Search for resonances in $^4$n, $^7$H and $^9$He via transfer reactions - IN2P3 - Institut national de physique nucléaire et de physique des particules Access content directly
Conference Papers Year : 2007

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

A. Fomichev
  • Function : Author
K. W. Kemper
  • Function : Author
U. Datta Pramanik
  • Function : Author
D. Santonocito
  • Function : Author
J. A. Scarpaci
S. V. Stepantsov
  • Function : Author
G. M. ter Akopian
  • Function : Author
R. Wolski
  • Function : Author

Abstract

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 ~=2 MeV above the t+4n emission threshold is proposed to be the ground state of 7H
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Dates and versions

in2p3-00157522 , version 1 (26-06-2007)

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Cite

S. Fortier, E. Tryggestad, E. Rich, D. Beaumel, E. Becheva, et al.. Search for resonances in $^4$n, $^7$H and $^9$He via transfer reactions. International Symposium on Exotic Nuclei, Jul 2006, Khanty-Mansiysk, Russia. pp.3-12, ⟨10.1063/1.2746575⟩. ⟨in2p3-00157522⟩
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