The prediction of quantum electrodynamics for elastic electron–proton scattering needs further modi¯cations to agree with experimental data. Two scattering mechanisms that may occur are the forward and backward scattering angles for four-momentum transfer Q2 ¼ 0:2 up to 0.8 (GeV/c)2. This is due to two di®erent scattering centers. But the forward scattering is observed only at relatively high values of Q2 1(GeV/c)2. The modi¯cations related to the electric and magnetic form factors characterize the proton's internal structure. These form factors' dependence on Q2 provides good agreement with other analysis methods. The proton's charge radius, which corresponds to the maximum value of the scattering radius, is 0:81 0:04fm. The scattered electron is sensitive to proton internal constituents, especially at high values of Q2 in which both scattering radius and photon wavelength decrease.