1. Direct Evidence of Octupole Deformation in Neutron-Rich ^{144}Ba
- Author
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Ching-Yen Wu, C. M. Campbell, D. Seweryniak, H. M. David, S. Zhu, A. L. Richard, E. T. Gregor, M. P. Carpenter, C. J. Chiara, F. G. Kondev, A. Wiens, M. Cromaz, Brian Bucher, Marcus Scheck, B. P. Kay, Calem Hoffman, Mallory Smith, A. B. Hayes, M. A. Riley, A. O. Macchiavelli, A. D. Ayangeakaa, P. A. Butler, R. V. F. Janssens, Guy Savard, Clayton Dickerson, T. Lauritsen, J. Harker, H. L. Crawford, Jason A. Clark, R. C. Pardo, R. C. Vondrasek, D. Cline, A. Korichi, M. Albers, Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM SNO), and Université Paris-Saclay-Univ. Paris-Sud-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)
- Subjects
General Physics ,Direct evidence ,General Physics and Astronomy ,FOS: Physical sciences ,Coulomb excitation ,[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex] ,nucl-ex ,01 natural sciences ,Mathematical Sciences ,Indirect evidence ,ENERGY ,Engineering ,0103 physical sciences ,medicine ,Neutron ,Matrix element ,Nuclear Experiment (nucl-ex) ,010306 general physics ,Nuclear Experiment ,Physics ,[PHYS]Physics [physics] ,PARITY ,010308 nuclear & particles physics ,RADIOACTIVE BEAMS ,DEFORMED-NUCLEI ,medicine.anatomical_structure ,BARIUM ISOTOPES ,GROUND-STATE ,Physical Sciences ,Atomic physics ,Deformation (engineering) ,Nucleus ,Beam (structure) - Abstract
The neutron-rich nucleus $^{144}$Ba ($t_{1/2}$=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, multi-step Coulomb excitation of a post-accelerated 650-MeV $^{144}$Ba beam on a 1.0-mg/cm$^2$ $^{208}$Pb target. The measured value of the matrix element, $\langle 3_1^- \| \mathcal{M}(E3) \| 0_1^+ \rangle=0.65(^{+17}_{-23})$ $e$b$^{3/2}$, 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., Comment: 5 pages, 2 figures, 1 table, Physical Review Letters 2016
- Published
- 2016