Introduction to perturbative gauge theories

Abstract: these lectures are meant to provide an introduction to perturbative gauge theories and make contact with some of the latest developments in this field. A tentative programme is as follow:

• Lect. 1: Yang-Mills beta function and the meaning of asymptotic freedom.
• Lect. 2: Yang-Mills theory as the effective action for the open string dynamics.
• Lect. 3: Useful tools in perturbative gauge theory (spinor helicity, color decomposition) and some tree-level results.
• Lect. 4-5:
  Differential equations for the scattering amplitudes; derivation of three-point amplitudes in complexified Minkowski for massless particles of spin s.
  BCFW recursion relations. Large-z behaviour.
  Derivation of the tree-level MHV amplitudes in Yang-Mills.
  
• Lect. 5-6:
  Unitarity and generalized unitarity.
  4-point 1-loop amplitudes in N=4 Super-Yang-Mills.
  N-point MHV amplitudes in N=4 Super-Yang-Mills. MHV diagrams. Examples.