Counting%20Quarks

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Counting Quarks
University of Southampton
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Our goal is to learn about the particles of
nature using real data from accelerators We will
not explore the theory too much just what you
see Nuclear matter (hadrons) is made of
quarks we are going to experimentally determine
how many quarks there are
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How to vote using your zapper
you can change your vote (until polling closes)
by pressing another button
this flashes green when you vote
click a button (0-9 or A-J) to vote for your
answer
it will not accept invalid answers
please dont press the GO button as it causes
problems
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A question to test your zapper
What did you drink with your breakfast this
morning?

1. Tea
2. Coffee
3. Fruit Juice
4. Water
5. Other
6. Nothing

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OPAL
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Some Simple Events
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Strong Nuclear Force
The force between quarks grows with distance
!!!!! Energy builds up between them until many
quarks are produced that arrange themselves into
strong force neutral hadrons we see jets
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Taus are heavier electrons again 3500 times
heavier They decay to quarks and electrons/muons
in the detector. Yuk!
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The Weak Nuclear Force (Beta Decay)
Neutrinos only interact by the weak force once
produced we never see them again
The likelihood that a W will decay to quarks or
leptons is the same.. If we produce Ws and count
the relative probabilities of outcomes we can
count how many quarks there are
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WW Events at LEP
The decays are so fast youll only see the final
products in the detector
Each W can decay to e, m, t plus a neutrino
LEPTONIC DECAY
Each W can decay to two quarks HADRONIC DECAY
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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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Events 11-20 (30 sec)
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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

28
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

29
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

30
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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Events 21-30 (15 sec)
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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

35
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

37
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

38
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

39
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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Events 31-40 (15 sec)
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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

46
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

47
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

48
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

49
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

51
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

52
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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Events 41-50 (15 sec)
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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

57
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

59
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

61
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

62
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

63
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

64
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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Events 51-60 (15 sec)
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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

67
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

68
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

69
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

70
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

71
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

72
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

73
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

74
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

75
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

78
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

79
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

80
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

81
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

82
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

83
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

84
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

85
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

86
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

87
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88
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

89
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

90
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

91
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

92
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

93
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

94
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

95
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

96
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

97
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

98
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99
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

100
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

101
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

102
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

103
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

104
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

105
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

106
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

107
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

108
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

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What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

111
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

112
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

113
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

114
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

115
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

116
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

117
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

118
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

119
What sort of WW decay is this?

1. Double hadronic decay
2. Mixed
3. Double leptonic decay

120
Results
We know there are three sorts of leptons (e,m,t)
so there are 9 ways to get double leptonic
events DL 9 If there are N quarks we expect N
double hadronic events DH N mixed decays M
2 x 3 x N 6 N
We saw ?
2
2
We saw ?
We saw ?
We got
N? N?
N?
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What should we have got?
LEP has enough energy to make four quarks
BUT there is an additional factor of three
because each quark has three different sorts of
charges associated with the strong
force RED GREEN BLUE
up
down
charm
strange
N 6