Search for resonances in 4n, 7H and 9He via transfer reactions

Journal Article · Tue May 22 00:00:00 EDT 2007 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.2746575· OSTI ID:21061824

Fortier, S; Tryggestad, E; Rich, E; Beaumel, D; Becheva, E; Blumenfeld, Y; Delaunay, F; Frascaria, N; Guillot, J; Hammache, F; Khan, E; Lima, V; Scarpaci, J A ^[1]; Drouart, A; Gillibert, A; Lapoux, V; Nalpas, L; Obertelli, A; Pollacco, E C; Skaza, F ^[2]

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1. IPNO, Universite Paris-Sud-11-CNRS/IN2P3, Orsay (France)
2. CEA-Saclay DSM/DAPNIA/SPhN, F91191 Gif sur Yvette (France)

Investigation of unbound nuclear systems 9He, 7H and 4n was performed at GANIL-SPIRAL using the 8He beam at 15.3 A MeV and a CD2 target. The missing mass spectra were deduced from kinetic energies and emission angles of light ejectiles detected by the Silicon array MUST. In addition to previously known low-lying narrow resonant states in 9He, the d(8He,p) reaction displays a structure just above neutron emission threshold, identified with the 'true' ground state of 9He. The analysis of angular distributions shows that the inversion of s1/2 and p1/2 neutron shells previously observed in 11Be and 10Li also exists in the lightest N=7 isotone 9He. The d(8He,3He) and d(8He,6Li) reactions were used to search for resonant states in the t+4n (7H) and 4n systems, respectively. The missing mass spectrum of the 4n system does not give evidence for the existence of a bound 'tetraneutron'. However the comparison with the results of 5-body phase-space calculations emphasizes the existence of correlations in the 4n system. The broad structure observed at {approx_equal}2 MeV above the t+4n emission threshold is proposed to be the ground state of 7H.

• OSTI ID: 21061824
• Journal Information: AIP Conference Proceedings, Vol. 912, Issue 1; Conference: International symposium on exotic nuclei, Khanty-Mansiysk (Russian Federation), 17-22 Jul 2006; Other Information: DOI: 10.1063/1.2746575; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ANGULAR DISTRIBUTION
BERYLLIUM 11
COMPARATIVE EVALUATIONS
CORRELATIONS
GANIL CYCLOTRON
GROUND STATES
HELIUM 3
HELIUM 8
HELIUM 9
HYDROGEN 7
ISOTONIC NUCLEI
LITHIUM 10
LITHIUM 6
MEV RANGE
MISSING-MASS SPECTRA
NEUTRON EMISSION
NEUTRONS
PHASE SPACE
TRANSFER REACTIONS