Introduction to perturbation theory

These lectures are designed to provide an introduction to perturbative techniques used to perform calculations for particle colliders. The aim of these lectures is to provide an overview (and starting point for further reading) of topics which are not typically covered as part of standard Quantum Field Theory graduate courses, but are nevertheless vital for modern applications of QFT for collider physics. Specifically the lectures will cover amplitude calculations using on-shell techniques at tree-level and one-loop, and tools for regularization of Infrared divergences at Next-to-Leading Order (NLO) and Next-to-Next-to Leading Order (NNLO).