Experimental evidence for subshell closure in {sup 8}He and indication of a resonant state in {sup 7}He below 1 MeV
- CEA-SACLAY DSM/DAPNIA/SPhN F-91191 Gif-sur-Yvette (France)
- Institut de Physique Nucleaire, IN2P3-CNRS, F-91406 Orsay (France)
- GANIL, Bld Henri Becquerel, BP 5027, F-14021 Caen Cedex (France)
- Department of Physics, Florida State University, Tallahassee, Florida 32306-4350, (United States)
The spectroscopy of the unstable {sup 8}He and unbound {sup 7}He nuclei is investigated via the p({sup 8}He, d) transfer reaction with a 15.7A MeV {sup 8}He beam from the SPIRAL facility. The emitted deuterons were detected by the telescope array MUST. The results are analyzed within the coupled-channels Born approximation framework, and a spectroscopic factor C{sup 2}S=4.4{+-}1.3 for neutron pickup to the {sup 7}He{sub g.s.} is deduced. This value is consistent with a full p3/2 subshell for {sup 8}He. Tentative evidence for the first excited state of {sup 7}He is found at E{sup *}=0.9{+-}0.5 MeV (width {gamma}=1.0{+-}0.9 MeV). The second one is observed at a position compatible with previous measurements, E{sup *}=2.9{+-}0.1 MeV. Both are in agreement with previous separate measurements. The reproduction of the first excited state below 1 MeV would be a challenge for the most sophisticated nuclear theories.
- OSTI ID:
- 20771427
- Journal Information:
- Physical Review. C, Nuclear Physics, Journal Name: Physical Review. C, Nuclear Physics Journal Issue: 4 Vol. 73; ISSN 0556-2813; ISSN PRVCAN
- Country of Publication:
- United States
- Language:
- English
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