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 Ao. 99*. 01 and that an/op=.91*.06. (Submitted to Physical Review -Letters) * Work supported by the U. S. Atomic Energy Commission, .IJohn (;uggcnhcim Memorial Foundntion Fel10~. Cross sections for the inelastic scattering of 12 GeV/c positive muons on hydrogen, carbon and copper have been measured using a large aperture optical spark chamber spectrometer in the muon beam’ at the Stanford Linear Accelerator Center. Preliminary results obtained from a small fraction of the data from this experiment have been reported previously, 2,3,4 and we refer the reader to Refs. 2 and 4 for descriptions of the apparatus and experimental method. In this letter we are concerned with the ratio of the scattering from carbon and copper to that from hydrogen. Inelastic muon (or electron) scattering can be understood in terms of the one-photon exchange model as the absorption by the hadronic target of the cloud of virtual photons carried by the lepton. 5 Indeed, the scattering cross section can be written: d2cr dq%K = rT(crT -IEU-~) = rT uA(K, s2) (1)