Experimental Determination of the Inelastic Neutron Form Factor by the Scattering of 12-GeV Muons on Hydrogen, Carbon, and Copper

Results for the ratios of the muon inelastic-scattering cross sections on carbon and copper to the cross sections on hydrogen, measured in the same experiment, are presented. The data are consistent with ratios of cross sections for real photoabsorption. In the kinematical region where coherent diffractive effects should be small or absent we find that the inelastic cross section varies as $A^{0.99\pm 0.01}$ and that $\frac{{\sigma }_n}{{\sigma }_p}=0.91\mathrm{}\pm 0.6$.