HERA Combined Cross Sections and Parton Densities

TL;DR

This paper combines deep inelastic scattering data from H1 and ZEUS to produce more precise parton density functions by coherently accounting for systematic uncertainties, improving the accuracy of QCD fits.

Contribution

It presents a novel combined analysis method that reduces uncertainties in parton density functions by coherently integrating systematic errors from two major experiments.

Findings

Reduced overall cross section uncertainty due to combined data

More precise parton density functions with lower experimental errors

Consistent NLO QCD fit results using combined measurements

Abstract

Deep inelastic scattering cross section measurements previously published by the H1 and ZEUS collaborations are combined. The procedure takes into account the systematic error correlations in a coherent way, leading to a significantly reduced overall cross section uncertainty. The combined H1 and ZEUS measurements of the inclusive neutral and charged current cross sections are used to perform a common NLO QCD fit. The consistent treatment of systematic uncertainties in the joint data set ensures that the resulting set of parton density functions (PDFs) have a much reduced experimental uncertainty compared to the previous PDF extractions performed separately by the H1 and ZEUS collaborations.