Dijet photoproduction at HERA and the structure of the photon
European Physical Journal C 23:4 (2002) 615-631
Abstract:
The dijet cross section in photoproduction has been measured with the ZEUS detector at HERA using an integrated luminosity of 38.6 pb-1. The events were required to have a virtuality of the incoming photon, Q2, of less than 1 GeV2 and a photon-proton centre-of-mass energy in the range 134 < Wγp < 277 GeV. Each event contains at least two jets satisfying transverse-energy requirements of ETjet1 > 14 GeV and ETjet2 > 11 GeV and pseudorapidity requirements of -1 < ηjet1,2 < 2.4. The measurements are compared to next-to-leading-order QCD predictions. The data show particular sensitivity to the density of partons in the photon, allowing the validity of the current parameterisations to be tested.Measurement of the Q2 and energy dependence of diffractive interactions at HERA
ArXiv hep-ex/0203039 (2002)
Dijet production in neutral current deep inelastic scattering at HERA
European Physical Journal C 23:1 (2002) 13-27
Abstract:
Dijet cross sections in neutral current deep inelastic ep scattering have been measured in the range 10 < Q2 < 104 GeV 2 with the ZEUS detector at HERA using an integrated luminosity of 38.4 pb-1. The cross sections, measured in the Breit frame using the kT jet algorithm, are compared with next-to-leading-order perturbative QCD calculations using proton parton distribution functions. The uncertainties of the QCD calculations have been studied. The predictions are in reasonable agreement with the measured cross sections over the entire kinematic range.Measurement of the photon-proton total cross section at a center-of-mass energy of 209 GeV at HERA
ArXiv hep-ex/0202034 (2002)