The Higgs boson discovery revisited

1
00:00:05,200 --> 00:00:08,240
Physics World. Hello, and welcome to the Physics

2
00:00:08,240 --> 00:00:10,880
World Stories Podcast. As a layman, I would

3
00:00:10,880 --> 00:00:11,619
now say,

4
00:00:12,320 --> 00:00:13,619
I think we have it.

5
00:00:14,625 --> 00:00:15,365
You agree?

6
00:00:15,744 --> 00:00:16,244
Yeah.

7
00:00:20,864 --> 00:00:22,644
That was Rolf Dieter Heuer,

8
00:00:23,184 --> 00:00:26,464
former director general of CERN, 10 years ago

9
00:00:26,464 --> 00:00:28,244
at the announcement of the discovery

10
00:00:28,625 --> 00:00:29,609
of the Higgs boson.

11
00:00:30,170 --> 00:00:32,090
In this episode of the podcast, we'll hear

12
00:00:32,090 --> 00:00:34,409
about the excitement at CERN at the time

13
00:00:34,409 --> 00:00:36,329
of their discovery. We'll hear about the research

14
00:00:36,329 --> 00:00:38,409
that's been happening looking into the Higgs since

15
00:00:38,409 --> 00:00:39,070
that discovery,

16
00:00:39,370 --> 00:00:41,789
and we'll look forward to what might come

17
00:00:41,850 --> 00:00:44,414
in particle physics. The Higgs boson is a

18
00:00:44,414 --> 00:00:47,475
fundamental particle associated with the Higgs field,

19
00:00:47,854 --> 00:00:50,195
a field that gives mass to other fundamental

20
00:00:50,335 --> 00:00:51,875
particles such as electrons

21
00:00:52,254 --> 00:00:52,994
and quarks.

22
00:00:53,454 --> 00:00:56,574
It's often known as the God particle because

23
00:00:56,574 --> 00:00:58,890
for a generation of scientists, it had to

24
00:00:58,890 --> 00:01:01,710
be taken on faith that it even existed.

25
00:01:02,409 --> 00:01:03,789
The Large Hadron Collider,

26
00:01:04,170 --> 00:01:07,290
a particle accelerator at CERN in Switzerland, was

27
00:01:07,290 --> 00:01:10,569
designed at least in significant part to see

28
00:01:10,569 --> 00:01:12,805
if that particle could be discovered. In a

29
00:01:12,805 --> 00:01:14,744
huge loop under Switzerland

30
00:01:15,045 --> 00:01:18,104
and into France, the Large Hadron Collider accelerates

31
00:01:18,244 --> 00:01:20,325
protons to near the speed of light and

32
00:01:20,325 --> 00:01:23,224
collides them. Around the ring, there are individual

33
00:01:23,364 --> 00:01:23,864
experiments

34
00:01:24,244 --> 00:01:26,344
like ATLAS and the CMS experiment,

35
00:01:27,049 --> 00:01:28,989
with teams of scientists working

36
00:01:29,369 --> 00:01:30,030
to study

37
00:01:30,489 --> 00:01:32,269
the aftermath of those collisions.

38
00:01:32,969 --> 00:01:35,469
Working at CMS at the time is Achintya

39
00:01:35,609 --> 00:01:37,209
Rao. I used to work as a science

40
00:01:37,209 --> 00:01:39,549
communicator for the CMS Collaboration between

41
00:01:40,275 --> 00:01:40,775
2,010

42
00:01:41,474 --> 00:01:43,795
and 2018, and I was at CERN helping

43
00:01:43,795 --> 00:01:45,954
with the communications when we announced the discovery

44
00:01:45,954 --> 00:01:48,034
of the Higgs boson. I'm guessing you didn't

45
00:01:48,034 --> 00:01:50,854
have any insight into that before the announcement.

46
00:01:50,915 --> 00:01:53,094
The LHC had been collecting data from 2,010

47
00:01:53,314 --> 00:01:53,730
onwards.

48
00:01:54,130 --> 00:01:56,210
2010 was just the beginning of the operations

49
00:01:56,210 --> 00:01:57,490
of this machine, so there was not a

50
00:01:57,490 --> 00:01:59,409
tremendous amount of data that were that were

51
00:01:59,409 --> 00:02:01,569
delivered to the collaborations, to the to the

52
00:02:01,569 --> 00:02:02,630
experimental teams.

53
00:02:03,250 --> 00:02:05,170
2011, however, there was a lot of data

54
00:02:05,170 --> 00:02:07,650
delivered that was enough to begin to make

55
00:02:07,650 --> 00:02:08,629
your first

56
00:02:08,985 --> 00:02:11,944
real inroads into determining whether the Higgs boson

57
00:02:11,944 --> 00:02:12,444
exists

58
00:02:12,745 --> 00:02:14,284
or if it doesn't.

59
00:02:14,664 --> 00:02:16,185
And that indeed was the promise of the

60
00:02:16,185 --> 00:02:18,344
LHC. It would either find the Higgs or

61
00:02:18,344 --> 00:02:20,044
rule out its existence entirely.

62
00:02:20,664 --> 00:02:21,164
Now

63
00:02:21,730 --> 00:02:22,550
in 2,011,

64
00:02:22,849 --> 00:02:24,469
all of the data that had been analyzed

65
00:02:25,569 --> 00:02:28,150
gave a very narrow window in which

66
00:02:28,450 --> 00:02:31,250
neither CMS nor Atlas could rule out the

67
00:02:31,250 --> 00:02:32,629
existence of the Higgs.

68
00:02:32,930 --> 00:02:35,590
The data showed us little a slight bump

69
00:02:36,075 --> 00:02:37,534
in in the mass distribution

70
00:02:37,915 --> 00:02:39,995
that had a significance of about 3 sigma

71
00:02:39,995 --> 00:02:41,915
on both CMS and ATLAS. And what this

72
00:02:41,915 --> 00:02:42,814
meant was that

73
00:02:43,754 --> 00:02:46,235
there either was something there that was causing

74
00:02:46,235 --> 00:02:46,974
this bump

75
00:02:47,355 --> 00:02:50,895
or it was a totally random statistical fluctuation

76
00:02:51,659 --> 00:02:54,459
that, emerged in both datasets. And this is,

77
00:02:54,459 --> 00:02:56,539
of course, very likely and has happened in

78
00:02:56,539 --> 00:02:58,300
the past and since as well. Just a

79
00:02:58,300 --> 00:03:00,219
quick aside, because I know that for many

80
00:03:00,219 --> 00:03:02,060
of you, the idea of Sigma will be

81
00:03:02,060 --> 00:03:04,224
something that is just part of your parlance.

82
00:03:04,224 --> 00:03:06,064
But when they plot the results on a

83
00:03:06,064 --> 00:03:07,764
graph, it would normally,

84
00:03:08,064 --> 00:03:09,284
in a normal distribution,

85
00:03:09,664 --> 00:03:12,224
be a bell curve with the highest point

86
00:03:12,224 --> 00:03:14,305
of the curve in the middle and tapering

87
00:03:14,305 --> 00:03:16,644
off on either side. And the deviation

88
00:03:17,025 --> 00:03:20,219
or sigma is how far any given point

89
00:03:20,219 --> 00:03:22,939
plotted on that graph is away from the

90
00:03:22,939 --> 00:03:24,959
average. One standard deviation

91
00:03:25,340 --> 00:03:26,400
or one sigma

92
00:03:26,699 --> 00:03:29,680
plotted either above or below the average value

93
00:03:29,819 --> 00:03:31,199
would include 68%

94
00:03:31,979 --> 00:03:34,534
of all the data points. For 2 sigma,

95
00:03:34,675 --> 00:03:35,495
it's 95%.

96
00:03:36,435 --> 00:03:37,495
For 3 sigma,

97
00:03:37,875 --> 00:03:38,615
it's 99.7%.

98
00:03:40,194 --> 00:03:42,615
In other words, the higher the sigma value,

99
00:03:42,915 --> 00:03:43,974
the less likely

100
00:03:44,275 --> 00:03:44,935
the discovery

101
00:03:45,474 --> 00:03:46,854
is to be accidental.

102
00:03:47,235 --> 00:03:50,449
Back to Archintia. So in 2011, once the

103
00:03:50,449 --> 00:03:52,530
experimental teams realized that there was this bump,

104
00:03:52,530 --> 00:03:55,250
what they decided in 2012, once fresh data

105
00:03:55,250 --> 00:03:57,330
from the LHC began to arrive, was to

106
00:03:57,330 --> 00:03:59,669
perform what is known as a blind analysis.

107
00:04:00,465 --> 00:04:03,205
And this means that, essentially, you ignore

108
00:04:03,584 --> 00:04:04,324
the regions

109
00:04:05,025 --> 00:04:07,264
that you could not rule out where there

110
00:04:07,264 --> 00:04:08,324
might be something,

111
00:04:08,784 --> 00:04:11,185
and you only analyze the data on either

112
00:04:11,185 --> 00:04:12,805
sides of that band.

113
00:04:13,459 --> 00:04:15,799
So you analyze data at a higher mass

114
00:04:15,939 --> 00:04:17,860
and at a lower mass, and you tweak

115
00:04:17,860 --> 00:04:20,339
your analysis. You perfect your analysis. You're you

116
00:04:20,339 --> 00:04:21,939
have a great deal of confidence in the

117
00:04:21,939 --> 00:04:24,100
methods that you applied. And then once you're

118
00:04:24,100 --> 00:04:27,060
satisfied that your analysis methods and protocols are

119
00:04:27,060 --> 00:04:28,120
sound, are robust,

120
00:04:28,774 --> 00:04:30,535
you then perform what is known as an

121
00:04:30,535 --> 00:04:31,035
unblinding.

122
00:04:31,654 --> 00:04:33,194
You apply that analysis

123
00:04:33,895 --> 00:04:34,795
to the data

124
00:04:35,175 --> 00:04:37,514
in the region that you had not excluded,

125
00:04:37,975 --> 00:04:39,735
and then you see whether there's something there

126
00:04:39,735 --> 00:04:40,235
or

127
00:04:40,930 --> 00:04:41,669
whether your signal disappears.

128
00:04:42,610 --> 00:04:44,610
And the reason scientists do it in this

129
00:04:44,610 --> 00:04:47,169
way at at, particle accelerators is essentially to

130
00:04:47,169 --> 00:04:50,129
avoid biasing yourself. Because if you if you

131
00:04:50,129 --> 00:04:52,209
have this notion that there is something there

132
00:04:52,209 --> 00:04:53,329
on a subconscious level

133
00:04:54,454 --> 00:04:55,735
I'm not saying people do this, but you

134
00:04:55,735 --> 00:04:57,415
want to rule out the possibility that there

135
00:04:57,415 --> 00:05:00,295
is any subconscious tweaking of your analysis to

136
00:05:00,295 --> 00:05:00,795
enhance

137
00:05:01,334 --> 00:05:02,795
what is potentially a signal.

138
00:05:03,254 --> 00:05:06,375
So the blind analysis is a process where

139
00:05:06,375 --> 00:05:08,214
you do not look at the sort of

140
00:05:08,214 --> 00:05:10,339
the hot region, the the region where there's

141
00:05:10,339 --> 00:05:12,259
interesting data. You don't analyze it. You analyze

142
00:05:12,259 --> 00:05:14,019
everything else, and then you apply your analysis

143
00:05:14,019 --> 00:05:14,919
to this region.

144
00:05:15,459 --> 00:05:15,959
And

145
00:05:16,419 --> 00:05:17,319
in June

146
00:05:17,939 --> 00:05:18,439
2012,

147
00:05:19,459 --> 00:05:21,939
so almost exactly 10 years ago at the

148
00:05:21,939 --> 00:05:23,079
time of our speaking,

149
00:05:23,685 --> 00:05:25,224
CMS had an unblinding

150
00:05:25,604 --> 00:05:27,944
of the data from the diphoton

151
00:05:28,324 --> 00:05:28,824
channel.

152
00:05:29,204 --> 00:05:30,185
So this is

153
00:05:30,644 --> 00:05:33,784
data that have been collected from proton collisions

154
00:05:33,844 --> 00:05:34,504
in which

155
00:05:34,805 --> 00:05:37,625
pairs of photons, 2 photons, have emerged

156
00:05:38,160 --> 00:05:40,240
that can be said to have emerged from

157
00:05:40,240 --> 00:05:42,639
the same collision of 2 protons within the

158
00:05:42,639 --> 00:05:43,699
Large Hadron Collider.

159
00:05:44,080 --> 00:05:45,920
So pairs of photons are produced, and so

160
00:05:45,920 --> 00:05:47,759
this is the diphoton channel, which is one

161
00:05:47,759 --> 00:05:49,199
of the channels for looking for the Higgs,

162
00:05:49,199 --> 00:05:50,819
one of the what is known as

163
00:05:51,455 --> 00:05:54,495
a high resolution channel because you can really

164
00:05:54,495 --> 00:05:55,875
find a very sharp peak

165
00:05:56,254 --> 00:05:57,154
in your data.

166
00:05:57,694 --> 00:05:59,935
So in June, in, I think, it was

167
00:05:59,935 --> 00:06:03,074
15th June, CMS performed an unblinding on 14th

168
00:06:03,134 --> 00:06:05,290
June, and then they revealed the results this

169
00:06:05,290 --> 00:06:07,550
unblinding internally within the collaboration.

170
00:06:08,490 --> 00:06:09,930
And that was a really cool moment. So

171
00:06:09,930 --> 00:06:11,870
what happens is small teams

172
00:06:12,490 --> 00:06:14,889
perform the analysis, and you select our priority,

173
00:06:14,889 --> 00:06:17,470
whichever analysis is going to be finally used.

174
00:06:17,529 --> 00:06:19,514
And then when you do an unblinding, it

175
00:06:19,514 --> 00:06:21,035
doesn't matter if you get another,

176
00:06:21,435 --> 00:06:23,835
analysis that is even better. You use the

177
00:06:23,835 --> 00:06:25,595
one that you our priority chose. That's how

178
00:06:25,595 --> 00:06:27,775
you prevent yourself from being biased once again.

179
00:06:28,074 --> 00:06:28,574
So

180
00:06:29,275 --> 00:06:31,779
the analysis was done, and the unblinding

181
00:06:32,080 --> 00:06:34,080
was then revealed to the CMS collaboration on

182
00:06:34,080 --> 00:06:36,400
15th June. You could sort of feel the

183
00:06:36,400 --> 00:06:38,240
excitement in the room. So we were there.

184
00:06:38,480 --> 00:06:40,720
This was just an internal meeting. Everyone was

185
00:06:41,040 --> 00:06:42,639
not everyone was in the room because out

186
00:06:42,639 --> 00:06:44,514
of about 2 and a half 1000 scientists,

187
00:06:44,514 --> 00:06:46,355
3,000 scientists, only a couple of 100 were

188
00:06:46,355 --> 00:06:46,855
there.

189
00:06:47,235 --> 00:06:48,935
The rest of them were watching via webcast

190
00:06:49,074 --> 00:06:50,774
or connected via video conferencing.

191
00:06:51,634 --> 00:06:53,475
That was when we saw that in this

192
00:06:53,475 --> 00:06:54,694
particular channel,

193
00:06:55,555 --> 00:06:56,454
the significance

194
00:06:56,754 --> 00:06:57,574
of the excess

195
00:06:58,800 --> 00:07:00,259
had breached 4 Sigma.

196
00:07:00,800 --> 00:07:02,480
And when you see more than 4 Sigma

197
00:07:02,480 --> 00:07:03,839
in one channel, you know, you have a

198
00:07:03,839 --> 00:07:05,279
feeling that when you combine it with the

199
00:07:05,279 --> 00:07:07,759
other channels that are that are key to

200
00:07:07,759 --> 00:07:10,160
discovering a new particle that it might be

201
00:07:10,160 --> 00:07:11,519
there. So that was the moment where we

202
00:07:11,519 --> 00:07:12,899
felt a real sense of excitement.

203
00:07:13,245 --> 00:07:15,665
I was recording that meeting. When this perhaps

204
00:07:16,205 --> 00:07:17,665
it's it's a little faster.

205
00:07:18,285 --> 00:07:19,665
So please, everybody,

206
00:07:20,205 --> 00:07:20,944
get ready

207
00:07:21,485 --> 00:07:23,264
for the next 15 minutes.

208
00:07:25,884 --> 00:07:27,839
So all this exciting and

209
00:07:29,040 --> 00:07:31,040
So what we had decided within the CMS

210
00:07:31,040 --> 00:07:33,139
collaboration was that these conversations,

211
00:07:33,439 --> 00:07:33,759
these,

212
00:07:34,319 --> 00:07:37,060
exchanges, these internal discussions were

213
00:07:37,519 --> 00:07:40,160
ultimately of historic value. And even though in

214
00:07:40,160 --> 00:07:41,839
the moment they couldn't be shared with the

215
00:07:41,839 --> 00:07:43,794
world, we should still have a record of

216
00:07:43,794 --> 00:07:45,574
it that we can then put out subsequently.

217
00:07:46,274 --> 00:07:47,735
So we have on record

218
00:07:48,435 --> 00:07:52,194
the, young researcher Mingming Yang announcing to the

219
00:07:52,194 --> 00:07:54,514
collaboration after she had sort of prepared the

220
00:07:54,514 --> 00:07:56,759
presentation and stuff that this is what CMS

221
00:07:56,759 --> 00:07:57,259
sees.

222
00:07:57,720 --> 00:07:58,220
This

223
00:07:59,479 --> 00:08:01,720
black one, okay, this is the combined. You

224
00:08:01,720 --> 00:08:04,199
can see it's beyond which line. Okay. 1,

225
00:08:04,199 --> 00:08:06,620
2, 3, and 4. The

226
00:08:10,064 --> 00:08:11,285
The break the break

227
00:08:12,785 --> 00:08:15,524
is, is for the and then the Magenta

228
00:08:15,584 --> 00:08:16,884
is for the 18.

229
00:08:17,264 --> 00:08:17,764
On

230
00:08:18,785 --> 00:08:19,444
the 28th

231
00:08:19,824 --> 00:08:20,324
June,

232
00:08:21,024 --> 00:08:22,884
just about a week before the announcement,

233
00:08:23,879 --> 00:08:25,500
another and, another

234
00:08:25,959 --> 00:08:28,060
presentation was made to the CMS collaboration.

235
00:08:28,680 --> 00:08:31,480
And this was by another young researcher, Andre

236
00:08:31,480 --> 00:08:31,980
David,

237
00:08:32,600 --> 00:08:33,100
who

238
00:08:33,399 --> 00:08:35,559
showed the results of the same analysis in

239
00:08:35,559 --> 00:08:37,934
the difoton channel, but with adding

240
00:08:38,315 --> 00:08:40,634
an additional 40% data that had been collected

241
00:08:40,634 --> 00:08:42,714
in those previous 2 weeks, preceding 2 weeks.

242
00:08:42,714 --> 00:08:45,195
And, we've gone through all of the needed

243
00:08:45,195 --> 00:08:47,914
steps in order to reopen the box. This

244
00:08:47,914 --> 00:08:50,654
means that we've resynchronized among the different frameworks.

245
00:08:51,059 --> 00:08:52,039
We've recalculated

246
00:08:52,340 --> 00:08:54,600
all the efficiency data to Monte Carlo

247
00:08:55,059 --> 00:08:56,039
correction factors,

248
00:08:56,419 --> 00:08:58,980
and we've rederied the energy scale and the

249
00:08:58,980 --> 00:08:59,480
resolution,

250
00:08:59,860 --> 00:09:00,360
corrections

251
00:09:01,059 --> 00:09:02,360
from, the data.

252
00:09:03,554 --> 00:09:06,674
We've also rerun, the algorithm that chooses the

253
00:09:06,674 --> 00:09:09,475
background model for the FITs in the mass

254
00:09:09,475 --> 00:09:09,975
distribution,

255
00:09:10,434 --> 00:09:12,434
and we've gone through the full and blinding

256
00:09:12,434 --> 00:09:12,934
procedure

257
00:09:13,475 --> 00:09:16,514
actually just some 16 hours ago. These results

258
00:09:16,514 --> 00:09:18,809
were again presented internally, and that was when

259
00:09:19,690 --> 00:09:22,250
the signal, the excess in the difocal channel

260
00:09:22,250 --> 00:09:24,350
had a significance of 4.1

261
00:09:25,049 --> 00:09:25,549
sigma

262
00:09:26,169 --> 00:09:29,210
internally. We knew. And this is across 3

263
00:09:29,210 --> 00:09:32,190
different analysis performed between dependent frameworks.

264
00:09:32,955 --> 00:09:35,115
So I personally think that this begs for

265
00:09:35,115 --> 00:09:35,615
interpretation.

266
00:09:36,315 --> 00:09:37,055
Thank you.

267
00:09:39,035 --> 00:09:40,815
We knew there was something there.

268
00:09:41,195 --> 00:09:43,274
The other channels were also happening at around

269
00:09:43,274 --> 00:09:44,875
the same time. There was the Higgs decaying

270
00:09:44,875 --> 00:09:45,274
into,

271
00:09:45,754 --> 00:09:46,815
2 zed bosons

272
00:09:47,115 --> 00:09:47,615
and

273
00:09:48,879 --> 00:09:50,820
the the other channels in which the Higgs

274
00:09:51,200 --> 00:09:54,660
transforms are much lower in resolution likelihood.

275
00:09:55,040 --> 00:09:56,879
So it was the Higgs to zed zed

276
00:09:56,879 --> 00:09:58,639
and Higgs to 2 photons channels that were

277
00:09:58,639 --> 00:10:00,585
the most interesting, most valuable ones at

278
00:10:03,065 --> 00:10:03,123
the time. But this is all internal to

279
00:10:03,123 --> 00:10:04,105
the CMS experiment at this point? We had

280
00:10:04,105 --> 00:10:06,264
no idea what ATLAS had, which is the

281
00:10:06,264 --> 00:10:08,904
other general purpose experiment at at CERN, at

282
00:10:08,904 --> 00:10:10,125
the Large Hadron Collider.

283
00:10:10,825 --> 00:10:11,325
Now

284
00:10:11,785 --> 00:10:13,465
the reason there are 2 experiments in the

285
00:10:13,465 --> 00:10:16,720
first place that are designed completely differently using

286
00:10:16,720 --> 00:10:19,919
very different technologies operated independently by 2 different

287
00:10:19,919 --> 00:10:20,419
teams

288
00:10:20,799 --> 00:10:23,360
is because we only have 1 Large Hadron

289
00:10:23,360 --> 00:10:25,120
Collider. There is no way that someone else

290
00:10:25,120 --> 00:10:26,959
can go and replicate your work and find

291
00:10:26,959 --> 00:10:27,459
another

292
00:10:28,315 --> 00:10:29,995
way of verifying your results. So you have

293
00:10:29,995 --> 00:10:32,014
2 teams that essentially are there to counterbalance

294
00:10:32,154 --> 00:10:33,754
one another. If one sees it and the

295
00:10:33,754 --> 00:10:36,014
other doesn't, then you need to know whether

296
00:10:36,154 --> 00:10:38,175
it's because of the limitation in the technology

297
00:10:38,394 --> 00:10:40,634
or if it's really an anomaly that one

298
00:10:40,634 --> 00:10:43,309
has seen, and it's not a real manifestation

299
00:10:43,309 --> 00:10:44,929
of what nature has to show you.

300
00:10:45,950 --> 00:10:47,389
So we didn't know what Atlas had to

301
00:10:47,389 --> 00:10:49,629
say. We only knew what what, you know,

302
00:10:49,629 --> 00:10:51,389
the researchers on CMS, who I was working

303
00:10:51,389 --> 00:10:52,669
with, what they had to say. I imagine

304
00:10:52,669 --> 00:10:54,910
that was a particularly exciting time to be

305
00:10:54,910 --> 00:10:58,975
around. The day before the announcements on the

306
00:10:58,975 --> 00:11:00,434
3rd July, I was up

307
00:11:00,815 --> 00:11:03,214
until very late at night, in my office,

308
00:11:03,214 --> 00:11:04,975
actually, in in my boss's office at the

309
00:11:04,975 --> 00:11:06,834
time, where we were putting together the website

310
00:11:06,894 --> 00:11:08,115
for the CMS collaboration,

311
00:11:08,735 --> 00:11:10,674
where we had an article that had

312
00:11:11,110 --> 00:11:13,269
essentially an explanation of what was going to

313
00:11:13,269 --> 00:11:14,710
be presented the next day, which would have

314
00:11:14,710 --> 00:11:17,190
only been made public once the presentation was

315
00:11:17,190 --> 00:11:19,590
made. So we had an article that described

316
00:11:19,590 --> 00:11:22,330
what the collaboration had seen. We had information

317
00:11:22,550 --> 00:11:25,305
that explained things like what is the statistical

318
00:11:25,365 --> 00:11:27,445
significance, what does 5 sigma mean, how do

319
00:11:27,445 --> 00:11:29,685
you collect data from proton collisions, what do

320
00:11:29,685 --> 00:11:31,524
the scientists look for to determine that you

321
00:11:31,524 --> 00:11:34,004
have seen something new, why is that important,

322
00:11:34,004 --> 00:11:34,904
and so forth.

323
00:11:35,925 --> 00:11:37,705
So we had been tweaking

324
00:11:38,240 --> 00:11:40,740
the website. We had been getting new information

325
00:11:40,959 --> 00:11:42,879
with fine grain numbers that had to change.

326
00:11:42,879 --> 00:11:44,240
And what we had also been doing is

327
00:11:44,240 --> 00:11:46,079
we were trying to get those translated into

328
00:11:46,079 --> 00:11:47,139
about 20 languages

329
00:11:48,720 --> 00:11:51,200
because we had an inkling that there was

330
00:11:51,200 --> 00:11:53,144
gonna be interest around the world and that

331
00:11:53,144 --> 00:11:54,764
not everyone might have

332
00:11:55,464 --> 00:11:57,245
the expertise to

333
00:11:57,625 --> 00:12:00,424
understand the scientific seminar on the day itself.

334
00:12:00,424 --> 00:12:02,504
And so we prepared these in in about

335
00:12:02,504 --> 00:12:04,345
20 languages. Sort of many people around the

336
00:12:04,345 --> 00:12:05,565
world could could read,

337
00:12:06,009 --> 00:12:07,529
in their own language, in the language that

338
00:12:07,529 --> 00:12:08,889
they prefer and didn't have to rely on

339
00:12:08,889 --> 00:12:10,990
an English or French version exclusively.

340
00:12:12,089 --> 00:12:14,509
So I was up late into the night,

341
00:12:14,970 --> 00:12:16,970
far later than I usually work, and I

342
00:12:16,970 --> 00:12:19,610
left for home a little past midnight. I

343
00:12:19,610 --> 00:12:21,470
took the last tram home.

344
00:12:21,825 --> 00:12:24,065
It was a very quiet night. There was

345
00:12:24,065 --> 00:12:24,565
just,

346
00:12:25,425 --> 00:12:26,804
I don't know, this this sense

347
00:12:27,665 --> 00:12:28,965
of calm outside

348
00:12:29,425 --> 00:12:29,925
soon.

349
00:12:30,785 --> 00:12:32,465
And as I was walking to the tram

350
00:12:32,465 --> 00:12:34,245
stop, I remember seeing a few

351
00:12:34,559 --> 00:12:37,519
students, young researchers camped outside the main auditorium

352
00:12:37,519 --> 00:12:39,759
where the conference would be where the seminar

353
00:12:39,759 --> 00:12:40,899
would be given from.

354
00:12:41,279 --> 00:12:43,360
And they had camped out the previous night

355
00:12:43,360 --> 00:12:45,039
because they knew that there were so few

356
00:12:45,039 --> 00:12:47,279
seats, so few free seats available that if

357
00:12:47,279 --> 00:12:48,559
they had showed up the next day and

358
00:12:48,559 --> 00:12:50,085
started queuing, they would not have managed to

359
00:12:50,085 --> 00:12:51,445
get in. So they just stayed out all

360
00:12:51,445 --> 00:12:53,764
night falling asleep outside the door of the

361
00:12:53,764 --> 00:12:54,585
main auditorium

362
00:12:55,524 --> 00:12:57,044
in order to guarantee that they get a

363
00:12:57,044 --> 00:12:57,544
seat.

364
00:12:57,845 --> 00:12:59,764
So I walked past them. I got onto

365
00:12:59,764 --> 00:13:02,004
the tram. I went home, slept for far

366
00:13:02,004 --> 00:13:02,985
too few hours,

367
00:13:03,610 --> 00:13:05,370
and took the tram back at 6 or

368
00:13:05,370 --> 00:13:06,889
so in the morning to come back on

369
00:13:06,889 --> 00:13:08,269
on-site at 7.

370
00:13:08,730 --> 00:13:09,710
And that's when

371
00:13:10,490 --> 00:13:12,590
we sort of settled into the seminar itself.

372
00:13:12,730 --> 00:13:14,509
At that seminar was Joe Incandela,

373
00:13:14,889 --> 00:13:18,029
the CMS spokesperson presenting the experiment's findings.

374
00:13:18,764 --> 00:13:20,044
What you see here is now the p

375
00:13:20,044 --> 00:13:22,044
values. This is the probability that the background

376
00:13:22,044 --> 00:13:22,704
could fluctuate

377
00:13:23,164 --> 00:13:25,565
to this extent. And you see combining the

378
00:13:25,565 --> 00:13:27,745
2 years, we're below we're beyond 4 sigma,

379
00:13:28,125 --> 00:13:30,524
about 4.1 standard deviations. If you look at

380
00:13:30,524 --> 00:13:31,345
the p values,

381
00:13:32,690 --> 00:13:33,190
well,

382
00:13:33,809 --> 00:13:34,950
our expected significance,

383
00:13:35,970 --> 00:13:37,669
for standard model Higgs at 125.5

384
00:13:38,049 --> 00:13:39,809
is 3.8 sigma, and what we're seeing is

385
00:13:39,809 --> 00:13:40,309
3.2.

386
00:13:40,929 --> 00:13:41,750
If we combine

387
00:13:42,529 --> 00:13:44,389
the z z and gamma gamma,

388
00:13:45,334 --> 00:13:47,014
this is what we get. They they line

389
00:13:47,014 --> 00:13:49,414
up extremely well, and in the region of

390
00:13:49,414 --> 00:13:50,714
125 GeV,

391
00:13:51,254 --> 00:13:53,014
they combine to give us a an ex

392
00:13:53,095 --> 00:13:55,674
a combined significance of 5 standard deviations.

393
00:14:06,629 --> 00:14:09,110
Give me an idea of how secret that

394
00:14:09,110 --> 00:14:11,529
that is. I mean, like, would Peter Higgs

395
00:14:12,044 --> 00:14:12,784
be invited

396
00:14:13,644 --> 00:14:15,964
on the basis of one of those, or

397
00:14:15,964 --> 00:14:17,565
does he know that both of them have

398
00:14:17,565 --> 00:14:18,304
found it?

399
00:14:19,004 --> 00:14:19,504
So,

400
00:14:21,644 --> 00:14:23,644
who knew that both experiments have seen it?

401
00:14:23,644 --> 00:14:25,804
So the protocol that had been established internally

402
00:14:25,804 --> 00:14:27,664
at some was that if

403
00:14:28,309 --> 00:14:30,169
one of the teams sees something

404
00:14:31,190 --> 00:14:33,850
beyond a certain significance that sort of guarantees

405
00:14:34,070 --> 00:14:35,289
discovery in quotes,

406
00:14:35,750 --> 00:14:38,009
they would approach the director general of CERN

407
00:14:38,230 --> 00:14:40,149
and say, this is what we have. And

408
00:14:40,149 --> 00:14:41,990
then the director general would invite the other

409
00:14:41,990 --> 00:14:42,490
team

410
00:14:43,214 --> 00:14:43,714
and

411
00:14:44,495 --> 00:14:47,375
say, this is what your opposing team has,

412
00:14:47,375 --> 00:14:48,754
the other collaboration has.

413
00:14:49,695 --> 00:14:52,115
What do you have? And if they were

414
00:14:52,254 --> 00:14:54,174
sort of in the same space of tweaking

415
00:14:54,174 --> 00:14:55,695
the analysis, then they would be given, like,

416
00:14:55,695 --> 00:14:57,134
a day or 2 to tweak it and

417
00:14:57,134 --> 00:14:58,952
and sort of come up with it because

418
00:14:58,952 --> 00:15:00,972
there is no way you can make drastic

419
00:15:00,972 --> 00:15:02,993
changes and invent the presence of a new

420
00:15:02,993 --> 00:15:05,266
particle, at the very last minute. So that

421
00:15:05,266 --> 00:15:07,286
was a protocol established, and what happened was

422
00:15:07,286 --> 00:15:09,306
in the end, both teams saw something at

423
00:15:09,306 --> 00:15:11,327
around the same time. They went to the

424
00:15:11,327 --> 00:15:13,334
director general at almost the same time to

425
00:15:13,334 --> 00:15:14,554
say this is what we have.

426
00:15:15,014 --> 00:15:17,495
So the director general obviously knew what both

427
00:15:17,495 --> 00:15:19,434
teams had and the spokespersons

428
00:15:19,814 --> 00:15:21,514
of both the experimental collaborations.

429
00:15:22,615 --> 00:15:24,855
So Joe and Candela from CMS and Fabiola

430
00:15:24,855 --> 00:15:26,934
Gianotti from ATLAS, they knew what the other

431
00:15:26,934 --> 00:15:29,000
had, but they kept it to themselves.

432
00:15:29,459 --> 00:15:29,959
So

433
00:15:30,579 --> 00:15:32,820
and, oh, okay. And the director of research

434
00:15:32,820 --> 00:15:34,339
at ZOEN also knew. So there were maybe

435
00:15:34,339 --> 00:15:36,339
4 people who knew that there was something

436
00:15:36,339 --> 00:15:37,159
there, but

437
00:15:38,100 --> 00:15:39,779
no one knew the specific numbers. No one

438
00:15:39,779 --> 00:15:41,459
knew the exact significance. No one knew whether

439
00:15:41,459 --> 00:15:42,825
it had breached 5 sigma or not. It

440
00:15:42,825 --> 00:15:44,845
could have been about 4.6, 4.7,

441
00:15:45,225 --> 00:15:45,725
4.95.

442
00:15:47,144 --> 00:15:49,144
No one knew, exactly what it would be.

443
00:15:49,144 --> 00:15:49,644
But

444
00:15:50,825 --> 00:15:52,504
the closer you got to the date as

445
00:15:52,504 --> 00:15:55,304
the analysis kept moving forward, you knew something

446
00:15:55,304 --> 00:15:56,365
was gonna happen.

447
00:15:57,480 --> 00:15:59,639
What happened with inviting Peter Higgs, as I

448
00:15:59,639 --> 00:16:01,980
found out very recently when I spoke with

449
00:16:03,000 --> 00:16:04,940
James Gillies, who was the head of communications

450
00:16:05,000 --> 00:16:06,779
at CERN at the time, was that

451
00:16:07,160 --> 00:16:10,300
CERN didn't initially extend invitations to

452
00:16:11,644 --> 00:16:13,664
to any of the any of the theorists.

453
00:16:14,284 --> 00:16:16,684
What happened was Carl Hagen, who was one

454
00:16:16,684 --> 00:16:18,544
of the 6 people who

455
00:16:19,004 --> 00:16:19,504
did

456
00:16:19,884 --> 00:16:22,384
the foundational theoretical work in 1964,

457
00:16:23,404 --> 00:16:26,144
he got in touch with James Gillies because,

458
00:16:26,420 --> 00:16:27,779
as you know, the story of the Higgs

459
00:16:27,779 --> 00:16:29,540
mechanism and the Higgs boson is is a

460
00:16:29,540 --> 00:16:30,279
is a

461
00:16:31,139 --> 00:16:33,700
complicated one. There were lots of actors involved

462
00:16:33,700 --> 00:16:35,300
in it, lots of different people who were

463
00:16:35,300 --> 00:16:37,300
doing work at around the same time. And

464
00:16:37,300 --> 00:16:38,680
the story goes,

465
00:16:39,220 --> 00:16:40,279
to put it very

466
00:16:40,654 --> 00:16:41,554
simply, that

467
00:16:41,855 --> 00:16:44,415
Francois Angler and Robert Braut put out one

468
00:16:44,415 --> 00:16:46,915
paper, Peter Higgs put out another paper, and,

469
00:16:47,615 --> 00:16:49,695
Hagen, Guralnick, and Kibble put out a third

470
00:16:49,695 --> 00:16:51,535
paper. And the reason we call it the

471
00:16:51,535 --> 00:16:53,695
Higgs boson was because Peter Higgs' paper was

472
00:16:53,695 --> 00:16:55,910
the first and only one to mention the

473
00:16:55,910 --> 00:16:58,870
existence of of the particle itself associated with

474
00:16:58,870 --> 00:16:59,690
this field.

475
00:17:00,629 --> 00:17:03,350
But the mechanism itself is commonly referred to

476
00:17:03,350 --> 00:17:04,009
as the

477
00:17:04,309 --> 00:17:05,930
Higgs mechanism, although

478
00:17:06,734 --> 00:17:08,974
Hagen, Goranlik, and Kibble argue that they should

479
00:17:08,974 --> 00:17:10,595
also be included in that.

480
00:17:12,015 --> 00:17:14,894
It's a complicated story, obviously, and everyone wants

481
00:17:14,894 --> 00:17:15,214
to,

482
00:17:15,855 --> 00:17:16,595
wants to

483
00:17:17,375 --> 00:17:19,855
take take, you know, get get their get

484
00:17:19,855 --> 00:17:21,394
given their due credit.

485
00:17:22,700 --> 00:17:25,019
So Hagen got in touch with James Gillies.

486
00:17:25,019 --> 00:17:26,460
Karl Hagen got in touch with James Gillies,

487
00:17:26,460 --> 00:17:28,559
the head of SON's communications, and said, look.

488
00:17:29,019 --> 00:17:30,320
We are hearing rumblings.

489
00:17:31,259 --> 00:17:33,099
We we expect that if we were to

490
00:17:33,099 --> 00:17:35,440
arrive to CERN that we would be given

491
00:17:36,224 --> 00:17:36,724
hospitality

492
00:17:37,345 --> 00:17:39,105
no less than what would be afforded to

493
00:17:39,105 --> 00:17:41,265
the other theorists who are involved in the

494
00:17:41,265 --> 00:17:42,244
work at the time.

495
00:17:43,345 --> 00:17:44,704
He said we would all like to come.

496
00:17:44,704 --> 00:17:46,224
So in the end, it was Hagen and

497
00:17:46,224 --> 00:17:48,779
Guralnik who came and and Kibble stayed in

498
00:17:48,779 --> 00:17:51,580
London where SDFC had organized a separate event.

499
00:17:51,580 --> 00:17:53,259
So they showed up. And once it was

500
00:17:53,259 --> 00:17:54,860
clear that they were gonna come, then CERN

501
00:17:54,860 --> 00:17:56,240
decided to reach out to,

502
00:17:57,740 --> 00:18:00,860
Francois Anglais and, and Peter Higgs and say,

503
00:18:00,860 --> 00:18:02,140
we would like to invite you to come

504
00:18:02,140 --> 00:18:02,714
to CERN.

505
00:18:03,115 --> 00:18:04,794
Robert Brout, of course, was the other theorist,

506
00:18:04,794 --> 00:18:06,095
had passed away in 2,011.

507
00:18:07,275 --> 00:18:07,775
Now,

508
00:18:09,115 --> 00:18:11,595
of course, people knew that something was going

509
00:18:11,595 --> 00:18:14,815
to happen, and the reason for that is

510
00:18:16,539 --> 00:18:18,559
that the seminar was supposed to be

511
00:18:19,099 --> 00:18:21,820
a regular talk given at the International Conference

512
00:18:21,820 --> 00:18:24,080
on High Energy Physics or ICHEP.

513
00:18:24,700 --> 00:18:26,380
It was supposed to be, like, a status

514
00:18:26,380 --> 00:18:28,299
update on where the collaborations are in the

515
00:18:28,299 --> 00:18:29,660
search for the Higgs boson. It had been

516
00:18:29,660 --> 00:18:31,519
penciled in to take place at this conference

517
00:18:31,634 --> 00:18:33,875
for months months, and the conference was taking

518
00:18:33,875 --> 00:18:35,335
place in Melbourne, Australia.

519
00:18:37,394 --> 00:18:37,894
And

520
00:18:38,595 --> 00:18:39,095
once

521
00:18:39,634 --> 00:18:42,295
it was clear that what would be presented,

522
00:18:42,515 --> 00:18:45,154
if not discovery, would be pretty close to

523
00:18:45,154 --> 00:18:46,695
discovery, it was decided

524
00:18:47,460 --> 00:18:48,599
that because

525
00:18:48,900 --> 00:18:50,759
CERN is funded by

526
00:18:51,140 --> 00:18:53,859
largely European member states. At that time, the

527
00:18:53,859 --> 00:18:56,740
expansion of CERN beyond Europe hadn't, reached the

528
00:18:56,740 --> 00:18:57,799
heights it has today.

529
00:18:58,339 --> 00:19:00,259
So largely funded by European member states, and

530
00:19:00,259 --> 00:19:02,179
and it and the director general of CERN

531
00:19:02,179 --> 00:19:04,154
told me recently that it was felt that

532
00:19:04,154 --> 00:19:06,014
CERN owed it to its sponsors,

533
00:19:06,394 --> 00:19:08,174
to the council members,

534
00:19:08,474 --> 00:19:10,255
the member states of CERN,

535
00:19:11,034 --> 00:19:13,294
to have any discovery announcement take place

536
00:19:13,595 --> 00:19:15,375
at home at CERN in Geneva.

537
00:19:17,115 --> 00:19:19,089
So, obviously, people began to say, hang on

538
00:19:19,089 --> 00:19:21,089
a minute. Why are they not having this

539
00:19:21,089 --> 00:19:22,230
talk at Melbourne,

540
00:19:22,529 --> 00:19:25,009
iCHAP, you know, as it was supposed to

541
00:19:25,009 --> 00:19:25,509
be?

542
00:19:26,529 --> 00:19:28,130
The only reason they do that is if

543
00:19:28,130 --> 00:19:29,750
they have something big to say.

544
00:19:30,644 --> 00:19:31,144
So

545
00:19:31,845 --> 00:19:34,825
I guess everyone speculate. Everyone had a hunch,

546
00:19:34,965 --> 00:19:36,805
and people on CMS obviously know what they

547
00:19:36,805 --> 00:19:38,725
had to say. People on Atlas probably knew

548
00:19:38,725 --> 00:19:40,164
what they had to say. And even if

549
00:19:40,164 --> 00:19:41,785
you aren't telling someone

550
00:19:42,700 --> 00:19:44,940
what you have, if you're walking past your

551
00:19:44,940 --> 00:19:46,700
friends who work on the other side of

552
00:19:46,700 --> 00:19:48,380
the ring, of the LHC ring when you're

553
00:19:48,380 --> 00:19:51,180
going for lunch and you see them grinning

554
00:19:51,180 --> 00:19:52,160
ear to ear,

555
00:19:52,460 --> 00:19:54,380
you know something, sir. You don't have to

556
00:19:54,380 --> 00:19:57,295
exchange words to know that, you know, there's

557
00:19:57,295 --> 00:19:59,375
excitement on the horizon. I can imagine, but

558
00:19:59,375 --> 00:20:01,535
it's this was a long time before I

559
00:20:01,535 --> 00:20:03,695
was doing this podcast, and I'd have loved

560
00:20:03,695 --> 00:20:05,375
to have been in that room. But were

561
00:20:05,375 --> 00:20:06,275
the press invited?

562
00:20:06,654 --> 00:20:09,154
The seminar took place in CERN's main auditorium,

563
00:20:09,295 --> 00:20:11,055
and next to it is the council chamber,

564
00:20:11,055 --> 00:20:11,955
which is where

565
00:20:12,619 --> 00:20:14,779
the council members usually meet for their discussions.

566
00:20:14,779 --> 00:20:17,100
And we had set up, that room. CERN

567
00:20:17,100 --> 00:20:19,180
communications team had set up that room for

568
00:20:19,180 --> 00:20:21,279
the press, essentially. Because,

569
00:20:22,460 --> 00:20:25,279
again, like Carl Hagen, the

570
00:20:26,144 --> 00:20:27,765
press had invited themselves

571
00:20:28,225 --> 00:20:28,725
over.

572
00:20:29,184 --> 00:20:31,585
SON had just issued a statement saying, we're

573
00:20:31,585 --> 00:20:34,144
going to provide an update on where we

574
00:20:34,144 --> 00:20:35,664
are in the search for the Higgs boson

575
00:20:35,664 --> 00:20:38,005
on the 4th July at 9 AM. Also,

576
00:20:38,065 --> 00:20:39,365
9 AM, unusual.

577
00:20:40,170 --> 00:20:41,769
Sun seminars don't take place that early in

578
00:20:41,769 --> 00:20:43,130
the day. They usually take place towards the

579
00:20:43,130 --> 00:20:44,490
end of the day, and the reason was

580
00:20:44,490 --> 00:20:46,029
it was still part of ICHIP.

581
00:20:46,570 --> 00:20:48,490
And because that's in Australia, you didn't want

582
00:20:48,490 --> 00:20:50,090
to do it after they've gone to bed.

583
00:20:50,090 --> 00:20:52,650
So 9 AM. So Sun says, this is

584
00:20:52,650 --> 00:20:55,065
happening. There's gonna be an update. That's it.

585
00:20:55,384 --> 00:20:57,085
Journalists start ringing in and saying,

586
00:20:57,944 --> 00:20:59,004
what's going on again?

587
00:20:59,704 --> 00:21:00,444
Do we?

588
00:21:01,464 --> 00:21:02,904
What are you gonna say? Can you tell

589
00:21:02,904 --> 00:21:04,125
us? And,

590
00:21:05,625 --> 00:21:07,704
again, I'm quoting the words of the director

591
00:21:07,704 --> 00:21:09,865
general who said, you would regret it if

592
00:21:09,865 --> 00:21:10,950
you weren't there.

593
00:21:11,669 --> 00:21:13,269
That's all. They didn't say anything more. They

594
00:21:13,269 --> 00:21:15,190
didn't say, oh, yes. Please come. We're gonna

595
00:21:15,190 --> 00:21:16,089
announce the discovery.

596
00:21:17,509 --> 00:21:18,889
It was implied that

597
00:21:19,190 --> 00:21:21,029
it was something you wouldn't want to miss.

598
00:21:21,029 --> 00:21:22,710
So, of course, journalists showed up. They showed

599
00:21:22,710 --> 00:21:24,069
up from all over the world, from the

600
00:21:24,069 --> 00:21:24,569
US,

601
00:21:25,375 --> 00:21:26,355
across Europe.

602
00:21:27,295 --> 00:21:29,775
So a separate room had been prepared to

603
00:21:29,775 --> 00:21:31,214
have the press conference where we had a

604
00:21:31,214 --> 00:21:33,375
lot of communicators present as well to help

605
00:21:33,375 --> 00:21:34,674
with any issues. And

606
00:21:36,095 --> 00:21:37,775
one of the things that Sun had realized

607
00:21:37,775 --> 00:21:40,200
very early on was, you know, the previous

608
00:21:40,340 --> 00:21:40,840
year,

609
00:21:42,259 --> 00:21:43,320
December 2011,

610
00:21:43,860 --> 00:21:46,740
there had been a similar seminar, a typical

611
00:21:46,740 --> 00:21:48,820
end of year seminar announcing, you know, where

612
00:21:48,820 --> 00:21:50,820
we are at the in in our physics

613
00:21:50,820 --> 00:21:51,320
research

614
00:21:51,995 --> 00:21:54,154
at the at the LHC and CMS and

615
00:21:54,154 --> 00:21:56,075
ATLAS presented where they were in the search

616
00:21:56,075 --> 00:21:57,615
for the Higgs boson. And

617
00:21:58,075 --> 00:21:59,835
at that time, both collaborations had, as I

618
00:21:59,835 --> 00:22:01,215
said, seen about 3 sigma.

619
00:22:03,035 --> 00:22:03,535
And

620
00:22:03,910 --> 00:22:05,529
this was supposed to be just

621
00:22:05,990 --> 00:22:09,190
a normal seminar webcast to the community so

622
00:22:09,190 --> 00:22:09,930
that everyone

623
00:22:10,630 --> 00:22:12,710
in the particle physics world can follow what's

624
00:22:12,710 --> 00:22:14,490
going on. And SIRNS webcast

625
00:22:14,789 --> 00:22:15,289
broke

626
00:22:16,304 --> 00:22:18,544
because there were tens of thousands of people

627
00:22:18,544 --> 00:22:20,404
watching this when they heard it was happening

628
00:22:20,464 --> 00:22:21,605
expecting a discovery.

629
00:22:23,424 --> 00:22:24,804
And this was,

630
00:22:26,784 --> 00:22:28,869
a huge number of people, which is obviously

631
00:22:28,869 --> 00:22:30,470
much more than someone had ever expected. So

632
00:22:30,470 --> 00:22:32,069
they knew that there was an interest happening.

633
00:22:32,069 --> 00:22:32,970
So they prepared,

634
00:22:34,470 --> 00:22:35,289
lay explanations,

635
00:22:35,669 --> 00:22:36,569
live blogging,

636
00:22:36,869 --> 00:22:38,549
lots of other things on the same day

637
00:22:38,549 --> 00:22:40,069
to explain to people what was going on.

638
00:22:40,069 --> 00:22:42,250
But to answer your question about the atmosphere,

639
00:22:43,349 --> 00:22:44,250
we were buzzing.

640
00:22:45,055 --> 00:22:47,075
I walked in that morning.

641
00:22:47,535 --> 00:22:48,275
I saw,

642
00:22:48,575 --> 00:22:49,934
by the time that I got in at

643
00:22:49,934 --> 00:22:52,115
about 7 o'clock, that there had already been

644
00:22:52,894 --> 00:22:55,634
a snake of a queue that went

645
00:22:56,015 --> 00:22:56,994
from the auditorium,

646
00:22:57,690 --> 00:23:00,569
went past the landing, down the stairs, went

647
00:23:00,569 --> 00:23:02,649
in front of the post office and the

648
00:23:02,649 --> 00:23:05,470
bank, the kiosk, skirted into the restaurant,

649
00:23:05,929 --> 00:23:08,009
went past the coffee machines, went into the

650
00:23:08,009 --> 00:23:10,409
extension of the restaurant, poured out into the

651
00:23:10,409 --> 00:23:10,909
garden.

652
00:23:12,545 --> 00:23:13,045
And

653
00:23:14,865 --> 00:23:17,025
this was amazing because the people knew they

654
00:23:17,025 --> 00:23:18,785
couldn't get in. They couldn't get in, and

655
00:23:18,785 --> 00:23:20,464
they were grinning ear to ear. They were

656
00:23:20,464 --> 00:23:21,684
smiling. They were jubilant.

657
00:23:22,144 --> 00:23:23,664
They just knew it was a special day.

658
00:23:23,664 --> 00:23:25,184
It didn't matter if they couldn't get in.

659
00:23:25,184 --> 00:23:27,000
They just wanted to feel like they were

660
00:23:27,000 --> 00:23:28,700
connected somehow with the room

661
00:23:29,080 --> 00:23:30,460
as part of this queue.

662
00:23:30,840 --> 00:23:32,920
They were connected with the the room that

663
00:23:32,920 --> 00:23:34,680
the seminar was where the seminar was gonna

664
00:23:34,680 --> 00:23:35,180
happen.

665
00:23:36,359 --> 00:23:36,859
And

666
00:23:38,215 --> 00:23:39,654
most of them, I mean, most of them

667
00:23:39,654 --> 00:23:40,775
didn't make it in the end to the

668
00:23:40,775 --> 00:23:42,215
room. They had to be dispersed. They were

669
00:23:42,215 --> 00:23:44,775
sent to various auxiliary conference rooms scattered around

670
00:23:44,775 --> 00:23:47,095
this the campus where a retransmission was taking

671
00:23:47,095 --> 00:23:48,795
place so they could all watch the proceedings

672
00:23:50,369 --> 00:23:52,849
in in on big screens in other rooms

673
00:23:52,849 --> 00:23:54,230
around around CERN.

674
00:23:55,250 --> 00:23:56,549
We went into the,

675
00:23:58,369 --> 00:24:00,289
into the council chamber where the press conference

676
00:24:00,289 --> 00:24:02,069
was taking place, and we were just

677
00:24:03,329 --> 00:24:03,829
buzzing.

678
00:24:04,234 --> 00:24:06,234
I mean, there is no other way to

679
00:24:06,234 --> 00:24:07,295
describe it. It was

680
00:24:08,154 --> 00:24:08,654
so

681
00:24:10,154 --> 00:24:11,615
incredible. And I remember

682
00:24:12,795 --> 00:24:14,815
our queue was when

683
00:24:15,755 --> 00:24:16,974
the CMS spokesperson,

684
00:24:17,275 --> 00:24:18,734
Joe and Candela, whose

685
00:24:19,180 --> 00:24:22,000
spokespersons are sort of elected representatives who

686
00:24:22,539 --> 00:24:25,039
lead the research team. So it's a democratic

687
00:24:25,099 --> 00:24:27,339
process where new people are elected to the

688
00:24:27,339 --> 00:24:29,339
role to lead the team. So you don't

689
00:24:29,339 --> 00:24:31,775
have 1 PI. You have rolling

690
00:24:33,195 --> 00:24:35,115
leaders of the team of the entire research

691
00:24:35,115 --> 00:24:35,615
collaboration.

692
00:24:36,875 --> 00:24:38,474
So Joe and Candela was gonna be presenting

693
00:24:38,474 --> 00:24:40,474
the CMS results. He presented the CMS results

694
00:24:40,474 --> 00:24:41,535
that day. And

695
00:24:42,715 --> 00:24:45,195
our cue was once he shows the money

696
00:24:45,195 --> 00:24:45,695
plot,

697
00:24:46,640 --> 00:24:47,919
when he says we have found a new

698
00:24:47,919 --> 00:24:49,859
particle with the significance of

699
00:24:50,240 --> 00:24:50,980
5 Sigma,

700
00:24:51,919 --> 00:24:53,779
was when we were gonna make that article

701
00:24:53,919 --> 00:24:56,179
public that we had prepared the previous night.

702
00:24:56,480 --> 00:24:58,079
So we were there waiting, and, you know,

703
00:24:58,079 --> 00:25:00,505
when everything happened, we went in we were

704
00:25:00,505 --> 00:25:02,265
logged into the back end of the website

705
00:25:02,265 --> 00:25:04,585
already waiting. We flipped the switch, flipped it

706
00:25:04,585 --> 00:25:07,065
to published, saved it, started sharing it on

707
00:25:07,065 --> 00:25:09,625
social media, started monitoring the buzz on social

708
00:25:09,625 --> 00:25:10,125
media.

709
00:25:10,744 --> 00:25:11,244
And

710
00:25:12,539 --> 00:25:15,019
Joe sat down, and our attention immediately turned

711
00:25:15,019 --> 00:25:16,399
to Fabiola's presentation

712
00:25:17,419 --> 00:25:19,339
because then we wanted to know what Atlas

713
00:25:19,339 --> 00:25:21,579
has because we didn't know what Atlas has.

714
00:25:21,579 --> 00:25:24,799
Representing Atlas at the meeting was Fabiola Gianotti,

715
00:25:25,339 --> 00:25:28,055
who is now CERN's director general. We have

716
00:25:28,055 --> 00:25:30,535
presented preliminary results on searches for a Standard

717
00:25:30,535 --> 00:25:32,775
Model X boson using the full data sample

718
00:25:32,775 --> 00:25:34,615
recorded so far for x 2 gamma gamma

719
00:25:34,615 --> 00:25:36,875
and x 2 4 leptons and the 2,011

720
00:25:37,095 --> 00:25:38,555
results for the other channels.

721
00:25:39,210 --> 00:25:42,029
I think these results represent an impressive accomplishment

722
00:25:42,169 --> 00:25:43,849
of the experiment in all its component. I

723
00:25:43,849 --> 00:25:45,849
would like just to mention that less than

724
00:25:45,849 --> 00:25:47,230
1 week after

725
00:25:47,769 --> 00:25:50,329
we recorded the latest data, so on the

726
00:25:50,329 --> 00:25:50,829
25th

727
00:25:51,289 --> 00:25:53,945
July or July, 1st plot containing the full

728
00:25:53,945 --> 00:25:56,664
statistics of the 2012 data first results on

729
00:25:56,664 --> 00:25:58,765
egg searches were already available

730
00:25:59,065 --> 00:26:01,644
with a fraction of good quality data certified

731
00:26:01,705 --> 00:26:03,625
at the level of 90% of the delivered

732
00:26:03,625 --> 00:26:05,625
luminosity. So for me, this is an impressive,

733
00:26:05,625 --> 00:26:09,440
remarkable, achievable of education and highly skilled work

734
00:26:09,440 --> 00:26:10,259
of the collaboration.

735
00:26:11,600 --> 00:26:13,440
We have looked for a standard model exposon

736
00:26:13,440 --> 00:26:15,359
over the mass region 100 10 to 600

737
00:26:15,359 --> 00:26:16,660
GeV in 12 channels.

738
00:26:16,960 --> 00:26:19,680
We have excluded a 99% confidence level at

739
00:26:19,680 --> 00:26:20,900
the region up to 523

740
00:26:21,279 --> 00:26:24,734
GeV, expect except a window. In that window,

741
00:26:24,794 --> 00:26:26,134
we observe a

742
00:26:27,034 --> 00:26:29,754
an excess with a local significant of 5.06

743
00:26:30,234 --> 00:26:33,454
6 5.0 sigma at a mass of 126.5

744
00:26:34,154 --> 00:26:34,654
GeV.

745
00:26:35,355 --> 00:26:37,194
The excess is driven by x 2 gamma

746
00:26:37,194 --> 00:26:39,279
gamma and 2 4 leptons is in agreement

747
00:26:39,279 --> 00:26:42,000
with that expected from a standard model x

748
00:26:42,000 --> 00:26:44,080
with the fitted signal strength of,

749
00:26:44,400 --> 00:26:46,880
1.2 plus or minus 0.3 of the standard

750
00:26:46,880 --> 00:26:48,720
model expectation. That was when we knew that

751
00:26:48,720 --> 00:26:49,779
it that it exists.

752
00:26:50,615 --> 00:26:51,515
It was a

753
00:26:53,575 --> 00:26:54,075
just

754
00:26:54,855 --> 00:26:55,355
moment

755
00:26:56,134 --> 00:26:56,634
of

756
00:26:57,414 --> 00:26:57,914
elation.

757
00:26:58,695 --> 00:26:59,195
Thank

758
00:26:59,974 --> 00:27:00,474
you.

759
00:27:01,255 --> 00:27:02,474
So after the

760
00:27:03,494 --> 00:27:05,195
seminar, we had a press conference

761
00:27:05,619 --> 00:27:06,440
where the spokespersons

762
00:27:07,059 --> 00:27:08,819
of CMS and Atlas, as well as the

763
00:27:08,819 --> 00:27:10,819
director of research for CERN and the director

764
00:27:10,819 --> 00:27:11,799
general of CERN

765
00:27:12,259 --> 00:27:14,500
and the head of the accelerator program, all

766
00:27:14,500 --> 00:27:16,179
came and spoke to the journalists. And Peter

767
00:27:16,179 --> 00:27:18,440
Higgs and Francois Engler were also there, and

768
00:27:19,715 --> 00:27:21,234
they answered all of the the questions that

769
00:27:21,234 --> 00:27:23,575
they had, and our senior researchers and and

770
00:27:23,715 --> 00:27:25,154
the scientists who were at the forefront of

771
00:27:25,154 --> 00:27:27,715
the research were all gathered there having interviews

772
00:27:27,715 --> 00:27:28,695
in their own languages.

773
00:27:29,555 --> 00:27:31,634
And by the time this was done, it

774
00:27:31,634 --> 00:27:32,615
was around lunchtime,

775
00:27:32,994 --> 00:27:35,690
and we decided to wander one floor down

776
00:27:35,690 --> 00:27:37,309
and go into Sun's main restaurant.

777
00:27:39,210 --> 00:27:40,330
And I can tell you that I don't

778
00:27:40,330 --> 00:27:42,730
remember what I ate. I don't remember anything

779
00:27:42,730 --> 00:27:44,730
about that meal. I have no recollection of

780
00:27:44,730 --> 00:27:47,769
it. I'd remember sitting in the extended area

781
00:27:47,769 --> 00:27:48,670
of the restaurant

782
00:27:50,744 --> 00:27:53,065
just smiling at my friends and colleagues, just

783
00:27:53,065 --> 00:27:55,465
going like, yeah. This has happened. This is

784
00:27:55,465 --> 00:27:55,965
real.

785
00:27:56,505 --> 00:27:57,005
And,

786
00:27:59,065 --> 00:28:01,724
it was amazing. I don't think anyone properly

787
00:28:01,785 --> 00:28:03,785
went back to work. People went back to

788
00:28:03,785 --> 00:28:06,710
their offices eventually after a couple of hours.

789
00:28:07,410 --> 00:28:08,769
But I don't know how many people actually

790
00:28:08,769 --> 00:28:10,049
went back to work that day because it

791
00:28:10,049 --> 00:28:11,730
was a day of celebration for the entire

792
00:28:11,730 --> 00:28:14,289
community and indeed for for anyone who's interested

793
00:28:14,289 --> 00:28:15,429
in in pure science.

794
00:28:16,210 --> 00:28:17,109
And, of course,

795
00:28:18,255 --> 00:28:20,015
you don't really begrudge them,

796
00:28:20,335 --> 00:28:21,455
the fact that they didn't go back and

797
00:28:21,455 --> 00:28:22,575
work the day because a lot of the

798
00:28:22,575 --> 00:28:24,515
people who are doing the research were working

799
00:28:24,815 --> 00:28:27,214
day in and day out, endless hours, getting

800
00:28:27,214 --> 00:28:28,035
fresh data,

801
00:28:28,414 --> 00:28:29,775
every day and trying to make sure that

802
00:28:29,775 --> 00:28:31,134
it was in good enough shape to present

803
00:28:31,134 --> 00:28:33,240
this discovery. Because one one of the funny

804
00:28:33,240 --> 00:28:35,339
things in which particle physics works is that

805
00:28:36,680 --> 00:28:38,220
ICHIP, the conference,

806
00:28:39,400 --> 00:28:40,460
was in the calendar

807
00:28:41,240 --> 00:28:43,799
months ago, months before the event. And so

808
00:28:43,799 --> 00:28:45,660
everything that had to happen had to happen

809
00:28:46,200 --> 00:28:48,140
on that day or up to that day.

810
00:28:48,515 --> 00:28:49,955
So there were quite a few long nights

811
00:28:49,955 --> 00:28:51,414
that people spent working on this,

812
00:28:51,795 --> 00:28:53,394
putting their heart and soul into it, and

813
00:28:53,394 --> 00:28:54,755
in the end, it was all worth it.

814
00:28:54,755 --> 00:28:57,075
You can read Asuncia's feature, a day in

815
00:28:57,075 --> 00:28:59,475
physics like no other, in the Physics World

816
00:28:59,475 --> 00:29:02,079
magazine. One of those researchers playing a key

817
00:29:02,079 --> 00:29:04,500
role who ended up in that conference room

818
00:29:04,639 --> 00:29:07,759
10 years ago is Christina Botter. Currently, I'm

819
00:29:07,759 --> 00:29:10,339
an assistant professor at the University of Zurich,

820
00:29:10,480 --> 00:29:11,359
but, yeah, my,

821
00:29:11,839 --> 00:29:13,139
particle physics story,

822
00:29:13,599 --> 00:29:15,839
started in Torino, at the University of Torino

823
00:29:15,839 --> 00:29:16,500
in Italy,

824
00:29:17,244 --> 00:29:18,464
where I did my PhD

825
00:29:19,484 --> 00:29:21,904
at the time. So it was between 2009

826
00:29:22,924 --> 00:29:23,744
and 2011,011.

827
00:29:24,284 --> 00:29:25,345
So just before,

828
00:29:25,644 --> 00:29:27,025
the Higgs boson discovery,

829
00:29:27,804 --> 00:29:29,424
the group of particle physicists,

830
00:29:29,724 --> 00:29:32,284
at the University of Torino were was working

831
00:29:32,284 --> 00:29:32,784
on

832
00:29:33,220 --> 00:29:36,579
reconstructing nuance. Nuance are a specific type of

833
00:29:36,579 --> 00:29:37,639
elementary particle,

834
00:29:38,259 --> 00:29:41,799
in one of the big detectors of particles,

835
00:29:43,299 --> 00:29:46,039
installed at the Large Hadron Collider at CERN.

836
00:29:46,659 --> 00:29:48,440
This experiment is called CMS.

837
00:29:48,815 --> 00:29:51,154
So I work in, with the CMS collaboration

838
00:29:51,214 --> 00:29:51,714
since

839
00:29:52,095 --> 00:29:52,595
2009.

840
00:29:52,974 --> 00:29:54,494
Just a quick aside, but the sound that

841
00:29:54,494 --> 00:29:57,454
you might be hearing is Christina's jewelry as

842
00:29:57,454 --> 00:29:58,194
she spoke.

843
00:29:58,494 --> 00:30:00,414
But I hope it's not too distracting, and

844
00:30:00,414 --> 00:30:02,815
in fact, it sort of conveys her passion

845
00:30:02,815 --> 00:30:05,339
for the project even more. And just while

846
00:30:05,339 --> 00:30:07,019
I'm here, for those of you who aren't

847
00:30:07,019 --> 00:30:09,599
part of the particle physics community,

848
00:30:10,140 --> 00:30:12,859
the standard model of particle physics is the

849
00:30:12,859 --> 00:30:14,640
framework through which physicists

850
00:30:15,180 --> 00:30:16,079
have understood

851
00:30:16,859 --> 00:30:19,420
the fundamental forces of nature over the past

852
00:30:19,420 --> 00:30:21,875
half a century. It was developed by theorists

853
00:30:21,875 --> 00:30:22,775
and experimentalists,

854
00:30:23,394 --> 00:30:25,894
and it's helped predict the existence of fundamental

855
00:30:26,115 --> 00:30:28,934
particles and how they interact with each other.

856
00:30:29,794 --> 00:30:31,335
Let's get back to Christina.

857
00:30:31,875 --> 00:30:33,335
So I got involved,

858
00:30:33,954 --> 00:30:34,454
in

859
00:30:35,220 --> 00:30:37,160
the analysis that turned out to be,

860
00:30:37,779 --> 00:30:40,099
one of the most sensitive analysis to the

861
00:30:40,099 --> 00:30:41,160
presence of,

862
00:30:41,619 --> 00:30:43,700
the Higgs boson in the data that in

863
00:30:43,700 --> 00:30:45,799
the collision data that we were recording,

864
00:30:46,579 --> 00:30:47,640
throughout 2,011,

865
00:30:48,099 --> 00:30:49,079
12, 13,

866
00:30:49,964 --> 00:30:52,444
because I I started to work on the

867
00:30:52,444 --> 00:30:54,924
search for the Higgs boson where the Higgs

868
00:30:54,924 --> 00:30:57,164
boson decays, the Higgs boson is not a

869
00:30:57,164 --> 00:31:00,285
stable particle. So it immediately decays into something

870
00:31:00,285 --> 00:31:02,765
else, something that you can detect in our

871
00:31:02,765 --> 00:31:03,265
detectors.

872
00:31:05,099 --> 00:31:07,339
And the channel where the Higgs boson decay

873
00:31:07,339 --> 00:31:08,720
into 4 mules

874
00:31:09,179 --> 00:31:11,980
is one of the most easily distinguishable with

875
00:31:11,980 --> 00:31:15,099
respect to all the other events that of

876
00:31:15,099 --> 00:31:16,559
particles that are produced

877
00:31:18,585 --> 00:31:19,085
in

878
00:31:19,544 --> 00:31:22,664
such the soft frequent collisions of the large

879
00:31:22,664 --> 00:31:24,125
other collider. So

880
00:31:25,384 --> 00:31:26,765
so, yes, I had this

881
00:31:27,304 --> 00:31:30,204
incredible choice to be there at that time,

882
00:31:30,900 --> 00:31:33,080
working on that specific analysis,

883
00:31:34,820 --> 00:31:37,619
and it was an an intense period and

884
00:31:37,619 --> 00:31:39,619
I feel very emotional to talk about it,

885
00:31:39,619 --> 00:31:40,519
of course, because,

886
00:31:42,694 --> 00:31:44,694
yeah, we were working day and night because

887
00:31:44,694 --> 00:31:47,815
data were coming in, every day, and there

888
00:31:47,815 --> 00:31:50,054
was a period where we thought that it

889
00:31:50,054 --> 00:31:51,835
was not going to be so

890
00:31:52,214 --> 00:31:53,595
quick that this if

891
00:31:53,894 --> 00:31:56,240
the eggs would have really existed, It would

892
00:31:56,240 --> 00:31:58,400
have taken much more time to discover it.

893
00:31:58,400 --> 00:32:00,660
But at some point, we understood that actually

894
00:32:00,880 --> 00:32:04,000
our analysis works more sensitive with respect to

895
00:32:04,000 --> 00:32:06,799
what we thought, at the beginning, and so

896
00:32:06,799 --> 00:32:08,660
things just got very fast.

897
00:32:09,119 --> 00:32:09,619
And,

898
00:32:12,015 --> 00:32:14,654
yeah. So the for for a few years,

899
00:32:14,654 --> 00:32:15,394
for 2010,

900
00:32:16,015 --> 00:32:16,515
2011,

901
00:32:17,295 --> 00:32:18,035
we excluded

902
00:32:18,335 --> 00:32:20,654
the presence of the Higgs boson in a

903
00:32:20,654 --> 00:32:23,549
certain ranges of masses. So we didn't know,

904
00:32:23,950 --> 00:32:25,890
which was the mass of the Higgs boson.

905
00:32:26,990 --> 00:32:29,950
It's not predicted by theory. Theory predicts all

906
00:32:29,950 --> 00:32:33,230
its behavior once the mass is measured and

907
00:32:33,230 --> 00:32:36,130
it's known. So we had to search for

908
00:32:37,085 --> 00:32:39,345
very wide ranges of possible masses.

909
00:32:40,365 --> 00:32:43,484
And, of course, with the mass hypothesis, it

910
00:32:43,484 --> 00:32:46,065
comes the rate of events that we,

911
00:32:46,845 --> 00:32:47,345
expect,

912
00:32:48,045 --> 00:32:50,924
in in our collisions, and so we started

913
00:32:50,924 --> 00:32:51,664
to exclude

914
00:32:52,589 --> 00:32:54,609
certain ranges of masses. And then

915
00:32:54,990 --> 00:32:56,670
at the end of my PhD, in my

916
00:32:56,670 --> 00:32:58,429
thesis, there was like this,

917
00:32:59,069 --> 00:33:01,710
plots that shows where the Higgs boson mass

918
00:33:01,710 --> 00:33:04,369
was excluded apart from a very tiny window

919
00:33:04,845 --> 00:33:06,924
around the actual mass of the Higgs boson,

920
00:33:06,924 --> 00:33:07,825
which is 125

921
00:33:08,765 --> 00:33:10,865
giga electron bolt, which is

922
00:33:11,325 --> 00:33:12,625
how we measure the mass.

923
00:33:14,525 --> 00:33:16,444
So, yeah, I ended my PhD with the

924
00:33:16,525 --> 00:33:17,825
in this moment where

925
00:33:18,444 --> 00:33:19,424
it was almost

926
00:33:20,960 --> 00:33:23,220
going to be discovered, and then I started

927
00:33:23,440 --> 00:33:24,099
a fellowship

928
00:33:24,400 --> 00:33:25,140
at CERN,

929
00:33:26,080 --> 00:33:26,580
and

930
00:33:27,680 --> 00:33:29,599
it got crazy. In the 1st year, it

931
00:33:29,599 --> 00:33:30,420
was indeed,

932
00:33:33,305 --> 00:33:33,964
the the LSCI,

933
00:33:34,265 --> 00:33:36,365
the large other collider really worked

934
00:33:36,904 --> 00:33:39,305
well in a sense that provided us, a

935
00:33:39,305 --> 00:33:41,224
lot of data in the 1st months of,

936
00:33:41,944 --> 00:33:42,444
2012,

937
00:33:43,865 --> 00:33:44,924
and in July,

938
00:33:47,140 --> 00:33:49,079
in 10 exactly 10 years ago.

939
00:33:49,700 --> 00:33:52,420
This is when we had enough data to

940
00:33:52,420 --> 00:33:56,519
claim the discovery, to claim it without any

941
00:33:59,154 --> 00:34:01,315
scientific doubt, let's say. So were you sort

942
00:34:01,315 --> 00:34:03,075
of one of the first people to see

943
00:34:03,075 --> 00:34:06,214
this data? Yeah. Because, I mean, of course,

944
00:34:07,394 --> 00:34:09,954
the Higgs was searched in many different decay

945
00:34:09,954 --> 00:34:12,614
channels as I said before, and ours,

946
00:34:13,394 --> 00:34:13,894
so

947
00:34:14,269 --> 00:34:16,269
I was working with the Torino, the university

948
00:34:16,269 --> 00:34:18,429
group that was working together with the,

949
00:34:19,150 --> 00:34:21,069
few people in the US and few people

950
00:34:21,069 --> 00:34:21,569
in,

951
00:34:21,949 --> 00:34:22,449
in

952
00:34:22,750 --> 00:34:23,250
Paris.

953
00:34:24,909 --> 00:34:26,690
We're working night and day altogether.

954
00:34:27,309 --> 00:34:27,630
So

955
00:34:28,695 --> 00:34:31,175
but, yes, indeed, I was really running the

956
00:34:31,175 --> 00:34:32,555
analysis myself. So,

957
00:34:33,655 --> 00:34:36,614
and that decay channel is so easy because

958
00:34:36,614 --> 00:34:39,015
you can really reconstruct the mass of the

959
00:34:39,015 --> 00:34:41,760
decay of the Higgs boson through the masses

960
00:34:41,760 --> 00:34:44,820
of the decay particles while reconstructing our detector.

961
00:34:46,559 --> 00:34:48,960
So the environment mass plots was showing an

962
00:34:48,960 --> 00:34:50,019
excess of events

963
00:34:50,480 --> 00:34:51,460
around the 125

964
00:34:52,079 --> 00:34:55,360
GBI possibility. So the analysis was blind, meaning

965
00:34:55,360 --> 00:34:56,724
that you don't

966
00:34:57,204 --> 00:34:58,905
you design your strategy

967
00:34:59,525 --> 00:35:00,025
and,

968
00:35:00,405 --> 00:35:02,585
only after your strategy is well,

969
00:35:03,045 --> 00:35:05,385
defined and approved by the whole collaboration,

970
00:35:06,085 --> 00:35:08,804
you run the analysis strategy on the data,

971
00:35:08,804 --> 00:35:09,545
which means

972
00:35:10,359 --> 00:35:10,859
particular

973
00:35:11,159 --> 00:35:12,300
set of selections,

974
00:35:13,320 --> 00:35:15,880
of criteria that you apply in order to

975
00:35:15,880 --> 00:35:17,579
reject other events that,

976
00:35:18,199 --> 00:35:19,980
are supposed to be background events.

977
00:35:21,079 --> 00:35:23,625
And so there was that specific moment when

978
00:35:23,625 --> 00:35:25,785
we decided that the full collaboration give us

979
00:35:25,785 --> 00:35:26,525
the approval,

980
00:35:27,304 --> 00:35:28,684
to unblinded, and

981
00:35:28,985 --> 00:35:31,625
I I remember very well that night, but

982
00:35:31,625 --> 00:35:33,324
everything happened very late at night.

983
00:35:33,704 --> 00:35:36,025
We decided to unblind with the full data

984
00:35:36,025 --> 00:35:37,485
set collected up to

985
00:35:37,820 --> 00:35:38,800
June 2012.

986
00:35:39,900 --> 00:35:41,840
Yeah, it was it was there. It was

987
00:35:42,380 --> 00:35:43,119
really visible.

988
00:35:43,739 --> 00:35:45,820
And the day after we we announced it,

989
00:35:45,820 --> 00:35:47,519
we showed it to all CMS.

990
00:35:47,900 --> 00:35:50,539
And in parallel, everything was happening in very

991
00:35:50,539 --> 00:35:52,925
same way in the ATLAS collaboration. So the

992
00:35:52,925 --> 00:35:55,005
other experiments, we were not talking to each

993
00:35:55,005 --> 00:35:56,144
other, not to

994
00:35:56,445 --> 00:35:58,605
bias each other because it's very easy to

995
00:35:58,605 --> 00:36:00,304
be biased, of course, if you,

996
00:36:01,965 --> 00:36:03,965
if you're searching for something that you really

997
00:36:03,965 --> 00:36:05,505
don't know where it is.

998
00:36:08,150 --> 00:36:09,050
Yeah. So

999
00:36:09,590 --> 00:36:12,230
it's true that our team really saw it,

1000
00:36:12,869 --> 00:36:15,670
in our office at, for the first time.

1001
00:36:15,670 --> 00:36:19,269
Amazing. Amazing. And and that day of the

1002
00:36:19,269 --> 00:36:19,769
announcement

1003
00:36:20,070 --> 00:36:20,570
to

1004
00:36:20,950 --> 00:36:21,610
the world,

1005
00:36:22,125 --> 00:36:24,925
you were actually in the room. Yeah. Yeah.

1006
00:36:24,925 --> 00:36:26,844
I was in the room because it was

1007
00:36:26,844 --> 00:36:28,545
very nice because we had, like,

1008
00:36:29,885 --> 00:36:30,385
until

1009
00:36:30,764 --> 00:36:32,925
very late in night and day before, we

1010
00:36:32,925 --> 00:36:35,109
helped. So there was each team. So I

1011
00:36:35,109 --> 00:36:37,030
was the full lactam team. Okay? The person

1012
00:36:37,030 --> 00:36:38,789
that worked for the full app. But the,

1013
00:36:38,949 --> 00:36:42,150
the statistical significance of the discovery was obtained

1014
00:36:42,150 --> 00:36:45,190
combining different channels. So there was each team

1015
00:36:45,190 --> 00:36:48,469
helping the spoke person of our collaborator join

1016
00:36:48,469 --> 00:36:50,835
Candela at the time, the the person that

1017
00:36:51,315 --> 00:36:53,335
give the speech on the 4th July.

1018
00:36:55,155 --> 00:36:55,655
And,

1019
00:36:56,355 --> 00:36:58,214
and all of us that, were

1020
00:36:58,594 --> 00:37:00,375
contacts for these, analysis

1021
00:37:01,074 --> 00:37:01,574
channels,

1022
00:37:02,275 --> 00:37:03,335
had a seat

1023
00:37:03,880 --> 00:37:06,119
reserve in the in the room, and you

1024
00:37:06,119 --> 00:37:08,119
were very young at the time. We're so

1025
00:37:08,119 --> 00:37:09,739
happy. We're all the,

1026
00:37:10,519 --> 00:37:11,019
super

1027
00:37:11,320 --> 00:37:12,300
experts of

1028
00:37:12,679 --> 00:37:13,659
the the machine,

1029
00:37:13,960 --> 00:37:14,699
the detector,

1030
00:37:15,079 --> 00:37:16,940
the theories, and then there was

1031
00:37:17,400 --> 00:37:18,224
a bunch of,

1032
00:37:18,704 --> 00:37:19,765
yeah, very young,

1033
00:37:20,465 --> 00:37:22,005
just graduated students,

1034
00:37:23,425 --> 00:37:25,744
in the front line. So still now, I

1035
00:37:25,744 --> 00:37:26,965
mean, I I sometimes,

1036
00:37:28,625 --> 00:37:29,445
watch again

1037
00:37:29,785 --> 00:37:30,285
the,

1038
00:37:30,864 --> 00:37:32,485
the recording of that day.

1039
00:37:33,849 --> 00:37:35,530
It fits but, also, it fits the motion

1040
00:37:35,530 --> 00:37:37,550
that there was 2 experiments completely.

1041
00:37:38,010 --> 00:37:40,570
They are different, and they were doing they

1042
00:37:40,570 --> 00:37:42,730
had the same goal, and they arrived on

1043
00:37:42,730 --> 00:37:43,630
the same day

1044
00:37:44,010 --> 00:37:45,389
with the same announcements.

1045
00:37:46,795 --> 00:37:49,535
It felt such it felt really that science

1046
00:37:49,675 --> 00:37:51,934
worked so well. Yeah.

1047
00:37:52,554 --> 00:37:55,114
Yeah. All the scientific method that we we

1048
00:37:55,114 --> 00:37:56,094
put in place,

1049
00:37:58,394 --> 00:37:59,695
years years of work,

1050
00:38:02,010 --> 00:38:04,969
yeah, came together in a very nicely way.

1051
00:38:04,969 --> 00:38:06,890
It's just it's just an incredible moment, wasn't

1052
00:38:06,890 --> 00:38:09,530
it? Particle physics that, you know, even people

1053
00:38:09,530 --> 00:38:11,769
who had never been interested, never even thought

1054
00:38:11,769 --> 00:38:14,454
about particle physics, this captured their imagination. Yeah.

1055
00:38:14,454 --> 00:38:16,375
I think it's all those boys now to

1056
00:38:16,375 --> 00:38:18,295
this to the fact that there was this

1057
00:38:18,295 --> 00:38:21,335
theorist, not the only one, so more than

1058
00:38:21,335 --> 00:38:23,034
one, but Higgs is the,

1059
00:38:23,574 --> 00:38:25,734
Peter Higgs is the one that gave the

1060
00:38:25,734 --> 00:38:27,355
name to the to the Higgs boson.

1061
00:38:28,569 --> 00:38:29,069
Anyhow,

1062
00:38:30,250 --> 00:38:31,389
there was this moment

1063
00:38:32,170 --> 00:38:33,549
so many years before

1064
00:38:34,170 --> 00:38:35,230
where mathematically

1065
00:38:35,530 --> 00:38:36,750
you predicted the

1066
00:38:38,730 --> 00:38:40,170
the the fact that if you want to

1067
00:38:40,170 --> 00:38:42,730
explain the masses of other particles, you need

1068
00:38:42,730 --> 00:38:43,230
this

1069
00:38:44,105 --> 00:38:46,744
mathematical trick. It's exactly that, that you need

1070
00:38:46,744 --> 00:38:48,045
to put it in the equations,

1071
00:38:48,984 --> 00:38:51,545
to make everything works and that predict the

1072
00:38:51,545 --> 00:38:52,924
existence of the new,

1073
00:38:54,264 --> 00:38:57,144
field that and quantum excitation of fields are

1074
00:38:57,144 --> 00:39:00,199
particles or a a new particle. And then

1075
00:39:00,420 --> 00:39:02,820
from that moment onwards, there was such a

1076
00:39:02,820 --> 00:39:04,519
huge experimental effort.

1077
00:39:05,380 --> 00:39:06,359
Previous accelerators,

1078
00:39:08,579 --> 00:39:11,619
the lap accelerator, the Tevatron in Chicago, and

1079
00:39:11,619 --> 00:39:12,119
then,

1080
00:39:13,460 --> 00:39:14,280
the LAC.

1081
00:39:15,364 --> 00:39:18,244
Thousands of people working on it. And when

1082
00:39:18,244 --> 00:39:20,105
you see our detectors, it's like

1083
00:39:20,804 --> 00:39:24,025
1,000,000,000 of cables. Okay? Millions of cables.

1084
00:39:25,125 --> 00:39:26,184
Everything works

1085
00:39:26,484 --> 00:39:26,984
to

1086
00:39:28,085 --> 00:39:29,464
together to detect

1087
00:39:30,699 --> 00:39:32,079
an invisible particles.

1088
00:39:32,780 --> 00:39:35,440
So many cables everywhere, and they're just here

1089
00:39:35,660 --> 00:39:38,059
because we wanna find out how everything works.

1090
00:39:38,059 --> 00:39:39,519
I really love it.

1091
00:39:41,179 --> 00:39:44,000
Okay. So that was 10 years ago.

1092
00:39:44,765 --> 00:39:46,765
What's happened since? Do we do is are

1093
00:39:46,765 --> 00:39:49,164
we still learning about this this Higgs boson?

1094
00:39:49,164 --> 00:39:51,105
Oh, yeah. The Higgs boson is a the

1095
00:39:51,325 --> 00:39:52,864
it has a few peculiar,

1096
00:39:53,405 --> 00:39:53,905
properties.

1097
00:39:54,844 --> 00:39:55,905
It's the only,

1098
00:39:56,285 --> 00:39:59,025
particle only elementary particle, at least

1099
00:39:59,589 --> 00:40:01,829
particle that we believe is elementary as of,

1100
00:40:02,069 --> 00:40:03,289
as what we know today,

1101
00:40:04,309 --> 00:40:06,409
that is a scalar, meaning that,

1102
00:40:06,710 --> 00:40:08,789
is a spin, which is a quantum property

1103
00:40:08,789 --> 00:40:10,170
of the particle is 0,

1104
00:40:10,469 --> 00:40:13,130
and because of this reason, this I don't

1105
00:40:13,269 --> 00:40:16,324
discuss the the the mathematics behind, but because

1106
00:40:16,324 --> 00:40:17,304
of this reason

1107
00:40:18,085 --> 00:40:18,405
in,

1108
00:40:19,125 --> 00:40:20,505
in quantum field theory,

1109
00:40:22,244 --> 00:40:24,905
it's very difficult to explain naturally

1110
00:40:25,284 --> 00:40:28,164
why this particle would have the mass that

1111
00:40:28,164 --> 00:40:30,590
it has. So the fact that the mass

1112
00:40:30,590 --> 00:40:33,070
of Higgs is so light is very difficult

1113
00:40:33,070 --> 00:40:35,090
to explain, it means that the theory

1114
00:40:35,469 --> 00:40:37,789
is very much fine tuned. So this is

1115
00:40:37,789 --> 00:40:38,769
a very mathematical

1116
00:40:39,869 --> 00:40:42,289
and awesome, somehow also philosophical concept,

1117
00:40:42,670 --> 00:40:43,454
but it

1118
00:40:43,934 --> 00:40:46,735
once you discover the Higgs boson every theory

1119
00:40:46,735 --> 00:40:47,235
was,

1120
00:40:48,335 --> 00:40:50,434
betting on the existence of

1121
00:40:50,815 --> 00:40:51,715
other particles.

1122
00:40:52,735 --> 00:40:53,555
Other particles

1123
00:40:54,175 --> 00:40:56,414
probably heavier for sure because we haven't seen

1124
00:40:56,414 --> 00:40:57,235
them before,

1125
00:40:58,839 --> 00:41:00,059
that could explain

1126
00:41:00,359 --> 00:41:02,219
why the mass of the Higgs is,

1127
00:41:03,000 --> 00:41:04,460
that is at that value,

1128
00:41:06,280 --> 00:41:08,519
and also could explain also other things that

1129
00:41:08,519 --> 00:41:11,414
we don't haven't understood yet, like what is

1130
00:41:11,414 --> 00:41:13,894
the particle content if it has a particle

1131
00:41:13,894 --> 00:41:16,875
content of, dark matter. K? That is

1132
00:41:17,255 --> 00:41:19,974
the matter of that is supposed to be

1133
00:41:19,974 --> 00:41:21,494
there in the universe, and we don't know

1134
00:41:21,494 --> 00:41:24,315
what it's made of. So for this reason,

1135
00:41:25,809 --> 00:41:27,109
LAC was

1136
00:41:27,409 --> 00:41:28,389
ready to,

1137
00:41:30,210 --> 00:41:33,829
was supposed to discover new states at energies

1138
00:41:34,289 --> 00:41:36,449
around the, the mass of the particle bakes,

1139
00:41:36,449 --> 00:41:38,150
and we didn't so far.

1140
00:41:38,824 --> 00:41:41,085
So this is one aspect of the story,

1141
00:41:42,344 --> 00:41:44,684
that we didn't so far, which is an

1142
00:41:45,065 --> 00:41:47,464
pretty much important piece of information. So,

1143
00:41:47,784 --> 00:41:50,284
they are not just out there with the

1144
00:41:52,039 --> 00:41:53,960
probability to be produced the,

1145
00:41:54,519 --> 00:41:56,219
of the value that we were expecting.

1146
00:41:56,840 --> 00:41:59,579
So there's something that we are not understanding,

1147
00:42:00,679 --> 00:42:02,300
and, it's fundamental.

1148
00:42:02,920 --> 00:42:03,420
It's

1149
00:42:04,215 --> 00:42:05,675
it's extremely interesting,

1150
00:42:06,055 --> 00:42:06,555
and

1151
00:42:08,055 --> 00:42:10,614
it this is why we really need to

1152
00:42:10,614 --> 00:42:12,775
add more data in front of us to

1153
00:42:12,775 --> 00:42:14,635
understand where things are,

1154
00:42:15,414 --> 00:42:15,914
hiding.

1155
00:42:17,489 --> 00:42:20,449
If things are really happening and if there

1156
00:42:20,449 --> 00:42:22,210
are new things at the energy scale that

1157
00:42:22,210 --> 00:42:23,030
we are exploring,

1158
00:42:23,410 --> 00:42:26,289
which is what many people believe for many

1159
00:42:26,289 --> 00:42:27,429
theoretical reasons.

1160
00:42:28,130 --> 00:42:29,730
On the other side, there is the Higgs

1161
00:42:29,730 --> 00:42:30,630
boson that

1162
00:42:31,265 --> 00:42:33,985
couples to anything that has mass. So any

1163
00:42:33,985 --> 00:42:36,144
new part any particle that has mass gets

1164
00:42:36,144 --> 00:42:38,144
the mass from its interaction with the Higgs

1165
00:42:38,144 --> 00:42:38,644
boson.

1166
00:42:39,184 --> 00:42:40,485
So it's not,

1167
00:42:41,265 --> 00:42:43,105
strange to think that if there would be

1168
00:42:43,105 --> 00:42:44,085
something new,

1169
00:42:44,400 --> 00:42:46,019
it would couple to the Higgs,

1170
00:42:47,119 --> 00:42:49,619
changing its properties lightly. So,

1171
00:42:50,559 --> 00:42:52,719
we have started to measure the properties of

1172
00:42:52,719 --> 00:42:54,639
the Higgs boson. So as I said before,

1173
00:42:54,639 --> 00:42:56,875
once you know the mass of it, you

1174
00:42:56,954 --> 00:42:59,675
the theory predict the probability that it would

1175
00:42:59,675 --> 00:43:02,075
decay into the 4 muons as I said

1176
00:43:02,075 --> 00:43:02,575
before,

1177
00:43:03,035 --> 00:43:05,135
into 2 photos, into 2,

1178
00:43:05,595 --> 00:43:07,355
bottom quarks, and so on and so forth.

1179
00:43:07,355 --> 00:43:09,114
So we go and measure the rate that

1180
00:43:09,114 --> 00:43:09,614
the,

1181
00:43:09,994 --> 00:43:12,175
how many events we saw,

1182
00:43:12,639 --> 00:43:15,119
given the total amount of Higgs boson events

1183
00:43:15,119 --> 00:43:15,619
produced

1184
00:43:15,920 --> 00:43:16,900
in our collisions,

1185
00:43:17,440 --> 00:43:19,619
that would decay in one particular channel.

1186
00:43:21,280 --> 00:43:23,539
But you need to know these ratios,

1187
00:43:24,239 --> 00:43:24,739
with

1188
00:43:25,405 --> 00:43:27,724
a very good precision in order to be

1189
00:43:27,724 --> 00:43:28,625
sure that,

1190
00:43:29,085 --> 00:43:30,625
the Higgs is behaving

1191
00:43:30,925 --> 00:43:31,425
exactly

1192
00:43:31,805 --> 00:43:32,704
as the theory,

1193
00:43:33,244 --> 00:43:33,985
is predicting.

1194
00:43:34,525 --> 00:43:35,025
So

1195
00:43:35,644 --> 00:43:38,865
after the discovery, it started a long, long

1196
00:43:41,670 --> 00:43:44,389
path toward the precise measurements of the property

1197
00:43:44,389 --> 00:43:46,309
of the Higgs boson. So if you take

1198
00:43:46,309 --> 00:43:48,630
the standard model of particle physics, all the

1199
00:43:48,630 --> 00:43:52,090
other particles since we are analyzing and measuring

1200
00:43:52,150 --> 00:43:52,889
their properties

1201
00:43:53,750 --> 00:43:54,489
much longer,

1202
00:43:54,949 --> 00:43:55,610
they are

1203
00:43:56,684 --> 00:43:58,545
better measured, okay, better understood.

1204
00:43:58,925 --> 00:44:00,224
The Higgs is still,

1205
00:44:00,684 --> 00:44:01,184
the

1206
00:44:02,204 --> 00:44:02,864
the uncertainty

1207
00:44:03,244 --> 00:44:05,345
on which we go with which we know

1208
00:44:05,565 --> 00:44:07,724
the property of the Higgs are about 10

1209
00:44:07,724 --> 00:44:08,385
to 20%,

1210
00:44:08,684 --> 00:44:11,319
which are huge uncertainties with respect to how

1211
00:44:11,319 --> 00:44:13,400
we know the other particles that are known

1212
00:44:13,400 --> 00:44:14,619
with the per mille uncertainty.

1213
00:44:14,920 --> 00:44:16,380
So there's still space.

1214
00:44:17,000 --> 00:44:18,219
All what we have measured

1215
00:44:18,760 --> 00:44:20,920
gave us the confidence that this is really

1216
00:44:20,920 --> 00:44:23,099
the Higgs boson because it's behaving

1217
00:44:23,945 --> 00:44:26,664
really has the theory is predicting, but there's

1218
00:44:26,664 --> 00:44:27,965
still space for,

1219
00:44:29,144 --> 00:44:29,644
misbehaviors

1220
00:44:30,025 --> 00:44:32,744
or something that is not really standard model

1221
00:44:32,744 --> 00:44:34,925
like. And these things takes time

1222
00:44:35,224 --> 00:44:37,625
because these measurements are very complex. You have

1223
00:44:37,625 --> 00:44:38,284
to really,

1224
00:44:39,039 --> 00:44:40,339
especially at a at

1225
00:44:40,880 --> 00:44:42,339
a we collide protons.

1226
00:44:42,880 --> 00:44:46,079
So the we our collision are characterized by

1227
00:44:46,079 --> 00:44:48,480
an hadronic environments. There's a lot of stuff

1228
00:44:48,480 --> 00:44:51,139
happening in our collision because of the constituents

1229
00:44:51,199 --> 00:44:53,219
of the protons. The protons are not elementary

1230
00:44:53,359 --> 00:44:53,859
particles.

1231
00:44:55,085 --> 00:44:57,744
And then we collide 10 to the 11

1232
00:44:57,804 --> 00:45:00,684
protons with 10 to the 11 protons. So

1233
00:45:00,684 --> 00:45:01,984
when we smash them,

1234
00:45:02,364 --> 00:45:05,405
there can be multiple collisions happening together. So

1235
00:45:05,405 --> 00:45:06,224
it's very,

1236
00:45:06,924 --> 00:45:08,144
difficult to

1237
00:45:09,260 --> 00:45:09,760
precisely

1238
00:45:10,059 --> 00:45:10,559
reconstruct,

1239
00:45:11,420 --> 00:45:12,639
each single event.

1240
00:45:14,380 --> 00:45:15,840
So you need a lot of data

1241
00:45:16,219 --> 00:45:17,679
and a lot of advanced,

1242
00:45:18,380 --> 00:45:20,079
techniques to analyze them

1243
00:45:20,635 --> 00:45:23,914
in order to really measure precisely the properties

1244
00:45:23,914 --> 00:45:25,055
of these new particles.

1245
00:45:25,355 --> 00:45:26,715
And here we are. We are at the

1246
00:45:26,715 --> 00:45:28,335
10 to 20% precision.

1247
00:45:28,795 --> 00:45:31,035
At the beginning, it was like, yeah, not

1248
00:45:31,035 --> 00:45:31,535
even

1249
00:45:32,489 --> 00:45:34,969
None of these properties were accessible at the

1250
00:45:34,969 --> 00:45:36,889
time of the discovery. We just saw that

1251
00:45:36,889 --> 00:45:38,030
there was a new particles,

1252
00:45:39,449 --> 00:45:40,670
with a certain mass,

1253
00:45:41,130 --> 00:45:42,429
but now we are really

1254
00:45:43,530 --> 00:45:45,070
getting everything looks

1255
00:45:45,610 --> 00:45:48,594
consistent with the theory as of today. There's

1256
00:45:48,594 --> 00:45:49,094
still

1257
00:45:49,875 --> 00:45:52,515
from 10% to 1 per mil, there's still

1258
00:45:52,515 --> 00:45:53,414
a long path

1259
00:45:53,795 --> 00:45:55,414
to go. Is there anything

1260
00:45:55,795 --> 00:45:56,775
that will sort

1261
00:45:57,474 --> 00:45:59,394
of excite the world the way that the

1262
00:45:59,394 --> 00:46:02,050
Higgs boson did? You know, this the Higgs

1263
00:46:02,050 --> 00:46:04,389
boson was not was exciting for

1264
00:46:05,089 --> 00:46:07,829
for us, for, like, for everybody that Adam

1265
00:46:07,889 --> 00:46:10,389
see that what didn't go through a discovery

1266
00:46:10,609 --> 00:46:11,109
before

1267
00:46:11,889 --> 00:46:12,614
for the

1268
00:46:13,094 --> 00:46:14,934
public outside because of the,

1269
00:46:15,335 --> 00:46:17,514
the story, not the drop to the discovery,

1270
00:46:17,894 --> 00:46:20,074
but was not so exciting for

1271
00:46:20,534 --> 00:46:22,695
the theories per se because it was just

1272
00:46:22,695 --> 00:46:23,195
confirming,

1273
00:46:25,094 --> 00:46:26,474
a piece that was missing

1274
00:46:26,799 --> 00:46:28,260
that the theory was predicting

1275
00:46:29,519 --> 00:46:32,339
and it fit with the the the

1276
00:46:32,639 --> 00:46:34,559
the the mode, the standard model of particle

1277
00:46:34,559 --> 00:46:36,559
physics. The the only theory we have in

1278
00:46:36,559 --> 00:46:37,779
our heads to predict,

1279
00:46:38,639 --> 00:46:39,779
fundamental phenomena,

1280
00:46:40,235 --> 00:46:41,135
but it doesn't,

1281
00:46:42,474 --> 00:46:43,215
bring us

1282
00:46:43,994 --> 00:46:46,554
anything new on what we don't know because

1283
00:46:46,554 --> 00:46:48,175
the standard model is not,

1284
00:46:48,875 --> 00:46:50,335
explaining many things.

1285
00:46:50,635 --> 00:46:52,735
We are just scratching the surface.

1286
00:46:53,434 --> 00:46:55,840
So all the things that we haven't understood

1287
00:46:55,840 --> 00:46:56,340
yet

1288
00:46:57,440 --> 00:46:59,280
are still we don't have any so the

1289
00:46:59,519 --> 00:47:01,760
we are not getting more clues with the

1290
00:47:01,760 --> 00:47:04,639
discovery of the Higgs boson. So something that

1291
00:47:04,639 --> 00:47:06,260
would be totally unpredicted

1292
00:47:06,800 --> 00:47:07,539
would be

1293
00:47:08,484 --> 00:47:08,984
even

1294
00:47:09,364 --> 00:47:11,284
more exciting than the Higgs boson. So if

1295
00:47:11,284 --> 00:47:12,264
we would discover,

1296
00:47:14,005 --> 00:47:16,724
a violation of the laws that the standard

1297
00:47:16,724 --> 00:47:17,224
model,

1298
00:47:18,405 --> 00:47:20,244
that up to to now we we thought

1299
00:47:20,244 --> 00:47:22,025
they are conserved in nature

1300
00:47:22,420 --> 00:47:24,579
or a new particles that is not predicted

1301
00:47:24,579 --> 00:47:26,119
by the standard model that

1302
00:47:27,139 --> 00:47:27,639
yeah.

1303
00:47:28,179 --> 00:47:29,639
That is what we are all

1304
00:47:31,860 --> 00:47:33,079
dreaming of because

1305
00:47:33,780 --> 00:47:34,099
we

1306
00:47:34,944 --> 00:47:36,864
something new we know that this is not

1307
00:47:36,864 --> 00:47:38,944
a fundamental theory because it has so many

1308
00:47:38,944 --> 00:47:40,244
things that it's not

1309
00:47:40,625 --> 00:47:41,125
covering,

1310
00:47:42,065 --> 00:47:44,065
but we just don't know at which energy

1311
00:47:44,065 --> 00:47:46,244
scale these new things will

1312
00:47:46,545 --> 00:47:47,605
manifest themselves.

1313
00:47:47,905 --> 00:47:48,405
So

1314
00:47:49,139 --> 00:47:50,760
it could be at this accelerator.

1315
00:47:51,859 --> 00:47:53,780
At the energy scale, we are probing with

1316
00:47:53,780 --> 00:47:54,440
this collision,

1317
00:47:55,380 --> 00:47:57,960
or we need a much more powerful accelerator.

1318
00:47:58,019 --> 00:48:00,579
So we it's but this would be much

1319
00:48:00,579 --> 00:48:02,679
more exciting because it's something that

1320
00:48:02,980 --> 00:48:03,480
unexpected.

1321
00:48:03,924 --> 00:48:04,724
It would be

1322
00:48:05,045 --> 00:48:07,204
there was a moment a few years ago

1323
00:48:07,204 --> 00:48:07,704
when,

1324
00:48:09,364 --> 00:48:11,924
both ATLAS and CMS started thinking that there

1325
00:48:11,924 --> 00:48:12,744
could have been,

1326
00:48:13,125 --> 00:48:14,904
a new state at 750

1327
00:48:15,684 --> 00:48:16,184
GeV

1328
00:48:16,539 --> 00:48:18,539
that would decay to 2 photons, then it

1329
00:48:18,539 --> 00:48:19,599
was never confirmed.

1330
00:48:20,380 --> 00:48:22,799
It didn't reach the statistical significance,

1331
00:48:24,299 --> 00:48:26,159
that we needed to claim a discovery.

1332
00:48:26,460 --> 00:48:28,539
But there was a hint of something, and

1333
00:48:28,539 --> 00:48:30,460
both experiments were seeing it. So it was,

1334
00:48:30,460 --> 00:48:30,960
wow.

1335
00:48:31,454 --> 00:48:33,614
It's not the statistical fluctuation, then it was

1336
00:48:33,614 --> 00:48:36,434
a statistical fluctuation. It went away. But

1337
00:48:37,614 --> 00:48:39,315
you can't imagine how many

1338
00:48:40,175 --> 00:48:41,075
theory paper,

1339
00:48:42,255 --> 00:48:43,635
happened the day after

1340
00:48:44,710 --> 00:48:46,789
when we had we had for this first

1341
00:48:46,789 --> 00:48:49,190
claim about this potential hint of new particle

1342
00:48:49,190 --> 00:48:49,690
because,

1343
00:48:51,269 --> 00:48:54,170
yeah, in this moment, theories also need

1344
00:48:54,550 --> 00:48:55,050
experimental

1345
00:48:55,430 --> 00:48:57,849
inputs to understand what is the fundamental

1346
00:48:58,150 --> 00:48:58,650
theory,

1347
00:49:00,215 --> 00:49:03,035
at least more fundamental than the standard model.

1348
00:49:03,735 --> 00:49:04,235
Okay.

1349
00:49:04,535 --> 00:49:06,795
The Large Hadron Collider is being upgraded.

1350
00:49:07,175 --> 00:49:09,515
Yes. Right. Exactly right now,

1351
00:49:10,614 --> 00:49:11,594
we are restarting

1352
00:49:11,974 --> 00:49:14,329
run 3. So we had 2 run, run

1353
00:49:14,329 --> 00:49:15,550
1 and run 2,

1354
00:49:16,570 --> 00:49:17,929
and run 3 is,

1355
00:49:19,690 --> 00:49:23,150
will start now and will end in 2,025.

1356
00:49:26,105 --> 00:49:28,125
Things are changing every day. So or 2025.

1357
00:49:28,585 --> 00:49:29,724
And this will be,

1358
00:49:30,664 --> 00:49:32,824
will record data with the same at the

1359
00:49:32,824 --> 00:49:35,864
same and similar, slightly higher energy, but with

1360
00:49:35,864 --> 00:49:37,464
the same intensity. So,

1361
00:49:37,784 --> 00:49:39,625
there will be the same amount of data

1362
00:49:39,625 --> 00:49:41,050
more or less collected,

1363
00:49:41,670 --> 00:49:43,190
per year as it was,

1364
00:49:43,750 --> 00:49:46,150
during in the past. But then we will

1365
00:49:46,150 --> 00:49:48,170
start a completely new phase in,

1366
00:49:49,190 --> 00:49:51,369
2000 around 2029, 2,030

1367
00:49:53,534 --> 00:49:55,875
that will last probably 10 years,

1368
00:49:56,655 --> 00:49:58,594
where we will, at the end,

1369
00:50:00,094 --> 00:50:02,974
collect a factor 10 more data than the

1370
00:50:02,974 --> 00:50:05,295
one that we have collected so far. This

1371
00:50:05,295 --> 00:50:06,674
is a big jump. So,

1372
00:50:07,295 --> 00:50:08,820
in order to reach that,

1373
00:50:09,380 --> 00:50:11,640
the machine is going undergoing

1374
00:50:11,940 --> 00:50:13,000
a major upgrade

1375
00:50:13,380 --> 00:50:14,599
in order to run,

1376
00:50:14,980 --> 00:50:16,840
at what we call high luminosity.

1377
00:50:17,219 --> 00:50:18,840
So it will be high luminosity

1378
00:50:19,300 --> 00:50:19,800
LAC.

1379
00:50:21,414 --> 00:50:23,335
It means that what I said before, we

1380
00:50:23,335 --> 00:50:25,755
will be smashing even more protons together,

1381
00:50:26,375 --> 00:50:28,554
and so we will have even more overlapping

1382
00:50:28,934 --> 00:50:31,594
proton proton collisions, so even more complex

1383
00:50:32,054 --> 00:50:33,275
event selection,

1384
00:50:34,134 --> 00:50:35,114
in our detectors,

1385
00:50:35,894 --> 00:50:38,590
but at the end what we obtain with

1386
00:50:38,590 --> 00:50:40,210
this higher luminosity is

1387
00:50:40,590 --> 00:50:41,090
more,

1388
00:50:41,630 --> 00:50:42,609
collision events,

1389
00:50:43,550 --> 00:50:45,230
at the in in 10 years at the

1390
00:50:45,230 --> 00:50:47,230
factor of 10 more than what we we

1391
00:50:47,230 --> 00:50:49,329
are able to collect right now.

1392
00:50:50,525 --> 00:50:52,204
And this is useful to get to the

1393
00:50:52,204 --> 00:50:54,684
precision, to much higher precision of the measurements

1394
00:50:54,684 --> 00:50:57,505
that we wanna do and also to still

1395
00:50:58,125 --> 00:51:01,005
to close this chapter on is there new

1396
00:51:01,005 --> 00:51:04,045
physics like new particle states at the energy

1397
00:51:04,045 --> 00:51:05,940
scale that we are probing. So we are

1398
00:51:05,940 --> 00:51:08,339
not jumping in energy scale. We are not

1399
00:51:08,339 --> 00:51:09,800
going to much more powerful,

1400
00:51:10,579 --> 00:51:13,300
accelerators in terms of energy on the collision.

1401
00:51:13,300 --> 00:51:15,139
We are just increasing the amount of data

1402
00:51:15,139 --> 00:51:16,119
that we will collect

1403
00:51:16,420 --> 00:51:17,480
such that if,

1404
00:51:18,114 --> 00:51:20,835
these new particles are rare, are more rare

1405
00:51:20,835 --> 00:51:22,215
than what we thought,

1406
00:51:22,914 --> 00:51:23,655
with these

1407
00:51:24,035 --> 00:51:25,894
larger statistics, we can,

1408
00:51:27,155 --> 00:51:29,094
infer the infer their presence.

1409
00:51:31,369 --> 00:51:32,510
Yeah. So we are

1410
00:51:32,809 --> 00:51:34,269
really going in the corners

1411
00:51:34,650 --> 00:51:36,809
to try to understand if there are new

1412
00:51:36,809 --> 00:51:39,070
particles at the energy scale we are probing.

1413
00:51:39,210 --> 00:51:41,610
Before going to higher energy scales with new

1414
00:51:41,610 --> 00:51:42,110
accelerators,

1415
00:51:42,650 --> 00:51:45,394
the next 10 years will be about exploring

1416
00:51:46,655 --> 00:51:48,914
this energy scale with much more scrutiny,

1417
00:51:49,934 --> 00:51:50,994
than what we have

1418
00:51:52,574 --> 00:51:55,054
pursued up to now. If the new particles

1419
00:51:55,054 --> 00:51:57,054
and new physics isn't found at these energy

1420
00:51:57,054 --> 00:51:57,554
scales,

1421
00:51:57,855 --> 00:51:59,635
what kind of size

1422
00:52:00,090 --> 00:52:03,050
particle accelerator do we need, and are they

1423
00:52:03,050 --> 00:52:05,070
actually being built? In these years,

1424
00:52:05,369 --> 00:52:06,750
there's a lot of discussion,

1425
00:52:07,769 --> 00:52:10,750
in the community to understand which is the

1426
00:52:10,970 --> 00:52:11,869
next machine.

1427
00:52:13,555 --> 00:52:16,195
And I talk for CERN, of course, because

1428
00:52:16,195 --> 00:52:16,695
I'm,

1429
00:52:17,954 --> 00:52:19,394
I've been for a long time a CERN

1430
00:52:19,394 --> 00:52:21,574
employee, and I'm working on CERN experiment.

1431
00:52:23,315 --> 00:52:24,535
CERN is proposing

1432
00:52:26,880 --> 00:52:30,500
the future circular collider, so a circular collider,

1433
00:52:30,719 --> 00:52:31,699
the same as,

1434
00:52:32,000 --> 00:52:34,559
is happening at LAC, so a circular collider

1435
00:52:34,559 --> 00:52:37,940
with 2 beams of particles that collides in,

1436
00:52:38,719 --> 00:52:42,465
in many collision many, 4 collision points usually.

1437
00:52:43,324 --> 00:52:44,304
And the size,

1438
00:52:44,684 --> 00:52:46,704
of it is a 300 kilometer

1439
00:52:47,164 --> 00:52:47,664
tunnel.

1440
00:52:48,684 --> 00:52:50,864
The current one is 27 kilometer.

1441
00:52:52,525 --> 00:52:53,025
So,

1442
00:52:53,719 --> 00:52:54,219
yeah,

1443
00:52:54,519 --> 00:52:55,239
we are going,

1444
00:52:55,719 --> 00:52:57,179
on a different scale.

1445
00:52:58,519 --> 00:53:00,440
But what is I would I would like

1446
00:53:00,440 --> 00:53:02,139
to stress that okay.

1447
00:53:03,480 --> 00:53:03,980
That,

1448
00:53:04,760 --> 00:53:06,299
that size is needed,

1449
00:53:07,239 --> 00:53:07,739
for

1450
00:53:09,324 --> 00:53:11,585
going to a 100 TeV,

1451
00:53:12,765 --> 00:53:15,324
collision. Okay? And now we are at 13

1452
00:53:15,324 --> 00:53:16,144
TeV collision.

1453
00:53:16,445 --> 00:53:17,265
So, again,

1454
00:53:17,724 --> 00:53:19,905
a factor 10 increase in energy,

1455
00:53:20,364 --> 00:53:22,445
and there you really probed a new energy

1456
00:53:22,445 --> 00:53:23,885
scale with respect to the one that we

1457
00:53:23,885 --> 00:53:25,180
are probing today.

1458
00:53:25,960 --> 00:53:28,220
But before, we also need,

1459
00:53:29,079 --> 00:53:32,700
to run an intense program of precision measurement,

1460
00:53:33,880 --> 00:53:36,140
that can be done also at the new,

1461
00:53:36,760 --> 00:53:37,260
machine.

1462
00:53:37,655 --> 00:53:39,974
So not only going to higher energy scale,

1463
00:53:39,974 --> 00:53:40,795
but also,

1464
00:53:41,574 --> 00:53:42,074
exploit

1465
00:53:42,375 --> 00:53:46,214
collision of elementary particles like electron, proton, and

1466
00:53:46,214 --> 00:53:49,734
positron, not smashing protons, but going to really

1467
00:53:49,734 --> 00:53:51,275
use elementary particles

1468
00:53:51,655 --> 00:53:53,195
such that it's more easy,

1469
00:53:53,930 --> 00:53:57,050
to precisely measure the properties of the Higgs

1470
00:53:57,050 --> 00:53:59,610
boson or everything that we haven't measured super

1471
00:53:59,610 --> 00:54:02,110
precisely because history told us that

1472
00:54:02,490 --> 00:54:05,369
usually you can guess which is the energy

1473
00:54:05,369 --> 00:54:05,869
scale,

1474
00:54:06,714 --> 00:54:08,335
where new physics will appear

1475
00:54:08,635 --> 00:54:09,614
from deviation

1476
00:54:10,234 --> 00:54:13,454
in precision measurements at a lower energy scale.

1477
00:54:13,675 --> 00:54:15,514
So by now we are searching, okay, we

1478
00:54:15,514 --> 00:54:17,454
are in a proton proton collision machine,

1479
00:54:18,900 --> 00:54:21,079
but if we haven't we don't find anything,

1480
00:54:21,460 --> 00:54:23,940
in order to really have some guess on

1481
00:54:23,940 --> 00:54:25,400
the next energy scale,

1482
00:54:25,780 --> 00:54:28,839
usually what particle physicists need is to run

1483
00:54:29,059 --> 00:54:30,679
an e plus e minus machine,

1484
00:54:31,494 --> 00:54:34,474
something that is really elementary particles that collides,

1485
00:54:34,614 --> 00:54:37,574
there's much less noise in each collision, and

1486
00:54:37,574 --> 00:54:40,295
therefore you can measure precisely to a per

1487
00:54:40,295 --> 00:54:42,534
mil precision the properties of the explosion, for

1488
00:54:42,534 --> 00:54:43,034
example.

1489
00:54:43,599 --> 00:54:47,139
And there, you any deviation would point to,

1490
00:54:47,679 --> 00:54:49,760
would tell us more about which is the

1491
00:54:49,760 --> 00:54:52,420
energy scale, where new physics will appear.

1492
00:54:52,719 --> 00:54:53,940
So we have this handle.

1493
00:54:56,224 --> 00:54:58,224
Still, we need a new machine, definitely. We

1494
00:54:58,224 --> 00:54:59,445
can't do that in

1495
00:54:59,744 --> 00:55:01,585
the in the large other collider. As Christina

1496
00:55:01,585 --> 00:55:03,445
mentioned, she speaks for CERN.

1497
00:55:03,905 --> 00:55:06,565
It's worth mentioning that there are other proposed

1498
00:55:06,864 --> 00:55:09,985
successors to the Large Hadron Collider, including the

1499
00:55:09,985 --> 00:55:12,219
International Linear Collider in Japan

1500
00:55:12,679 --> 00:55:15,980
and the Circular Electron Positron Collider in China.

1501
00:55:16,199 --> 00:55:18,699
Let's just return to that conversation with Christina.

1502
00:55:18,920 --> 00:55:20,679
What are you gonna do anything on July

1503
00:55:20,679 --> 00:55:21,900
4th? Are you sort

1504
00:55:22,279 --> 00:55:24,920
of involved in any celebrations? Or I'll go

1505
00:55:24,920 --> 00:55:26,760
to the event at CERN. There will be,

1506
00:55:26,760 --> 00:55:27,260
like,

1507
00:55:27,855 --> 00:55:29,875
there is a celebration the all day.

1508
00:55:31,295 --> 00:55:32,355
I will be participating.

1509
00:55:32,894 --> 00:55:34,434
There will be talks by

1510
00:55:36,175 --> 00:55:38,195
the each the spoke person of our collaboration.

1511
00:55:38,494 --> 00:55:39,474
There will be, like,

1512
00:55:40,760 --> 00:55:43,480
theories that presents their their view on wall,

1513
00:55:43,480 --> 00:55:45,639
what we have met all we all they

1514
00:55:45,639 --> 00:55:47,639
have understood about the Higgs boson, thanks to

1515
00:55:47,639 --> 00:55:48,380
our measurements,

1516
00:55:50,039 --> 00:55:51,820
experimentalists that we show,

1517
00:55:52,359 --> 00:55:54,059
the status of all searches

1518
00:55:55,255 --> 00:55:58,295
today. I'm not anymore working directly on Higgs

1519
00:55:58,295 --> 00:55:59,114
boson properties.

1520
00:55:59,735 --> 00:56:02,875
I I I switch to searches for supersymmetry,

1521
00:56:03,255 --> 00:56:04,875
which we haven't found it,

1522
00:56:05,815 --> 00:56:06,315
yet

1523
00:56:06,695 --> 00:56:09,014
or never. I don't know. But still

1524
00:56:10,150 --> 00:56:11,369
so I'm not anymore

1525
00:56:11,670 --> 00:56:13,369
working on the exposome myself,

1526
00:56:13,670 --> 00:56:15,269
but I will be there, of course, because

1527
00:56:15,269 --> 00:56:17,349
I've been working on that for 10 years

1528
00:56:17,349 --> 00:56:19,349
and more. Thank you so much to Christina

1529
00:56:19,349 --> 00:56:21,829
Botter and Achinti Rao for talking to me.

1530
00:56:21,829 --> 00:56:23,610
And don't forget that you can find Achinti

1531
00:56:23,750 --> 00:56:24,815
Rao's feature,

1532
00:56:25,114 --> 00:56:27,355
a day in physics like no other in

1533
00:56:27,355 --> 00:56:28,734
the Physics World magazine.

1534
00:56:29,195 --> 00:56:30,875
And if you go to the Physics World

1535
00:56:30,875 --> 00:56:33,355
magazine or indeed the Physics World website, physics

1536
00:56:33,355 --> 00:56:35,514
world dot com, you'll find a host of

1537
00:56:35,514 --> 00:56:36,494
features and articles

1538
00:56:36,795 --> 00:56:38,714
all about the 10 years of the Higgs

1539
00:56:38,714 --> 00:56:39,214
boson.

1540
00:56:39,570 --> 00:56:41,329
We'll be back next month when we'll be

1541
00:56:41,329 --> 00:56:43,570
looking at something else from this wonderful world

1542
00:56:43,570 --> 00:56:44,230
of physics.

1543
00:56:44,610 --> 00:56:46,710
And thank you very much for listening.

1544
00:56:51,489 --> 00:56:52,710
Physics world.