309 research outputs found

    Diffractive Double-Elastic Production of η\eta' and ηc\eta_c in the pppXpp p \to p X p Reaction

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    I discuss double-diffractive (double-elastic) production of the η\eta' and ηc\eta_c mesons in the pppXppp \to p X p reaction within the formalism of unintegrated gluon distribution functions (UGDF). The contribution of γγη\gamma^* \gamma^* \to \eta' fusion is estimated. The distributions in the Feynman xFx_F (or rapidity), transferred four-momenta squared between initial and final protons (t1t_1, t2t_2) and azimuthal angle difference between outgoing protons (Φ\Phi) are calculated and discussed. The results are compared with the WA102 data. Predictions at higher energies are presented.Comment: a talk presented at the international conference MESON2006, Cracow, Poland, June, 2006; 5 pages, 3 figures, 1 tabl

    Diffractive pQCD mechanisms of exclusive production of bbˉb \bar b dijets and W+WW^+ W^- pairs in proton-proton collisions

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    We discuss central exclusive production of W+WW^+W^- pairs in proton-proton collisions at LHC. Predictions for the total cross section and differential distributions in transverse momentum of W±W^{\pm} and WWWW invariant mass are presented. We discuss both γγW+W\gamma \gamma \to W^+ W^- mechanism as well as a new mechanism of exclusive diffractive production. The amplitude for the latter process is calculated in the Durham model. We compare the two (QED and QCD) types of contributions. The diffractive contribution is only a small fraction of fb compared to the γγ\gamma \gamma contribution which is of the order of 100 fb. This opens a possibility of searches for anomalous four-boson γγW+W\gamma \gamma W^+ W^- coupling due to physics beyond Standard Model.Comment: invited talk at the DIS2012 workshop, Bonn, Germany, 26-30 March 201

    Production of ccˉc \bar c pairs at LHC: ktk_t-factorization and double-parton scattering

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    We discuss charm production at LHC. The production of single ccˉc \bar c pairs is calculated in the ktk_t-factorization approach. We use several unintegrated gluon distributions from the literature. Differential distributions for several charmed mesons are presented and compared to recent results of the ALICE and LHCb collaborations. Some missing strength can be observed. Furthermore we discuss production of two ccˉc \bar c pairs within a simple formalism of double-parton scattering (DPS). Surprisingly large cross sections, comparable to single-parton scattering (SPS) contribution to ccˉc \bar c production, are predicted for LHC energies.Comment: invited talk at DIS2012 workshop, Bonn, Germany, 26-30 March 201