Selected topics in diffraction with protons and nuclei: past, present, and future

TL;DR

This review explores the diverse phenomena of diffraction in high-energy collisions involving protons and nuclei, emphasizing the interplay of perturbative and non-perturbative QCD, and discusses past, present, and future experimental insights and open questions.

Contribution

It provides a comprehensive overview of diffraction phenomena across various collision types, integrating experimental results with theoretical models and highlighting future research directions.

Findings

Key results from HERA and LHC experiments on diffraction.

Insights into dipole models and parton saturation at low x.

Identification of open questions for future collider experiments.

Abstract

We review a broad range of phenomena in diffraction in the context of hadron-hadron, hadron-nucleus collisions and deep inelastic lepton-proton/nucleus scattering focusing on the interplay between the perturbative QCD and non-perturbative models. We discuss inclusive diffraction in DIS, phenomenology of dipole models, resummation and parton saturation at low $x$, hard diffractive production of vector mesons, inelastic diffraction in hadron-hadron scattering, formalism of color fluctuations, inclusive coherent and incoherent diffraction as well as soft and hard diffraction phenomena in hadron-hadron/nucleus and photon-nucleus collisions. For each topic we review key results from the past and present experiments including HERA and the LHC. Finally, we identify the remaining open questions, which could be addressed in the continuing experiments, in particular in photon-induced reactions at the LHC and the future Electron-Ion Collider (EIC) in the US, Large Hadron electron Collider (LHeC) and Future Circular Collider (FCC) at CERN.