Particle Physics - Elementary particles

Definition: A particle is called elementary if it is not made out of any smaller component particles.

Quarks

Six different flavors:

Top; Bottom; Charm; Strange; Up; Down

Hadrons

Baryon: made up by three quarks

Meson: made up by one quark and one anti-quark

Example:

Neutron: up, down, down

Proton: up, up, down

Example:

positively charged Pion: up, anti-down

Conservation laws

Baryon number

Charge

Strangeness number

See data booklet!!! (Very important)

Strangeness would be conserved in strong and electromagnetic interactions but could be violated in weak interactions.

Leptons

Six types

Electron & its neutrino; muon & its neutrino; tau & its neutrino

All leptons interact with the weak nuclear interaction.Those that have electric charge (e−, μ− and τ−) also interact with the electromagnetic interaction.

Conservation laws

family lepton number

Charge

Exchange particles

Definition: particle that mediates interaction between two particles

4 forces

Strong nuclear interaction

Weak nuclear interaction

Gravity

Electromagnetic

graviton (theoretical)

gluon

W+, W- and Z0

photon

Higgs field

  1. All elementary particles have no mass;
  2. mass is given by Higgs field, exchange particle of Higgs field are Higgs bosons