Particles Flashcards
3 Principles of Particle Physics
- Composition
- Symmetry
- Unification
Composition Definition
Complex objects are made up of smaller, simpler objects. Bound by 1 or more of the 4 forces
Fundamental Forces
- Gravity
- Electromagnetic
- Strong Force
- Weak Force
Which particles interact with the Electromagnetic Force
Particles carrying electric charge
Which particles interact with the Strong Force
Particles carrying colour
Which particles interact with the Weak Force
Particles with weak charge/weak isospin
Units of Mass and Momentum
- Mass - eV/c^2
- Momentum - eV/c
Total Energy of a particle with mass m and momentum p
E^2 = (pc)^2 + (mc^2)^2
Spin is quantised into what
Discrete units of ћ/2
Leptons (Forces, Conservation, Types)
- Do not feel strong force
- Does not carry colour
- Electric charge, Weak isospin and Lepton number is conserved
- 2 Types : Charged Leptons and Neutrinos
Charge and Weak Isospin of Charged Leptons and Neutrinos
- Charged Leptons - Q = -1, T_w = -1/2
- Neutrinos - Q = 0, T_w = 1/2
Lepton Number Rules
- Leptons and Neutrinos = +1
- Anti Leptons and Anti Neutrinos = -1
- Everything Else = 0
Quarks (Forces, Conservations)
- Feels all forces
- Electric charge, Weak Isospin, Colour and Baryon Number is conserved
- Flavour is conserved (Not weak IA)
Charge and Spin for Quarks
- u,c,t - Q = 2/3, T_w = 1/2
- d,s,b - Q = -1/3, T_w = -1/2
Quark Flavour Conservation Rules
- u,d - Flavour = 1/2 (sign)
- Everything else - Flavour = sign
Colour
- 3 Types: Red, Green, Blue
- r + g + b = white/colourless
- Each quark carries colour
- Each anti quark carries anti colour
- r + r = g + g = b + b = white/colourless
- Strong force interacts using colour
Hadrons (Types, Definition, Charge,Colour)
- A composite particle made up of multiple quarks
- 0/Integer charge
- 0 colour
- 2 types: Mesons and Baryons
Mesons (Combination, Charge, Colour)
- quark + anti quark
- 0/Integer charge
- White/Colourless
Baryons (Combination, Charge, Colour)
- Combination of 3 quarks/3 anti quarks
- Can have different flavours (uud)
- 0/Integer Charge
- White/Colourless
- Baryons have ±1 baryon number
Fermions (Definition)
- Comprised of quarks and leptons
- Different types of fermions are flavours
Bosons (Definition, Types)
- Each force is associated with a boson
- Photon γ is carrier of EM force
- Gluon g is carrier of Strong Force
- Charged and Neutral Boson is carrier of Weak Force (W±, Z0)
Order for checking conservation
- Charge
- Baryon Number
- Global Lepton Number
- Lepton Number
- Quark Flavour number
- Rest Mass - Initial Rest Mass ≥ Final Rest Mass
