Is the Coulomb sum rule violated in nuclei?

Guided by the experimental confirmation of the validity of the Effective Mo mentum Approximation (EMA) in quasi-elastic scattering off nuclei, we have re-examined the extraction of the longitudinal and transverse response func tions in medium-weight and heavy nuclei. In the EMA we have performed a Ros enbluth separation of the available world data on Ca-40, Ca-48, Fe-56, Au-1 97, Pb-208 and U-238. We find that the longitudinal response function for t hese nuclei is "quenched" and that the Coulomb sum is not saturated, at odd s with claims in the literature. (C) 2001 Elsevier Science B.V. All rights reserved.