Unit 1.7 Particles and Nuclear structure - Matter Flashcards
1
Q
What are smaller than the atom, the once thought to be smallest fundamental particle?
A
Quarks and leptons
2
Q
How many generations of matter are there?
A
3
3
Q
Which generation do the quarks and leptons we’re looking at fall under?
A
I
4
Q
Name the two leptons, including their symbols
A
Electron (e-) and Electron neutrino (Ve)
5
Q
Name two quarks, including their symbols
A
Up (u) and down (d)
6
Q
What’s the charge of an electron lepton?
A
-1
7
Q
What’s the charge of an electron neutrino lepton?
A
0
8
Q
What’s the charge of an up quark?
A
+2/3
9
Q
What’s the charge of a down quark?
A
-1/3
10
Q
What does each particle have?
A
An equivalent antiparticle
11
Q
What’s similar and what’s different between a particle and an antiparticle?
A
They share the exact same properties (eg - mass) but have opposite charges, lepton numbers and baryon numbers
12
Q
Which antiparticle can have two different names? What are they?
A
The antielectron or positron
13
Q
What are the antileptons, including their symbols?
A
–
Antielectron/positron (e+) and electron antineutrino (Ve)
14
Q
What do all antiparticle symbols use? Which one is an exception?
A
The little bar above the normal particle symbol, apart from e-, which changes to e+ in the antiparticle form
15
Q
What are the antiquarks, including their symbols?
A
antiup (u) and antidown (d)
16
Q
Antielectron/positron charge
A
+1
17
Q
Electron antineutrino charge
A
0
18
Q
Antiup charge
A
-2/3
19
Q
Antidown charge
A
+1/3
20
Q
What happens when a particle and an antiparticle meet?
A
They annihilate eachother and mass is converted into energy
21
Q
What happens in the example of a particle and an antiparticle meeting, when an electron encounters a positron?
A
It releases two photons of gamma energy in opposite directions
22
Q
Which are the lightest of subatomic particles?
A
Leptons
23
Q
How do leptons exist?
A
Always exist separately and do not combine to form composite subatomic particles
24
Q
What’s the lepton number of our leptons?
A
Both electrons and electron neutrinos have a lepton number of 1
25
What is the lepton number of the leptons antiparticles?
1-
26
Electrons charge
-1e
27
Electron neutrinos charge
0
28
How do quarks and antiquarks exist?
They do not exist separately. They combine to form composite subatomic particles
29
What do quarks and antiquarks combine to form?
composite subatomic particles, known as hadrons
30
What are there three types of?
Hadrons
31
What are the three types of hadrons?
Baryons, antibaryons and mesons
32
What do baryons consist of?
3 quarks
33
What do antibaryons consist of?
3 antiquarks
34
What do mesons consist of?
1 quark and 1 antiquark
35
What are not to be confused in this unit please?
Baron/lepton numbers and charges
36
What are all quarks baryon numbers?
+1/3
37
Antiquarks baryon number
-1/3
38
All baryons baryon number
1
39
Antibaryon baryon number
-1
40
What are the most commonly known baryons?
Protons and neutrons
41
What are protons and neutrons?
Baryons, the most commonly known ones
42
What does a quark composition make up?
Charge, NOT baryon number
43
Proton charge
1+
44
Proton baryon number
1
45
Proton quark composition
uud
(to make the charge of +1)
46
Neutron charge
0
47
Neutron baryon number
1
48
Neutron quark composition
udd
(to make a charge of 0)
49
What combine to form the pions?
The first generation of quarks and antiquarks
50
What do the first generation of quarks and antiquarks combine to form?
The pions
51
ℼ+ quark composition and charge
-
ud
1e charge
52
ℼ- quark composition and charge
-
ud
-1e
53
ℼ0 quark composition and charge
-
uu
0 charge
OR
-
dd
0 charge
(notice that there's two possible ways of making of the neutral pion)
54
What are responsible for giving particles baryon numbers?
Quarks
55
What's an electrons baryon number?
0
(remember - electrons are leptons, therefore they exist separately and do not have a quark composition. They do have a lepton number though, which is 1)
56
What other two baryons apart from protons and neutrons are common and what are their quark makeups and charges?
Δ- (delta minus) - ddd = -1
Δ++ (delta plus plus) - uuu = 2+
57
What are the pions?
Mesons
58
Proton and neutron symbols
p and n
59
What's the phrase for leptons existing separately and on their own?
Fundamental
60
What are the fractions of charge for the quarks fractions of?
Fractions of the e charge (on the front of the data booklet in exam)
61
Why do we only look into 3 types of hadrons?
Only mesons and baryons have been observed
62
Up quark up number
+1
63
Up quark down number
0
64
Down quark up number
0
65
Down quark down number
+1
66
What is anything that isn’t an up or down quarks quark number?
0
67
What is an antiup quarks up number?
-1
68
What is an antidown quarks down number?
-1
69
What is the gravitational force experienced by?
All matter
70
What is the gravitational forces range?
Infinite
71
Additional comments on the gravitational interaction
Very weak - negligible except between large objects like planets
72
What is the weak force experienced by?
All leptons and all quarks so also all hadrons too
73
Weak force range
Very short
74
Additional comments on the weak force
Only significant when the e-m and strong interactions do not operate
75
What’s the electromagnetic (e-m) force experienced by?
all charged particles
76
Electromagnetic force range
Infinite
77
Additional comments on the electromagnetic force
Also experienced by neutral hadrons, as these are composed of quarks
78
What’s the strong force experienced by?
All quarks, so all hadrons
79
Strong force range
short
80
What are the four fundamental forces?
Gravitational, weak, electromagnetic (e-m), strong
81
What’s the phrase for being observed on an everyday scale?
Macroscopically
82
Which forces are observed macroscopically?
Electromagnetic and gravitational
83
What do we know with regular forces that they do when they’re close? Which force tells us this?
Electromagnetic forces tell us that protons ought to strongly repel as they’re so close
84
What are forces modelled using in the quantum world? What are they called?
Exchange particles - Bosons
85
What are bosons and what do they do?
Particles that “carry” the force- they govern the interaction
86
What are the types of boson?
The photon, the gluon, the W boson, the Z boson and the Higgs boson
87
Electromagnetic boson
Photon
88
Gravitational boson
Graviton
89
Strong boson
Gluon
90
Weak bosons
W+, W-, Z
91
What does Higgs Boson explain?
Why the photon has no mass whilst the W and Z bosons do, and also where electrons and other particles get their mass
92
What can the strong force do?
Overcome the large repulsion between protons
93
Which force is the strong force much stronger than, and by how much?
100x stronger than the electromagnetic force
94
Which force has the shortest lifetime?
Strong
95
Why is the strong forces range so small?
Within the nucleus of an atom, typically in collisions between particles
It becomes negligible at longer distances, therefore we have no everyday experiences of it
96
Which forces is the weak force much weaker than, and by how much?
Several magnitudes weaker than the strong and electromagnetic forces
97
What’s a common example of the weak force?
Particle decaying by beta emission
98
Which force always has a particular fermion that is always involved in its interactions? What is it?
The weak force - electro neutrinos
99
Which force includes a quark changing “flavour”?
The weak force
100
Which force is responsible for practically all phenomena encountered in ordinary life?
Electromagnetic force
101
Which force keeps electrons in orbit around a nucleus?
Electromagnetic
102
Which force holds atoms and molecules together?
Electromagnetic
103
What is always involved in an electromagnetic force? What is its symbol?
A photon (squirly Y)
104
Which is the weakest force?
Gravitational
105
Which force is dominant on a macroscopic scale? Why? What’s wrong with this?
Gravitational force, due to its large range
This causes problems within the standard model
106
Which force is not compatible with the current understanding of quantum mechanics?
The gravitational force
107
What’s the first question to ask yourself when forgoing out which force is responsible? If yes, what type of force is it?
Is there a neutrino present?
Weak
108
What’s a different indicator that leads immediately to the weak interaction?
Change of quark flavour
109
What’s the second question to ask when working out which force is responsible? If yes, which type of interaction is it?
Are all the particles made up of quarks? (all mesons or baryons)
Strong interaction
110
What’s the third question to ask to work out which force is responsible? If yes, which force is it?
Are the particles charged (quarks or electron and positron)?
Electromagnetic interaction
111
What’s another immediate sign that a reaction is electromagnetic?
A photon (squirly Y) is involved
112
Is the electromagnetic interaction experienced by neutral hadrons?
Yes, as these are composed of quarks
113
Which particle was instrumental in the development of quark theory?
Delta plus plus
114
Two features of the pi mesons
-Short lifetimes, in the order 10-8s
-Decay by weak interaction - 1 quark changes flavour, producing a neutrino
115
Which interaction do the pi mesons decay by?
Weak interaction
116
What’s the energy conservation rule?
Energy cannot be destroyed or created, simply transformed from one form to another
117
When balancing a particle equation, what do we need to be equal on both sides?
-Charge
-Lepton number
-Baryon number
118
What’s a useful trick for if you’re explaining why you chose a specific force involved in an interaction?
Point out ones it clearly can’t be, yanno things like neutrino involved probably is weak, or a change of flavour is weak
119
Which interaction consists of only quarks?
Strong force
120
Which is the only force involving leptons?
Weak force
121
What’s the lifetime of the strong force?
10-24s (shortest)
122
What’s the lifetime of the weak force?
10-8s
123
What’s the lifetime of the electromagnetic force?
10-12-10-18 s
124
Which force has a common example and what is it?
The weak force - particle decaying by beta emission
125
Word for insignificant in terms of forces
Negligible
126
Negligible
Insignificant and not worth considering (like the gravitational force unless experienced between large objects)
127
When does the strong force become negligible?
At longer distances
128
What’s a mesons baryon number?
0
129
What’s the only matter that isn’t effected by the gravitational force?
The photon
130
Describe the life span of the pions.
Which is the shortest and why?
Very short lifespans, especially pi0 as the quark and antiquark pair annihilate eachother
131
Why are neutrinos and anti neutrinos so difficult to detect?
-100,000s of times smaller than an electron, so they’re too small to detect with the current equipment
-No charge, so they don’t react with other atomic particles
132
Elementary particles
Not combinations of other particles (leptons)
133
Composite particles
Combination of other particles (quarks)
134
What does the fact that leptons are fundamental make them?
Structureless
135
What type of intereactions can electrons take part in?
All interactions except strong
136
In which type of reaction is the quark flavour not conserved?
Weak
137
Why are electron neutrinos so difficult to detect?
-100,000s of time smaller than electrons
-no equipment
-no charge = don’t react with other atomic particles
-interact via weak force, which has a very small range
138
What is everything for a photon?
0
139
In a conservation on up and down quarks, what is it important to do?
Break the particle into its quark makeup
140
What do you do with any of the equation questions involving symbols for elements e.g- 2
H
1
Just think - what protons and neutrons are in it? And work from there
141
Rate the forces in order of strength, starting from the weakest
-Gravitational
-Weak
-Electromagnetic
-Strong
142
what does the strong force have?
A short range
143
What do we have to do if a question asks “in quarks”?
Make sure we write out the whole formula (fractions and stuff), not just uud for example
144
Composite
Made up of quarks
(e.g - baryons, anti-baryons and mesons)
145
Word for ‘made up of quarks’ (e.g - baryons, anti-baryons and mesons)
Composite
146
Fundamental
Existing separately + do not combine to form composite subatomic particles
(e.g - leptons)
147
Which interaction is rare?
Weak interaction
148
What is the baryon number of a meson?
0
149
Which type of force doesn’t affect leptons?
Strong force
150
Which groups of particles are affected by the weak nuclear force?
Mesons, leptons, quarks
151
Which groups of particles are affected by the strong nuclear force?
Mesons and quarks
