Jet cross sections and $\alpha_s$ in deep inelastic scattering and photoproduction at HERA

TL;DR

This paper presents new measurements of jet cross sections in deep inelastic scattering at HERA, demonstrating consistency with NLO QCD and providing competitive determinations of the strong coupling constant, alpha_s.

Contribution

It offers the first extraction of alpha_s from neutral current DIS jet data at HERA and re-analyzes photoproduction data, enhancing the precision of alpha_s measurements.

Findings

Jet cross sections agree with NLO QCD predictions.

New alpha_s values are consistent with the world average.

Data can help constrain the gluon density in the proton.

Abstract

Recent ZEUS measurements of inclusive-jet and dijet cross sections in neutral current deep inelastic ep scattering at HERA are presented. The data correspond to more than a two-fold increase in statistics compared to previous studies. The cross sections are measured in the Breit frame, for boson virtualities of Q^2 > 125 GeV^2, as functions of various kinematic and jet observables. The data are found to be well described by NLO QCD and have the potential to constrain the gluon density in the proton. Two new extractions of the strong coupling, alpha_s, are also presented: the first is determined from the inclusive-jet neutral current DIS measurement presented here, while the second is from a re-analysis of previously published data on inclusive jet photoproduction. Both measurements are of competitive precision and in agreement with the world average.