Reaction cross sections for 8B, 7Be, and 6Li + 58Ni near the Coulomb barrier : Proton-halo effects

Elastic scattering of 8 8, 7 Be, and 6 Li on a 58 Ni target has been measured at energies near the Coulomb barrier. Optical-model fits were made to the experimental angular distributions, and total reaction cross sections were deduced. A comparison with other systems provides striking evidence for proton-halo effects on 8 B reactions. As opposed to the situation for the neutron-halo nucleus 6 He, for which particle transfer dominates, the "extra" cross section observed for 8 B appears to result entirely from projectile breakup.