Leptons

• What are leptons classified as?

  Fundamental particles
• Why are leptons considered fundamental particles?

  They are not made of other particles
• Through which interactions do leptons interact with other particles?

  Weak, gravitational, or electromagnetic interactions
• Which force do leptons not interact via?

  Strong nuclear force
• What are the most common leptons?

  • Electron (e)
  • Electron neutrino (ν)
  • Muon (μ)
  • Muon neutrino (ν)

  
• How does the muon compare to the electron?

  The muon is slightly heavier than the electron
• What is the mass of an electron?

  About 0.0005u
• What is the mass of a muon?

  About 0.1u
• What charge do electrons and muons have?

  -1e

  
• What are neutrinos known for?

  Being the most abundant leptons
• What is the charge and mass of neutrinos?

  No charge and negligible mass
• How are quarks different from leptons?

  Quarks interact via the strong force
• What is lepton number and how is it defined?

  • Lepton number (L) indicates the number of leptons.
  • L = +1 for leptons
  • L = -1 for anti-leptons
  • L = 0 for non-leptons

  
• Why is lepton number important in interactions?

  It is conserved in all interactions
• What is the lepton number of leptons?

  +1
• What is the lepton number of anti-leptons?

  -1
• What is the lepton number of particles that are not leptons?

  0
• What are the steps to determine lepton number conservation in a decay?

  1. Determine lepton numbers of all particles.
  2. Ensure total lepton number is equal on both sides.
  3. Identify unknown particles based on conservation.
• What do muons typically decay into?

  An electron

  
• What do anti-muons typically decay into?

  Positrons

  
• Through which interaction does muon decay occur?

  Weak interaction
• What indicates muon decay in a Feynman diagram?

  Exchange of the W boson

  
• What conservation laws must be satisfied in muon decay?

  • Charge conservation
  • Electron lepton number conservation
  • Muon lepton number conservation
• What is the charge of muons?

  -1
• How do you verify conservation laws in muon decay?

  By checking quantities on both sides
• What conclusion can be drawn if all quantities balance in muon decay?

  Muon decay satisfies conservation laws