Gluon Saturation and S-Matrix Unitarity

Abstract

The impact parameter dependent gluon distribution of the proton xG(x,Q^2,b) is investigated in a loop-loop correlation model that respects the S-matrix unitarity condition in impact parameter space. We find low-x saturation of G(x,Q^2,b) as a manifestation of S-matrix unitarity. The integrated gluon distribution xG(x,Q^2) does not saturate because of the growth of the effective proton radius with decreasing x.

Comments: 4 pages, 2 figures. Talk presented at the XXXVIIth Rencontres de Moriond "QCD and High Energy Hadronic Interactions", Les Arcs, France, March 16-23, 2002