THE SEMICLASSICAL APPROACH TO THE EXCLUSIVE ELECTRON-SCATTERING

The semi-classical approach, successfully applied in the past to the i nelastic, inclusive electron scattering off nuclei, is extended to the treatment of exclusive processes. The associated formalism goes beyon d the plane wave impulse approximation, since it can account also for the final states interaction in the mean field approximation, respecti ng the Pauli principle. We then explore, in the frame of two admittedl y crude approximations, the impact on the exclusive cross section of t he distortion of the outgoing nucleon wave. In addition also the influ ence, on the same observable, of the shape of the potential binding th e nucleons into the nucleus is investigated. In accord with the findin gs of fully quantum mechanical calculations, the exclusive scattering is found to be quite sensitive to the mean field final states interact ion, unlike the inclusive one. Indeed we verify that the latter is not affected, as implied by unitarity, by the distortion of the outgoing nucleon wave except for the effect of relativity, which is modest in t he range of momenta up to about 500 MeV/c., Furthermore, depending upo n the correlations between the directions of the outgoing and of the i nitial nucleon, the exclusive cross-section turns out to be remarkably sensitive to the shape of the potential binding the nucleons. These c orrelations also critically affect the domain in the missing energy - missing momentum plane where the exclusive process occurs. Finally the issue of the validity of the semi-classical framework, in leading ord er of the (h) over bar expansion, in providing a description of the ex clusive processes is shortly addressed. (C) 1998 Elsevier Science B.V.