Subatomic physics

particle is a countable entity with fixed properties (mass, charge)

• size

  • composite - have a size (proton, neutron, atom)

  • fundamental - are are a wavefunction (electrons, quarks, neutrinos)

    • behave as waves (lambda = h/p)

  • Size can be seen with collisions with others

    • large distances/low energies —> point like

    • free space —> plane waves

Special relativity

a particle with speed larger than 0.1c must be treated with SR