Literature: We will mostly rely on recent and not-so-recent reviews such as ``Simplifying Multi-Jet QCD computations'' by M. Peskin (hep-ph/1101.2414), ``A brief introduction to modern amplitude methods'', by L.Dixon (hep-ph/1301.5353),

``Calculating scattering amplitudes efficiently'' ( hep-ph/9601359)

Course Description: In this mini-course we will study analytic methods that are useful for calculating scattering amplitudes in gauge field theories, such as Quantum Chromodynamics (QCD). We will discuss spinor-helicity formalism for massless fermions and bosons, its generalization to the massive case, color-ordering for scattering amplitudes, BCFW recursion formula that allows on-shell computation of scattering amplitudes. We will also talk about factorization properties of scattering amplitudes in infra-red and collinear kinematic regions and how these properties can be used to organize computations of jet cross-sections for collider physics