2018 Impact factor 4.843
Particles and Fields
Eur. Phys. J. C 4, 591-606
DOI 10.1007/s100529800916

High-ET inclusive jet cross sections in photoproduction at HERA

The ZEUS Collaboration
J.Breitweg - et al.

Argonne National Laboratory, Argonne, IL, USA

Received: 11 February 1998 / Published online: 2 July 1998

Abstract
Inclusive jet differential cross sections for the reaction $e^+p\rightarrow e^+\ +\ {\rm jet}\ + \ {\rm X}$ with quasi-real photons have been measured with the ZEUS detector at HERA. These cross sections are given for the photon-proton centre-of-mass energy interval 134 <W< 277GeV and jet pseudorapidity in the range $-1<\eta^{jet}<2$ in the laboratory frame. The results are presented for three cone radii in the $\eta-\varphi$ plane, $R=1.0,\ 0.7\ {\rm and}\ 0.5$. Measurements of $d\sigma/d\eta^{jet}$ above various jet-transverse-energy thresholds up to 25GeV and in three ranges of W are presented and compared to next-to-leading order (NLO) QCD calculations. For jets defined with R=1.0 differences between data and NLO calculations are seen at high $\eta^{jet}$ and low ETjet. The measured cross sections for jets defined with R=0.7 are well described by the calculations in the entire measured range of $\eta^{jet}$ and ETjet. The inclusive jet cross section for ETjet>21GeV is consistent with an approximately linear variation with the cone radius R in the range between 0.5 and 1.0, and with NLO calculations.


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