Abstract
We investigate the multineutron excitations of neutron-rich in the electric dipole strength using a five-body model. Many-body unbound states of are obtained in the complex scaling method. We found that the different excitation modes coexist in the dipole strength below the excitation energy of 20 MeV. The strength below 10 MeV comes from the channel, indicating the sequential breakup of via the resonance to . Above 10 MeV, the strength is obtained from many-body continuum states with strong configuration mixings, suggesting a new collective motion of four neutrons with the dipole oscillation against .
- Received 30 May 2022
- Accepted 22 July 2022
DOI:https://doi.org/10.1103/PhysRevC.106.L021302
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