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, $q^2$, in the range 6.0 to 30.0 ${\mathrm{F}}^{-2\mathrm{}}$ 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 $q^2$ when normalized to unity at $q^2=0\mathrm{}$, 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.