Tidal symmetry in nuclear reactions: application to the scattering of polarised projectiles

Abstract

The consequences for nucleus-nucleus collisions of the invariance (tidal symmetry) of arbitrary but momentum-independent interactions under rotations about the relative coordinate of the interacting nuclei are examined. In conjunction with an approximate treatment of the centrifugal barrier this symmetry leads to a partial diagonalisation of the coupled-channels description of the scattering of the two nuclei. This approximation is found to give an accurate description of the tensor polarisation observables in a specific heavy-ion elastic scattering case. A consequence of the treatment given here is that the so-called 'shape effect' relations can be satisfied in strong-coupling situations.