Dynamic polarization potentials for the halo nucleus ⁶He in medium-energy elastic scattering

We study dynamic polarization potentials for a halo nucleus ⁶He scattered by a ¹²C target in the eikonal approximation. We use a realistic, six-nucleon wave function of ⁶He to include both the halo-neutron and the core-nucleon excitations on an equal footing. We discuss the energy dependence of the polarization potential in relation to that of the nucleon-target optical potential. The imaginary part of the polarization potential changes a sign (negative to positive with increasing energy) around the incident energy of 200 MeV∕nucleon, which gives different contributions, depending on the energy, to the elastic differential cross section as well as the reaction cross section.