Interactions at large distances and spin effects in nucleon-nucleon and nucleon-nuclei scattering

The momentum-transfer dependence of the slopes of the spin-non-flip and spin-flip amplitudes is analysed. It is shown that the long tail of the hadronic potential in impact parameter space leads for hadron-hadron interactions to a larger value of the slope for the reduced spin-flip amplitude than for the spin-non-flip amplitude. It is shown that the preliminary measurement of AN obtained by the E950 Collaboration confirms such a behaviour of the hadron spin-flip amplitude. The diffractive polarised experiments at HERA and RHIC allow to study the spin properties of the quark-pomeron and proton-pomeron vertices, and to search for a possible odderon contribution. This provides an important test of the spin properties of QCD at large distances. In all of these cases, pomeron exchange is expected to contribute to the observed spin effects at some level [1]. In the general case, the form of the analysing power AN and the position of its +