Recent studies with radioactive beams at RIKEN

In this paper, I present three new experimental results obtained by RIKEN groups. The first is a measurement of proton inelastic scattering of 11Li at 65A MeV at RIKEN/RIPS. The obtained excitation spectrum show several sharp resonances between 0 to 12 MeV including the resonance at excitation energy of 1.3 MeV. The comparison of these levels to those of 9Li indicates that the 1.3 MeV level is an excited state of the neutron halo. The second is the measurement of the interaction cross sections of Na isotopes from mass number 20 to 32 using the FRS at GSI. An combined analysis of deduced matter radii and the charge radii indicate an existence of neutron skins in neutron rich Na isotopes. The possible relation between neutron skin and the equation of state of an asymmetric nuclear matter is also discussed. The last is the re-measurement of interaction cross section of 8B at 800A MeV. The new cross section is consistent with the previous one. The discrepancies in determination of the density distribution of 8B are discussed in relation to an existence of proton halo in this nucleus. (orig.)