Diffractive cross sections at HERA and diffractive PDFs

TL;DR

This paper reviews extensive measurements of diffractive dissociation in electron-proton collisions at HERA, comparing experimental techniques and discussing how diffractive PDFs explain observed features.

Contribution

It provides a comprehensive overview of diffractive cross section measurements and demonstrates how diffractive PDFs can account for the experimental observations.

Findings

Compatibility between different experimental techniques and detectors

Presence of common fundamental features in all data sets

Diffractive PDFs effectively describe the measurements

Abstract

A large collection of results for the diffractive dissociation of virtual photons, $\gamma^{\star}p \to Xp$, have been obtained with the H1 and ZEUS detectors at HERA. Different experimental techniques have been used, by requiring a large rapidity gap between $X$ and the outgoing proton, by analyzing the mass distribution, $M_X$, of the hadronic final state, as well as by directly tagging the proton. A reasonable compatibility between those techniques and between H1 and ZEUS results have been observed. Some common fundamental features in the measurements are also present in all data sets. They are detailed in this document. Diffractive PDFs can give a good account of those features. Ideas and results are discussed in the following.