Coulomb distortion effects for electron or positron induced (e,e ') reactions in the quasielastic region - art. no. 044607

In response to recent experimental studies we investigate Coulomb distortio n effects on (e,e') reactions from medium and heavy nuclei for the case of electrons and positrons. We extend our previously reported full distorted-w ave Born approximation treatment of Coulomb distortions to the case of posi trons for the Pb-208 (e,e') reaction in the quasielastic region for a parti cular nuclear model. In addition, we use previously reported successful app roaches to treating Coulomb corrections in an approximate way to calculate the Coulomb distortion effects for (e,e') reactions for both electrons and positrons for the case of a simple nuclear model for quasielastic knockout of nucleons. With these results in hand we develop a simple ad hoc approxim ation for use in analyzing experiments, and discuss methods of extracting t he "longitudinal structure function" which enters into evaluation of the Co ulomb sum rule. These techniques are generally valid for lepton induced rea ctions on nuclei with momentum transfers greater than approximately 300 MeV /c.