Back to Teaching Rota
Particle Physics - Objectives
• Constituents of the atom
• Stable and unstable nuclei
• Particles, antiparticles and photons
• Particle interactions
• Classification of particles
• Quarks and antiquarks
Students should know:
- Simple model of the atom: Proton, neutron, electron; their charge and mass in SI units and relative units.
- Specific charge of nuclei and of ions. Atomic mass unit is not required.
- Proton number Z, nucleon number A, nuclide notation
- The meaning of isotopes and the use of isotopic data
- The strong nuclear force; its role in keeping the nucleus stable; short-range attraction to about 3 fm, very-short range repulsion below about 0.5 fm
- Equations for alpha decay and β - decay including the need for the neutrino.
- That the existence of the neutrino was hypothesised to account for the conservation of energy in beta decay
- for every type of particle, there is a corresponding antiparticle.
- the positron, the antiproton, the antineutron and the antineutrino are the antiparticles of the electron, the proton, the neutron and the neutrino respectively.
- Comparison of particle and antiparticle masses, charge and rest energy in MeV.
- Photon model of electromagnetic radiation, the Planck constant, E = hf = λ/hc
- There are four fundamental interactions: gravity, electromagnetic, weak nuclear, strong nuclear (the strong nuclear force may be referred to as the strong interaction)
- Knowledge of annihilation and pair production processes and the respective energies involved. The use of E = mc2 is not required in calculations.
- Concept of exchange particles to explain forces between elementary particles (knowledge of the gluon, Zo and graviton will not be tested).
- The electromagnetic force; virtual photons as the exchange particle.
- The weak interaction limited β - , β + decay, electron capture and electron-proton collisions; W + and W - as the exchange particles.
- Simple Feynman diagrams to represent the above reactions or interactions in terms of particles going in and out and exchange particles.
- Hadrons: baryons (proton, neutron) and antibaryons (antiproton and antineutron) and mesons (pion, kaon).
- Hadrons are subject to the strong nuclear force.
- Candidates should know that the proton is the only stable baryon into which other baryons eventually decay; the decay of the neutron should be known.
- Baryon number as a quantum number
- Conservation of baryon number
- The pion as the exchange particle of the strong nuclear force.
- The kaon as a particle that can decay into pions.
- Leptons: electron, muon, neutrino (electron and muon types).
- Leptons are subject to the weak interaction.
- Lepton number as a quantum number
- Conservation of lepton number for muon leptons and electron leptons.
- The muon as a particle that decays into an electron
- Strange particles are produced through the strong interaction and decay thorugh the weak interaction (e.g. kaons)
- Strangeness as a quantum number to reflect the fact that strange particles are always created in pairs.
- Conservation of strangeness in strong interactions.
- Strangeness can change by 0, +1, or -1 in weak interactions
- Particle physics relies on the collaborative efforts of large teams of scientists and engineers to validate new knowledge.
- Up (u), down (d) and strange (s) quarks only.
- Properties of quarks: charge, baryon number and strangeness.
- Combinations of quarks and antiquarks required for baryons (proton and neutron only), antibaryons (antiproton and antineutron only) and mesons (pion and kaon) only.
- Change of quark character in β - and β + decay.
- Application of the conservation laws for charge, baryon number, lepton number and strangeness to particle interactions. The necessary data will be provided in questions for particles outside those specified.
- Energy and momentum are conserved in interactions.
Back to Teaching Rota