Résumé du preprint DAPNIA-06-674

DAPNIA-06-674
Low-lying states and structure of the exotic 8He via direct reactions on proton
F. Skaza, V. Lapoux, N. Keeley, N. Alamanos, F. Auger, D. Beaumel, E. Becheva, Y. Blumenfeld, F. Delaunay, A. Drouart, A. Gillibert, L. Giot, E. Khan, L. Nalpas, A. Pakou, E. Pollacco, R. Raabe, P. Roussel-Chomaz, K. Rusek, J-A. Scarpaci, J-L. Sida, S. Stepantsov and R. Wolski.
The structure of the light exotic nucleus 8He was investigated using direct reactions of the 8He SPIRAL beam on 
a proton-rich target. The (p,p\') scattering to the 2+ state, the (p,d)7He and (p,t)6He transfer reactions, were 
measured at the energy Elab=15.7 A.MeV. The light charged particles (p,d,t) were detected in the MUST Si-strip 
telescope array. The excitation spectrum of 8He was extracted from the (p,p\') reaction. 
Above the known 2+ excited state at 3.6 MeV, a second resonance was found around 5.4 MeV. 
The cross sections were analyzed within the coupled-reaction channels framework, using microscopic potentials. 
It is inferred that the 8He ground state has a more complex neutron-skin structure than suggested by previous 
alpha+4n models assuming a pure (1p3/2)4 configuration.

 

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