par Adahchour, Abderrahim 
;Descouvemont, Pierre
Référence Physical Review C, 96, 5, 054319
Publication Publié, 2017-11
;Descouvemont, Pierre Référence Physical Review C, 96, 5, 054319
Publication Publié, 2017-11
Article révisé par les pairs
| Résumé : | We investigate the O26 unbound nucleus in a O24+n+n three-body model. We use the hyperspherical formalism, which relies only on O24+n and n+n interactions. As O26 is unbound, even in its ground state, the long-range behavior of the wave functions is crucial. We adapt the R-matrix technique to derive the wave functions and the associated phase shifts. We start from a O24+n potential which nicely reproduces the known O25 properties. Using a weakly repulsive three-body potential, we find the O26 ground state at 0.08 MeV, i.e., just above the threshold, in agreement with the latest experimental value. An analysis of the wave function suggests a dominant dineutron configuration. We extend the model to J=1- and J=2+. For J=2+, we find a relatively narrow resonance near ER=1.3 MeV (Γ≈0.4 MeV), which is supported by recent experimental data. Broad structures are seen in the 0+ and 1- phase shifts but cannot be associated with physical resonances. |
