Particles

Question 1

3 Principles of Particle Physics

Answer 1

• Composition
• Symmetry
• Unification

Question 2

Composition Definition

Answer 2

Complex objects are made up of smaller, simpler objects. Bound by 1 or more of the 4 forces

Question 3

Fundamental Forces

Answer 3

• Gravity
• Electromagnetic
• Strong Force
• Weak Force

Question 4

Which particles interact with the Electromagnetic Force

Answer 4

Particles carrying electric charge

Question 5

Which particles interact with the Strong Force

Answer 5

Particles carrying colour

Question 6

Which particles interact with the Weak Force

Answer 6

Particles with weak charge/weak isospin

Question 7

Units of Mass and Momentum

Answer 7

• Mass - eV/c^2
• Momentum - eV/c

Question 8

Total Energy of a particle with mass m and momentum p

Answer 8

E^2 = (pc)^2 + (mc^2)^2

Question 9

Spin is quantised into what

Answer 9

Discrete units of ћ/2

Question 10

Leptons (Forces, Conservation, Types)

Answer 10

• Do not feel strong force
• Does not carry colour
• Electric charge, Weak isospin and Lepton number is conserved
• 2 Types : Charged Leptons and Neutrinos

Question 11

Charge and Weak Isospin of Charged Leptons and Neutrinos

Answer 11

• Charged Leptons - Q = -1, T_w = -1/2
• Neutrinos - Q = 0, T_w = 1/2

Question 12

Lepton Number Rules

Answer 12

• Leptons and Neutrinos = +1
• Anti Leptons and Anti Neutrinos = -1
• Everything Else = 0

Question 13

Quarks (Forces, Conservations)

Answer 13

• Feels all forces
• Electric charge, Weak Isospin, Colour and Baryon Number is conserved
• Flavour is conserved (Not weak IA)

Question 14

Charge and Spin for Quarks

Answer 14

• u,c,t - Q = 2/3, T_w = 1/2
• d,s,b - Q = -1/3, T_w = -1/2

Question 15

Quark Flavour Conservation Rules

Answer 15

• u,d - Flavour = 1/2 (sign)
• Everything else - Flavour = sign

Question 16

Colour

Answer 16

• 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

Question 17

Hadrons (Types, Definition, Charge,Colour)

Answer 17

• A composite particle made up of multiple quarks
• 0/Integer charge
• 0 colour
• 2 types: Mesons and Baryons

Question 18

Mesons (Combination, Charge, Colour)

Answer 18

• quark + anti quark
• 0/Integer charge
• White/Colourless

Question 19

Baryons (Combination, Charge, Colour)

Answer 19

• Combination of 3 quarks/3 anti quarks
• Can have different flavours (uud)
• 0/Integer Charge
• White/Colourless
• Baryons have ±1 baryon number

Question 20

Fermions (Definition)

Answer 20

• Comprised of quarks and leptons
• Different types of fermions are flavours

Question 21

Bosons (Definition, Types)

Answer 21

• 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)

Question 22

Order for checking conservation

Answer 22

• Charge
• Baryon Number
• Global Lepton Number
• Lepton Number
• Quark Flavour number
• Rest Mass - Initial Rest Mass ≥ Final Rest Mass