Particle Physics (PP | INU7017U)

Description: Basic Concepts

Four vector notation, invariants and natural units. Feynman diagrams as a tool for qualitative description of interactions. Cross sections, differential cross sections and luminosity. The Mandelstam variables s, t and u for scattering. The family of fundamental particles: leptons and quarks and vector bosons. Interactions of leptons and quarks, summarised in terms of characteristic decay times, ranges and the mediating bosons. Yukawa field.

Relativistic QM
Relativistic wave equations (Klein-Gordon, Dirac). Negative energy solutions and the Feynmann-Stuckelberg interpretation. Conserved Current and Propagators. Invariant amplitude.

Symmetries and conservation laws.
Translational invariance and momentum conservation as a worked example. Symmetries of the Strong and Electromagnetic Interactions: Relation between symmetry, invariance and conservation laws; parity (invariance of Hamiltonian, fermions and antifermions, quarks and hadrons). Higgs mechanism and spontaneous symmetry breaking.

Particle Detectors
These will be covered as an integral part of the study of current experiments. Basic principles of calorimeters, drift chambers and silicon vertex detectors.

Leptons and Hadrons
Discovery of leptons. Evidence for lepton universality, lepton number conservation. Parity, C Symmetry. Quarks, and hadrons. Multiplets and Quark diagrams. Resonances. Breit-Wigner formula.

Quarks and QCD
Colour. Confinement. Screening, Asymptotic freedom and Jets. Rhad for e+e− annihilation. 2- and 3-jet events. The discovery of the top quark through the measurement of jets at the CDF detector at Fermilab, including a look at basic calorimetry.

More on Leptons, and Weak Interactions
Discovery and properties of W and Z bosons. Quark and lepton doublets and Cabibbo mixing. Comparing the weak and electromagnetic couplings. Parity and C-Parity violation and handedness of neutrinos. The measurement of Z width at LEP. Electroweak Theory: Unification of weak and electromagnetic. Gauge transformations.

Deep Inelastic Scattering
Elastic electron-proton scattering. Deep Inelastic scattering. Scaling and the quark parton model. Factorisation. Scaling violations and QCD. Triggering at HERA. Measurement of proton structure at HERA. Neutral and Charged Currents at HERA.

The Standard Model and What Next?
Some idea of current open questions. Neutrino oscillations, running couplings, SUSY. Cosmological connections: dark matter, CP violation, very high energy cosmic rays.

This module is taught by UCL.