G. Cara Romeo

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  • J Breitweg, M Derrick, D Krakauer, S Magill, D Mikunas, B Musgrave +403 others
  • 2008
The photoproduction reaction γp → µ + µ − p has been studied in ep interactions using the ZEUS detector at HERA. The data sample corresponds to an integrated luminosity of 43.2 pb −1. The Υ meson has been observed in photoproduction for the first time. The sum of the products of the elastic Υ(1S), Υ(2S), Υ(3S) photoproduction cross sections with their(More)
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)
Differential inclusive jet cross sections in neutral current deep inelastic ep scattering have been measured with the ZEUS detector using an integrated luminosity of 38.7 pb −1. The jets have been identified using the k T cluster algorithm in the longitudinally invariant inclusive mode in the laboratory frame; they have been selected with jet transverse(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)
  • Zeus Collaboration, J Breitweg, S Chekanov, M Derrick, D Krakauer, S Magill +412 others
  • 2007
Exclusive production of 0 and J== mesons in e + p collisions has been studied with the ZEUS detector in the kinematic range 0:25 < Q 2 < 50 GeV 2 , 20 < W < 167 GeV for the 0 data and 2 < Q 2 < 40 GeV 2 , 50 < W < 150 GeV for the J== data. Cross sections for exclusive 0 and J== production have been measured as a function of Q 2 , W and t. The spin-density(More)
  • J Breitweg, M Derrick, D Krakauer, S Magill, D Mikunas, B Musgrave +421 others
  • 2007
Using the ZEUS detector at HERA, we have studied the reaction e + p ! e + X for Q 2 > 5000 GeV 2 with a 20:1 pb ?1 data sample collected during the years 1994 to 1996. For Q 2 below 15000GeV 2 , the data are in good agreement with Standard Model expectations. For Q 2 > 35000 GeV 2 , two events are observed while 0:145 0:013 events are expected. A(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)
  • J Breitweg, M Derrick, D Krakauer, S Magill, D Mikunas, B Musgrave +412 others
  • 1997
The reaction γ p → J/ψ p has been studied in ep interactions using the ZEUS detector at HERA. The cross section for elastic J/ψ photoproduction has been measured as a function of the photon-proton centre of mass energy W in the range 40 < W < 140 GeV at a median photon virtuality Q 2 of 5 × 10 −5 GeV 2. The photoproduction cross section, σ γp→J/ψp , is(More)
  • Zeus Collaboration, M Derrick, D Krakauer, S Magill, B Musgrave, J Repond +449 others
  • 1995
Events with a large rapidity gap and total transverse energy greater than 5 GeV have been observed in quasi-real photoproduction at HERA with the ZEUS detector. The distribution of these events as a function of the γp centre of mass energy is consistent with diffractive scattering. For total transverse energies above 12 GeV, the hadronic final states show(More)
Measurements of cross sections of inelastic and diffractive processes in proton–proton collisions at LHC energies were carried out with the ALICE detector. The fractions of diffractive processes in inelastic collisions were determined from a study of gaps in charged particle pseudora-pidity distributions: for single diffraction (diffractive mass