PX156 - F2 - categorization

• according to spins, fermion and bosons are distinguished

fermions

• have spins of $\frac{\hslash }{2},\frac{3\hslash }{2},\frac{5\hslash }{2},\dots$

• three generations/families

• each generation is a higher mass copy of the preceding one

• the types of fermions are known as flavours

• each fermion also has an associated anti-particle, with the same mass but opposite electric charge

• further split into two classes

quarks

• make up the nuclei
• generally feel all the forces
• can never be seen alone outside a nucleus - "confined in the nucleus prison"

leptons

• involved in destruction

• feel weak and electromagnetic forces (not neutrinos)

• do not feel the strong force

• two types:

  • electrically charged: electron, muon, tau
  • electrically neutral: electron, muon and tau neutrinos

bosons

• have spins of $0\hslash ,1\hslash ,2\hslash$
• force carriers
• heavier a boson, the shorter its range

gauge bosons

gluon

• carriers of the strong force

photon

• carriers of the EM force

z boson

• neutral carriers of the weak force

w boson

• electrically charged carriers of the weak force ($W^{\pm }$)
• carry a weak isospin of $T_W=\pm 1$, therefore an interaction with W boson changes $T_W$ by $\pm 1$

higgs bosons

• couples to/creates mass for particles