Phenomenology of hard diffraction at high energies

TL;DR

This paper reviews the application of perturbative QCD to hard diffractive processes at high energies, highlighting phenomenology in hadron-hadron and ep interactions, with emphasis on gluon saturation effects modeled by the color dipole formalism.

Contribution

It provides a comprehensive overview of phenomenological applications of perturbative QCD to diffractive processes, including recent insights into gluon saturation effects via the color dipole approach.

Findings

Gluon content of the proton is crucial for diffractive processes.

Color dipole formalism effectively describes saturation effects.

Phenomenological models match experimental data on vector meson production.

Abstract

We present some of the topics covered in two lectures under the same title that were given at the "Summer School on High Energy Physics at the LHC: New trends in HEP" in Natal, Brazil. In this contribution we give a brief review on the application of perturbative QCD to the hard diffractive processes. Some examples of phenomenology for the diffractive production of $W/Z$, heavy $Q\bar{Q}$ and quarkonium in hadron-hadron reactions are presented. It is also discussed the exclusive diffractive processes in $ep$ interactions. They are in general driven by the gluon content of proton which is strongly subject to parton saturation effects in the very high energy limit. These saturation effects are well described within the color dipole formalism. We present some examples of corresponding phenomenology as the elastic vector meson production and the DVCS relying on the color dipole approach.