Gluon- vs. Sea quark-Shadowing

Abstract

We calculate the shadowing of sea quarks and gluons and show that the shadowing of gluons is {\it not} simply given by the sea quark shadowing, especially at small $x$. The calculations are done in the lab frame approach by using the generalized vector meson dominance model. Here the virtual photon turns into a hadronic fluctuation long before the nucleus. The subsequent coherent interaction with more than one nucleon in the nucleus leads to the depletion $\sigma ({\gamma }^{\ast }A)<A\sigma ({\gamma }^{\ast }N)$ known as shadowing. A comparison of the shadowing of quarks to E665 data for ${}^{40}Ca$ and ${}^{207}Pb$ shows good agreement.

Comments: 9 pages, 3 eps figures