Johannes Tandler

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The beauty production cross section for deep inelastic scattering events with at least one hard jet in the Breit frame together with a muon has been measured, for photon virtualities Q 2 > 2 GeV 2 , with the ZEUS detector at HERA using integrated luminosity of 72 pb −1. The total visible cross section is σ bb (ep → e jet µ X) = 40.9 ± 5.7 (stat.) +6.0 −4.4(More)
  • Zeus Collaboration, S Chekanov, D Krakauer, S Magill, B Musgrave, J Repond +358 others
  • 2008
Next-to-leading-order QCD analyses of the ZEUS data on deep inelastic scattering together with fixed-target data have been performed, from which the gluon and quark densities of the proton and the value of the strong coupling constant, α s (M Z), were extracted. The study includes a full treatment of the experimental systematic uncertainties including(More)
  • J Breitweg, S Chekanov, M Derrick, D Krakauer, S Magill, B Musgrave +384 others
  • 1999
Elastic and proton–dissociative photoproduction of ρ 0 , φ and J/ψ vector mesons (γp → V p, γp → V N , respectively) have been measured in e + p interactions at HERA up to −t = 3 GeV 2 , where t is the four-momentum transfer squared at the photon–vector meson vertex. The analysis is based on a data sample in which photoproduction reactions were tagged by(More)
  • S Chekanov, M Derrick, D Krakauer, J H Loizides, S Magill, B Musgrave +321 others
  • 2003
Dijet angular distributions of photoproduction events in which a D * ± meson is produced in association with one of two energetic jets have been measured with the ZEUS detector at HERA, using an integrated luminosity of 120 pb −1. Differential cross sections as a function of the angle between the charm-jet and the proton-beam direction in the dijet rest(More)
  • Zeus Collaboration, S Chekanov, M Derrick, D Krakauer, J H Loizides, S Magill +316 others
  • 2004
First measurements of cross sections for isolated prompt photon production in deep inelastic ep scattering have been made using the ZEUS detector at the HERA electron-proton collider using an integrated luminosity of 121 pb −1. A signal for isolated photons in the transverse energy and rapidity ranges 5 < E γ T < 10 GeV and −0.7 < η γ < 0.9 was observed for(More)
  • J Breitweg, S Chekanov, M Derrick, D Krakauer, S Magill, B Musgrave +382 others
  • 2000
The distribution of the azimuthal angle for the charged hadrons has been studied in the hadronic centre-of-mass system for neutral current deep inelastic positron-proton scattering with the ZEUS detector at HERA. Measurements of the dependence of the moments of this distribution on the transverse momenta of the charged hadrons are presented. Asymmetries(More)
  • J Breitweg, S Chekanov, M Derrick, D Krakauer, S Magill, B Musgrave +364 others
  • 2008
First inclusive measurements of isolated prompt photons in photoproduction at the HERA ep collider have been made with the ZEUS detector, using an integrated luminosity of 38.4 pb −1. Cross sections are given as a function of the pseudorapidity and the transverse energy (η γ , E γ T) of the photon, for E γ T > 5 GeV in the γp centre-of-mass energy range(More)
  • Zeus Collaboration, S Chekanov, M Derrick, D Krakauer, J H Loizides, S Magill +322 others
  • 2008
A search for narrow-width resonances that decay into electron+jet or neu-trino+jet has been performed with the ZEUS detector at HERA operating at center-of-mass energies of 300 and 318 GeV. An integrated e + p luminosity of 114.8 pb −1 and e − p luminosity of 16.7 pb −1 were used. No evidence for any resonance was found. Limits were derived on the Yukawa(More)
  • Zeus Collaboration, J Breitweg, S Chekanov, M Derrick, D Krakauer, S Magill +404 others
  • 2007
The e + p neutral-current deep inelastic scattering diierential cross-sections dd=dQ 2 , for Q 2 > 400 GeV 2 , dd=dx and dd=dy, for Q 2 > 400, 2500 and 10000 GeV 2 , have been measured with the ZEUS detector at HERA. The data sample of 47.7 pb ?1 was collected at a center-of-mass energy of 300 GeV. The cross-section, dd=dQ 2 , falls by six orders of(More)
The dependence of dijet production on the virtuality of the exchanged photon, Q 2 , has been studied by measuring dijet cross sections in the range 0 < ∼ Q 2 < 2000 GeV 2 with the ZEUS detector at HERA using an integrated luminosity of 38.6 pb −1. Dijet cross sections were measured for jets with transverse energy E jet T > 7.5 and 6.5 GeV and(More)