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PX147 Introduction to Particle Physics

Lecturer: Gary Barker

Weighting: 6 CATS

The elementary constituents of matter are classified into three generations of quarks and leptons (electrons and neutrinos), which interact with each other through the electromagnetic, the weak and the strong forces. An account of how to classify the elementary particles and their interactions, and a description of some of the experimental tools used to probe their properties, is the subject of this introductory module. The module discusses the relationship between conservation laws and the symmetry of the families of elementary particles. Understanding this relationship is the key to understanding how elementary particles behave. We look at which quantities are conserved by which interactions and how this allows us to interpret simple reactions between particles. We also study how elementary particles interact with matter. One example is that of neutrinos in cosmic rays and their interaction with the earth's atmosphere.

To provide an introduction to elementary particle physics including the naming and classification of particles, their detection and their interaction with matter.

At the end of the module you should be able to:

  1. Define the main terms in use to classify and name the elementary particles. Make correct charge and flavour assignments to all the quark and lepton flavours.
  2. Discuss qualitatively the relationship between symmetries and conservation laws. Know the conserved quantities of the four fundamental interactions and be able to make simple applications of conservation laws.
  3. Be able to write-down the classical equation of motion for a charged particle in uniform magnetic and electric fields (non-radiative approximation), and solve for its motion in each case. Be able to discuss the main principles behind cathode ray tubes, mass spectrometers and particle accelerators.
  4. Be able to discuss qualitatively, several natural sources of radiation. Eg. Natural radioactivity, cosmic rays, solar and atmospheric neutrinos. Be able to calculate decay length of relativistic muon. Be able to discuss qualitatively the solar and atmospheric neutrino anomalies.
  5. Describe the main processes at work when particles of different types pass through matter. Be able to describe the principles behind the operation of common particle detectors.


  1. Introduction: the Guiding Principles of Elementary Particle Physics: Simplicity, Composition, Symmetry, Unification
  2. Quarks and Leptons as basic building blocks: Periodic Table of Quarks and Leptons Basic compostion rules for hadrons
  3. The four forces and their roles: Electromagnetism, Gravity, Strong nuclear force, Weak nuclear force.
  4. Symmetries and conservation laws Introduction through simple examples Qualitative treatment of relationship between symmetries and conservation Laws Conservations Laws of EPP.
  5. Particle Physics in the natural world: Natural radioactivity, source of geothermal energy Cosmic rays Natural sources of neutrinos: radioactivity, solar, atmospheric.
  6. Charged particles in electric and magnetic fields. e/m of the electron, Mass spectrometry, Cathode ray tube. Particle accelerators.
  7. Interactions of particles with matter. Ionisation. Pair creation by photons and Bremsstrahlung. Hadronic interactions. Exponential probability of interaction: radiation and interaction lengths.
  8. Particle Detectors.
  9. The Big questions. Origin of Mass and the Higgs Grand Unification as a goal. Neutrino character and mass

This module has a home page.

Recommended Text: H D Young and R A Freedman, University Physics, Pearson.

Leads from: A-level Physics and Mathematics