The proton elastic electric and magnetic form factors, ${\mathit{G}}_{\mathit{E}\mathit{p}}$(${\mathit{Q}}^2$) and ${\mathit{G}}_{\mathit{M}\mathit{p}}$(${\mathit{Q}}^2$), have been separately measured in the range ${\mathit{Q}}^2$=1.75 to 8.83 (GeV/c${)}^2$, more than doubling the ${\mathit{Q}}^2$ range of previous data. Scaled by the dipole fit, ${\mathit{G}}_{\mathit{D}}$(${\mathit{Q}}^2$), the results for ${\mathit{G}}_{\mathit{M}\mathit{p}}$(${\mathit{Q}}^2$)/${\mathrm{\mu }}_{\mathit{p}}$${\mathit{G}}_{\mathit{D}}$(${\mathit{Q}}^2$) decrease smoothly from 1.05 to 0.91, while ${\mathit{G}}_{\mathit{E}\mathit{p}}$(${\mathit{Q}}^2$)/${\mathit{G}}_{\mathit{D}}$(${\mathit{Q}}^2$) is consistent with unity. Comparisons are made to QCD sum rule, diquark, constitutent quark, and vector meson dominance models, none of which agree with all of the new data. The ratio ${\mathit{Q}}^2$${\mathit{F}}_2$/${\mathit{F}}_1$ approaches a constant value for ${\mathit{Q}}^2$>3 (GeV/c${)}^2$.

• Received 16 March 1992

DOI:https://doi.org/10.1103/PhysRevLett.68.3841