Comparison of Neutrino and Muon Structure Functions, Shadowing Corrections and Charge Symmetry Violation

Comparison of structure functions measured in neutrino and charged lepton deep inelastic scattering can be used to test basic properties of parton distribution functions such as the validity of charge symmetry. Recent experiments indicate a substantial discrepancy between $F_2^\nu$ and $F_2^\mu$ in the region of small Bjorken-x. We discuss nuclear corrections and strange and anti strange quark effects and show that none of them can account for the observed discrepancy. These results suggest surprisingly large CSV effects in nucleon sea distributions.