Q(2) dependence of nuclear shadowing

We reexamine the predictions of a two-phase model of shadowing in nuclear deep-inelastic scattering in light of new NMC data on the x, A, and Q² dependence of the ratios of structure functions. The model, which combines vector meson dominance at low Q² with diffractive Pomeron exchange for large Q², agrees with the observed small, but nonzero, slopes in logQ², which indicate the importance of higher twist shadowing effects in the transition region, 0.1≲Q²≲1 GeV². We note also that the latest E665 data on the deuteron to proton ratio suggests the presence of a small amount of shadowing in the deuteron.W. Melnitchouk, A. W. Thoma