We all hope that LHC will be a `New Physics Machine'. We know with certainty, however, that it is a `QCD machine': the overwhelming majority of LHC events is QCD-dominated. In order to understand possible new physics scenarios, we need to master QCD effects with an unprecedented degree of precision. This challenge, together with some new theoretical insights, has generated massive progress in our understanding of perturbative QCD, and in the efficiency of the calculational tools that are needed at LHC. I will review some of this recent progress, touching upon the physics of QCD jets, the determination of parton distributions, new techniques for NLO calculations, and new results concerning the structure of infrared and collinear singularities to all orders in perturbation theory.
The Particle Physics Theory seminar is a weekly series of talks reflecting the diverse interests of the group. Topics include analytic and numerical calculations based on the Standard Model of elementary particle physics, theories exploring new physics, as well as more formal developments in gauge theories and gravity..