Elastic scattering for the ⁸B and ⁷Be + ²⁰⁸Pb systems at near-Coulomb barrier energies

The elastic scattering of the weakly bound radioactive nuclei ⁸B and ⁷Be from a ²⁰⁸Pb target was measured for the first time in the energy range around the Coulomb barrier. The data were analyzed using the optical model and the continuum discretized coupled channels (CDCC) formalisms. The reaction cross sections extracted from the optical model fits clearly indicate a remarkably enhanced reaction probability for the very weakly bound ⁸B (S_p=137.5keV) compared to similar mass nuclei interacting with the same target nucleus. CDCC calculations assuming a ³He+⁴He cluster model well described the ⁷Be experimental elastic scattering angular distributions, whereas the use of a ⁷Be+p cluster model of ⁸B with an inert ⁷Be core gave a relatively poor description of the corresponding experimental data, suggesting that this model may be too simplistic and the possibility of core excitation should not be ignored.