Sub-barrier fusion of the magic nuclei 40,48Ca+48Ca

Abstract

The fusion excitation functions of ${}^{40,48}\mathrm{Ca}{+}^{48}\mathrm{Ca}$ have been measured near and below the Coulomb barrier and the fusion barrier distributions have been extracted from the data. The cross sections for ${}^{48}\mathrm{Ca}{+}^{48}\mathrm{Ca}$ are well reproduced by coupled-channels (CC) calculations, including inelastic excitations to the ${2}^{+}$ and ${3}^{\ensuremath{-}}$ states of both nuclei and using a standard potential. The cross sections of ${}^{40}\mathrm{Ca}{+}^{48}\mathrm{Ca}$ are significantly larger than previous data for the same system, especially near and above the barrier. While a much better agreement between present data and CC calculations is found in that energy range, the sub-barrier cross sections are still underpredicted.