Role of the Coulomb distortion in form-factor calculations for 12C with alpha-clusterization and nucleon-nucleon correlations

The elastic form factor of 12C is calculated in the plane-wave Born approximation (BA) and also by accounting for distortions of electron waves in the nuclear Coulomb field both within the high-energy approximation (HEA) and by numerical solving of the Dirac equation (SDE). The nuclear wave function includes peculiarities associated with the alpha-clusterization and short-range correlations of nucleons. It is shown that these correlations affect the form factors at comparably large transfer momenta, where a considerable difference takes place between different schemes of calculations, namely, BA, HEA and SDE methods. It is concluded that the SDE method is preferable when studying the influence on the form factors of the short- and middle-range nucleon correlations in nuclei