par Descouvemont, Pierre 
;Dufour, Marianne
Référence AIP Conference Proceedings, 1269, page (276-282)
Publication Publié, 2010
;Dufour, MarianneRéférence AIP Conference Proceedings, 1269, page (276-282)
Publication Publié, 2010
Article révisé par les pairs
| Résumé : | The E2 component of the 12C(α,γ )16O cross section is investigated by a microscopic cluster model, and by R-matrix fits. The first approach provides S E2(300 keV)≈50 keV-b for ground-state transitions. In the R-matrix theory, we show that the background term plays a crucial role, and cannot be determined without ambiguity. Only an upper limit on the extrapolated S factor can be obtained [SE2(300 keV)<190 keV-b]. To constrain the R-matrix analysis, we use the GCM Asymptotic Normalization Constant (ANC) of the 21+ level. This procedure strongly reduces the uncertainties on the R-matrix fit, and we end up with a recommended value of SE2 (300 keV) =42± 2 keV-b. As ANC values derived from indirect methods are not consistent with the 12C(α,γ )16O cascade transitions to the 2 +1 state, we suggest a remeasurement of this cross section. © 2010 American Institute of Physics. |
