Particles – Classification
Definitions
• Fundamental – particles cannot be broken into smaller particles.
• Lepton – electron, muon, electron neutrino and muon neutrino.
• Anti-Lepton – positron, anti muon, positron neutrino and anti-muon neutrino
• Hadrons – a group of particles composed of quarks.
• Baryons: protons and neutrons.
• Antibaryons: antiprotons and antineutrons.
• Mesons: pions and kaons.
• Kaon – particle that decays into pions.
• Muon – particle that decays into an electron.
Particle accelerator experiments produced new particles and a method was used to classify
them. Particles are in two classes: fundamental and not fundamental.
Lepton
Electron: charge:-1, lepton number: +1, rest mass (MeV): 0.511
Muon: charge:-1, lepton number: +1, rest mass (MeV): 105.7
Tau: charge:-1, lepton number: +1, rest mass (MeV): 1780
Electron neutrino: charge: 0, lepton number: +1, rest mass (MeV): 0
Muon neutrino: charge: 0, lepton number: +1, rest mass (MeV): 0
Tau neutrino: charge: 0, lepton number: +1, rest mass (MeV): 0
Anti-Lepton
Positron: charge: +1, lepton number: -1, rest mass (MeV): 0.511
Anti-Muon: charge:+1, lepton number: -1, rest mass (MeV): 105.7
Anti-Tau: charge:+1, lepton number: -1, rest mass (MeV): 1780
Positron neutrino: charge: 0, lepton number: -1, rest mass (MeV): 0
Anti-Muon neutrino: charge: 0, lepton number: -1, rest mass (MeV): 0
Anti-Tau neutrino: charge: 0, lepton number: -1, rest mass (MeV): 0
Muons decay into electrons. Leptons have a lepton number of +1. Anti-leptons have a lepton
number of -1. Non-leptons have a lepton number of 0. Lepton number is always conserved
because lepton number remains unchanged.
Definitions
• Fundamental – particles cannot be broken into smaller particles.
• Lepton – electron, muon, electron neutrino and muon neutrino.
• Anti-Lepton – positron, anti muon, positron neutrino and anti-muon neutrino
• Hadrons – a group of particles composed of quarks.
• Baryons: protons and neutrons.
• Antibaryons: antiprotons and antineutrons.
• Mesons: pions and kaons.
• Kaon – particle that decays into pions.
• Muon – particle that decays into an electron.
Particle accelerator experiments produced new particles and a method was used to classify
them. Particles are in two classes: fundamental and not fundamental.
Lepton
Electron: charge:-1, lepton number: +1, rest mass (MeV): 0.511
Muon: charge:-1, lepton number: +1, rest mass (MeV): 105.7
Tau: charge:-1, lepton number: +1, rest mass (MeV): 1780
Electron neutrino: charge: 0, lepton number: +1, rest mass (MeV): 0
Muon neutrino: charge: 0, lepton number: +1, rest mass (MeV): 0
Tau neutrino: charge: 0, lepton number: +1, rest mass (MeV): 0
Anti-Lepton
Positron: charge: +1, lepton number: -1, rest mass (MeV): 0.511
Anti-Muon: charge:+1, lepton number: -1, rest mass (MeV): 105.7
Anti-Tau: charge:+1, lepton number: -1, rest mass (MeV): 1780
Positron neutrino: charge: 0, lepton number: -1, rest mass (MeV): 0
Anti-Muon neutrino: charge: 0, lepton number: -1, rest mass (MeV): 0
Anti-Tau neutrino: charge: 0, lepton number: -1, rest mass (MeV): 0
Muons decay into electrons. Leptons have a lepton number of +1. Anti-leptons have a lepton
number of -1. Non-leptons have a lepton number of 0. Lepton number is always conserved
because lepton number remains unchanged.
