Interaction cross section and interaction radius of the B-8 nucleus

The interaction cross section (sigma(I)) was re-measured by a transmission-type measurement for B-8(5)3 at 790A . MeV on a C target confirming the previously reported value. B-8, although it has a very small proton separation energy 0.137 MeV, shows no remarkable enhancement of the sigma(I) expected from a possible proton halo, as suggested from studies of the quadrupole moment and other recent data such as the reaction cross section at low energies. The root-mean-square (RMS) radius of the nucleon distribution has been deduced using the Glauber model. The relation between the halo tail and the separation energy is discussed on the mirror nuclei B-8 and Li-8. It was also found that the previously reported narrow momentum distribution of Be-7 from the fragmentation of B-8 is well reproduced by the presently determined density distribution.