  We study the properties of the Triple Pomeron Vertex in the perturbative QCD
using the twist expansion method. Such analysis allows us to find the momenta
configurations preferred by the vertex. When the momentum transfer is zero, the
dominant contribution in the limit when Nc goes to infty comes from
anticollinear pole. This is in agreement with result obtained without
expanding, but by direct averaging of the Triple Pomeron Vertex over angles.
Resulting theta functions show that the anticollinear configuration is optimal
for the vertex. In the finite Nc case the collinear term also contributes.
Using the Triple Pomeron Vertex we construct a pomeron loop and we also
consider four gluon propagation between two Triple Pomeron Vertices. We apply
the Triple Pomeron Vertex to construct the Hamiltonian from which we derive the
Balitsky- Kovchegov equation for an unintegrated gluon density. In order to
apply this equation to phenomenology, we apply the Kwiecinski-Martin-Stasto
model for higher order corrections to a linear part of the Balitsky-Kovchegov
equation. We introduce the definition of the saturation scale which reflects
properties of this equation. Finally, we use it for computation of observables,
such as the F2 structure function and diffractive Higgs boson production cross
section. The impact of screening corrections on F2 is negligible, but those
effects turn out to be significant for diffractive Higgs boson production at
LHC.
