Fall and rise of the gluon splitting function

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

A Practical Seedless Infrared Safe Cone Algorithm

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

QCD in hadron collisions

This talk examines recent progress in collider QCD and some facets of the interplay between these developments and searches for new particles and phenomena at the Tevatron and LHC.Comment: 9 pages, 4 figures, contribution to the proceedings of La Thuile 2012, the XXVI Rencontres de Physique de la Vall\'ee d'Aost

Soft emissions and the equivalence of BFKL and CCFM final states

This article demonstrates that the BFKL and CCFM equations, despite their different physical content, lead to equivalent results for any final-state observable at leading single-logarithmic order. A novel and fundamental element is the treatment also of the soft (z->1 divergent) part of the splitting function in the CCFM equation.Comment: 18 pages, 7 figures. Version 2 contains a few extra sentences to emphasise that the equivalence applies to the predictions from the equation

CAESAR: Computer Automated Resummations

This talk gives a brief discussion of the motivations and principles behind computer automated expert semi-analytical resummation (CAESAR) for QCD final states.Comment: 4 pages; talk presented at DIS 2004, Strbske Pleso, Slovakia, April 200

Infrared safe definition of jet flavour

Though it is widely taken for granted that it makes sense to separately discuss quark and gluon jets, normal jet algorithms lead to a net parton-level jet flavour that is infrared (IR) unsafe. This writeup illustrates the problem and explains how the kt algorithm can be modified to provide an IR safe parton-level flavour. As well as being of use in theoretical calculations that require a projection of higher-order contributions onto a flavour-channel of the lowest order, jet-flavour algorithms also open up the prospect of significant improvements in the accuracy of heavy-quark jet predictions.Comment: 4 pages, 3 figures, to appear in the proceedings of XLIst Rencontres de Moriond QCD and High Energy Hadronic Interactions, La Thuile, Aosta Valley, Italy, March 2006 and (in abridged form) in the proceedings of DIS 2006, Tsukuba, Japan, April 200