676 research outputs found

    Total Cross-sections and Bloch-Nordsieck Gluon Resummation

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    The physics underlying the fall and eventual rise in various total cross-sections at high energies has been investigated over a decade using a model based on the Bloch-Nordsieck resummation in QCD. Here a brief review of our latest results is presented and comparison made with experimental data on pppp, γproton\gamma proton and γγ\gamma \gamma total cross-sections.Comment: Presented by G. Pancheri at ISMD04, Sonoma State University. Under publication in Acta Physica Polonica. LaTeX format, 10 *.eps files, 7 page

    Total cross-section at LHC from minijets and soft gluon resummation in the infrared region

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    A model for total cross-sections incorporating QCD jet cross-sections and soft gluon resummation is described and compared with present data on pppp and pˉp{\bar p}p cross-sections. Predictions for LHC are presented for different parameter sets. It is shown that they differ according to the small x-behaviour of available parton density functions.Comment: 10 pages, 3 figures, uses appolb.cls, LaTeX. Talk presented by G. Pancheri at the EURIDICE Final Meeting, August 24-27th, 2006, Kazimierz, Polan

    Total Cross-sections at very high energies: from protons to photons

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    A model for both proton and photon total cross-sections is presented and compared with data. The model is based on the eikonal representation, with QCD mini-jets to drive the rise and soft gluon kt-resummation into the Infrared region to tame the excessive rise due to low-x perturbative gluons. We discuss the effects of a singular but integrable expression for the Infrared gluon spectrum on the high energy behaviour of the total cross-section expected in this model.Comment: 13 pages, 4 figures, Tenth Workshop on Non-Perturbative Quantum Chromodynamics at l'Institut Astrophysique de Paris, June 8-12, 200

    Soft Gluons and the Energy Dependence of Total Cross-Sections

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    We discuss the high energy behaviour of total cross-sections for protons and photons, in a QCD based framework with particular emphasis on the role played by soft gluonsComment: 13 pages, 10 figures, Presented by G. Pancheri at the International Workshop on QCD, Martina Franca, Italy, June 16-20,2001. To appear in the proceeding

    Total cross sections and soft gluon resummation

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    We discuss a model for total hadronic and photonic cross-sections which includes hard parton-parton scattering to drive the rise and soft gluon resummation to tame it. Unitarity is ensured by embedding the cross-section in the eikonal formalism. Predictions for LHC and ILC are presented.Comment: 9 pages, 2 figures, Presented at PLC2005, Kazimierz, September 2005, requires appolb.cl

    QCD Mini-jet contribution to the total cross section

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    We present the predictions of a model for proton-proton total cross-section at LHC. It takes into account both hard partonic processes and soft gluon emission effects to describe the proper high energy behavior and to respect the Froissart bound.Comment: 7 pages, 3 figures, presented at MPI08, Perugia, October 27-31, 200

    Mini-jet Total Cross-sections and Overlap Functions through Bloch-Nordsieck Summation

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    Predictions for total inelastic cross-sections for photon induced processes are discussed in the context of the QCD-inspired minijet model. Large theoretical uncertainties exist, some of them related to the parton distributions of hadrons in impact parameter space. A model for such distribution is presented, based on soft gluon summation. This model incorporates (the salient features of distributions obtained from) the intrinsic transverse momentum behaviour of hadrons. Under the assumption that the intrinsic behaviour is dominated by soft gluon emission stimulated by the scattering process, the b-spectrum becomes softer and softer as the scattering energy increases. In minijet models for the inclusive cross-sections, this will counter the increase from σjet\sigma_{jet} .Comment: 11 pages, two postscript figures, latex, uses epsfig.sty, a4wide.sty full postscript file of the paper is available at http://hpteor.lnf.infn.it/pancheri/starelesna.p

    Zero momentum gluons and the total pp and pbarp cross-sections

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    We describe a QCD motivated model for total cross-sections which uses the eikonal representation and incorporates QCD mini-jets to drive the rise with energy of the cross-section, while the impact parameter distribution is obtained through the Fourier transform of the transverse momentum distribution of soft gluons emitted in the parton-parton interactions giving rise to mini-jets in the final state. A singular but integral expression for the running coupling constant in the infrared region is part of this model.Comment: 4 pages, 1 figure, uses slac_one.rtx, 34th ICHEP Conference, Philadelphia 200

    Total Cross-Sections : Cross-Talk between HERA, LHC and LC

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    We discuss the need to compare total cross-section measurements at LHC and HERA with each other and with available models in order to obtain a more precise prediction of the total hadronic cross-section at the future Linear Collider, thus leading to a better estimate of the hadronic background.Comment: 5 pages, three figures, Talk presented by G. Pancheri at the International Linear Collider Workshop, Paris, April, 200

    Hierarchical hybrid control: A case study

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    A case study of the difficulties encountered in the design of hierarchical, hybrid control systems is presented. As our example we use the Intelligent Vehicle Highway System (IVHS) architecture proposed for vehicle platooning, a system that involves both continuous state and discrete event controllers. We point out that even though conventional analysis tools suggest that the proposed design should fulfill certain performance requirements, simulation results show that it does not. We consider this as an indication that the conventional tools currently in use for the design and verification of control systems may be inadequate for the design of hierarchical controllers for hybrid systems. The analysis also indicates certain shortcomings of the current IVHS design. We propose solutions to fix these problems
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