁶Dy

The exact nature of the lowest Kπ=2⁺ rotational bands in all deformed nuclei remains obscure. Traditionally they are assumed to be collective vibrations of the nuclear shape in the γ degree of freedom perpendicular to the nuclear symmetry axis. Very few such γ-bands have been traced past the usual back-bending rotational alignments of high-j nucleons. We have investigated the structure of positive-parity bands in the N=90 nucleus ¹⁵⁶Dy, using the ¹⁴⁸Nd(¹²C,4n)¹⁵⁶Dy reaction at 65 MeV, observing the resulting γ-ray transitions with the Gammasphere array. The even- and odd-spin members of the π=2⁺ γ-band are observed to 32⁺ and 31⁺ respectively. This rotational band faithfully tracks the ground-state configuration to the highest spins. The members of a possible γ-vibration built on the aligned yrast S-band are observed to spins 28⁺ and 27⁺. An even-spin positive-parity band, observed to spin 24⁺, is a candidate for an aligned S-band built on the seniority-zero configuration of the 0₂⁺ state at 676 keV. As a result, the crossing of this band with the 0₂⁺ band is at hwc = 0.28(1) MeV and is consistent with the configuration of the 0₂⁺ band not producing any blocking of the monopole pairing.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [5] ;  [6] ;  [6] ;  [7] ;  [8] ;  [8] ;  [9] ;  [6] ;  [6] ;  [10] ;  [6] ;  [11] ;  [3] ;  [8] ;  [12] more »;  [13] ;  [14] ;  [6] ;  [7] ;  [13] ;  [10] ;  [15] ;  [6] « less
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. US Naval Academy, Annapolis, MD (United States)
  3. Univ. of Tennessee, Knoxville, TN (United States)
  4. Univ. of Western Cape, Bellville (South Africa)
  5. Univ. of Richmond, Richmond, VA (United States)
  6. Argonne National Lab. (ANL), Argonne, IL (United States)
  7. Yale Univ., New Haven, CT (United States)
  8. Univ. de Strasbourg, Strasbourg (France)
  9. Univ. of Guelph, ON (Canada)
  10. Georgia Inst. of Technology, Atlanta, GA (United States)
  11. Argonne National Lab. (ANL), Argonne, IL (United States); Brookhaven National Lab. (BNL), Upton, NY (United States)
  12. Inst. de Physique Nucleaire Lyon, Villeurbanne (France)
  13. Florida State Univ., Tallahassee, FL (United States)
  14. Science and Technology Facilities Council (STFC), Daresbury (United Kingdom). Daresbury Lab.
  15. iThemba LABS, National Research Foundation, Somerset-West (South Africa); Univ. of Cape Town, Rondebosch (South Africa)
Publication Date:
OSTI Identifier:
1183876
Report Number(s):
BNL--108019-2015-JA
Journal ID: ISSN 0556-2813; PRVCAN; R&D Project: EST-003-NEFA; KB0301041
Grant/Contract Number:
SC00112704
Type:
Accepted Manuscript
Journal Name:
Physical Review. C, Nuclear Physics
Additional Journal Information:
Journal Volume: 91; Journal Issue: 3; Journal ID: ISSN 0556-2813
Publisher:
American Physical Society (APS)
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS national nuclear data center