Quasielastic scattering ofB8andBe7onC12at 40 MeV/nucleon

The quasielastic scattering of the exotic nucleus $^{8}\mathrm{B}$ on a $^{12}\mathrm{C}$ target has been studied at an energy of 320 MeV and compared with that of $^{7}\mathrm{Be}$ at the same velocity. The quasielastic scattering of $^{12}\mathrm{C}$ + $^{12}\mathrm{C}$ at 20 MeV/nucleon, also performed as a secondary beam experiment, was used to check the data reduction method. The results are interpreted in terms of a semimicroscopic double folding model and coupled-channels calculation. The difference in the total reaction cross section (8%) between $^{8}\mathrm{B}$ and $^{7}\mathrm{Be}$ is consistent with the measured one proton removal cross section and corresponds to an increase in the interaction radius of 4%. The existence of a substantial proton halo in $^{8}\mathrm{B}$ is not supported by the present data.