Shadowing Aspects of Nuclear Parton Distributions

Various shadowing aspects of nuclear parton distributions are discussed in a parton-model framework. We explain existing x dependent data of F 2A / F 2D, then the model is applied to a flavour asymmetry – d in a nucleus, to shadowing in valence-quark distributions, and to nuclear dependence of Q 2 evolution. First, we find that a finite nuclear u – d distribution could be possible due to nuclear interactions even in the flavour symmetric case in the nucleon ( u – d = 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 Q 2 evolution ? [ F 2Sn/ F 2C]/?[ln Q 2], 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 Q 2 evolution.