Direct fusion measurement of the B proton-halo nucleus at near-barrier energies

Direct measurements of the total fusion cross section for B8+40Ar were achieved with the active target technique. The fusion excitation function was extracted at energies near the Coulomb barrier. The cross section is well described by a coupled reaction channels calculation. The data were compared with previous B8 fusion experiments on Si28 and Ni58 targets. No evidence of striking enhancement of the total fusion cross section at near the Coulomb barrier, that was previously reported for the B8+58Ni system, was observed in these direct measurements. The present data are systematically consistent with the results for B8+28Si at higher energies and with other weakly-bound systems at near-barrier energies.