10,876 research outputs found

    Have we seen anything beyond (N)NLO DGLAP at HERA?

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    The evidence from HERA for parton saturation, and other low-xx effects beyond the conventional DGLAP formalism, is recalled and critically reviewed in the light of new data and analyses presented at the conference.Comment: 4 pages, 5 figures, Contribution to the discussion session at Intenrational Symposium on Multiparticle Dynamics, ISMD08, Hambur

    Including heavy quark production in ZEUS-PDF fits

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    At HERA heavy quarks may contribute up to 30% of the structure function F2F_2. The potential of including heavy-quark data in the ZEUS PDF fits is explored, using D∗D^* double differential cross-sections as well as the inclusive quantities F2ccˉF_2^{c\bar{c}}, F2ccˉF_2^{c\bar{c}}. The introduction of heavy quarks requires an extension of the DGLAP formalism. The effect of using different heavy flavour number schemes, and different approaches to the running of αs\alpha_s, are compared.Comment: 4 pages, 4 figures. To be published in the Proceedings of the 16th International Workshop on Deep Inelastic Scattering, DIS2008, London, April 7-11th 200

    Improved measurement of parton distribution functions and αs(MZ)\alpha_s(M_Z) with the LHeC

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    The potential of the LHeC, a future electron-proton collider, for precision Deep Inelastic Scattering measurements is reviewed with particular emphasis on the reduction of uncertainties on the parton distribution functions (PDFs) of the proton and on the measurement of αs(MZ)\alpha_s(M_Z). The interpretation of possible Beyond Standard Model (BSM) signals at the LHC is crucially dependent on precise knowledge of the predictions of the Standard Model (SM) and the uncertainties on PDFs and αs(MZ)\alpha_s(M_Z) are a limiting factor. The LHeC project, running in parallel with later stages of LHC running, would provide much improved precision on the PDFs as compared to the precision expected from LHC data alone.Comment: 6 pages, 8 figures, proceedings of the XXIV International Workshop on Deep-Inelastic Scattering and Related Subjects. arXiv admin note: substantial text overlap with arXiv:1310.066

    Measurements of αs\alpha_s and parton distribution functions using HERA jet data

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    Use of HERA jet production cross sections can extend our knowledge of the gluon parton distribution function and yield accurate measurements of αs(MZ)\alpha_s(M_Z) in addition to illustrating the running of αs\alpha_s with scale.Comment: Proceedings of the Ringberg Workshop on `New Trends in HERA Physics 2005
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