Interplay of soft and hard interactions in nuclear shadowing at highQ 2 and lowx

Nuclear shadowing corrections are known to be dominated by soft interactions. They grow as function of 1/x more slowly than the single scattering term, which has an essential contribution from hard interactions. Therefore, we predict that nuclear shadowing vanishes eventually at very lowx, provided thatQ ² is high and fixed. At the same time, at medium and lowQ ², nuclear shadowing grows with 1/x. Our formalism nicely explains also the recent NMC data onQ ²-dependence of the nuclear shadowing. The effect of gluon fusion is found to be of little importance for the nuclear structure function in the available range ofx. Communicated by W. Weise