α breakup of 6Li and 7Li near the Coulomb barrier -: art. no. 024601

Angular distributions of the alpha -particle production differential cross section from the breakup of Li-6 and Li-7 projectiles incident on a Pb-208 target have been measured at seven projectile energies between 29 and 52 MeV. The alpha -breakup cross section of Li-6 was found to be systematically greater than that of Li-7 across the entire energy range. These data have been compared with previously reported results and with the predictions of continuum-discretized coupled channels (CDCC) calculations including resonant and nonresonant projectile breakup. The present data compare well with previous measurements, while the CDCC calculations provide a reasonable prediction of the relative alpha -breakup cross sections but underpredict their absolute values. The calculations confirm that a major factor in the enhancement of the Li-6 to Li-7 alpha -breakup cross section is the difference between the alpha -breakup thresholds of the two isotopes. These results have implications for structural studies of light exotic nuclei based on elastic scattering.