Combined Measurement and QCD Analysis of the Inclusive ep Scattering Cross Sections at HERA

TL;DR

This paper combines HERA ep scattering data from H1 and ZEUS to produce a highly accurate set of parton distribution functions, advancing our understanding of proton structure through a comprehensive NLO QCD analysis.

Contribution

It presents a novel combination method for scattering data that accounts for systematic correlations, leading to the HERAPDF1.0 parton distribution set with reduced uncertainties.

Findings

Combined data improves measurement accuracy

HERAPDF1.0 provides precise parton distributions

Analysis covers a wide Q^2 and x range

Abstract

A combination is presented of the inclusive deep inelastic cross sections measured by the H1 and ZEUS Collaborations in neutral and charged current unpolarised ep scattering at HERA during the period 1994-2000. The data span six orders of magnitude in negative four-momentum-transfer squared, Q^2, and in Bjorken x. The combination method used takes the correlations of systematic uncertainties into account, resulting in an improved accuracy. The combined data are the sole input in a NLO QCD analysis which determines a new set of parton distributions, HERAPDF1.0, with small experimental uncertainties. This set includes an estimate of the model and parametrisation uncertainties of the fit result.