Backward-Angle Electron-Proton Elastic Scattering and Proton Electromagnetic Form Factors

Abstract

Elastic electron-proton scattering cross sections were measured at backward angles (80\ifmmode^\circ\else\textdegree\fi{}-90\ifmmode^\circ\else\textdegree\fi{}) in the laboratory for four-momentum transfers between 7 ${\mathrm{F}}^{\ensuremath{-}2}$ and 45 ${\mathrm{F}}^{\ensuremath{-}2}$. Experimental errors range from 3.1% to 5.3%, including a systematic error estimated to be 1.9% added in quadrature. Electric and magnetic form factors are computed from all the recent data in this ${q}^{2}$ range, with allowance made for possible normalization differences. The results show a deviation from the scaling law.