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Observation of isoscalar and isovector dipole excitations in neutron-rich 20O.
- Source :
-
Physics Letters B . May2017, Vol. 768, p387-392. 6p. - Publication Year :
- 2017
-
Abstract
- The isospin characters of low-energy dipole excitations in neutron-rich unstable nucleus 20 O were investigated, for the first time in unstable nuclei. Two spectra obtained from a dominant isovector probe ( O 20 + Au ) and a dominant isoscalar probe ( O 20 + α ) were compared and analyzed by the distorted-wave Born approximation to extract independently the isovector and isoscalar dipole strengths. Two known 1 − states with large isovector dipole strengths at energies of 5.36(5) MeV ( 1 1 − ) and 6.84(7) MeV ( 1 2 − ) were also excited by the isoscalar probe. These two states were found to have different isoscalar dipole strengths, 2.70(32)% ( 1 1 − ) and 0.67(12)% ( 1 2 − ), respectively, in exhaustion of the isoscalar dipole-energy-weighted sum rule. The difference in isoscalar strength indicated that they have different underlying structures. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 03702693
- Volume :
- 768
- Database :
- Academic Search Index
- Journal :
- Physics Letters B
- Publication Type :
- Academic Journal
- Accession number :
- 122370739
- Full Text :
- https://doi.org/10.1016/j.physletb.2017.03.017