Particles

Quarks: Spin of 1/2, Charge of +-1/3, +-2/3. Quarks experience all four fundamental interactions. By virtue of the strong interaction mediated by gluons (QCD), quarks are hadronized -- confined to hadrons. Within hadrons, they enjoy asymptotic freedom.

Top quark

• 175GeV, +2/3. EXCEPT the top quark, whose lifetime is too short to be mediated by gluons, and is thus always observed bare

Strong nuclear force

• Repulsive at small distances (~.7fm), attractive at larger distances (through 2.5fm), falls off to 0
  • This repulsion gives nucleons their "size"
• Mediated by gluons between quarks.
• Holds quarks together in hadrons, nucleons together in nucleus.
  • Other quarks are only oberved confined
  • Their presence is indicated by deep inelastic scattering experiments
    • Color is white, charge is not

Fermions

• Half-integer spin, Fermi-Dirac statistics (Pauli Exclusion Principle)
• All leptons
• 3-quark hadrons (baryons)

Leptons

Fundamental (not made of quarks, pointlike) fermions.

Charged (Electron-like)

Massive.

• Electron / positron
• Muon / antimuon
• Tau / antitau

Neutral (Neutrinos)

At least two of these are massive.

• Neutrino / antineutrino
• Tau n/an
• Muon n/an

Bosons

• Integer spin, Bose-Einstein statistics (no Pauli Exclusion Principle)
• 2-quark hadrons (mesons)

W/Z Bosons

• Mediators of the weak nuclear force

Hadrons

• Color confinement: hadrons must be "white"
  • Quark of a color with anti-quark of the other color
  • Three quarks (or antiquarks) of different colors
• Made of quarks, held together by strong force mediated by gluons
  • Mesons: Bosons (one quark + one antiquark -> integer spin)
  • Baryons: Fermions (three quarks -> half-integer spin)