Aspects of QCD, from the Tevatron to the LHC

This contribution presents a selection of the topics (parton densities, fixed-order calculations, parton showers, soft-gluon resummation) discussed in my introductory lectures at the Workshop and includes a pedagogical overview of the corresponding theoretical tools.Comment: 29 pages, latex, 13 postscript figures, to appear in the Proceedings of the Workshop Physics at TeV Colliders, Les Houches, France June 199

NLO calculations in QCD: a general algorithm

We briefly describe a new general algorithm for carrying out QCD calculations to next-to-leading order in perturbation theory. The algorithm can be used for computing arbitrary jet cross sections in arbitrary processes and can be straightforwardly implemented in general-purpose Monte Carlo programs.Comment: 10 pages, uses espcrc2.sty. Talk presented at the DESY-Zeuthen Workshop QCD and QED in Higher Orders, Rheinsberg, Germany, April 1996. This paper can also be obtained from http://surya11.cern.ch/users/seymour/pubs/rheinsberg.ps.

QCD jet calculations in DIS based on the subtraction method and dipole formalism

We briefly describe a new general algorithm for carrying out QCD calculations to next-to-leading order in perturbation theory. The algorithm can be used for computing arbitrary jet cross sections in arbitrary processes and can be straightforwardly implemented in general purpose Monte Carlo programs. We show numerical results for the specific case of jet cross sections in deep inelastic scattering.Comment: 5 pages, 2 figures. Presented at the International Workshop on Deep Inelastic Scattering and Related Phenomena (DIS 96), Rome, Italy, 15-19 Apr 1996. This paper can also be obtained from http://surya11.cern.ch/users/seymour/pubs/rome.ps.

The Forward-Backward Asymmetry in NNLO QCD

We have recently calculated the second-order QCD corrections to the forward-backward asymmetry in e+e- annihilation (hep-ph/9905424). Here we recall the results and compare them to others in the literature.Comment: 14 pages, LaTeX, uses lathuile.sty (included). Talk given by M. Seymour at 13th Rencontres de Physique de la Vallee d'Aoste, Results and Perspectives in Particle Physics, La Thuile, Aosta Valley, Italy, February 28th-March 6th, 199

Momentum Conservation at Small x

We discuss how momentum conservation is implemented in perturbative computations based on expansions of anomalous dimensions appropriate at small $x$. We show that for any given choice of $F_2$ coefficient functions there always exists a factorization scheme where the gluon is defined in such a way that momentum is conserved at next to leading order.Comment: 11 pages, plain TeX with harvma

Determination of alpha_s from F_2^p at HERA

We compute the proton structure function F_2^p at small x and large Q^2 at next-to-leading order in alpha_s(Q^2), including summations of all leading and subleading logarithms of Q^2 and 1/x in a way consistent with momentum conservation. We perform a detailed comparison to the 1993 HERA data, and show that they may be used to determine alpha_s(M_Z^2)=0.120 pm 0.005(exp) pm 0.009(th). The theoretical error is dominated by the renormalization and factorization scheme ambiguities.Comment: 24 pages, TeX with harvmac and epsf, 10 figures in compressed postscript. Final (published) versio