Upper limits on polarization effects in nuclear collisions

The increase in cross section for inelastic collisions due to polarization of the target by the projectile has an upper limit in a simple model. The usual treatment of core polarization in nuclear collisions gives a polarization potential which is too large because of the use of perturbation theory and the neglect of dynamic effects, and which is in phase with the direct coupling potential contrary to recent experimental evidence and to channel coupling theory. (author)