Measurement of proton and neutron electromagnetic form factors at squared four-momentum transfers up to 3 (GeV/c) 2
Electron-proton elastic scattering cross sections have been measured at squared four-momentum transfers q2 of 0.67, 1.00, 1.17, 1.50, 1.75, 2.33 and 3.00 (GeV/ c) 2 and Electron scattering angles θe between 10° and 20° and at about 86° in the laboratory. The proton electromagnetic form factors GEp and GMp were determined. The results indicate that GEp ( q2) decreases faster with increasing q2 than GMp ( q2). Quasi-elastic electron-deuteron cross sections have been determined at values of q2 = 0.39, 0.565, 0.78, 1.0 and 1.5 (GeV/ c) 2 and scattering angles between 10° and 12°. At q2 = 0.565 (GeV/ c2 data have also been taken with θe = 35° and at q2 = 1.0 and 1.5 (GeV/ c) 2 with θe = 86°. Electron-proton as well as electron-neutron scattering cross sections have been deduced by the ratio method. The theoretical uncertainties of this procedure are shown to be small by comparison of the bound with the free proton cross sections. The magnetic form factor of the neutron GMn derived from the data is consistent with the scaling law. The charge form factor of the neutron is found to be small.