2016/02/03 by B. Bucher, S. Zhu, C. Y. Wu +31 · 1 citation
Physics and Astronomy · #nucl-ex
paper · pdf · doi:10.1103/physrevlett.116.112503
published as Phys. Rev. Lett. 116, 112503 (2016) · 5 pages, 2 figures, 1 table, Physical Review Letters 2016
arxiv created 2016/02/03 · arxiv updated 2016/03/23
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, multi-step 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.