High-mass dijet cross sections in photoproduction at HERA
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 531:1-2 (2002) 9-27
Abstract:
Dijet differential cross sections for the reaction e+ p → e+ + jet + jet + X in the photoproduction regime have been measured with the ZEUS detector at HERA using an integrated luminosity of 42.7 pb-. The cross sections are given for photon-proton centre-of-mass energies in the range 134 < W < 277 GeV. The differential cross sections as a function of the dijet mass, MJJ, and of the dijet angular variables have been measured for 47 < MJJ < 160 GeV and compared to next-to-leading-order QCD calculations. The dijet events in the region 75 < MJJ < 100 GeV have been used to derive a 95% C.L. upper limit on the cross section for Z0 photoproduction of σ e+p→e+Z0X < 5.9 pb. Upper limits on the photoproduction of new heavy resonances decaying into two jets are also presented for masses in the range between 60 GeV and 155 GeV. © 2002 Elsevier Science B.V. All rights reserved.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.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.Properties of hadronic final states in diffractive deep inelastic ep scattering at DESY HERA
Physical Review D 65:5 (2002)
Abstract:
Characteristics of the hadronic final state of diffractive deep inelastic scattering events ep→eXp were studied in the kinematic range 4Exclusive photoproduction of J/ψ mesons at HERA
EUROPEAN PHYSICAL JOURNAL C 24:3 (2002) 345-360