The Colour Glass Condensate

Abstract

I review the physical and mathematical foundations for the theoretical description of the hadron wavefunction at small $x$ as a Colour Glass Condensate. In this context, I discuss the phenomenon of gluon saturation and some of its remarkable consequences: a new ``geometric scaling'' for $F_2$, which has been recently identified at HERA, and the unitarization of the hadronic cross-sections at high energy. I show that by combining saturation and confinement one obtains cross-sections which saturate the Froissart bound.

Comments: 20 pages, Plenary talk at Quark Matter 2002 (QM 2002), Nantes, France, 18-24 Jul 2002. One reference added to recent results by PHOBOS