Combined HERA Deep Inelastic Scattering Data and NLO QCD Fits

TL;DR

This paper combines HERA deep inelastic scattering data using a new method, leading to highly precise proton PDFs with reduced uncertainties, advancing our understanding of proton structure.

Contribution

It introduces a model-independent combination method for HERA data and performs a NLO QCD fit to extract highly precise proton PDFs.

Findings

Reduced uncertainties in combined cross section measurements.

Proton PDFs with significantly improved precision.

Careful consideration of model and parameterisation uncertainties.

Abstract

Previously published data on inclusive neutral and charged current e+p and e-p deep inelastic scattering from HERA have been combined. The new, model-independent method of combining the measured cross sections takes full account of correlated systematics in a coherent way, leading to significantly reduced uncertainties in the combined measurement across the (x, Q^2) plane. The combined cross section data have been used as the sole input for a new next-to-leading order QCD fit to extract the parton distribution functions (PDFs) of the proton. The PDFs extracted have greatly reduced experimental uncertainties, compared to separate QCD analyses on data from H1 and ZEUS. Model uncertainties, including those arising from the parameterisation dependence, have also been carefully considered. The resulting HERA PDFs have impressive precision.