Particle Physics

  1. How was the Rutherford modle of the atom discovered by Geiger & Marsden ?
    Geiger & Marsden fired alpha particles at gold leaf which had a detector screen behind it. They found that a very small proportion of particles (about 1 in 8000) were deflected through large angles (>90o) while most passed straight through. This lead to the 'Rutherford model of the atom' where almost all of an atoms mass is concentrated in a tiny portion of the atom containing all of an atom's positive charge.
  2. How was Fine structure discovered?
    Deep inelastic scattering experiments showed that protons & neutrons have their own internal structure. They are composed of subatomic particles (quarks) and so can no longer be though of as elementary particles. High energy electrons were used to overcome the electrostatic forces and to provide an electron de Broglie wavelength small enough to reveal these tiny particles (quarks).
  3. What are the Elimentary particles ?
    Quarks: (up/down/strange/charm/top/bottom) are strongly interacting particles.

    Leptons: (eg electrons, neutrinos & their anti-particles) are weakly interacting particles.
  4. What are Baryons?
    • Quarks triplets:
    • eg neutron = udd (up/down/down) and Proton = uud (up/up/down)
Card Set
Particle Physics
nuclear physics