  Saturation of gluon distribution is a consequence of the non-linear evolution
equations of QCD. Saturation implies the existence of so called saturation
momentum which is defined as a gluon density per unit rapidity per transverse
area. At large energies for certain kinematical domains saturation momentum is
the only scale for physical processes. As a consequence different observables
exhibit geometrical scaling (GS). We discuss a number of examples of GS in
different reactions.

High Energy Physics - Phenomenology