Electron-Positron Elastic Scattering at 5 GeV Center-of-Mass Energy

We have measured the cross section, the distribution of scattering angles, and the distribution of noncoplanarity angles for electron-positron elastic scattering at 5 GeV c. m. energy. An analysis based on 230 events with scattering angles between 50 and 130\ifmmode^\circ\else\textdegree\fi{} yields a ratio of the experimental to theoretical quantum-electrodynamic cross section of 1.03 \ifmmode\pm\else\textpm\fi{} 0.09. The scattering-angle and noncoplanarity-angle distributions are also found to be in excellent agreement with the quantum-electrodynamic predictions.