Enhanced dynamics in fusion of neutron-rich oxygen nuclei at above-barrier energies

Above-barrier fusion cross sections for an isotopic chain of oxygen isotopes with A=16-19 incident on a C12 target are presented. Experimental data are compared with both static and dynamical microscopic calculations. These calculations are unable to explain the ≈37% increase in the average above-barrier fusion cross section observed for O19 as compared to β-stable oxygen isotopes. This result suggests that for neutron-rich nuclei existing time-dependent Hartree-Fock calculations underpredict the role of dynamics at near-barrier energies. High-quality measurement of above-barrier fusion for an isotopic chain of increasingly neutron-rich nuclei provides an effective means to probe this fusion dynamics.