This course explains how special relativity and quantum mechanics combine to give birth to the relativistic Quantum Field Theory (QFT). The students will understand the origin of antiparticles, of the running coupling, learn relativistic quantum scattering theory and, specifically, its applications to high-energy interactions. The concept of gauge theories is introduced, and Quantum Electrodynamics (QED) is dealt with in detail as the first example of a successful gauge theory based on the abelian gauge group U(1) of phase transformations. A generalization to the non-abelian gauge group SU(2) forms the base for constructing the weak interaction sector of the Electroweak theory. Spontaneous symmetry breaking gives masses to all intermediate weak bosons (Z,W,H) as well as to fundamental matter fields (leptons, quarks). Non-abelian “colour” symmetry SU(3) leads to Quantum Chromodynamics (QCD), which complements the Standard Model.
The physical origin of Asymptotic Freedom is explained. An emphasis is put on multi-particle production in energetic lepton-hadron and hadron-hadron collisions which is due to quark-gluon cascades, and a manifestation of quarks and gluons as hadron jets in the final state of hard processes.