General discussion

The Gerhard Herzberg fonds is held at the NRC Archives. Contact [email protected] for information about access.Le fonds Gerhard Herzberg est conserv\ue9 aux Archives du CNRC. Contactez [email protected] pour des informations sur l'acc\ue8s.Peer reviewed: YesNRC publication: Ye

Elastic and Proton-Dissociative Photoproduction of J/ψJ/\psi Mesons at HERA

Cross sections for elastic and proton-dissociative photoproduction of J/ψ mesons are measured with the H1 detector in positron-proton collisions at HERA. The data were collected at ep centre-of-mass energies s√≈318 GeV and s√≈225 GeV , corresponding to integrated luminosities of L=130 pb−1 and L=10.8 pb−1 , respectively. The cross sections are measured as a function of the photon-proton centre-of-mass energy in the range 25<W γp <110 GeV. Differential cross sections dσ/dt, where t is the squared four-momentum transfer at the proton vertex, are measured in the range |t|<1.2 GeV2 for the elastic process and |t|<8 GeV2 for proton dissociation. The results are compared to other measurements. The W γp and t-dependences are parametrised using phenomenological fits

Production of D∗±D^{*\pm} Mesons with Dijets in Deep-Inelastic Scattering at HERA

Inclusive D*± production is measured in deep-inelastic ep scattering at HERA with the H1 detector. In addition, the production of dijets in events with a D*± meson is investigated. The analysis covers values of photon virtuality 2 ≤ Q2 ≤ 100 GeV2 and of inelasticity 0.05≤y≤0.7. Differential cross sections are measured as a function of Q2 and x and of various D*± meson and jet observables. Within the experimental and theoretical uncertainties all measured cross sections are found to be adequately described by next-to-leading order (NLO) QCD calculations, based on the photon–gluon fusion process and DGLAP evolution, without the need for an additional resolved component of the photon beyond what is included at NLO. A reasonable description of the data is also achieved by a prediction based on the CCFM evolution of partons involving the kT-unintegrated gluon distribution of the proton