Two-neutron stripping reaction dynamics in the system at near-barrier energies
Phys. Rev. C 114, 034612 – Published 14 September, 2026
DOI: https://doi.org/10.1103/6g8r-xqv5
Abstract
We report measurements of the total two-neutron stripping cross section for the reaction across the energy range = 63–125 MeV, corresponding to . The experiment employed the stacked-foil activation technique, where eight thin gold targets were irradiated sequentially arranged in a stack by an beam. The resulting activities were measured via offline -ray spectroscopy. The production of was confirmed by observing its characteristic rays (-ray transitions in following the decay of ), and further validated through decay-curve analysis of the half-life. Absolute cross sections for the two-neutron stripping channel were extracted and compared with theoretical model predictions. The measured cross sections increase sharply near the Coulomb barrier, from mb at to approximately 40–42 mb at energies above the barrier. Theoretical calculations using the semiclassical GRAZING model systematically underestimate the data, particularly at sub-barrier energies, suggesting limitations in its treatment of pair-correlated transfer. Coupled-reaction-channel calculations performed with the code indicate that two-neutron stripping mechanism is dominated mainly by simultaneous transfer of two neutrons rather than the sequential two-step process. The data are best reproduced by a cluster model with reduced spectroscopic amplitudes, pointing to the role of pairing correlations and configuration mixing in the transfer process. This work provides new absolute cross-section data for two-neutron transfer on a heavy target at sub-barrier energies and highlights challenges in current theoretical descriptions of pair-transfer reactions near the Coulomb barrier.
