Measurement of the π − form factor

An experiment to measure the electromagnetic form factor of the negative $\ensuremath{\pi}$ meson has been carried out at Fermilab by elastically scattering 100-GeV/c pions from the atomic electrons in a liquid-hydrogen target. We find that the elastic differential scattering cross section is characterized by a root-mean-square pion charge radius of 0.56\ifmmode\pm\else\textpm\fi{}0.04 fm. This paper described our experimental design, measurement resolutions, event triggering logic, event reconstruction, experimental corrections, and form-factor results.