Quasielastic Electron Scattering and Pion Electroproduction fromC12

Abstract

This paper reports measurements made at the Cambridge Electron Accelerator of the electron-carbon scattering cross section at incident energies of 1, 1.5, 2.25, 3, and 4 GeV and at lab angles of 8.5, 12, and 18°. The measurements included quasielastic scattering and inelastic scattering through the region of the first pion-nucleon resonance. The data are compared with a spectrum generated by summing the known elastic cross section, the known cross sections for excitation of nuclear levels, and a theoretical expression for quasielastic scattering based on the Fermi model for the nucleus. The agreement is satisfactory. The meson electroproduction cross section was derived by subtracting the above calculated spectrum from the data. The total equivalent photoabsorption cross section is consistent with the cross section expected for 12 independent nucleons; the existing Fermi-model calculation does not, however, correctly predict the shape of the electron momentum spectrum. The data are also used to test the Drell-Schwartz sum rule.