Summary

• Elementary Particles (pdf) concept map
• fermions
  • Fermions …
    • are the particles of matter.
    • obey fermi-dirac statistics.
    • have half integral spin (±½ℏ, ±1½ℏ, ±2½ℏ, ±3½ℏ, … ).
    • come in one of twelve flavors.
    • belong to one of three generations.
      1. ordinary matter (the parts needed to make an atom)
      2. exotic matter (produced in high energy collisions)
      3. very exotic matter (produced in high very energy collisions)
  • The elementary fermions are either quarks or leptons.
    • Quarks …
      • come in one of six flavors …
        • three in the up group, each with a charge of +2/3e
          1. up
          2. strange
          3. top
        • three in the down group, each with a charge of −1/3e
          1. down
          2. charm
          3. bottom
      • have a property called color
        • Color is something like electric charge.
        • All quarks can be found in any one of three colors.
          • red
          • green
          • blue
        • Color (in this context) has nothing to do with human vision or visible light.
        • Only quarks and gluons are colored.
      • are more massive than other fermions within the same generation.
      • are always bound to other quarks (by the strong force) at all but exceptionally high energies.
    • Leptons …
      • come in one of six flavors …
        • the three heavy leptons
          1. electron
          2. muon
          3. tauon
          • each with a charge of −e
          • can be found free or bound to other particles (by the electromagnetic force)
          • are less massive than quarks but much, much more massive than the neutrinos
        • and three corresponding neutrinos
          1. electron neutrino
          2. muon neutrino
          3. tauon neutrino
          • all of them are electrically neutral
          • only interact with themselves and other particles via the weak force
          • are very nearly massless
  • The composite fermions arranged in order of increasing complexity are …
    • hadrons: color neutral quark composites
      • mesons: quark-antiquark pairs (pions, etc.)
      • baryons: quark triplets
        • nucleons (protons and neutrons)
        • hyperons (heavy and exotic particles)
    • nuclei: groups of protons and neutrons
    • atoms: nuclei with electrons (one for every proton)
    • molecules: atoms sharing electrons
    • macroscopic material objects: assemblages of atoms and molecules
      (rocks, plants, animals, clouds, planets, stars, etc.)
• bosons
  • Bosons …
    • are the force particles
    • obey bose-einstein statistics
    • have integral spin (±0ℏ, ±1ℏ, ±2ℏ, ±3ℏ, … )
    • belong to one of four types each associated with a fundamental force
  • Types of Bosons
    • The photon …
      • carries the electromagnetic force between particles with charge
      • has an infinite range
      • is massless
      • exerts a force that is moderately strong relative to the other fundamental forces
      • has no charge or color
      • is described by the theory of quantum electrodynamics (QED)
      • is discussed in more detail in a another section of this book
    • Gluons
      • carry the strong force between particles with color (only quarks and gluons)
      • have a short range (~ 10⁻¹⁵ m, about the diameter of a nucleon)
      • are massless
      • exert a force which is very strong relative to the other fundamental forces
      • come in one of eight color pairs, but carry no charge
      • are described by the theory of quantum chromodynamics (QCD)
      • are discussed in more detail in a another section of this book
    • The intermediate vector bosons
      • carry the weak force between certain particles with flavor
      • have an extremely short range (~ 10⁻¹⁸ m, smaller than any known object)
      • are the only family of bosons with mass
      • exert a force that is moderately weak relative to the other fundamental forces
      • come in charged and uncharged varieties, but are not colored
        • W⁺ [double u plus] has a charge of +1e
        • W⁻ [double u minus] has a charge of −1e
        • Z⁰ [zee zero] has no charge
        • Some versions of the standard model include a higgs boson (H⁰) or a trio of higg bosons (H⁺, H⁻, H⁰)
      • would be called quantum flavordynamics (QFD), but are usually joined with electromagnetism in electroweak theory (EWT)
      • are discussed in more detail in a another section of this book
    • The graviton …
      • carries the gravitational force between particles with mass-energy
      • has an infinite range
      • is massless
      • extremely weak
      • interacts with all particles including itself (since it possesses energy)
      • would be called quantum geometrodynamics (QGD), but usually called quantum gravitation
      • entirely hypothetical at this point and not a part of the standard model at all