Quantitative analysis of two-neutron correlations in the C-12(O-18,O-16)C-14 reaction

The C-12(O-18,O-16)C-14 and C-12,C-13(O-18,O-17)C-13,C-14 reactions are studied at 84 MeV. Mass distributions and energy spectra of the ejectiles are measured, indicating the selectivity of these reactions to populate two-and one-neutron configurations in the states of the residual nucleus, respectively. The measured absolute cross-section angular distributions are analyzed by exact finite range coupled reaction channel calculations based on a parameter free double-folding optical potential. The form factors for the (O-18,O-16) reaction are extracted within an extreme cluster and independent particles scheme with shell-model-derived coupling strengths. The results show that the measured cross sections are accurately described for the first time without the need for any arbitrary scaling factor. The (O-18,O-16) reaction is thus found to be a powerful tool for quantitative spectroscopic studies of pair configurations in nuclear states.