Coulomb distortion in quasielastic (e, e ') scattering on nuclei: Effective momentum approximation and beyond

The role of the effective momentum approximation to disentangle Coulomb dis tortion effects in quasielastic (e, e') reactions is investigated. The sepa ration of the cross section in longitudinal and transverse components is di scussed including higher-order DWBA corrections due to the focusing of the electron waves. The experimental studies performed, in the last few years, making use of different approximate treatments are shown to be sometime inc onsistent. As a consequence some of the longitudinal and transverse respons es, extracted from the inclusive cross sections cannot be considered reliab le. A separation procedure based on the effective momentum approximation is discussed in connection with the recent experimental data on electron/posi tron quasielastic scattering on C-12 and Pb-208. (C) 2001 Elsevier Science B.V. All rights reserved.