Shadowing Aspects of Nuclear Parton Distributions

Abstract

Various shadowing aspects of nuclear parton distributions are discussed in a parton-model framework. We explain existing x dependent data of F₂^A /F₂^D, then the model is applied to a flavour asymmetry – d in a nucleus, to shadowing in valence-quark distributions, and to nuclear dependence of Q² evolution. First, we find that a finite nuclear ū – đ distribution could be possible due to nuclear interactions even in the flavour symmetric case in the nucleon ( ū – đ = 0). Second, it is indicated that valence-quark shadowing could be used for discriminating among various shadowing models. Third, we find that nuclear dependence of Q² evolution ∂ [F₂^Sn/F₂^C]/∂[ln Q²], which was found by the New Muon Collaboration (NMC), is essentially understood by modification of parton distributions in nuclei. However, higher-twist effects in nuclear interactions could be tested by studying the details of the nuclear Q² evolution.