A Precise Measurement of the Nuclear Dependence of Structure Functions in Light Nuclei

We propose to measure inclusive electron scattering from light nuclei over a broad range of x (0:3 < x < 1:0) up to Q 8:0(GeV/c). We will take data on hydrogen, deuterium, He, and He to make a precision measurement of the EMC e ect (ratio of nuclear to deuteron cross section). The EMC e ect has been measured on He, but the uncertainty is large enough that it cannot distinguish between di erent models for the A-dependence in light nuclei. We will improve on existing He measurements, as well as making the rst measurement of the EMC e ect on He for x > 0:5. This will have a signi cant impact on our understanding of the A-dependence of the EMC e ect for light nuclei, allowing us to test models of the EMC e ect and providing guidance for calculations that try to model nuclear e ects in deuterium. We will also extract the neutron structure function by comparing the deuteron and proton cross sections. Additionally, the He and He measurements will test models of nuclear e ects which are used to extract the neutron structure function. This will also allow for a better understanding of the systematic uncertainties in the procedure used to extract the neutron structure function from measurements on nuclear targets.