Particle Physics
These notes provide a gentle, but detailed, introduction to particle physics, using little more than high school mathematics. They are written, in part, for the CERN summer school. Please do email me if you find any typos or mistakes.
“If we consider protons and neutrons as elementary particles, we would have three kinds of elementary particles [p,n,e].... This number may seem large but, from that point of view, two is already a large number.”
Paul Dirac, 1933 Solvay Conference
Introduction
Quantum fields and natural units. Some history: X-rays, alpha and beta radiation, the electron, the proton, and the neutron.
A First Look at Quantum Fields
Matter fields and force fields, bosons and fermion. Spin, the Dirac eqaution, and anti-matter. Quantum electrodynamics, Feynman diagrams. Renormalisation. Some history: Cosmic rays, the positron, the muon and the pion.
The Strong Force
Yang-Mills theory, gluons, asymptotic freedom and the mass gap. Quarks and colour. Baryons, mesons and the eightfold way. Some history: The cyclotron and synchrotron. Resonances, anti-protons, deep inelastic scattering, charmonium, and the top quark.
The Weak Force
The structure of the Standard Model, parity violation, quantum anomaly cancellation. The Higgs field, the Higgs potential, W- and Z-bosons, and the weak decays. Flavours of fermions, Yukawa interactions, symmetry breaking, quark mixing, CP violation and time reversal, conservation laws. Neutrinos, neutrino masses and neutrino oscillations. Some history: the discovery of neutrinos, the theta-tau puzzle, bosons at CERN, and neutrino oscillations.
What We Don't Know
Beyond the Standard Model, unification, naturalness and fine-tuning, axions. General relativity and quantum gravity. Cosmology, the cosmological constant, dark matter, baryogenesis, primordial fluctuations.