1. Direct Evidence of Octupole Deformation in Neutron-Rich Ba144
- Author
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Bucher, B, Zhu, S, Wu, CY, Janssens, RVF, Cline, D, Hayes, AB, Albers, M, Ayangeakaa, AD, Butler, PA, Campbell, CM, Carpenter, MP, Chiara, CJ, Clark, JA, Crawford, HL, Cromaz, M, David, HM, Dickerson, C, Gregor, ET, Harker, J, Hoffman, CR, Kay, BP, Kondev, FG, Korichi, A, Lauritsen, T, Macchiavelli, AO, Pardo, RC, Richard, A, Riley, MA, Savard, G, Scheck, M, Seweryniak, D, Smith, MK, Vondrasek, R, and Wiens, A
- Subjects
Nuclear and Plasma Physics ,Synchrotrons and Accelerators ,Physical Sciences ,nucl-ex ,Mathematical Sciences ,Engineering ,General Physics ,Mathematical sciences ,Physical sciences - 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, multistep 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, ⟨3_{1}^{-}∥M(E3)∥0_{1}^{+}⟩=0.65(+17/-23) eb^{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.
- Published
- 2016