Final combined deep inelastic scattering cross sections at HERA

TL;DR

This paper combines all HERA deep inelastic scattering data to produce a comprehensive set of cross sections, enabling improved quantum chromodynamics analyses and the determination of parton distribution functions and the strong coupling constant.

Contribution

It provides the first combined HERA data set for inclusive DIS cross sections, leading to the HERAPDF2.0 parton distribution functions and a precise measurement of the strong coupling constant.

Findings

Produced a comprehensive combined data set spanning six orders of magnitude in Q^2 and x.

Derived new parton distribution functions, HERAPDF2.0, from combined data.

Achieved a precise determination of the strong coupling constant.

Abstract

The combination is presented of all inclusive deep inelastic scattering cross sections previously published by the H1 and ZEUS collaborations at HERA for neutral and charged current $ep$ scattering for zero beam polarisation. The data were taken at proton beam energies of 920, 820, 575 and 460 GeV and an electron beam energy of 27.5 GeV. The data correspond to an integrated luminosity of about 1 fb$^{-1}$ and span six orders of magnitude in negative four-momentum-transfer squared, $Q^2$, and Bjorken $x$. The correlations of the systematic uncertainties were evaluated and taken into account for the combination. The combined cross sections were input to QCD analyses at leading order, next-to-leading order and at next-to-next-to-leading order, providing a new set of parton distribution functions, called HERAPDF2.0. Additionally, the inclusion of jet-production cross sections made a simultaneous and precise determination of parton distributions and the strong coupling constant possible. Brief highlights of the results are presented.