Breakup of the proton halo nucleus 8B at a sub-Coulomb energy

Abstract

We report inclusive breakup measurements of the proton halo nucleus 8B on a medium mass target, 90Zr. The experiment was carried out at the TriSol facility of the University of Notre Dame at a beam energy of 26.5 MeV, corresponding to 90% of the Coulomb barrier. The data include angular distributions of the 7Be breakup fragment and of the elastically scattered 8B nuclei, allowing a good normalization of the 7Be yields. The latter are found to be in good agreement with the prediction of continuum-discretized coupled-channel calculations, thus pointing to the direct excitation to the continuum as the main production mechanism. The integrated breakup cross section, 𝜎bu=170±40 mb, exhausts most of the total reaction cross section, indicating the dominance of direct processes below the barrier. A comparison of all existing breakup cross sections, on various targets at sub- and near-barrier energies, is also included.