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07 Particle Physics (The Structure of Matter (Feynman Diagram (Time axis …

- - - - Strongly attractive at \(10^{-15}m\)
      - Very strong
      - Acts on hadrons but not leptons
    - - Range of \(10^{-18}m\)
      - Responsible for nuclear beta decay
  - - - Baryons
        
        3 quarks or 3 antiquarks
        
        Neutrons
        
        :arrow_up:|:arrow_down::arrow_down:
        
        Protons
        
        :arrow_up::arrow_up:|:arrow_down:
      - Mesons
        
        1 quark + 1 antiquark
        
        \(\pi^-\)
        
        :arrow_down::arrow_double_up:
        
        \(\pi^+\)
        
        :arrow_up::arrow_double_down:
        
        any symbol you don't recognise is probably a meson
      - particle made of quarks
    - - Quarks
        
        Charge :zap:
        
        Up, charm, top :arrow_right: 2/3 charge
        
        Down, strange, bottom :arrow_right: -1/3 charge
        
        Baryon number
        
        Quark: 1/3
        
        Not a quark: 0
        
        Anti-quark: -1/3
        
        Strangeness
        
        Strange quark has -1
      - Leptons
        
        Charge :zap:
        
        electron, muon, tau (\(e,\mu,\tau\)): -1
        
        neutrinos (\(v_e,v_\mu,v_\tau\)): 0
        
        Lepton Number
        
        Leptons: 1
        
        Anti-leptons: -1
    - - mediates forces between particles
      - Strong force between quarks mediated by gluons
      - Electromagnetic force between charged particles mediated by photon
      - Weak force mediated by w+, w- or z0 bosons
    - - Baryon number:
        
        Lepton number:
        
        Charge:
        
        Strangeness:
  - - - in general direction of particle arrow
    - - axis parallel to wavy/dotted line :question:
  - - - Evacuated chamber
        
        Ensures deflection of alpha particles ONLY due to collision with gold foil
      - Gold
        
        Thin gold foil
        
        Allows alpha particles to pass through
        
        So malleable you can flatten it to the thickness of an atom
      - Small number of alpha particles scattered at large angles
        
        By \(F=k\frac{q_1q_2}{r^2}\)
        a radius of order \(10^{-10}\) cannot generate enough repulsive force to cause large scattering angles
- - - - Electrons :zap: transit from high to low energy levels by emitting photons :bulb: with energy equal to energy difference
        
        \(\Delta E=\frac{hc}{\lambda}\)
      - :one: By photons :bulb::
        
        Atom electron is only excited if \(KE_e=\Delta E\)
        
        :two:By electrons :zap:
        
        Atom electron is excited if \(KE_e≥\Delta E\)
  - - - \(E=\frac{hc}{\lambda}\)
  - - - \(\Delta E=E_2-E_1\)
- - - - Proton turns into neutron, emitting positron \(e^+\) and neutrino
      - Decreases atomic number
    - - \(^{234}_{90}Th \rightarrow ^{234}_{91}Pa+^0_{-1}e+^0_0\overline{v}_e\)
      - Neutron turns into proton, emitting electron \(e^-\) and anti-neutrino
      - Increases atomic number
    - - \(\frac{mv^2}{r}=Bqv\)
        
        \(r=\frac{mv}{Bq}\)
- - - - Too many protons → Undergoes beta + decay
    - - Too many neutrons → Undergoes beta - decay
- - - - Results in loss in mass
        (Mass Defect)
        
        Binding energy
- - - - Light emitted is passed through a prism
- - - - Atom returns to ground state, emitting the same photon in all directions
        
        Explains why some frequencies are missing
- - - - If mass is in u's, \(\delta\times 931.5\)
        
        Energy will be in MeV
      - Binding energy per nucleon
        
        Step 4 ÷ nucleon number
- - - - If mass is in u's, \(\delta\times 931.5\)
        
        Energy will be in MeV
      - If polarity is "-", energy is supplied