These lectures are meant to be a reference and handbook
for an introductory course in Theoretical Particle
Physics, suitable for advanced undergraduates or beginning graduate
students. Their purpose is to reconcile theoretical rigour
and completeness with a careful analysis of more phenomenological
aspects of the physics. They aim at filling the gap
between quantum field theory textbooks and purely
phenomenological treatments of fundamental interactions.
The first part provides an introduction to scattering
in relativistic quantum field theory. Thanks to an original
approach to relativistic processes, the relevant computational
techniques are derived cleanly and simply in the semi-classical
approximation. The second part contains a detailed presentation of
the gauge theory of electroweak interactions with particular
focus to the processes of greatest phenomenological interest.
The main novelties of the present second edition are a more complete
discussion of relativistic scattering theory and an expansion of the
study of the corrections to the semi-classical approximation,
including important processes in LHC physics. The extension of the
standard model to include neutrino masses and oscillations is also
discussed, and updated with new results.