Author/Authors :
H.T. Johansson، نويسنده , , Yu. Aksyutina، نويسنده , , T. Aumann، نويسنده , , K. Boretzky، نويسنده , , M.J.G. Borge، نويسنده , , A. Chatillon، نويسنده , , L.V. Chulkov، نويسنده , , D. Cortina Gil، نويسنده , , U. Datta Pramanik، نويسنده , , H. Emling، نويسنده , , C. Forssen، نويسنده , , H.O.U. Fynbo، نويسنده , , H. Geissel، نويسنده , , G. Ickert، نويسنده , , B. Jonson، نويسنده , , R. Kulessa، نويسنده , , C. Langer، نويسنده , , M. Lantz، نويسنده , , T. LeBleis، نويسنده , , K. Maha، نويسنده ,
Abstract :
The unbound nuclei 9He and 10He have been produced in proton-knockout reactions from a 280 MeV/u 11Li beam impinging on a liquid hydrogen target at the ALADIN-LAND setup at GSI. Information on their nuclear structure has been obtained from the relative-energy spectra, image and image, employing reaction models incorporating the structure of 11Li.
The image relative-energy spectrum is dominated by a strong peak-like structure at low energy, which may be interpreted within the effective-range approximation as the result of an s-wave interaction with a neutron scattering length of image. This spectrum also shows evidence for resonance states at image and at 2.4 MeV above the image threshold. It is argued that the s-state might not be the 9He ground state.
For image, the analysis of the relative-energy spectrum gives two alternative possibilities for an interpretation: either a narrow resonance at image (image) superimposed on a correlated background, or two overlapping resonances, a ground state at 1.54(11) MeV (image) together with an excited state at 3.99(26) MeV (image). The two possible interpretations are discussed.
Keywords :
measured , fragment spectra , Neutron spectra , relative energy spectra , NUCLEAR REACTIONS , deduced resonance state parameters , 1H(11Li , (11Li , View the MathML sourcen2p) , View the MathML source2p) , E=280 MeV/nucleonE=280 MeV/nucleon , (fragment) (neutron)-coin
