Particle physics is fascinating for its ability to help explain the Universe, starting from a small set of fundamental building blocks and the laws of their interactions. The course gives the chance to study in some depth the current theoretical framework and to examine the latest experimental results in the field of paricle physics.

The theoretical framework that describes the interactions of elementary particles is outlined, making the connection with perturbation theory in quantum mechanics. A range of current particle physics experiments are discussed, which make use of this framework to study the known particles, and to seek for new physics beyond the Standard Model. The choice of experiments develops from one year to the next, following the most important current developments in the field. The course begins by discussing the formalism of scattering processes, cross-sections and phase space. The key role of Feynman diagrams is stressed, and illustrated with examples from QED. The weak interaction is looked at in depth, considering both quark and neutrino mixing matrices, and their very different phenomenological manifestations. This leads into a discussion of electroweak unification and how predictions of the Z boson properties arise, as well as an introduction to the Higgs mechanism. The strong interaction has been discussed in an earlier course: in this module the theory of QCD is re-considered in the light of the different renormalisation behaviour resulting from the gluon self-coupling - this leads on to a review of hadronic scattering descriptions using parton densities.

By the end of the module the student should be able to:

• Describe the Yukawa potential, and discuss how range relates to the mass of an exchanged particle; discuss the relevance of virtual particles
• Discuss and apply the concepts of total and differential cross-sections, flux, luminosity and phase space;
• Perform relativistic kinematics calculations, including applying the Mandelstam variables to problems involving more than one frame of reference, and derive angular distributions of simple scattering and decay processes;
• Draw relevant QED, electroweak and QCD Feynman diagrams at leading and higher orders, and write down key coupling and propagator factors by inspection of diagrams;
• Explain qualitatively the key concepts of renormalisation, and how they affect the physical manifestations of the QED and QCD interactions, including the running of coupling constants;
• Explain and apply the concepts of parity, C-parity, time invariance symmetry, and helicity, particularly in relation to the handedness of the weak interaction;
• Discuss the charged-current and neutral-current weak interactions, and the understanding of these via exchange of W and Z bosons;
• Explain how the unitarity triangle arises from the CKM matrix;
• Discuss CP violation in the quark sector: in what kind of processes it may be observed, where it has been observed experimentally, and the typical experimental set-up used;
• Compare and contrast the CKM mixing matrix with the MNS matrix for neutrinos;
• Derive and apply the neutrino oscillation formula as a function of baseline;
• Discuss neutrino experiments;
• Discuss the relevance of the concepts of confinement, asymptotic freedom, hadronisation, jets and partons to hadronic interaction processes;
• Describe, and discuss the goals of frontier experiments in particle physics, including those at the Large Hadron Collider (LHC)
• Describe and discuss the discovery of the Higgs Boson at LHC