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

The fusion excitation functions of 40,48Ca+48Ca have been measured near and below the Coulomb barrier and the fusion barrier distributions have been extracted from the data. The cross sections for 48Ca+48Ca are well reproduced by coupled-channels (CC) calculations, including inelastic excitations to the 2+ and 3- states of both nuclei and using a standard potential. The cross sections of 40Ca+48Ca 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.