Professor Claire Gwenlan

Abstract:

Diffractive production of D^*±(2010) mesons in deep inelastic scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of 44.3 pb^-1. Diffractive charm production is identified by the presence of a large rapidity gap in the final state of events in which a D^*±(2010) meson is reconstructed in the decay channel D^*+ → (D⁰ → K^-π⁺)πs ⁺ (+ charge conjugate). Differential cross sections when compared with theoretical predictions indicate the importance of gluons in such diffractive interactions. © 2002 Elsevier Science B.V. All rights reserved.

Abstract:

Cross-sections for the photoproduction of events containing four high-ET jets have been measured with the ZEUS detector using an integrated luminosity of 38.7 pb-1. At low invariant mass of the four-jet system, m4J, the observed event distributions are sensitive to the underlying event model. The inclusion of multi-parton interactions in Monte Carlo simulations lead to a significantly better description of the data. For m4J > 50 GeV the data is adequately described by models with no simulation of an underlying event, suggesting that this is a kinematic region suitable for comparison with perturbative QCD calculations.

Abstract:

Cross sections for e- p charged current deep inelastic scattering have been measured at a centre-of-mass energy of 318 GeV with an integrated luminosity of 16.4 pb-1 using the ZEUS detector at HERA. Differential cross sections dσ/dQ2, dσ/dx and dσ/dy are presented for Q2 > 200 GeV2. In addition, d2σ/(dxdQ2) was measured in the kinematic range 280 GeV2 < Q2 < 30 000 GeV2 and 0.015 < × < 0.42. The predictions of the Standard Model agree well with the measured cross sections. The mass of the W boson, determined from a fit to dσ/dQ2, is MW = 80.3±2.1(stat.) ± 1.2(syst.) ± 1.0(PDF) GeV. © 2002 Published by Elsevier Science B.V.

Abstract:

The photon-proton total cross section has been measured in the process e⁺ p → e⁺ γp → e⁺ X with the ZEUS detector at HERA. Events were collected with photon virtuality Q² < 0.02 GeV² and average γp center-of-mass energy Wγp = 209 GeV in a dedicated run, designed to control systematic effects, with an integrated luminosity of 49 nb^-1. The measured total cross section is σtot ^γp = 174 ± 1 (stat.) ± 13 (syst.) μb. The energy dependence of the cross section is compatible with parameterizations of high-energy pp and pap data. © 2002 Elsevier Science B.V. All rights reserved.