Coulomb distortion measurements by comparing electron and positron quasielastic scattering off C-12 and Pb-208 - art. no. 044308

Positron and electron quasielastic cross sections on C-12 and Pb-208 were m easured at the Saclay linear accelerator (ALS) to test Coulomb corrections to the plane-wave Born approximation The positron and electron response fun ctions at the same effective kinematics were found to be equal within a 3% experimental uncertainty, which allows us to discriminate between different theoretical models of Coulomb distortions. Our result strongly supports th e effective momentum approximation, even for nuclei as heavy as Pb-208. [S0 556-2813(99)01210-8].