Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5495239 | Physics Letters B | 2017 | 6 Pages |
Abstract
The isospin characters of low-energy dipole excitations in neutron-rich unstable nucleus 20O were investigated, for the first time in unstable nuclei. Two spectra obtained from a dominant isovector probe (O20+Au) and a dominant isoscalar probe (O20+α) were compared and analyzed by the distorted-wave Born approximation to extract independently the isovector and isoscalar dipole strengths. Two known 1â states with large isovector dipole strengths at energies of 5.36(5) MeV (11â) and 6.84(7) MeV (12â) were also excited by the isoscalar probe. These two states were found to have different isoscalar dipole strengths, 2.70(32)% (11â) and 0.67(12)% (12â), respectively, in exhaustion of the isoscalar dipole-energy-weighted sum rule. The difference in isoscalar strength indicated that they have different underlying structures.
Keywords
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Physical Sciences and Engineering
Physics and Astronomy
Nuclear and High Energy Physics
Authors
N. Nakatsuka, H. Baba, T. Aumann, R. Avigo, S.R. Banerjee, A. Bracco, C. Caesar, F. Camera, S. Ceruti, S. Chen, V. Derya, P. Doornenbal, A. Giaz, A. Horvat, K. Ieki, T. Inakura, N. Imai, T. Kawabata, J. Zenihiro,