22,101 research outputs found

    Fall and rise of the gluon splitting function

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    This talk reviews some recent results on the NLL resummed small-x gluon splitting function, as determined including renormalisation-group improvements. It also discusses the observation that the LO, NLO, NNLO, etc. hierarchy for the gluon splitting function breaks down not when (alpha_s log 1/x) is of order one but rather for (alpha_s log^2 1/x) of order one.Comment: 7 pages, 3 figures; Talk presented at DIS 2004, Strbske Pleso, Slovakia, April 2004, and at the Eighth Workshop on Non-Perturbative Quantum Chromodynamics, Paris, France, June 200

    The status of NLL BFKL

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    This talk summarises the current status of the NLL corrections to BFKL physics and discusses the question of small-x factorisation.Comment: 4 pages, 2 figures. Uses moriond.sty (included). Talk presented at the XXXVth Rencontres de Moriond, QCD and High Energy Hadronic Interactions, Les Arcs, France, March 18-25, 200

    Recent developments in perturbative QCD

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    A brief overview of some recently active topics in perturbative QCD, including: string-inspired recursion techniques at tree level; recursion approaches and automation of standard techniques for 1-loop calculations; the status of NNLO jet calculations; and non-trivial structures that appear in higher-order calculations.Comment: 9 pages, 1 figure. Invited talk at the XIV International Workshop on Deep Inelastic Scattering (DIS 2006), April 2006, Tsukuba, Japa

    Moriond 2009, QCD and High Energy Interactions: Theory Summary

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    These proceedings provide a brief summary of the theoretical topics that were covered at Moriond QCD 2009, including non-perturbative QCD, perturbative QCD at colliders, a small component of physics beyond the standard model and heavy-ion collisions.Comment: 13 pages, 7 figures; v2 adds a reference; v3 includes small changes to tex

    A Practical Seedless Infrared Safe Cone Algorithm

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    This writeup highlights the infrared unsafety of the "midpoint" cone jet-algorithm and provides a brief overview of why this is a serious issue. It then shows how one can build a safe (seedless) cone algorithm and discusses the potential impact on measurements.Comment: 4 pages, 4 figures. Talk presented at the XLII Rencontres de Moriond, QCD and Hadronic Interactions, La Thuile, March 200

    A resummation of large sub-leading corrections at small x

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    The NLL corrections to the BFKL kernel are known to be very large, to the extent that even for small values of alpha_s, they lead to physical cross sections which are not positive definite. It is shown in the context of a toy model, that such pathological behaviour is an artifact of the truncation at NLL order, and is associated in particular with double transverse logarithms. These are resummed in a manner consistent with the full NLL kernel, and are shown to change its properties quite considerably.Comment: 19 pages LaTeX, 5 figures, includes JHEP.cls and cite.sty. Version 2 additionally includes an appendix, numerous clarifications, correction of typos and extra reference
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