Inclusive-jet photoproduction at HERA and determination of αs

Abstract

Inclusive-jet cross sections have been measured in the reaction for photon virtuality and γp centre-of-mass energies in the region with the ZEUS detector at HERA using an integrated luminosity of . Jets were identified using the , anti- or SIScone jet algorithms in the laboratory frame. Single-differential cross sections are presented as functions of the jet transverse energy, , and pseudorapidity, , for jets with and . In addition, measurements of double-differential inclusive-jet cross sections are presented as functions of in different regions of . Next-to-leading-order QCD calculations give a good description of the measurements, except for jets with low and high . The influence of non-perturbative effects not related to hadronisation was studied. Measurements of the ratios of cross sections using different jet algorithms are also presented; the measured ratios are well described by calculations including up to terms. Values of were extracted from the measurements and the energy-scale dependence of the coupling was determined. The value of extracted from the measurements based on the jet algorithm is ; the results from the anti- and SIScone algorithms are compatible with this value and have a similar precision