Structure of 9C through proton resonance scattering with the Texas Active Target detector
Abstract
Background: Level structure of the most neutron-deficient nucleon-bound carbon isotope, 9C, is not well known. Definitive spin-parity assignments are only available for two excited states. No positive-parity states have been conclusively identified so far and the location of the s d shell in the A =9 , T =3 /2 isospin quadruplet is not known.
Purpose: We have studied the level structure of exotic nucleus 9C at excitation energies below 6.4 MeV. Methods: Excited states in 9C were populated in 8B+p resonance elastic scattering and excitation functions were measured using the active target approach. Results: Two excited states in 9C were conclusively observed, and R -matrix analysis of the excitation functions was performed to make the spin-parity assignments. The first positive-parity state in the A =9 , T =3 /2 nuclear system, the 5 /2+ resonance at 4.3 MeV, has been identified. Conclusions: The new 5 /2+ state at 4.3 MeV in 9C is a single-particle ℓ =0 broad resonance and it determines the energy of the 2 s shell. The 2 s shell in this exotic nucleus appears well within the region dominated by the p -shell states.- Publication:
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Physical Review C
- Pub Date:
- November 2019
- DOI:
- 10.1103/PhysRevC.100.054618
- arXiv:
- arXiv:1903.01402
- Bibcode:
- 2019PhRvC.100e4618H
- Keywords:
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- Nuclear Experiment
- E-Print:
- 9 pages, 12 figures