In 1973, with the discovery of asymptotic freedom , QCD was at the frontier of particle physics studies. Now, in 2006, QCD is strongly installed (returning) at the center of particle physics researches. This, not only because of the abundance of data on jet emission at HERA and Tevatron, but especially for the necessity of preparing tools for discoveries at LHC. Indeed, events with large ET , a...

We study the phase diagrams of N = ∞ vector-like, asymptotically free gauge theories as a function of volume, on S3 × S1. The theories of interest are the ones with fermions in two index representations [adjoint, (anti)symmetric, and bifundamental abbreviated as QCD(adj), QCD(AS/S) and QCD(BF)], and are interrelated via orbifold or orientifold projections. The phase diagrams reveal interesting ...

We study the phase diagrams of N = ∞ vector-like, asymptotically free gauge theories as a function of volume, on S3 × S1. The theories of interest are the ones with fermions in two index representations [adjoint, (anti)symmetric, and bifundamental abbreviated as QCD(adj), QCD(AS/S) and QCD(BF)], and are interrelated via orbifold or orientifold projections. The phase diagrams reveal interesting ...

The title ‘Chiral extrapolations’ of this contribution refers more precisely to chiral extrapolations of lattice QCD data. We shall deal with low-energy aspects of QCD, which are not accessible to ordinary weak-coupling perturbation theory. Possible alternatives to weak-coupling perturbation theory in the low-energy domain of QCD include the investigation of specific models, Monte Carlo simulat...

The current status of theoretical work and experimental analyses on power corrections in QCD for ee annihilation will be reviewed. Measurements of the number of active quark flavours nf and the QCD colour factors CA and CF derived from QCD fits to event shape distributions at lower energies and LEP energies will be presented. The fits are based on O(α2s)+NLLA QCD predictions with power correcti...

The study of QCD processes at the LHC will serve two main goals. First the predictions of QCD will be tested and precision measurements will be performed. Second QCD processes represent a major part of the background to other Standard Model processes and signals of new physics at the LHC and thus need to be understood precisely in the new kinematic region available here. Furthermore, the produc...

It is shown that the quark mass aligns QCD θ vacuum in such a way that the strong CP is conserved, resolving the strong CP problem. Quantum chromodynamics (QCD) is well established as the fundamental theory for the strong interactions. However, there has been a persistent puzzle with QCD, namely the smallness of the strong CP violation. The most general QCD Lagrangian is given in the form: