Using the NMC and E665 nuclear structure function ratios $F_2^A/F_2^D$ and $F_2^A/F_2^{ C}$ from deep inelastic lepton-nucleus collisions, and the E772 Drell--Yan dilepton cross sections from proton-nucleus collisions, and incorporating baryon number and momentum sum rules, we determine nuclear parton distributions at an initial scale $Q_0^2$. With these distributions, we study QCD scale evolution of nuclear parton densities. The emphasis is on small values of $x$, especially on scale dependence of nuclear shadowing. As the main result, we show that a consistent picture can be obtained within the leading twist DGLAP evolution, and in particular, that the calculated $Q^2$ dependence of $F_2^{ Sn}/F_2^{ C}$ agrees very well with the recent NMC data.
Categories: hep-ph nucl-th