Parton saturation at small x and in large nuclei

Abstract

Quark and gluon distributions in the light-cone wavefunction of a high energy hadron or nucleus are calculated in the saturation regime. One loop calculations are performed explicitly using the equivalence between the parton distribution in the light-cone wavefunction and the production distribution of that parton in a current-nucleon (nucleus) scattering. We argue that, except for some overall numerical factors, the Weizsäcker-Williams wavefunction correctly gives the physics of the gluon distribution in a light-cone wavefunction.