1
00:00:00,040 --> 00:00:04,840
The God particle, right? Oh no, oh no! I'm 
thinking about the number of stars in the galaxy. 

2
00:00:04,840 --> 00:00:09,678
There's dark energy. I've got the dark energy, 
I've got it right in my coffee cup

3
00:00:09,678 --> 00:00:14,848
[Music]

4
00:00:14,848 --> 00:00:25,920
Hello everybody and welcome to Early Morning Coffee at CERN. My name is Steven Goldfarb and my name is Joni Pham and we have a really nice show for you today. 

5
00:00:25,920 --> 00:00:32,640
It's on a topic which is perhaps one of our favourites here at CERN, that's the discovery of the Higgs boson 

6
00:00:32,640 --> 00:00:39,760
and believe  it or not, it's been about 12 years now since that 
discovery. With us to talk about the discovery are a  

7
00:00:39,760 --> 00:00:45,240
couple people who were there at the time working 
on the physics, so we have Heather Grey next to  

8
00:00:45,240 --> 00:00:52,440
me who is working on the ATLAS experiment. You're 
from UC Berkeley? Yes, that's right. And Andre David  

9
00:00:52,440 --> 00:00:57,440
who's from the CMS experiment, the other experiment 
that was also working on the discovery of the Higgs boson.

10
00:00:57,440 --> 00:01:04,880
Both of them announced together another 
the discovery back then, July 4th it was.  

11
00:01:04,880 --> 00:01:11,160
Andre you're a CERN physicist. Yeah, that's right. 
So, let's get started right away.  

12
00:01:11,160 --> 00:01:17,360
I think it'd be nice to hear from you maybe a brief 
introduction of yourself Heather.   

13
00:01:17,360 --> 00:01:24,200
What brought you here to CERN and what have you been working on? 
Sure, happy to do that.  

14
00:01:24,200 --> 00:01:32,489
So I think the first time I came to CERN was, gosh, almost 20 years ago now. 
You were a kid. I was a kid, yeah.

15
00:01:32,489 --> 00:01:37,800
I was a CERN summer student and so I'm from South Africa and back  

16
00:01:37,800 --> 00:01:43,440
in the day they had money to bring one summer 
student from the whole of Africa to CERN  

17
00:01:43,440 --> 00:01:47,880
for the summer programme and sort of a month or two 
before the programme was going to start they didn't  

18
00:01:47,880 --> 00:01:52,360
have anybody, so my professor at the time 
came to me, and said, "Would you like to go CERN?" 

19
00:01:52,360 --> 00:02:00,330
I said, "hmm, okay!" So they took only the very best volunteers 
is what you're saying. They took "a" volunteer at the time  

20
00:02:00,330 --> 00:02:05,120
who happened to be the very best, of course. No but it's actually 
quite funny because before that I thought I was  

21
00:02:05,120 --> 00:02:10,320
going to be a theoretical physicist as do many 
when they're young, but somehow being at CERN for  

22
00:02:10,320 --> 00:02:14,440
the summer and seeing all the experiments and 
already seeing experimental physics, I was an  

23
00:02:14,440 --> 00:02:19,665
experimentalist and that was done for after that.
Well that's great, and you've stuck with it.

24
00:02:19,665 --> 00:02:24,240
You're associate professor. Yeah I'm 
an associate professor at UC Berkeley. 

25
00:02:24,240 --> 00:02:28,840
I actually have a sort of joint appointment which means I'm 
half at UC Berkeley and half at Lawrence Berkeley  

26
00:02:28,840 --> 00:02:34,800
lab, which is great because it means I only 
have to teach half a load compared to everybody  

27
00:02:34,800 --> 00:02:39,800
else and I get to come visit CERN and do things like 
that. I'm sure you love teaching though but you  

28
00:02:39,800 --> 00:02:45,720
love the experiments as well, right? I like both of them. Excellent.
But no it gives extra flexibility  

29
00:02:45,720 --> 00:02:52,760
Andre. Well, I hail from Portugal and 
I was a student, I was working on theoretical  

30
00:02:52,760 --> 00:02:59,520
nuclear physics and microtechnology, so making 
chips and then somebody told me, "Andre, you're

31
00:02:59,520 --> 00:03:04,000
not really good at this theoretical stuff 
but I know of someone who has something going on  

32
00:03:04,000 --> 00:03:09,400
at CERN." And I didn't really know what CERN was, and 
I came here for two weeks at the end of the year  

33
00:03:09,400 --> 00:03:17,360
2000 and I did get hooked. I mean just seeing 
all of the kinds of things that are done here.  

34
00:03:17,360 --> 00:03:21,680
So I've been here for the last 24 years working in 
different types of experiments and you were also  

35
00:03:21,680 --> 00:03:28,995
a kid when you came here, I guess. We were students at some point.

36
00:03:28,995 --> 00:03:36,480
So another question for you, Andre, on July 4th 2012 where were you?

37
00:03:36,480 --> 00:03:45,413
It depends on the time. I think that when 
when the day started I was still here in building 40 

38
00:03:45,413 --> 00:03:50,880
where we have a lot of our offices, trying 
to make sure that all the last dots, you know all  

39
00:03:50,880 --> 00:03:56,600
the i's were dotted, and the t's were crossed 
on the slide deck that was going to be shown and  

40
00:03:56,600 --> 00:04:02,120
then I went for a walk to look at the people who 
were by the seminar room, the main auditorium here at CERN.

41
00:04:02,120 --> 00:04:06,560
There was already a big queue 
and people were playing cards. This was like a sort  

42
00:04:06,560 --> 00:04:14,524
of a wild camp going on and then during the 
day after taking a shower, I came back and I was in the main auditorium.

43
00:04:14,524 --> 00:04:19,122
For the announcement. Just so that everybody knows, it was a very exciting time

44
00:04:19,122 --> 00:04:24,200
we knew something was going to be 
shown, right? It was the result of our searches and  

45
00:04:24,200 --> 00:04:32,680
we've been searching for the Higgs boson for many 
years actually before the LHC.

46
00:04:32,680 --> 00:04:38,640
I was tricked, okay, I wasn't here. I was in Australia for the conference where it  

47
00:04:38,640 --> 00:04:44,760
was originally going to be announced and 
the CERN Council in their wisdom decided

48
00:04:44,760 --> 00:04:50,200
that it should be presented at CERN. Were you 
here? No. Where were you?  

49
00:04:50,200 --> 00:04:56,320
It was quite amusing I was actually at, there's 
an annual meeting of Nobel laureates in Lindau in Germany

50
00:04:56,320 --> 00:05:01,840
where they get together, you know, a large 
number of Nobel laureates and also some young students.

51
00:05:01,840 --> 00:05:08,080
So I was there at the time. Being a Nobel 
laureate you were. Obviously. No, I was

52
00:05:08,080 --> 00:05:14,120
the young student of course. But it was quite 
funny because it was the middle of the programme  

53
00:05:14,120 --> 00:05:18,080
of the meeting and we sort of said, "We 
think, we should broadcast the seminar." We went to  

54
00:05:18,080 --> 00:05:22,760
the organizers and they said no no no the other 
Noble laureate said no they refused to cancel their talks.

55
00:05:22,760 --> 00:05:28,880
 Oh yeah. So, me and a couple others about 
10 of us initially we set up a sort of bootleg  

56
00:05:28,880 --> 00:05:33,640
setup, with you know, a bunch of computers and things 
because the connection kept dropping because so  

57
00:05:33,640 --> 00:05:38,880
many people were connected to what was going on 
at CERN. So when one died we switched to the next one  

58
00:05:38,880 --> 00:05:44,880
and we kind of got a growing following including 
a number of Nobel Laureates watching our bootleg. I guess so.  

59
00:05:44,880 --> 00:05:51,800
People felt there was something exciting going on.
Joni, where were you? So, 12 years ago, I was  

60
00:05:51,800 --> 00:05:56,360
still an undergraduate student at the University of 
Melbourne and at that time when the announcement  

61
00:05:56,360 --> 00:06:01,800
was made, it was made almost like simultaneously, 
right? Like one at the auditorium here at CERN

62
00:06:01,800 --> 00:06:06,720
and the other at the International Conference 
of High–energy physics (ICHEP) in Melbourne and the University  

63
00:06:06,720 --> 00:06:13,080
of Melbourne was one of the organizers, so I was 
begging my physics professor  

64
00:06:13,080 --> 00:06:18,040
to somehow sneak me in the conference. That's 
where I saw you the first time. You looked a

65
00:06:18,040 --> 00:06:22,080
lot younger than you are now. I was younger, you 
you were the same age, I think, but I was younger.

66
00:06:22,080 --> 00:06:29,680
That's true. I said I got tricked, right, and that trick happened because

67
00:06:29,680 --> 00:06:36,880
I guess it was in December of 2011, we had 
a hint that there was something in our data and  

68
00:06:36,880 --> 00:06:43,120
I got very excited by this hint. We always get 
tricked by three sigma events but in this case  

69
00:06:43,120 --> 00:06:47,920
things look lined up, it looked like we might have 
something and so I booked my flight right away. 

70
00:06:47,920 --> 00:06:52,720
I knew that the next major conference, there 
was going to be a presentation and that was at  

71
00:06:52,720 --> 00:07:00,560
Melbourne, the ICHEP, that was organized there. So we were far away, but fortunately, we  

72
00:07:00,560 --> 00:07:06,360
had this nice webcast. It was done in both places 
simultaneously and we could watch it. 

73
00:07:06,360 --> 00:07:11,080
Was it in the middle of the night in Melbourne that you 
were doing it? No actually we managed it so that

74
00:07:11,080 --> 00:07:15,920
it was done early here. It was done 
in the morning and it was

75
00:07:15,920 --> 00:07:20,520
late there. It was like 5 o' clock or something 
like that in the evening. It wasn't wasn't too  

76
00:07:20,520 --> 00:07:26,000
unreasonable. It's not like the watch parties that 
I've seen from the US where they had pyjama-like  

77
00:07:26,000 --> 00:07:29,680
things to watch. Yeah they weren't so happy 
that we arranged it to be in the morning here  

78
00:07:29,680 --> 00:07:33,800
because in the States it was whatever 2 in the 
morning or whenever that they had

79
00:07:33,800 --> 00:07:37,640
to watch it but yeah there were people in their 
pyjamas watching from Fermilab and other places in the US.  

80
00:07:37,640 --> 00:07:45,720
It was a very exciting time which 
brings a natural question, why do you think

81
00:07:45,720 --> 00:07:53,600
this so exciting for us? What what was so 
important about the discovery of this particular particle?  

82
00:07:53,600 --> 00:08:00,400
We've discovered particles before. Why 
was the Higgs boson an important discovery for our field.

83
00:08:00,400 --> 00:08:10,600
You mean, the God particle, right? Oh no, oh no. Okay that was 
Chetna, our producer in the back here  

84
00:08:10,600 --> 00:08:17,480
asking if it's called the God particle. So this 
terrible name, name we don't like because we  

85
00:08:17,480 --> 00:08:22,400
didn't really call it that, it came about 
because of a book that was put out, which is a  

86
00:08:22,400 --> 00:08:27,400
good book, by the way, if you want to read more 
about the Higgs boson. Leon Lederman and Dick Teresi

87
00:08:27,400 --> 00:08:34,000
they wrote this book together and 
the story that I heard and it was only sort  

88
00:08:34,000 --> 00:08:40,920
of secondhand, someone who knew Leon Lederman, who 
told me this, so I hope I got this right.   

89
00:08:40,920 --> 00:08:45,240
Leon Lederman had just given a lecture to his students 
and he was talking about symmetry. Symmetries are  

90
00:08:45,240 --> 00:08:50,480
extremely important in physics, right? We look 
for those all the time because we seem to find  

91
00:08:50,480 --> 00:08:56,400
bit by bit that some forces which we think were 
separate are actually two sides of the same coin.  

92
00:08:56,400 --> 00:09:01,280
Electricity and magnetism. Electromagnetism and the 
weak nuclear force, that turns out you can make a  

93
00:09:01,280 --> 00:09:06,360
theory that combines them and so he was showing 
this to his class and he said it could be maybe we  

94
00:09:06,360 --> 00:09:11,680
can dream that one day all of the forces will come 
together and maybe there'll be just one particle  

95
00:09:11,680 --> 00:09:15,960
and an explanation that describes the movements 
of this particle and we could call it, and he said,  

96
00:09:15,960 --> 00:09:20,760
"Well let's call it the God particle." So he 
made this lecture to his class and Dick was in  

97
00:09:20,760 --> 00:09:24,520
the room and saw this and then they went together 
and they were talking about this manuscript, this  

98
00:09:24,520 --> 00:09:29,520
book that they were about to publish and Dick said, 
"Look they've asked us to give a working  

99
00:09:29,520 --> 00:09:35,680
title to this book," and Dick said, "I 
propose that we call it the God particle."  

100
00:09:35,680 --> 00:09:41,440
And Leon Lederman said no absolutely not and 
Dick said now hold on now every single book  

101
00:09:41,440 --> 00:09:47,880
that I've ever written in the past whenever they 
ask us for a title to propose a title for it they  

102
00:09:47,880 --> 00:09:52,960
never accept my working title and so if we call 
it this, it's guaranteed it won't be called that.  

103
00:09:52,960 --> 00:09:58,200
Unfortunately this time the publishers decided 
to call it the God particle and to which Leon  

104
00:09:58,200 --> 00:10:02,640
Lederman said it would have been much better 
to call it the goddamn particle because we've  

105
00:10:02,640 --> 00:10:06,760
been searching for it, it's really hard to 
predict where to find. We had no idea what its mass would be. 

106
00:10:06,760 --> 00:10:13,240
So there you go, Chetna. I hope 
you're happy. We've laid that to rest, no one is  

107
00:10:13,240 --> 00:10:20,720
ever going to call it that again for eternity okay
but let's move on. This particular particle which  

108
00:10:20,720 --> 00:10:30,200
got this horrible nickname, the Higgs boson, 
why is it so important to to our current theory?  

109
00:10:30,200 --> 00:10:35,880
So we have this model which describes all the 
particles and their interactions, the Standard  

110
00:10:35,880 --> 00:10:44,120
Model and this is something that was come up 
with by a bunch of theorists half a century ago

111
00:10:44,120 --> 00:10:48,280
a little bit longer well there were various 
pieces that came along and in this theory

112
00:10:48,280 --> 00:10:55,400
provides a description of everything we 
know so all the particles all their interactions  

113
00:10:55,400 --> 00:11:00,040
however it has one problem which would be that 
certain particles don't have any masses.

114
00:11:00,040 --> 00:11:05,120
So this is a problem because we 
have nice experimental measurements which showed  

115
00:11:05,120 --> 00:11:11,520
us that the particles do have mass. 
And so one way to think about the Higgs boson  

116
00:11:11,520 --> 00:11:17,360
and indeed the Higgs mechanism which is kind of 
how it does it is it's a mathematical trick.  

117
00:11:17,360 --> 00:11:22,560
It basically allows us to preserve the symmetries 
of the theory which you need the particles to be  

118
00:11:22,560 --> 00:11:29,360
massless yet for them at the same time to have 
mass as we know experimentally to do it and  

119
00:11:29,360 --> 00:11:35,000
so it's really critical in this Standard Model because 
it resolves this apparent contradiction between  

120
00:11:35,000 --> 00:11:40,840
you know what the theory says we need it to have 
and then what we saw in the experiment.  

121
00:11:40,840 --> 00:11:47,840
And even inside the theory, it's completely 
unique it's the only elementary particle that is  

122
00:11:47,840 --> 00:11:54,880
a scaler. What's that? I knew you're going to go there.  

123
00:11:54,880 --> 00:11:58,960
It means it has no notion of direction, it just 
permeates, there's a field that permeates the  

124
00:11:58,960 --> 00:12:05,280
whole of of the universe and different particles 
interact differently with it but it's the only  

125
00:12:05,280 --> 00:12:11,960
particle in the theory that we have right now with 
these properties. There could be others but right  

126
00:12:11,960 --> 00:12:19,640
now this is what is needed for the theory to work 
but the theory, I mean, it's very beautiful

127
00:12:19,640 --> 00:12:28,000
the mathematical edifice for which this Higgs boson 
was created and then a little later came an idea  

128
00:12:28,000 --> 00:12:34,160
of hey since we already have this thing in and 
this is Steven Weinberg, why don't we just write  

129
00:12:34,160 --> 00:12:40,440
a few more terms and insert a lot of arbitrary 
parameters to give masses to other particles like  

130
00:12:40,440 --> 00:12:47,400
the leptons (like the electron, the muon) and the 
quarks and so you end up having like this one  

131
00:12:47,400 --> 00:12:53,480
single actor playing two very different roles in 
one single theory and that's really really strange  

132
00:12:53,480 --> 00:12:59,440
how the two things are mixed together so the Higgs 
participates in that beautiful symmetry breaking  

133
00:12:59,440 --> 00:13:05,080
that Heather was talking about and then it also participates in a, you get a coupling (the strength of interaction between particles), you get a coupling,

134
00:13:05,080 --> 00:13:10,720
you get a mass, you get a mass, which has a very ad hoc feeling. Yeah, it's funny you

135
00:13:10,720 --> 00:13:15,560
mentioned that, so that messy part of the Standard 
Model, that's the part that I study because it  

136
00:13:15,560 --> 00:13:20,160
bothers me a lot, right? I really don't like the 
fact that for all these individual particles  

137
00:13:20,160 --> 00:13:25,280
we have these different parameters and so if I 
want to take a bet of you know where should we  

138
00:13:25,280 --> 00:13:30,480
go and have a look for something that might be 
different, it's there and so where my research  

139
00:13:30,480 --> 00:13:35,240
is trying to go through and measure some of the 
more tricky ones in that area. In particular

140
00:13:35,240 --> 00:13:42,000
I'm looking to see if the Higgs boson interacts 
with the charm quarks. Okay. We've been seeing  

141
00:13:42,000 --> 00:13:49,400
that it interacts with the more massive quarks 
or the more massive elementary particles more  

142
00:13:49,400 --> 00:13:54,240
strongly because.. that's exactly what comes out of the theory is that  

143
00:13:54,240 --> 00:13:59,040
if you interact more strongly with the Higgs boson 
you end up appearing as having a larger mass.  

144
00:13:59,640 --> 00:14:03,560
Okay. Or the other way around, yeah okay it it does become circular but that's okay.

145
00:14:03,560 --> 00:14:07,840
I agree wait wait wait 
because this is important because it's  

146
00:14:07,840 --> 00:14:11,840
like when you measure the mass of a particle 
you're measuring the mass of the particle  

147
00:14:11,840 --> 00:14:17,560
that's the thing that you measure experimentally. 
Then you take that mass and you can infer what  

148
00:14:17,560 --> 00:14:23,240
is the coupling, which the coupling is a theory 
parameter so you can go, you go that way, it's a good  

149
00:14:23,240 --> 00:14:29,240
point. So the coupling is how strongly it interacts 
with other things. So it's interesting.  

150
00:14:29,240 --> 00:14:33,000
I should actually step back a second and 
say you know we've referred to this as  

151
00:14:33,000 --> 00:14:41,120
the Higgs boson all the way through this. So 
it was proposed by Peter Higgs, there were others

152
00:14:41,120 --> 00:14:47,400
involved, right? In fact there was a long list of 
people. This is my second least favourite question  

153
00:14:47,400 --> 00:14:52,680
about Higgs boson. You got the first one correct. 
I'm going for it. I'll get them all.

154
00:14:52,680 --> 00:14:57,000
You got the god question first. 
Yeah exactly. But I took that over, okay,

155
00:14:57,000 --> 00:15:03,520
but now who would like to? I mean there is 
a list of people. No that's why it was  

156
00:15:03,520 --> 00:15:08,480
something I think probably there's a long list 
of people and I think probably the reason for  

157
00:15:08,480 --> 00:15:15,640
that is that it was a natural thought to have at 
the time in terms of the theoretical development  

158
00:15:15,640 --> 00:15:20,960
and that's why it turned out that a number of 
people came up with it independently this is  

159
00:15:20,960 --> 00:15:25,760
at least my understanding of it. Yeah 
so part of the math was actually taken from  

160
00:15:25,760 --> 00:15:33,240
solid state physics because there you 
actually have things condensating together  

161
00:15:33,240 --> 00:15:39,280
and behaving as one and the idea here was to do 
some of that let's say mathematical machinery but  

162
00:15:39,280 --> 00:15:46,200
for the elementary particles and you do have 
people who contributed before Peter Higgs but then  

163
00:15:46,200 --> 00:15:53,680
Peter Higgs crucially got his paper rejected and 
then he added a paragraph and it's that paragraph which 

164
00:15:53,680 --> 00:15:58,920
is absolutely crucial because it's a paragraph 
that says and this particle will have a mass  

165
00:15:59,600 --> 00:16:03,760
and so that's the thing that actually 
makes it distinctive and I think that's the  

166
00:16:03,760 --> 00:16:08,360
reason why we call it the Higgs boson and not 
the Brout-Englert-Higgs boson but we do call it the  

167
00:16:08,360 --> 00:16:14,280
Brout-Englert-Higgs mechanism because it's the 
underlying symmetry breaking mechanism that  

168
00:16:14,280 --> 00:16:19,440
Heather was mentioning that one does involve 
a bit more but then it was not over there because  

169
00:16:19,440 --> 00:16:24,040
once you start adding these ingredients 
but you still need to make a recipe that does  

170
00:16:24,040 --> 00:16:28,280
not kill you when you try to eat it so there were 
other ingredients that were contributed by other  

171
00:16:28,280 --> 00:16:34,520
people like for instance making sure that you can 
still have massive particles but a photon that is  

172
00:16:34,520 --> 00:16:40,160
pretty massless from what we can observe so 
getting all of those things cooked together in a  

173
00:16:40,160 --> 00:16:46,360
way that you can make reasonable predictions 
took the effort of many people and taking hints  

174
00:16:46,360 --> 00:16:51,280
from many different places. And then you mentioned 
before right the fermionic side, right, so we were  

175
00:16:51,280 --> 00:16:56,400
talking about the Higgs being a boson. Particles 
can be two types, they can be bosons and fermions but  

176
00:16:56,400 --> 00:17:01,280
that came kind of separately and that was 
largely I believe from Steven Weinberg.  

177
00:17:01,280 --> 00:17:07,160
He had a very nice paper. Two and a half pages long. 
I know I mean you look back at these papers even  

178
00:17:07,160 --> 00:17:12,880
Peter Higgs' paper, right, I think it's four pages 
or something, few pages to do it and we need 15  

179
00:17:12,880 --> 00:17:18,080
pages for labelling the number of the physicists, 
the names of the physicists who were involved.

180
00:17:18,080 --> 00:17:25,520
Wait wait wait wait, please do not mix theoretical 
work with experimental work because

181
00:17:25,520 --> 00:17:29,640
one of the things that I really admire about 
theorists is their ability to just go walk in  

182
00:17:29,640 --> 00:17:34,800
the Alps and come back and write four pages with 
a completely new idea that then we have to go and  

183
00:17:34,800 --> 00:17:40,800
build a detector and get thousands of people 
together to build these detectors to disprove  

184
00:17:40,800 --> 00:17:46,040
that idea but there's a very different exercise 
of working together as experimentalists.

185
00:17:46,040 --> 00:17:51,360
Don't forget when they took that walk it was because 
they'd read our papers from before that showed  

186
00:17:51,360 --> 00:17:55,640
them that we had found some patterns or some 
particle or something. Sometimes. Sometimes they

187
00:17:55,640 --> 00:18:00,480
just go off in their own directions you.
Since you mentioned the Higgs paper in 1964 

188
00:18:00,480 --> 00:18:07,560
and as far as I remember he didn't 
propose like any experiment that can verify his  

189
00:18:07,560 --> 00:18:15,120
theory so why did the scientific community take 
him seriously and decided to spend like

190
00:18:15,120 --> 00:18:21,520
billions of euro on building the detectors to 
search for the boson. Well I don't think they did

191
00:18:21,520 --> 00:18:30,400
immediately to do it right. I mean this was in 
the 60s which is now 60 years ago to do it.   

192
00:18:30,400 --> 00:18:35,240
There was another paper I think it came out 
in the ' 80s if I remember correctly,

193
00:18:35,240 --> 00:18:42,200
the one of John Ellis and Mary K to do it 
which is called on the experimental profile

194
00:18:42,200 --> 00:18:47,640
of the Higgs boson or something like that. It has this 
beautiful coda. Exactly and the coda basically in  

195
00:18:47,640 --> 00:18:50,960
this paper I think it was the 80s I could be 
slightly wrong about it.The phenomenological profile.

196
00:18:50,960 --> 00:18:57,240
Yes that's the one. It basically says 
we do not encourage

197
00:18:57,240 --> 00:19:02,160
large experimental searches for such a boson 
but the paper basically is out, you know, here's

198
00:19:02,160 --> 00:19:05,720
the Higgs, here's how you might look for it and 
things like that. If it has this mass it looks  

199
00:19:05,720 --> 00:19:10,200
like this if it has that mass it looks like that. 
That was quite useful and they discouraged  

200
00:19:10,200 --> 00:19:17,760
us simply because it's so hard, right, it's not easy 
to wasn't an easy task to find. It was hard and it  

201
00:19:17,760 --> 00:19:22,880
the mass was unknown, which is something Andre, I 
think, already mentioned which meant that it's not  

202
00:19:22,880 --> 00:19:26,720
like you could build an experiment to go find this 
particle of a specific mass you had to be able to  

203
00:19:26,720 --> 00:19:32,240
cover this entire range and if it was infinite 
you would maybe not find it at all to do it

204
00:19:32,240 --> 00:19:37,320
but then subsequently we added extra constraints 
which able to sort of narrow down the range where  

205
00:19:37,320 --> 00:19:40,640
we were doing. So I think what the answer I'm 
trying to give is it was a bit of a process.

206
00:19:40,640 --> 00:19:44,760
So it wasn't like you know Peter Higgs had this idea and 
they said okay let's go and do a 60-year programme  

207
00:19:44,760 --> 00:19:49,680
to find the Higgs boson to do it. They started 
actually by exploring the Standard Model because  

208
00:19:49,680 --> 00:19:55,000
there were a number of these particles they had 
to discover along the way and then as things were  

209
00:19:55,000 --> 00:20:01,600
discovered how to search for it became more clear 
and then the decision was taken and when you

210
00:20:01,600 --> 00:20:08,280
come back to the billions so one of the things 
that the LHC had going for it is that you either  

211
00:20:08,280 --> 00:20:15,040
find the Higgs boson or we would be operating, 
we would be doing collisions at such an energy that  

212
00:20:15,040 --> 00:20:20,720
the theory becomes invalid and then something else 
has to come up. So out of these two outcomes we did  

213
00:20:20,720 --> 00:20:27,440
find something that looks like a Higgs boson which 
is great so we now have a new tool with which to  

214
00:20:27,440 --> 00:20:34,760
hammer nature and get the truth out but 
this was called a no-lose theorem and that

215
00:20:34,760 --> 00:20:40,720
was critical for actually going and spending the 
money but I don't think Peter Higgs even thought  

216
00:20:40,720 --> 00:20:46,240
about spending the money. So back in the 1960s 
they were trying to figure out how to make the  

217
00:20:46,240 --> 00:20:53,000
math work. How can you make the observations, 
how can you reconcile the observations with what  

218
00:20:53,000 --> 00:20:58,400
the theory is saying because in the beginning before 
Brout, Englert, HIggs

219
00:20:58,400 --> 00:21:05,480
all of these people got the math worked out, the theory 
just said all particles are massless and then  

220
00:21:05,480 --> 00:21:10,440
it was clear that they weren't because 
we had experimental evidence that they weren't.  

221
00:21:10,440 --> 00:21:13,560
So they figured out that problem and then there were 
other problems with the theory and then at some  

222
00:21:13,560 --> 00:21:20,480
point we reached the point where we could build 
an accelerator that would make collisions that  

223
00:21:20,480 --> 00:21:26,040
if there is no Higgs boson, then the calculations 
start giving answers like infinity and infinity  

224
00:21:26,040 --> 00:21:30,560
is a very large number. Yeah, I mean I actually 
really like that we were very lucky to have this  

225
00:21:30,560 --> 00:21:35,960
no-lose theorem. It's very rare that you can build 
an experiment like that but it was even I mean  

226
00:21:35,960 --> 00:21:40,400
when you say the theory breaks, it was quantum 
mechanics that would break, right, so it's not just  

227
00:21:40,400 --> 00:21:45,000
you know the Higgs would not be there or something, 
it would be that something very fundamental in  

228
00:21:45,000 --> 00:21:50,200
our understanding of physics would have been wrong. 
And that would have been great.  

229
00:21:50,200 --> 00:21:55,880
This is something that, well, it would have been a 
challenging time. No, no, no, so I agree with

230
00:21:55,880 --> 00:22:01,880
what you're saying but some people panic 
when there's a crisis,

231
00:22:01,880 --> 00:22:07,520
some people panic, some people calm down.
I don't know how to put it.

232
00:22:07,520 --> 00:22:13,080
So when things break it's an 
actual opportunity to go and try and understand

233
00:22:13,080 --> 00:22:19,080
why doesn't it work because the measurements don't 
lie, the measurements are statements about nature.

234
00:22:19,080 --> 00:22:23,640
Then how can we explain the measurements if we no 
longer have a way of explaining them, you have to  

235
00:22:23,640 --> 00:22:28,360
find a different way of explaining them. This 
could be like Michelson–Morley and not finding  

236
00:22:28,360 --> 00:22:32,400
the ether and then you have someone like 
Einstein come along and say of course there's no ether.

237
00:22:32,400 --> 00:22:41,360
Here's another solution. We do like it 
when our physical theories  

238
00:22:41,360 --> 00:22:45,200
are broken and when we find something wrong with 
them and we spend a lot of time trying to find  

239
00:22:45,200 --> 00:22:53,760
what's wrong with our theories, right? Were either 
of you part of the LHC bet about the Higgs boson?

240
00:22:53,760 --> 00:22:59,880
No, I heard about it. Was it a bet about 
whether or not or was it a bet about it was? So it was

241
00:22:59,880 --> 00:23:04,840
a pool and I think it was 10 Francs or 
something like that and basically you could  

242
00:23:04,840 --> 00:23:11,520
bet on do we find the Higgs boson on or not 
and if so what mass it would have. Who won?

243
00:23:11,520 --> 00:23:16,440
I don't actually know that question. We have 
to look that up. I know who did the poll, so I can  

244
00:23:16,440 --> 00:23:21,240
write to him and ask him. We're going to 
give it a challenge to our audience they can they  

245
00:23:21,240 --> 00:23:28,440
can put that into our comments on our 
YouTube channel if you find out who won the bet

246
00:23:29,280 --> 00:23:35,000
of the pool as you say of the Higgs mass 
that'd be interesting to know. I bet on no Higgs boson.  

247
00:23:35,000 --> 00:23:40,360
Oh, you bet on no Higgs boson, yeah, really? That's 
what I wanted. That's interesting since you brought  

248
00:23:40,360 --> 00:23:46,880
up like the topic about the mass of the Higgs 
boson and like we didn't know prior like  

249
00:23:46,880 --> 00:23:53,160
what was the mass of Higgs boson and it made 
it so hard that we call it the goddamn particle  

250
00:23:53,160 --> 00:23:58,960
but I wonder because like I think that we already 
have like the Standard Model which is a  

251
00:23:58,960 --> 00:24:07,240
very good theory like the best theory we have 
so far and the data from the LEP (the Large  

252
00:24:07,240 --> 00:24:14,480
Electron-Positron collider) so we already had the 
constraint on the mass of the Higgs like before  

253
00:24:14,480 --> 00:24:21,960
the Large Hadron Collider come into play so why was it 
still very hard and why was it like searching for  

254
00:24:21,960 --> 00:24:28,480
the needle in the hay? Oh gosh, there's a 
lot of different questions all in one.

255
00:24:28,480 --> 00:24:35,920
So maybe I'll go back to what 
we knew about it right so LEP which was the Large  

256
00:24:35,920 --> 00:24:41,800
Electron-Positron collider, it actually found 
something that some people thought might have  

257
00:24:41,800 --> 00:24:45,400
been a Higgs boson right at the end, so there 
was all sorts of excitement. There was a

258
00:24:45,400 --> 00:24:51,240
little excess to do it and should we extend it 
should they shut down in the LHC etc.  

259
00:24:51,240 --> 00:24:56,200
But in the end after the analysis you know they 
put a constraint I think it was 114 GeV if I  

260
00:24:56,200 --> 00:25:00,200
remember correctly so that was a lower bound and 
that was super clear. But then what you were talking  

261
00:25:00,200 --> 00:25:05,800
about the Standard Model this is more complex. 
So what this was is like taking all the different

262
00:25:05,800 --> 00:25:11,680
parameters in the Standard Model doing a global 
fit and saying are they all consistent and  

263
00:25:11,680 --> 00:25:16,600
with that you could put a kind of you know this 
is around where the Higgs should be. Also, this is

264
00:25:16,600 --> 00:25:22,240
sort of more at the same time as the LHC I would 
say the Tevatron started to give some bounds as well  

265
00:25:22,240 --> 00:25:28,120
in the mid kind of range on the Higgs boson 
so we had that as well. But I think one of the  

266
00:25:28,120 --> 00:25:32,720
reason why we still weren't sure about the 
mass is that it's still possible you could change  

267
00:25:32,720 --> 00:25:38,080
the Standard Model a little bit and then that whole fit 
wouldn't make sense right so you still needed to  

268
00:25:38,080 --> 00:25:42,000
look over that full range at least that's how 
I kind of thought about it.

269
00:25:42,000 --> 00:25:45,960
I know that's not exactly your question I'm answering, 
the first half. It's a good point

270
00:25:45,960 --> 00:25:52,280
though because we spend a lot of effort up to this 
day still measuring the standard model parameters  

271
00:25:52,280 --> 00:25:57,520
as precisely as we possibly can actually for some 
of us at least hoping there'll be disagreement at  

272
00:25:57,520 --> 00:26:01,480
some point because there's many things that are 
not in the Standard Model that are not explained  

273
00:26:01,480 --> 00:26:05,200
by the Standard Model. So it's just because the 
Standard Model says so it doesn't mean it happens

274
00:26:05,200 --> 00:26:13,600
in nature like that. I mean for all the successes 
of the Standard Model it explains what 5% of the universe.  

275
00:26:13,600 --> 00:26:20,080
I mean it's sometimes hard to hold this thought
in my mind wow it's a beautiful theory

276
00:26:20,080 --> 00:26:24,960
I work with it every day it makes predictions 
I can go and measure things and  

277
00:26:24,960 --> 00:26:31,320
at the same time it's only 1/20th of everything 
that's out there. You're referring to the fact

278
00:26:31,320 --> 00:26:37,080
that there's a lot of the universe, about a 
quarter is dark matter, which we have no clue what  

279
00:26:37,080 --> 00:26:44,960
it is and then about 2/3rd is dark energy and there's 
dark matter dark energy. I've got dark energy, I've got it right

280
00:26:44,960 --> 00:26:51,840
in my in coffee cup dark Energy and that's 
that's like a huge portion, the amount of energy,  

281
00:26:51,840 --> 00:26:57,720
whatever is making our universe expand by a lot 
more and more, right? 

282
00:26:57,720 --> 00:27:02,160
We have even less of a clue.

283
00:27:02,160 --> 00:27:08,160
If a physicist calls it dark it's 
just a measure of the ignorance. Exactly. 

284
00:27:08,160 --> 00:27:15,120
I do want to mention and oh 
by the way of the 5% we don't  

285
00:27:15,120 --> 00:27:21,400
get gravity too right so this is even of that 
we aren't we don't have a complete understanding  

286
00:27:21,400 --> 00:27:27,240
but I I did want to mention a few names because 
we've said their names several times   

287
00:27:27,240 --> 00:27:33,000
Robert Brout and François Englert didn't say their full names. 
They along with, it is interesting the story that  

288
00:27:33,000 --> 00:27:38,560
you said when Peter Higgs had first put his paper 
out and then it got rejected simply you know  

289
00:27:38,560 --> 00:27:43,800
for by the CERN referees I think it was. 
I don't know exactly there's a whole history  

290
00:27:43,800 --> 00:27:49,360
of that in a book that I cannot recall the name 
right now but there's a whole explanation of how  

291
00:27:49,360 --> 00:27:53,920
it happened and of course humans were involved in 
that. We're stuck with humans I think

292
00:27:53,920 --> 00:27:59,400
for now until whales can help us out 
with our papers.

293
00:27:59,400 --> 00:28:06,320
But also I mean François Englert and Robert Brout they then 
got their their paper published first but then

294
00:28:06,320 --> 00:28:11,680
then came in the Higgs paper and the reason we call 
the Higgs boson of course is because he included the  

295
00:28:11,680 --> 00:28:16,480
fact that there was a particle associated with 
the field which everybody knew there's a field  

296
00:28:16,480 --> 00:28:22,280
there's a particle there's a particle there's 
a field and I can feel I can feel a question

297
00:28:22,280 --> 00:28:29,400
coming from Chetna about the Higgs "boson". Do you 
have a question about the Higgs boson, Chetna?

298
00:28:29,400 --> 00:28:35,960
Yeah, enough of the Higgs, let's talk about what's boson 
where did the term come from? The boson.

299
00:28:35,960 --> 00:28:41,320
So that's a very important point and this was actually brought up by, I do remember when there was the discovery,

300
00:28:41,320 --> 00:28:46,240
there were some complaints that came mainly out 
of India asking like how come we're not talking about Bose.

301
00:28:55,480 --> 00:29:02,240
when bosons get together they distribute themselves in a certain way 
and when fermions named after Enrico Fermi

302
00:29:02,240 --> 00:29:07,760
they don't get together so they distribute themselves 
in a different way. So bosons tend to be the force carrying 

303
00:29:07,760 --> 00:29:13,560
particles call them. Excitations of field. They're 
all excitations of field in quantum field theory yet.

304
00:29:13,560 --> 00:29:21,240
We're not going to go into quantum field theory 
yet but anyway yeah there's

305
00:29:21,240 --> 00:29:28,120
different kinds of statistics that was there was 
Bose-Einstein statistics, Fermi-Dirac statistics.  

306
00:29:28,120 --> 00:29:33,280
So boson was very important. In my response there 
were some people who complained they said how  

307
00:29:33,280 --> 00:29:39,920
come Higgs is capitalised and boson is not 
capitalised and my claim is that it's even  

308
00:29:39,920 --> 00:29:46,680
a greater honour to have your name used with a 
small letter without the capital letter that means  

309
00:29:46,680 --> 00:29:55,320
it's common and bosons are very important and common 
throughout our field.

310
00:29:55,320 --> 00:30:03,080
Bosons are integral, these photons heating up our 
room here and giving us light, they are bosons

311
00:30:03,080 --> 00:30:09,640
and boson is not capitalised for that and 
same with fermions so there's Bose-Einstein statistics

312
00:30:09,640 --> 00:30:15,200
which describe the bosons and there's Fermi-Dirac statistics which 
describe the fermions which tend to be the sort of  

313
00:30:15,200 --> 00:30:22,920
matter particles as opposed to the force carrying 
particles (bosons). So we got the boson point in and

314
00:30:22,920 --> 00:30:28,360
Chetna is happy about that. I did want to mention 
there's a few things that when you guys want  

315
00:30:28,360 --> 00:30:34,920
to get more information there's some nice books 
out there we already mentioned the God particle

316
00:30:34,920 --> 00:30:40,760
book of course. I really liked this very 
short book, easy to read, by Lisa Randall called

317
00:30:40,760 --> 00:30:46,440
The Higgs Discovery simply. There's also a 
new one that came out by Matt Strassler.

318
00:30:46,440 --> 00:30:51,760
He's a theorist and he wrote a book that's called 
Waves In An Impossible Sea.   

319
00:30:51,760 --> 00:30:58,160
So I actually interviewed 
Matt in Berkeley recently about his book  

320
00:30:58,160 --> 00:31:04,760
and what's interesting about this 
book is he doesn't like the way we explain  

321
00:31:04,760 --> 00:31:11,480
the Higgs Boson and the Higgs mechanism to the public. 
He thinks that we use metaphors that are wrong.

322
00:31:11,480 --> 00:31:17,040
So the basic idea of the book, he's 
right of course, is to actually explain it from  

323
00:31:17,040 --> 00:31:22,440
scratch how things really work without, 
you know, using any metaphors and things like that.  

324
00:31:22,440 --> 00:31:26,280
So he's deeply critical of all the metaphors we've 
been using today. Okay, Matt, I will read your book.

325
00:31:26,280 --> 00:31:32,640
Back in 2012

326
00:31:32,640 --> 00:31:38,600
I was working as our outreach coordinator for the ATLAS experiment. 
Full disclosure, I'm on ATLAS and my good friend  

327
00:31:38,600 --> 00:31:45,480
Dave Barney was the outreach coordinator for the CMS experiment 
and we got together and we made a Ted Ed animation

328
00:31:45,480 --> 00:31:51,480
 which was a lot of fun and it was all 
about the fact that whenever we asked all of our  

329
00:31:51,480 --> 00:31:57,360
friends how to describe the Higgs boson and the Higgs 
field they would go through all of these different  

330
00:31:57,360 --> 00:32:03,200
metaphors we finally settled on one which I'm 
sure Matt won't like which was a cherry  

331
00:32:03,200 --> 00:32:11,080
being dropped into a a shake and the splash of the 
cherry in the shake and the splash, it's an injection  

332
00:32:11,080 --> 00:32:18,720
of energy into a field that splash that excitation 
of the field was I mean that was the best we could do.  

333
00:32:18,720 --> 00:32:24,200
It sounds more delicious than the one I heard of 
of dropping a stone on the lake. 

334
00:32:24,200 --> 00:32:31,000
It was fun and it's true that you know we 
live in the this we're you know all macroscopic  

335
00:32:31,000 --> 00:32:39,640
and we all move non-relativistically and so 
to actually even comprehend this is perhaps  

336
00:32:39,640 --> 00:32:45,920
beyond our imagination but I'm interested to see 
what how Matt made it accessible. Did he make it accessible?

337
00:32:45,920 --> 00:32:51,720
I found it very interesting 
to read so there's a lot about relativity so  

338
00:32:51,720 --> 00:32:55,920
he starts with relativity right and sort of 
explaining you know hard it works and things  

339
00:32:55,920 --> 00:33:02,080
like that no equations by the way so oh that's 
nice yeah know. It's a fun book.

340
00:33:02,080 --> 00:33:06,560
Let's move on. So we we found it, we've already 
declared victory, we found the Higgs boson.  

341
00:33:06,560 --> 00:33:12,200
So then we just turn off the Large Hadron Collider (LHC) and go home, right?  

342
00:33:12,200 --> 00:33:18,840
Why do you carry on? What have we been doing for the 
past 12 years with this Higgs boson? Has it taught  

343
00:33:18,840 --> 00:33:23,840
us more and what have we learned more about it? Well of 
course that would be great because then we could  

344
00:33:23,840 --> 00:33:27,960
you know just sit at home and drink coffee. Exactly. 
Actually no it would really suck.

345
00:33:27,960 --> 00:33:34,280
The truth is of course is we found a 
particle consistent with the Standard Model, Higgs boson.  

346
00:33:34,280 --> 00:33:38,800
I believe that was the precise statement which 
meant actually we had a whole bunch of things we  

347
00:33:38,800 --> 00:33:44,960
needed to know, right? We needed to know was it the 
Standard Model of the Higgs boson. We needed to know what

348
00:33:44,960 --> 00:33:50,320
was its mass to do it but the first one, this is
the Standard model of the Higgs boson, that actually gives you

349
00:33:50,320 --> 00:33:54,360
a whole bunch of other questions. 
Andre talked a whole lot about all the different  

350
00:33:54,360 --> 00:34:00,880
particles that it needs to interact with, we needed 
to measure each those because you know if some of  

351
00:34:00,880 --> 00:34:06,160
them were just not there then there was something 
wrong with the theory to do it. We had to  

352
00:34:06,160 --> 00:34:09,880
measure its mass, we talked about how we 
didn't know the mass at all and then people came  

353
00:34:09,880 --> 00:34:14,120
up with some clever things for example probing 
the width of the Higgs boson which was something

354
00:34:14,120 --> 00:34:20,040
that was meant to be impossible at the LHC like 
three orders of magnitude impossible but yet  

355
00:34:20,040 --> 00:34:25,240
I mean there are some assumptions.
Quantum mechanical trickery. I should mention  

356
00:34:25,240 --> 00:34:29,760
orders of magnitude we use that all the time 
three orders of magnitude means you have three  

357
00:34:29,760 --> 00:34:37,280
zeros after the one so it's a thousand times away. 
The Higgs boson is a thousand times narrower than the  

358
00:34:37,280 --> 00:34:43,240
resolution of our detectors. So our detectors 
measure things with only a finite resolution

359
00:34:43,240 --> 00:34:47,760
and the Higgs boson width is much smaller than 
that so we had to resort to quantum mechanical  

360
00:34:47,760 --> 00:34:54,720
trickery. Ah quantum mechanical trickery yep that's 
that's a beautiful way to describe it. And were we able to measure that width?

361
00:34:54,720 --> 00:35:01,600
Yes, well, we're at small number of significance 
but we're starting to probe the width

362
00:35:01,600 --> 00:35:04,975
unfortunately consistent with Standard Model

363
00:35:04,975 --> 00:35:12,800
but we're not done by the way so we have not measured everything yet. 
A big thing that's missing is one of the funny things

364
00:35:12,800 --> 00:35:18,080
about the Higgs boson is that it needs to interact 
with itself without changing itself this comes

365
00:35:18,080 --> 00:35:25,080
from some of the Higgs. HIggs boson gives mass. 
So we need to probe that and there's  

366
00:35:25,080 --> 00:35:29,600
a way to do it where you need to look for events 
containing two Higgs boson but they're very rare.  

367
00:35:29,600 --> 00:35:35,080
The di-Higgs searches. These are the di-Higgs searches so 
that needs to be done there also a number of  

368
00:35:35,080 --> 00:35:40,320
these decays of the Higgs boson just you know the 
particles it produces when it disappears that we  

369
00:35:40,320 --> 00:35:45,360
haven't been able to measure just yet. 
We also need to look for ones that it shouldn't  

370
00:35:45,360 --> 00:35:51,520
do right particles it could decay to so we're 
sort of I don't know we've got a basic profile of  

371
00:35:51,520 --> 00:35:57,200
it but there's still big pieces missing that's 
sort of how I would see it. So we were talking  

372
00:35:57,200 --> 00:36:04,000
earlier about the fermions like the quarks and the 
leptons so for an example of a forbidden decay is  

373
00:36:04,000 --> 00:36:10,640
like the Higgs boson decaying into a muon and an 
electron. It can go into an electron

374
00:36:10,640 --> 00:36:17,000
and a positron, a muon and anti-muon, a beauty quark and an anti-beauty quark,  charm quark and anti-charm quark

375
00:36:17,000 --> 00:36:24,400
but mixing things around it should not be 
able to to mix things. So indeed one of the

376
00:36:24,400 --> 00:36:32,280
biggest thrusts of let's say the Higgs physics 
programme is not only going and probing these  

377
00:36:32,280 --> 00:36:39,040
interactions if it decays into these lighter and 
lighter particles because those are more rarified  

378
00:36:39,040 --> 00:36:46,680
interactions they are not as strong. It's also this 
question of how does the Higgs interact with itself  

379
00:36:46,680 --> 00:36:53,800
and that has some interesting consequences, 
connections because it connects to the vacuum

380
00:36:53,800 --> 00:37:01,640
structure of the universe and you know this sounds 
very arcane, it is a bit arcane but basically at least  

381
00:37:01,640 --> 00:37:06,040
for me as an experimentalist what is important is 
that the Standard Model says it must be exactly  

382
00:37:06,040 --> 00:37:13,760
like this so the Standard Model says that this 
potential of a vacuum energy in the universe must  

383
00:37:13,760 --> 00:37:20,000
have a specific very very specific shape 
and you do not really you cannot deviate from  

384
00:37:20,000 --> 00:37:25,600
it without breaking the Standard Model so if we 
are able to measure how the Higgs boson interacts with  

385
00:37:25,600 --> 00:37:31,560
itself we can check whether or not that is what 
is realized in nature so measuring the shape of  

386
00:37:31,560 --> 00:37:39,400
this potential becomes something that the Higgs 
boson allows us to do and so it's a big thrust  

387
00:37:39,400 --> 00:37:44,960
not just for the LHC so we've barely touched the 
surface at the LHC but for the upgrades of the LHC

388
00:37:44,960 --> 00:37:52,200
that will start in 2029. Just to explain how the 
LHC works. We collide bunches

389
00:37:52,200 --> 00:38:00,400
it's not really a continuous beam of protons but 
we collide bunches of of protons every 25 nanoseconds

390
00:38:00,400 --> 00:38:05,840
at the different places where we have the 
detectors so there's four collision points and  

391
00:38:05,840 --> 00:38:13,040
these bunches go through each other, each bunch is 
a galaxy of protons, roughly 100 billion

392
00:38:13,040 --> 00:38:18,200
protons so you have Andromeda, the Milky Way 
passing through each other every 25 nanoseconds, roughly speaking.

393
00:38:18,200 --> 00:38:22,000
Yeah no no no I'm thinking about the 
number of stars in a galaxy yeah it's  

394
00:38:22,000 --> 00:38:26,920
roughly 100 billion and actually if Andromeda 
and Milky Way are going to do this

395
00:38:26,920 --> 00:38:31,720
it goes slower, much more slowly and they predict

396
00:38:31,720 --> 00:38:36,720
none of the stars are actually going to hit each 
other probably they won't even though those are  

397
00:38:36,720 --> 00:38:42,680
pretty dense galaxies but in our case we really 
put these bunches together as densely as possible  

398
00:38:42,680 --> 00:38:46,600
which you have to do because they don't want to 
be together they're protons they have charges

399
00:38:46,600 --> 00:38:51,280
that make them push apart and they go through each 
other and as tight as we squeeze them as well as  

400
00:38:51,280 --> 00:38:56,760
we focus them and bring them through each other

401
00:38:56,760 --> 00:39:02,320
we get actually on average about 60 will actually 
go through each other pass through each other and

402
00:39:02,320 --> 00:39:06,120
then of that less than that will actually interact 
and give us something that's interesting yeah and  

403
00:39:06,120 --> 00:39:12,680
we call it luminosity because you make the beams
as narrow as possible

404
00:39:12,680 --> 00:39:17,040
because you are saying here they are 
as bright as possible right

405
00:39:17,040 --> 00:39:22,840
so the brighter they are the more collisions you get 
and the more luminous the interaction region is.

406
00:39:22,840 --> 00:39:27,360
So I wanted to clarify one thing we don't actually want these 
60 collisions to happen, so what we want

407
00:39:28,000 --> 00:39:33,320
is we would like our rare processes right like 
Higgs boson to happen as much as possible. On demand.

408
00:39:33,320 --> 00:39:40,320
And on the background ones to stay away but 
so but the problem is like increasing the rate of  

409
00:39:40,320 --> 00:39:45,960
those processes has a side effect of having 
these extra collisions and it makes

410
00:39:45,960 --> 00:39:50,480
our life harder because we have to actually search 
through those extra ones to find out the ones that we rarely want.

411
00:39:50,480 --> 00:39:56,760
We get it when when something 
interesting, we label as "interesting"

412
00:39:56,760 --> 00:40:02,040
triggers our detectors we call the system a "trigger" 
like taking a picture it's because something  

413
00:40:02,040 --> 00:40:07,680
something came out from this passing of these two 
bunches like a muon coming out or electron or some  

414
00:40:07,680 --> 00:40:13,760
energy or some balance or something that we put 
into our our menu of things we want to look for  

415
00:40:13,760 --> 00:40:18,480
and then you've got all of these other collisions 
that happened at the same time and then you have  

416
00:40:18,480 --> 00:40:25,320
to sort them out from that so that's 
what we're going to be going up for in four  

417
00:40:25,320 --> 00:40:31,760
years time or something like that. We will actually 
go up to, we hope we get everything on time and  

418
00:40:31,760 --> 00:40:37,840
in that case we can look for things which are 
much more rare and we can look for maybe 

419
00:40:37,840 --> 00:40:43,360
Higgs bosons interacting with muons for example or 
transforming to muons maybe we'll have that at  

420
00:40:43,360 --> 00:40:49,160
the end of this run. Yeah that's coming and thanks 
to a lot of work, I mean Heather knows

421
00:40:49,160 --> 00:40:53,360
this better than anyone here, there's a lot 
of techniques from machine learning that have  

422
00:40:53,360 --> 00:40:58,800
been helping us distinguish between like what a 
beauty quark looks like in our detector and a charm quark

423
00:40:58,800 --> 00:41:04,240
looks like in our detector and it's very 
 titillating that we are being able to tease out  

424
00:41:04,240 --> 00:41:09,000
all these charming signals. Yeah no this is kind 
of one of the things that motivates me the best  

425
00:41:09,000 --> 00:41:13,720
way to get me to do something is tell me it's 
impossible then I like to go and solve the  

426
00:41:13,720 --> 00:41:20,520
problem to do it but you're right it's actually 
amazing just how much better things are in certain  

427
00:41:20,520 --> 00:41:24,920
places than we predicted right we found and I 
think it comes there's a whole chunk from machine  

428
00:41:24,920 --> 00:41:30,160
learning like you were saying but I also think 
that that people get clever in a wide variety  

429
00:41:30,160 --> 00:41:34,440
of ways and if you sort of compare you know what 
people thought we would do and what we actually  

430
00:41:34,440 --> 00:41:40,720
do we do far better than any of the predictions 
that we had like you know we're probably going

431
00:41:40,720 --> 00:41:46,160
to see Higgs to mumu in Run 3 looks like that 
at least with combination between ATLAS and CMS

432
00:41:46,160 --> 00:41:52,280
and then di-Higgs we are getting awfully close 
whereas that initially was maybe we'd  

433
00:41:52,280 --> 00:41:58,320
see it at the High-Luminosity LHC
so it's kind of pretty cool I find this

434
00:41:58,320 --> 00:42:04,160
something very exciting about how well we actually 
end up doing our physics yeah. So one interesting

435
00:42:04,160 --> 00:42:10,160
phenomenon here is that when you turn on the 
detector, the detector is also partly unknown  

436
00:42:10,160 --> 00:42:18,160
so with time you learn all its features, the good 
parts, the not so great parts and you learn how to  

437
00:42:18,160 --> 00:42:24,080
calibrate it and you know extract more reliable 
information from it so yes we get smarter at  

438
00:42:24,080 --> 00:42:29,000
figuring out the detectors that we build.
So I want to ask you one more thing before before we end this

439
00:42:29,000 --> 00:42:37,000
about the future, I think they can be just 
predictions what you want to happen. I mean the

440
00:42:37,000 --> 00:42:46,320
Higgs boson, what we've established it interacts with 
any elementary particle that has a mass so far

441
00:42:46,320 --> 00:42:52,600
that's proposed and that's what we hope we're 
seeing. One thought about this dark matter for

442
00:42:52,600 --> 00:43:00,920
example is that there's this stuff out there which 
we've seen really clearly Vera Rubin saw it, he actually

443
00:43:00,920 --> 00:43:07,160
calculated first how much dark matter there was 
in our galaxy and since then we've mapped out this  

444
00:43:07,160 --> 00:43:15,480
existence of dark matter all over our universe 
right and one possibility is that's an

445
00:43:15,480 --> 00:43:22,000
elementary particle so if it were an elementary 
particle does it necessarily mean that we will be  

446
00:43:22,000 --> 00:43:33,040
able to find it if we look hard enough through 
the Higgs boson on or not? So I take exception to the

447
00:43:33,040 --> 00:43:38,440
notion if you'll find it if you look hard enough. 
The way I see things is that, if you don't look

448
00:43:38,440 --> 00:43:43,560
you will not find, that's definitely 
the case. Now as you were pointing out the  

449
00:43:43,560 --> 00:43:51,160
fact that this Higgs boson speaks or talks with 
many different types of particles you know we've  

450
00:43:51,160 --> 00:43:58,720
discussed the bosons and the fermions, perhaps it 
also interacts with dark matter, if dark matter is  

451
00:43:58,720 --> 00:44:04,880
an elementary particle. The Standard Model really 
has no allowance for dark matter particles but  

452
00:44:04,880 --> 00:44:10,280
again one of the reasons why it's called a model 
is because it's always tentative it's something

453
00:44:10,280 --> 00:44:17,880
that can be built upon and so it might be that 
it needs a certain extension in order to   

454
00:44:17,880 --> 00:44:22,680
if we find that kind of interaction of the Higgs boson with 
dark matter particles it will have to be extended  

455
00:44:22,680 --> 00:44:28,360
to account for reality. It would be great. Will it happen? 
I don't know, it depends on what nature has in store.

456
00:44:28,360 --> 00:44:34,680
And what we build, right? 
There are proposals out there now  

457
00:44:34,680 --> 00:44:39,080
which we're discussing amongst ourselves. 
We take it very seriously when we talk about the  

458
00:44:39,080 --> 00:44:45,600
future in our field because it's a big investment 
for all of us and it's a long term, very long-term.  

459
00:44:45,600 --> 00:44:49,560
The plans I've see right now are 
talking about something covering 70 years

460
00:44:49,560 --> 00:44:56,760
to actually build the next scale so and there's 
different ideas out there, we've talked about  

461
00:44:56,760 --> 00:45:02,320
building another ring that's much larger, 
higher energy, order magnitude higher energy  

462
00:45:02,320 --> 00:45:09,560
I use the term order magnitude again that would 
mean one order is 10. Huge and maybe up to  

463
00:45:09,560 --> 00:45:18,400
you know 91 to 100 kilometers around whereas 
the LHC is small, 27-km around or other ideas

464
00:45:18,400 --> 00:45:26,960
like a linear collider which could run at with the 
same energy as the mass of the Higgs Boson to produce

465
00:45:27,640 --> 00:45:34,720
lots and lots of Higgs bosons. So those are 
possibilities. There's also this idea of a muon collider

466
00:45:34,720 --> 00:45:41,880
that's out there which could possibly 
run at that mass. What do you think

467
00:45:41,880 --> 00:45:49,960
about the future for our field? So I'm in 
an interesting state right now I think our field  

468
00:45:49,960 --> 00:45:56,920
we've had a paradigm about how we're looking for 
new physics that the LHC has shown us is maybe not correct, right? 

469
00:45:57,760 --> 00:46:01,960
So we had the Higgs boson on which 
we've been talking about which we found but  

470
00:46:01,960 --> 00:46:06,240
we also had many predictions for you know there 
should be new physics around the TeV scale we had  

471
00:46:06,240 --> 00:46:11,920
a whole range of theories like that so I actually 
think we're at a very interesting time is there's  

472
00:46:11,920 --> 00:46:18,440
a paradigm shift that's needed towards thinking 
I mean there are many possible options for it but  

473
00:46:18,440 --> 00:46:24,760
at least to me I don't see which way we're going 
to go so I preface that by saying and then we  

474
00:46:24,760 --> 00:46:28,600
talk about you know what collider should we 
build we talked all about the no-lose theorem

475
00:46:28,600 --> 00:46:32,680
we were in this fantastic situation at the LHC 
right we said we had this thing we knew which  

476
00:46:32,680 --> 00:46:38,120
one to build and we built it and we found it to do it.
We're not there now and so I  

477
00:46:38,120 --> 00:46:44,600
think we're in a stage where we need to go and 
explore as broadly as possible because right now  

478
00:46:44,600 --> 00:46:53,800
the theory is not clear and maybe it's a time 
when experiment needs to lead the way to do it.  

479
00:46:53,800 --> 00:46:59,800
So if it was up to me I would go to search 
as far as possible to do it. There are many

480
00:46:59,800 --> 00:47:05,080
constraints it's a complex space 
and so you can't necessarily do that but that's  

481
00:47:05,080 --> 00:47:08,600
at least the way I think about it because I think 
it's unknown and we need to try and look as far  

482
00:47:08,600 --> 00:47:17,080
as possible and then we may find big answers that 
change things yeah. I agree especially because

483
00:47:17,080 --> 00:47:22,880
projects take so long if you think about it the 
the Higgs boson was found like 50 odd years after  

484
00:47:22,880 --> 00:47:32,720
it was predicted. During those 50 years, theory was 
guiding the way right and and indeed I totally

485
00:47:32,720 --> 00:47:40,600
agree with what Heather has said we are now in a data 
driven era if you want and in that case  

486
00:47:40,600 --> 00:47:46,800
the question is what kind of tools are we building 
to gather data and to explore nature and I don't  

487
00:47:46,800 --> 00:47:52,560
think there's ever a promise that can be made 
that oh we are going to find the but that's the  

488
00:47:52,560 --> 00:47:57,240
thing if if you don't look for it if you don't 
try you're definitely never going to find it.  

489
00:47:57,240 --> 00:48:01,120
I think there was a sort of a consensus in the 
community that the next machine should be what

490
00:48:01,120 --> 00:48:09,400
we call a Higgs factory which is you make collisions 
and lots of Higgses come out because it has  

491
00:48:09,400 --> 00:48:15,520
not only this very central role regardless of it 
having a central role in the theory it has this  

492
00:48:15,520 --> 00:48:21,120
very central role it talks to many particles as 
you were saying, Steve. We also do not understand  

493
00:48:21,120 --> 00:48:29,320
how come there's only one, is there only one? 
Who knows if there's only one and changes in the  

494
00:48:29,320 --> 00:48:33,160
properties predicted by the Standard Model for 
this particle can tell us whether there are more Higgs bosons  

495
00:48:33,160 --> 00:48:37,960
if there are other interactions for 
instance measuring the total width is really  

496
00:48:37,960 --> 00:48:46,080
cool because the total width via some quantum 
mechanical trickery is related to all the possible  

497
00:48:46,080 --> 00:48:51,720
ways that the Higgs boson can decay into other particles. 
So if you would find something anomalous  

498
00:48:51,720 --> 00:48:56,960
there you know some departure with respect to 
Standard Model it could be because it is the  

499
00:48:56,960 --> 00:49:03,400
go into I don't know the dark matter particles 
if they are there. So all of these things, many

500
00:49:03,400 --> 00:49:09,320
people think well think of the Higgs boson as a 
sort of object of study. I think of it as a tool  

501
00:49:09,320 --> 00:49:14,120
so it's a tool that we can now go and try 
in different types of screws and different

502
00:49:14,120 --> 00:49:19,960
types of knobs and wrenches so you just try 
it out and see exactly how does it operate in  

503
00:49:19,960 --> 00:49:25,920
that particular context. Very good. Let's leave it 
at that. That's a very nice conclusion there.

504
00:49:25,920 --> 00:49:31,800
I'm looking forward to these new accelerators 
wherever and whatever they they may be.

505
00:49:31,800 --> 00:49:39,560
Andre David is a CERN physicist on the CMS experiment 
here on the Large Hadron Collider. Heather Grey is an

506
00:49:39,560 --> 00:49:45,320
associate professor at UC Berkeley in Berkeley 
lab working on the ATLAS experiment here on  

507
00:49:45,320 --> 00:49:51,360
the Large Hadron Collider. Thank you both for coming 
here and being on Early Morning Coffee at CERN.

508
00:49:51,360 --> 00:49:57,920
Okay Joni it's time for you. You have a question 
for the audience. So my question for you is that,

509
00:49:57,920 --> 00:50:05,800
what is the other important discovery 
that brought a CERN physicist a Nobel prize after

510
00:50:05,800 --> 00:50:12,640
the benchmark for the Higgs discovery?
So we have Nobel Prize that was awarded

511
00:50:12,640 --> 00:50:19,840
to Peter Higgs, François Englert. Unfortunately, 
Robert Brout died the year before we discovered it but  

512
00:50:19,840 --> 00:50:26,760
before that there had been a Nobel Prize at CERN 
so tell us what that Nobel Prize was and you said  

513
00:50:26,760 --> 00:50:36,440
to send it to CERN social media so @CERN on 
pretty much any social platform right with #EMC2 and

514
00:50:36,440 --> 00:50:41,880
you can also put comments in our YouTube channel 
and you're going to be able to follow all of our  

515
00:50:41,880 --> 00:50:49,160
podcasts on anywhere you get your podcast.
We look forward to seeing you again soon.

516
00:50:49,160 --> 00:50:56,200
Next time we are going to probe into the experiment called LHCb 
which is a very interesting experiment because

517
00:50:56,200 --> 00:51:01,120
they don't just just look at the quarks, the 
elementary particles but they look at various  

518
00:51:01,120 --> 00:51:06,400
combinations of these quarks and they found a lot 
so they've made a lot of discoveries a big list  

519
00:51:06,400 --> 00:51:12,320
of discoveries that have come from LHCb filling 
up our particle data group books with discoveries.

520
00:51:12,320 --> 00:51:24,440
So we'll be talking about that next time so 
have a great time and thank you for listening.