Electric dipole response of halo nuclei

Characteristic features of electric dipole transitions at low excitation energies (soft E1 excitation) for halo nuclei are presented. Energy spectra of soft E1 excitations in the one neutron halo nucleus 11Be and in the two neutron halo nucleus 11Li using the Coulomb breakup reactions are shown, which illustrate the mechanism of the soft E1 excitation in these cases. We also show recent experimental results on inclusive Coulomb breakup performed at the new-generation RI beam facility, RIBF, at RIKEN. There, we have obtained evidence for halo structure in the very neutron rich nucleus 31Ne, which is the heaviest halo ever known.