R-ratios and moments of nuclear structure functions

Abstract

We study implications of a model, which links nuclear and nucleon structure functions. Computed Callen-Gross functions $\kappa^A(x,Q^2)= 2xF_1^A(x,Q^2)/F_2^A(x,Q^2)$ appear for finite $Q^2$ to be close to their asymptotic value 1. Using those $\kappa$, we compure $R$ ratios for $Q^2\ge 5 GeV^2$. We review approximate methods in use for the extraction of $R$ from inclusive scattering and ENC data. Further we calcuate ratios of the moments of $F_k$ and find these to describe the data, in particular their $Q^2$ dependence. The above observables, as well as inclusive cross sections, are sensitive tests for the underlying relation between nucleonic and nuclear structure functions. In view of the overall agreement, we speculate that the above relation effectively circumvents a QCD calculation.