819 research outputs found

    Recent Low x and Diffractive Collider Data

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    Selected recent data from collider experiments pertaining to the understanding of QCD at low Bjorken-x are reviewed. The status of QCD and Regge factorisation in hard diffractive interactions is discussed in terms of data from HERA and the Tevatron. The possibility of anomalous behaviour in the γγ\gamma \gamma total cross section is confronted with the most recent measurements from LEP. Data from all three colliders that are sensitive to possible BFKL effects are presented and different interpretations are discussed.Comment: 9 pages, introductory talk from the 1999 Durham Phenomenology Workshop on Collider Physic

    Measurement of Feynman-x Spectra of Photons and Neutrons in the Very Forward Direction in Deep-Inelastic Scattering at HERA

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    Measurements of normalised cross sections for the production of photons and neutrons at very small angles with respect to the proton beam direction in deep-inelastic epep scattering at HERA are presented as a function of the Feynman variable xFx_F and of the centre-of-mass energy of the virtual photon-proton system WW. The data are taken with the H1 detector in the years 2006 and 2007 and correspond to an integrated luminosity of 131pb1131 \mathrm{pb}^{-1}. The measurement is restricted to photons and neutrons in the pseudorapidity range η>7.9\eta>7.9 and covers the range of negative four momentum transfer squared at the positron vertex 6<Q2<1006<Q^2<100 GeV2^2, of inelasticity 0.05<y<0.60.05<y<0.6 and of 70<W<24570<W<245 GeV. To test the Feynman scaling hypothesis the WW dependence of the xFx_F dependent cross sections is investigated. Predictions of deep-inelastic scattering models and of models for hadronic interactions of high energy cosmic rays are compared to the measured cross sections.Comment: 30 pages, 5 tables, 10 figures, submitted to EPJ

    Jet production at HERA I

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    This article reviews recent jet physics results from HERA