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Title: Direct evidence of octupole deformation in neutron-rich 144Ba

Here, the neutron-rich nucleus 144Ba (t1/2 = 11.5 s) is expected to exhibit some of the strongest octupole correlations among nuclei with mass numbers A less than 200. Until now, indirect evidence for such strong correlations has been inferred from observations such as enhanced E1 transitions and interleaving positive- and negative-parity levels in the ground-state band. In this experiment, the octupole strength was measured directly by sub-barrier, multistep Coulomb excitation of a post-accelerated 650-MeV 144Ba beam on a 1.0–mg/cm2 208Pb target. The measured value of the matrix element, < 31–∥M(E3)∥01+ >= 0.65(+17–23) eb3/2, corresponds to a reduced B(E3) transition probability of 48(+25–34) W.u. This result represents an unambiguous determination of the octupole collectivity, is larger than any available theoretical prediction, and is consistent with octupole deformation.
Authors:
 [1] ;  [2] ;  [1] ;  [2] ;  [3] ;  [3] ;  [2] ;  [2] ;  [4] ;  [5] ;  [2] ;  [6] ;  [2] ;  [7] ;  [5] ;  [2] ;  [8] ;  [2] ;  [6] ;  [2] more »;  [2] ;  [9] ;  [2] ;  [5] ;  [2] ;  [7] ;  [10] ;  [2] ;  [11] ;  [2] ;  [12] ;  [5] ;  [2] « less
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. Argonne National Lab. (ANL), Argonne, IL (United States)
  3. Univ. of Rochester, Rochester, NY (United States)
  4. Univ. of Liverpool, Liverpool (United Kingdom)
  5. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  6. Argonne National Lab. (ANL), Argonne, IL (United States); Univ. of Maryland, College Park, MD (United States)
  7. Ohio Univ., Athens, OH (United States)
  8. Univ. of West of Scotland, Paisley (United Kingdom); Scottish Univ. Physics Alliance, Glasgow (United Kingdom)
  9. Argonne National Lab. (ANL), Argonne, IL (United States); IN2P3-CNRS, Orsay Campus (France)
  10. Florida State Univ., Tallahassee, FL (United States)
  11. Univ. of the West of Scotland, Paisley (United Kingdom); Scottish Univ., Physics Alliance, Glasgow (United Kingdom)
  12. Univ. of Notre Dame, Notre Dame, IN (United States)
Publication Date:
OSTI Identifier:
1260475
Report Number(s):
LLNL-JRNL--676868
Journal ID: ISSN 0031-9007; PRLTAO
Grant/Contract Number:
AC52-07NA27344
Type:
Accepted Manuscript
Journal Name:
Physical Review Letters
Additional Journal Information:
Journal Volume: 116; Journal Issue: 11; Journal ID: ISSN 0031-9007
Publisher:
American Physical Society (APS)
Research Org:
Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
22 GENERAL STUDIES OF NUCLEAR REACTORS; 73 NUCLEAR PHYSICS AND RADIATION PHYSICS