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

J. Arrington (spokesperson), F. Dohrmann, D. F. Geesaman, H. E. Jackson,
B. Mueller, T. G. O'Neill, D. H. Potterveld, P. E. Reimer, B. Zeidman
Argonne National Laboratory, Argonne, IL

P. Gueye, C. E. Keppel, I. Niculescu
Hampton University, Hampton, VA

R. Ent, A. F. Lung, D. J. Mack
Jefferson Laboratory, Newport News, VA

D. Gaskell
Oregon State University, Corvallis, OR

H. Mkrtchyan
Yerevan Physics Institute, Armenia

June 2, 2000

Abstract:

We propose to measure inclusive electron scattering from light nuclei over a broad range of x (0.3 < x < 1.0) up to $Q^2 \approx 8.0$(GeV/c)². We will take data on hydrogen, deuterium, ³He, and ⁴He to make a precision measurement of the EMC effect (ratio of nuclear to deuteron cross section). The EMC effect has been measured on ⁴He, but the uncertainty is large enough that it cannot distinguish between different models for the A-dependence in light nuclei. We will improve on existing ⁴He measurements, as well as making the first measurement of the EMC effect on ³He for x > 0.5. This will have a significant impact on our understanding of the A-dependence of the EMC effect for light nuclei, allowing us to test models of the EMC effect and providing guidance for calculations that try to model nuclear effects in deuterium. We will also extract the neutron structure function by comparing the deuteron and proton cross sections. Additionally, the ³He and ⁴He measurements will test models of nuclear effects 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.