Standard Model

Question 1

In the standard model what theory is used to describe the electromagnetic and weak interaction?

Answer 1

Electroweak theory

Question 2

In the standard model what theory describes strong interactions?

Answer 2

Quantum chromodynamics

Question 3

What are the fundamental constituents of matter in the Standard Model?

Answer 3

Quarks and leptons.

Question 4

What spin do quarks and leptons have?

Answer 4

Spin 1/2.

Question 5

How many quark flavours exist?

Answer 5

Six: up, down, strange, charm, bottom, top.

Question 6

How many colours of quarks are there?

Answer 6

3

Question 7

How many lepton flavours exist?

Answer 7

Six: electron, muon, tau, and their neutrinos.

Question 8

What exchange particle do leptons and quarks interact via?

Answer 8

Gauge boson
spin -1

Question 9

How many generations of particles exist?

Answer 9

Three generations.

Question 10

Which generation is most common in nature?

Answer 10

The first generation.

Question 11

What are the four fundamental forces?

Answer 11

Strong, electromagnetic, weak, and gravitational.

Question 12

Which force is NOT part of the Standard Model?

Answer 12

Gravity.

Question 13

What mediates forces in the Standard Model?

Answer 13

Exchange particles called gauge bosons.

Question 14

What is the hypothetical force carrier of gravity?

Answer 14

The graviton.

Question 15

What is the weakest fundamental force?

Answer 15

Gravity

Question 16

What is the range of gravity?

Answer 16

infinite

Question 17

What force is responsible for beta decay?

Answer 17

Weak nuclear

Question 18

What particles only interact via weak nuclear force?

Answer 18

Neutrinos

Question 19

What are the exchange particles for the weak nuclear force?

Answer 19

W +- and Z bosons

Question 20

Why is the weak force short range?

Answer 20

Because its mediators (W and Z bosons) are massive.

Question 21

What is the exchange particle for the electromagnetic force?

Answer 21

Photon

Question 22

Why is electromagnetism infinite range?

Answer 22

Because the photon is massless.

Question 23

What is the exchange particle for the strong nuclear force?

Answer 23

Gluon

Question 24

Why is the strong force short range despite massless gluons?

Answer 24

Due to colour confinement.

Question 25

What is colour charge?

Answer 25

A type of charge carried by quarks related to the strong interaction.

Question 26

What colours do quarks come in?

Answer 26

Red, green, and blue.

Question 27

Why are free quarks never observed?

Answer 27

Because of colour confinement.

Question 28

What are fermions?

Answer 28

Matter particles with spin 1/2 that obey the Pauli exclusion principle. Eg Leptons and Baryons

Question 29

What are bosons?

Answer 29

Force carrier particles with integer spin.

Question 30

What symmetry property do fermion wavefunctions have?

Answer 30

They are antisymmetric under exchange of two identical particles.

Question 31

What symmetry property do boson wavefunctions have?

Answer 31

They are symmetric under exchange of identical particles.

Question 32

What is the Pauli exclusion principle?

Answer 32

No two identical fermions can occupy the same quantum state.

Question 33

What are leptons?

Answer 33

Spin 1/2 fermions Come in 6 flavours

Question 34

What are hadrons?

Answer 34

Particles made of quarks.

Question 35

What are baryons?

Answer 35

Hadrons made of three quarks.

Question 36

Give an example of a baryon.

Answer 36

Proton or neutron.

Question 37

What are mesons?

Answer 37

Hadrons made of a quark-antiquark pair.

Question 38

Are mesons stable?

Answer 38

No, they decay quickly.

Question 39

What fractional charges do quarks have?

Answer 39

+2/3e or −1/3e.

Question 40

What is Quantum Chromodynamics (QCD)?

Answer 40

The theory describing the strong interaction.

Question 41

What is electroweak theory?

Answer 41

The unified theory of electromagnetic and weak interactions.

Question 42

What conservation law corresponds to time translation symmetry?

Answer 42

Energy conservation.

Question 43

What conservation law corresponds to spatial translation symmetry?

Answer 43

Momentum conservation.

Question 44

What conservation law corresponds to rotational symmetry?

Answer 44

Angular momentum conservation.

Question 45

Which interaction violates parity?

Answer 45

The weak interaction.

Question 46

Which interaction violates charge conjugation?

Answer 46

The weak interaction.

Question 47

What symmetry is always conserved?

Answer 47

CPT symmetry. Charge Conjugation, Parity, Time reversal

Question 48

What is the Higgs boson?

Answer 48

A spin-0 particle responsible for giving mass to other particles.

Question 49

What is the mass of the Higgs boson?

Answer 49

About 125 GeV/c^2.

Question 50

What mechanism gives particles mass?

Answer 50

The Higgs mechanism.

Question 51

Do all particles have antiparticles?

Answer 51

Yes.

Question 52

What happens to charge for antiparticles?

Answer 52

It is opposite to the particle.

Question 53

Why are neutrinos difficult to detect?

Answer 53

They interact only via the weak force.

Question 54

What mediates interactions between quarks?

Answer 54

Gluons.

Question 55

What mediates interactions between charged particles?

Answer 55

Photons.