Proton Form Factors from Elastic Electron-Proton Scattering

Absolute measurements of the elastic electron-proton cross section have been made with a precision of about 4% for values of the square of the four-momentum transfer, q², in the range 6.0 to 30.0 F^-2 and for electron scattering angles in the range 45^∘{} to 145^∘{}. To within the experimental errors, it is found that the charge and magnetic form factors of the proton have a common dependence on q² when normalized to unity at q²=0, and that an accurate representation of the behavior of the form factor and that of the cross sections themselves can be given in terms of a three-pole approximation to the dispersion theory of nucleon form factors.