SUPPRESSION OF CORE POLARIZATION IN HALO NUCLEI

Halo nuclei are studied using a G-matrix interaction derived from the Paris and Bonn potentials and employing a two-frequency shell model ap proach. 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, wh ich presently can be evaluated with a high degree of accuracy. The exp erimental pairing energies between the two halo neutrons in He-6 and L i-11 nuclei are satisfactorily reproduced by our calculation. It is su ggested that the fundamental nucleon-nucleon interaction can be probed in a clearer and more direct way in halo nuclei than in ordinary nucl ei.