A ZEUS next-to-leading-order QCD analysis of data on deep inelastic scattering

TL;DR

This paper presents a next-to-leading-order QCD analysis of ZEUS deep inelastic scattering data, extracting proton parton densities and the strong coupling constant with comprehensive uncertainty treatment, highlighting the significance of HERA data.

Contribution

It provides a novel NLO QCD analysis combining ZEUS and fixed-target data, including systematic uncertainties, to accurately determine proton parton densities and alpha_s(M_Z).

Findings

Alpha_s(M_Z) consistent with world average

Parton densities highlight importance of HERA data at low x

Uncertainty analysis includes point-to-point correlations

Abstract

Next-to-leading order QCD analyses of the ZEUS data on deep inelastic scattering together with fixed-target data have been perfomed, from which the gluon and the quark densities of the proton and the value of the strong coupling constant, alpha_s(M_Z), were extracted. The study includes a full treatment of the experimental systematic uncertainties including point-to-point correlations. The resulting uncertainties in the parton density functions are presented. A combined fit for alpha_s(M_Z) and the gluon and qurak densities yields a value of alpha_s(M_Z) in agreement with the world average. The parton density functions derived from ZEUS data alone indicate the importance of HERA data in determining sea quark and gluon distributions at low x. The limits of applicability of the theoretical formalism have been explored by comparing the fit predictions to ZEUS data at very low Q^2.