Suppression of core polarization in halo nuclei

We present a microscopic study of halo nuclei, starting from the Paris and Bonn potentials and employing a two-frequency shell model approach. It is found that the core-polarization effect is dramatically suppressed in such nuclei. Consequently the effective interaction for halo nucleons is almost entirely given by the bare G-matrix alone, which presently can be evaluated with a high degree of accuracy. The experimental pairing energies between the two halo neutrons in 6He and 11Li nuclei are satisfactorily reproduced by our calculation. It is suggested that the fundamental nucleon-nucleon interaction can be probed in a clearer and more direct way in halo nuclei than in ordinary nuclei. PACS numbers: 21.30.+y,21.60.Cs, 21.90.+f Typeset using REVTEX