The Quark and Gluon Structure of the Proton

TL;DR

This review summarizes the current understanding of the proton's internal structure, focusing on parton distribution functions derived from various scattering experiments, including recent LHC data, to improve predictions in high-energy physics.

Contribution

It provides a comprehensive overview of the methods and results in extracting proton PDFs, highlighting recent experimental data and their impact on theoretical models.

Findings

HERA data covers a wide kinematic range.

LHC measurements influence PDF updates.

Predictions for LHC processes are consistent with initial measurements.

Abstract

In this article we present a review of the structure of the proton and the current status of our knowledge of the parton distribution functions (PDFs). The lepton-nucleon scattering experiments which provide the main constraints in PDF extractions are introduced and their measurements are discussed. Particular emphasis is given to the HERA data which cover a wide kinematic region. Hadron-hadron scattering measurements which provide supplementary information are also discussed. The methods used by various groups to extract the PDFs in QCD analyses of hard scattering data are presented and their results are compared. The use of existing measurements allows predictions for cross sections at the LHC to be made. A comparison of these predictions for selected processes is given. First measurements from the LHC experiments are compared to predictions and some initial studies of the impact of this new data on the PDFs are presented.