SCALING VARIABLE FOR NUCLEAR SHADOWING IN DEEP-INELASTIC SCATTERING

A new scaling variable is introduced in terms of which nuclear shadowi ng in deep-inelastic scattering is universal, i.e., independent of A, Q(2) and x. This variable can be interpreted as a measure of the numbe r of gluons probed by the hadronic fluctuations of a virtual photon du ring their lifetime. The shadowing correction grows at small x substan tially less steeply than is suggested by the eikonal approximation. Th is results from the fact that shadowing is dominated by soft rather th an hard interactions.