7,966 research outputs found

    Virtual Photon Structure Functions

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    We discuss the perturbatively calculable virtual photon structure functions. First we present the framework for analyzing the structure functions of the virtual photon and derive a first moment of g1γg_1^\gamma of the virtual photon. We then investigate the three positivity constraints satisfied by the eight structure functions of the virtual photon.Comment: 5 pages, LaTeX, 5 eps figures, npb.sty file included Talk given at RADCOR/Loops and Legs 2002, Kloster Banz, Germany, September 8-13, 2002, to appear in the Proceeding

    Nucleon spin structure and its connections to various sum rules

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    Our knowledge on the nucleon spin structure has greatly improved over the last twenty years or so, but still many fundamental questions remain unsolved. I will try to review some of the puzzling aspects of the origin of the nucleon spin. I will emphasize the connection with several sum rules and, when using this tool, the relevance of some kinematic regions for testing them in the QCD dynamics framework.Comment: 10 pages, 4 figures, Invited talk presented at GDH2004, June 2-5 2004, Old Dominion University, Virginia, US

    Do we understand elastic scattering up to LHC energies?

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    The measurements of high energy \bar p p and pp elastic at ISR, SPS and Tevatron colliders have provided usefull informations on the behavior of the scattering amplitude. A large step in energy domain is accomplished with the LHC collider presently running, giving a unique opportunity to improve our knowledge on the asymptotic regime of the elastic scattering amplitude and to verify the validity of our theoretical approach, to describe the total cross section \sigma_{tot}(s), the total elastic cross section \sigma_{el}(s), the ratio of the real to imaginary parts of the forward amplitude \rho(s) and the differential cross section d\sigma (s,t)/dt.Comment: 6 pages, 2 figures, Invited talk at " DIFFRACTION 2012"', Puerto del Carmen, Lanzarote Canary Islands (Spain), September 10-15 2012, to appear in AIP Conference Proceedings (2013

    Recent Progress in the Statistical Approach of Parton Distributions

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    We recall the physical features of the parton distributions in the quantum statistical approach of the nucleon. Some predictions from a next-to-leading order QCD analysis are compared to recent experimental results. We also consider their extension to include their transverse momentum dependence.Comment: 6 pages, 3 figures, Invited talk at DIFFRACTION 2010, Otranto, Italy, September 10 - 15, 2010, to appear in the AIP Conference Proceeding
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