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2012 promises to be a truly historic year for science. | 0:00:06 | 0:00:09 | |
Just before Christmas, researchers working at CERN | 0:00:14 | 0:00:17 | |
near Geneva, announced that they had caught a tantalising glimpse | 0:00:17 | 0:00:22 | |
of the Higgs boson. | 0:00:22 | 0:00:23 | |
I'm Jim Al-Khalili and, as a physicist, | 0:00:26 | 0:00:28 | |
I must say that following the search | 0:00:28 | 0:00:30 | |
for this so-called "God particle" has been incredibly exciting. | 0:00:30 | 0:00:34 | |
Sometime this year, researchers hope to be able to declare | 0:00:34 | 0:00:38 | |
the Higgs finally, officially discovered. | 0:00:38 | 0:00:42 | |
If confirmed, it will be the most important scientific discovery | 0:00:42 | 0:00:46 | |
of my lifetime. | 0:00:46 | 0:00:47 | |
It'll be evidence for one of the most | 0:00:47 | 0:00:50 | |
all-encompassing ideas in physics. | 0:00:50 | 0:00:53 | |
That at the heart of everything | 0:00:53 | 0:00:55 | |
is the simple and enchanting idea | 0:00:55 | 0:00:58 | |
of symmetry. | 0:00:58 | 0:01:00 | |
The search for the Higgs takes us deep into the most important | 0:01:00 | 0:01:04 | |
questions about how the universe works and how it was created. | 0:01:04 | 0:01:08 | |
Horizon has been following the final stages of the hunt | 0:01:10 | 0:01:14 | |
for this most important and elusive of particles. | 0:01:14 | 0:01:18 | |
This is CERN, headquarters | 0:01:48 | 0:01:50 | |
of the European Organisation for Nuclear Research. | 0:01:50 | 0:01:54 | |
It's home to some of the thousands of scientists | 0:01:54 | 0:01:57 | |
who have been doggedly hunting | 0:01:57 | 0:02:00 | |
the elusive Higgs boson | 0:02:00 | 0:02:03 | |
and the £6 billion experiment that they're using to do it. | 0:02:03 | 0:02:07 | |
Especially built to find the one particle | 0:02:07 | 0:02:10 | |
that's thought to give substance to everything in the universe. | 0:02:10 | 0:02:14 | |
This is fantastic. Any one of those 40 million collisions | 0:02:19 | 0:02:22 | |
happening every second could be giving us a Higgs boson. | 0:02:22 | 0:02:25 | |
Could be that one right there. | 0:02:25 | 0:02:27 | |
In the autumn of 2011, | 0:02:27 | 0:02:30 | |
when Horizon was at CERN, | 0:02:30 | 0:02:32 | |
there was already a sense that this near 50-year quest | 0:02:32 | 0:02:35 | |
was reaching its final stages. | 0:02:35 | 0:02:37 | |
Yeah, I think this is the end. This is the end, one way or another. | 0:02:37 | 0:02:41 | |
We're definitely in the endgame now. | 0:02:41 | 0:02:43 | |
I think that this time next year, | 0:02:43 | 0:02:46 | |
it will be there or it won't be. | 0:02:46 | 0:02:48 | |
It's a search that's dominated the careers | 0:02:51 | 0:02:54 | |
of a generation of physicists. | 0:02:54 | 0:02:56 | |
Personally, I got a job saying I wanted to do this in 1993. | 0:02:56 | 0:03:00 | |
It's the 11th year now. | 0:03:00 | 0:03:02 | |
-About ten years, me. -Yeah, and about 5 years for me. | 0:03:02 | 0:03:05 | |
Since 1989. | 0:03:05 | 0:03:06 | |
That's over 20 years. | 0:03:06 | 0:03:10 | |
But while there are thousands of scientists in pursuit, | 0:03:10 | 0:03:13 | |
only for a few will there be prizes | 0:03:13 | 0:03:17 | |
and a place in history. | 0:03:17 | 0:03:19 | |
The Higgs is going to win a Nobel Prize, | 0:03:19 | 0:03:21 | |
so everybody wants to be a part of it. This is the goal | 0:03:21 | 0:03:23 | |
of every physicist. I mean, you won't spend 20 years | 0:03:23 | 0:03:26 | |
if you don't believe in something. | 0:03:26 | 0:03:28 | |
There's a lot of people who are interested in this, so... | 0:03:28 | 0:03:31 | |
So yeah, it tends to get exciting. | 0:03:31 | 0:03:33 | |
Not sleeping very much! | 0:03:33 | 0:03:35 | |
It's a big collaboration. "What did you do?" | 0:03:35 | 0:03:37 | |
Everyone wants an answer to that. | 0:03:37 | 0:03:39 | |
INTERVIEWER: And are you two competing or working together? | 0:03:39 | 0:03:42 | |
Together. If he finds it, I'll take the credit. | 0:03:42 | 0:03:45 | |
Amongst the intrepid Higgs hunters | 0:03:50 | 0:03:53 | |
are Jon Butterworth | 0:03:53 | 0:03:55 | |
and his colleague Adam Davison, from University College London. | 0:03:55 | 0:04:00 | |
They've been drawn here, like all the other scientists, | 0:04:00 | 0:04:03 | |
by the potential of the Large Hadron Collider | 0:04:03 | 0:04:06 | |
to find the missing boson at last. | 0:04:06 | 0:04:08 | |
It's a great opportunity for us to finally understand | 0:04:11 | 0:04:15 | |
whether the Higgs exists. | 0:04:15 | 0:04:17 | |
Physics won't be the same after this. | 0:04:17 | 0:04:19 | |
Even a null result here will re-write the text books. | 0:04:19 | 0:04:23 | |
This is it. This is where it's going to happen. | 0:04:23 | 0:04:26 | |
The problem with hunting for the Higgs | 0:04:32 | 0:04:35 | |
is it can't be detected in everyday conditions. | 0:04:35 | 0:04:39 | |
To find it, scientists need to return | 0:04:39 | 0:04:42 | |
to those at the very beginning. | 0:04:42 | 0:04:45 | |
Well, almost - to the conditions just after the big bang. | 0:04:45 | 0:04:49 | |
When, the theory goes, the Higgs and everything else | 0:04:49 | 0:04:54 | |
was first created. | 0:04:54 | 0:04:55 | |
So here we have the big bang. | 0:04:57 | 0:04:59 | |
Deserves a little bit of colour, I think. | 0:05:03 | 0:05:05 | |
BOOMING EXPLOSION | 0:05:05 | 0:05:06 | |
And then the timeline of the universe. | 0:05:06 | 0:05:10 | |
This is where we are. | 0:05:10 | 0:05:11 | |
It's now, the age of the universe, | 0:05:11 | 0:05:15 | |
about 13.7 billion years | 0:05:15 | 0:05:18 | |
after the big bang. | 0:05:18 | 0:05:21 | |
So working backwards, | 0:05:21 | 0:05:23 | |
we know that a few hundred thousand years ago, | 0:05:23 | 0:05:27 | |
we had the dinosaurs. | 0:05:27 | 0:05:29 | |
So, here's a dinosaur. | 0:05:29 | 0:05:31 | |
DINOSAUR ROARS | 0:05:31 | 0:05:33 | |
Then life itself, the first DNA, | 0:05:33 | 0:05:36 | |
is about 4 billion years ago. | 0:05:36 | 0:05:39 | |
Before DNA, there was the Earth. | 0:05:39 | 0:05:44 | |
Before that, stars. | 0:05:45 | 0:05:48 | |
Before them, atoms. | 0:05:48 | 0:05:51 | |
And inside atoms, | 0:05:55 | 0:05:56 | |
you have the most fundamental building blocks of existence. | 0:05:56 | 0:06:00 | |
The big question is where did those building blocks come from? | 0:06:02 | 0:06:06 | |
The answer to all that lies in the first second. | 0:06:06 | 0:06:10 | |
In this one crucial second, all the elementary particles were created. | 0:06:10 | 0:06:16 | |
Including, scientists believe, the Higgs boson. | 0:06:16 | 0:06:20 | |
The mysteries of existence lie within this second. | 0:06:20 | 0:06:22 | |
Certainly, we understand the science, we understand the physics. | 0:06:22 | 0:06:26 | |
Backwards into this second, | 0:06:26 | 0:06:28 | |
but at some point we just run out of knowledge. | 0:06:28 | 0:06:30 | |
The Large Hadron Collider is allowing us to see | 0:06:33 | 0:06:37 | |
right back to 10 to the -12 seconds | 0:06:37 | 0:06:41 | |
after the big bang. | 0:06:41 | 0:06:43 | |
Beyond that, here be dragons. Or dinosaurs! | 0:06:43 | 0:06:46 | |
The Large Hadron Collider's technique to transport scientists | 0:06:55 | 0:06:59 | |
to the moment just after the big bang is as violent | 0:06:59 | 0:07:03 | |
as it is ambitious. 100 metres underground, it takes protons | 0:07:03 | 0:07:08 | |
from the nuclei of atoms | 0:07:08 | 0:07:09 | |
and collides them, at almost the speed of light. | 0:07:09 | 0:07:14 | |
These protons are colliding at huge energies, | 0:07:26 | 0:07:29 | |
and in those collisions | 0:07:29 | 0:07:30 | |
a large number of particles are produced, hundreds, thousands even. | 0:07:30 | 0:07:34 | |
And trying to look at those particles that are produced, | 0:07:34 | 0:07:38 | |
and understand what happened in those collisions, | 0:07:38 | 0:07:41 | |
is what the LHC is all about. | 0:07:41 | 0:07:43 | |
Somewhere buried in this wreckage, they hope to unearth the Higgs. | 0:07:56 | 0:08:00 | |
It would be proof of the existence of a field | 0:08:02 | 0:08:06 | |
that scientists believe surrounds us all the time. | 0:08:06 | 0:08:11 | |
And that appeared in that first second of creation. | 0:08:11 | 0:08:14 | |
As the heat and fury ebbed out of the big bang, | 0:08:19 | 0:08:22 | |
so the theory goes, the Higgs field condensed. | 0:08:22 | 0:08:26 | |
As particles travel through this field | 0:08:26 | 0:08:29 | |
they get slowed down, like travelling through treacle. | 0:08:29 | 0:08:32 | |
This is what gives them mass. | 0:08:32 | 0:08:34 | |
Without gaining mass, particles | 0:08:43 | 0:08:45 | |
would have continued to fly through the universe at the speed of light. | 0:08:45 | 0:08:51 | |
Never clumping together to form you, me, blackboards, well, anything. | 0:08:53 | 0:09:00 | |
To have deduced the presence of something as weird as the Higgs, | 0:09:04 | 0:09:08 | |
just from theory and from other previous data, | 0:09:08 | 0:09:10 | |
and then to find it in nature, would be a hugely exciting vindication | 0:09:10 | 0:09:13 | |
of our picture of what is going on. | 0:09:13 | 0:09:15 | |
Finding something that's all around us is surprisingly tricky. | 0:09:17 | 0:09:22 | |
Scientists need to create a disturbance in the Higgs field | 0:09:23 | 0:09:26 | |
to detect the boson itself. | 0:09:26 | 0:09:29 | |
This is what the LHC is attempting to do, by colliding particles. | 0:09:30 | 0:09:36 | |
It's a challenge other particle accelerators | 0:09:39 | 0:09:41 | |
have tried and been unable to complete. | 0:09:41 | 0:09:46 | |
Because for all scientists sense that the Higgs ought to be there, | 0:09:46 | 0:09:49 | |
it has proven spectacularly difficult to find. | 0:09:49 | 0:09:54 | |
The idea of the Higgs boson was first proposed in 1964. | 0:09:54 | 0:09:58 | |
Which was a very long time ago, before I was even born. | 0:09:58 | 0:10:02 | |
Many years of work have been leading up to this point, | 0:10:02 | 0:10:05 | |
so it is absolutely exciting to be here | 0:10:05 | 0:10:08 | |
at the point where the discovery might happen. | 0:10:08 | 0:10:11 | |
What's made all the difference at the LHC | 0:10:17 | 0:10:19 | |
are the incredible energy levels the collider can reach. | 0:10:19 | 0:10:23 | |
Pushing further back in time into that crucial first second. | 0:10:26 | 0:10:30 | |
This has opened up new places to search for the Higgs, | 0:10:34 | 0:10:38 | |
a hunt that's defined in terms | 0:10:38 | 0:10:40 | |
of what mass the Higgs itself might have, | 0:10:40 | 0:10:43 | |
measured in GeV, or giga electron volts. | 0:10:43 | 0:10:49 | |
So on this line of what the mass of the Higgs might be, | 0:10:49 | 0:10:52 | |
we can draw on what previous experiments have tried, | 0:10:52 | 0:10:56 | |
and where they have been able to exclude it from being. | 0:10:56 | 0:11:00 | |
After decades of work, the LEP collider at CERN, | 0:11:00 | 0:11:05 | |
a predecessor of the LHC, | 0:11:05 | 0:11:06 | |
ruled out the Higgs being at the bottom end of potential masses. | 0:11:06 | 0:11:11 | |
In fact, they were able to say that the mass of the Higgs is, | 0:11:12 | 0:11:16 | |
with 95% confidence, 114 GeV, or more. | 0:11:16 | 0:11:23 | |
So after LEP, the next major milestone in the Higgs search | 0:11:23 | 0:11:27 | |
was limits set by another collider in the US called the Tevatron. | 0:11:27 | 0:11:32 | |
The Tevatron was able to exclude a range here, | 0:11:32 | 0:11:38 | |
around 160 GeV here. | 0:11:38 | 0:11:41 | |
And by November 2011, the LHC had already radically narrowed the search. | 0:11:41 | 0:11:48 | |
The LHC has been able to rule out a big region | 0:11:48 | 0:11:51 | |
from 145... | 0:11:51 | 0:11:54 | |
..quite far up. | 0:11:55 | 0:11:57 | |
It's been decades' worth of work | 0:11:59 | 0:12:01 | |
to gradually eliminate more and more of the space where the Higgs boson could be, | 0:12:01 | 0:12:06 | |
and now we are finally in this regime | 0:12:06 | 0:12:09 | |
where in the next couple of years | 0:12:09 | 0:12:10 | |
we might be able to close this gap | 0:12:10 | 0:12:13 | |
and finally know for sure whether it is there or not. | 0:12:13 | 0:12:16 | |
In November, that left a region of just 30 GeV | 0:12:21 | 0:12:26 | |
for the Higgs to be hiding in. | 0:12:26 | 0:12:28 | |
But this last remaining energy range is also the trickiest to search. | 0:12:28 | 0:12:35 | |
It is the area in which the unique signature of the Higgs | 0:12:35 | 0:12:39 | |
is most deeply buried | 0:12:39 | 0:12:41 | |
under the background noise of other particles created in the collider. | 0:12:41 | 0:12:46 | |
Not that the Higgs hunters were deterred. | 0:12:50 | 0:12:52 | |
The data is piling up and we know how to do it, | 0:12:52 | 0:12:55 | |
we just don't have enough data to tell you today what the answer is. | 0:12:55 | 0:12:58 | |
If I was to bet, I would probably put it at 130 GeV. | 0:13:04 | 0:13:10 | |
At the moment, probably somewhere around 120 GeV. | 0:13:10 | 0:13:14 | |
I would predict somewhere between 120 and 130 GeV. | 0:13:14 | 0:13:17 | |
I would put the Higgs somewhere close to 114 GeV, | 0:13:17 | 0:13:23 | |
because it is the most difficult place to look, | 0:13:23 | 0:13:25 | |
and we haven't found it yet. | 0:13:25 | 0:13:27 | |
That is a good question, because, you know, | 0:13:27 | 0:13:30 | |
you are assuming it actually exists, | 0:13:30 | 0:13:32 | |
which I am starting to believe it probably does not exist. | 0:13:32 | 0:13:36 | |
I'm really oscillating between thinking it is clearly there, | 0:13:41 | 0:13:45 | |
and then thinking, no, it's not going to turn up, is it? | 0:13:45 | 0:13:48 | |
Yeah, I don't know, | 0:13:48 | 0:13:50 | |
I think I have decided not to have a strong opinion. | 0:13:50 | 0:13:53 | |
I keep trying not to. | 0:13:53 | 0:13:55 | |
In almost every way, I think it would be more exciting | 0:13:55 | 0:13:57 | |
to prove it doesn't exist. | 0:13:57 | 0:13:59 | |
Yeah, it would be a longer-term bigger result, I think, | 0:13:59 | 0:14:02 | |
the negative result would have a longer-term bigger impact, | 0:14:02 | 0:14:05 | |
because it would really put us back to the drawing board. | 0:14:05 | 0:14:08 | |
On the other hand, in the short-term, it'd be disappointing | 0:14:08 | 0:14:11 | |
because a positive result is positive. | 0:14:11 | 0:14:13 | |
-You'd like to see that. -I don't think that's true at all. | 0:14:13 | 0:14:16 | |
I think a negative result, even in the short-term, would be more exciting. | 0:14:16 | 0:14:20 | |
It's the opposite of what people expect, right? | 0:14:20 | 0:14:23 | |
It's like... It'd be a lot more fun. | 0:14:23 | 0:14:25 | |
The experimental physicists here at CERN | 0:14:26 | 0:14:29 | |
have already put some of the ideas of their colleagues, | 0:14:29 | 0:14:33 | |
the theorists, to the test, and not all the results have been positive. | 0:14:33 | 0:14:38 | |
It's a whole bunch of theoretical models and papers. | 0:14:38 | 0:14:41 | |
There's been a bonfire of them since the LHC started. | 0:14:41 | 0:14:44 | |
There are whole swathes of potential speculation | 0:14:44 | 0:14:46 | |
that are now pointless. They're obviously a dead end | 0:14:46 | 0:14:49 | |
because the data says this. | 0:14:49 | 0:14:51 | |
But what's at stake with the Higgs isn't just one particle, | 0:14:51 | 0:14:55 | |
however elusive, or any old theory. | 0:14:55 | 0:15:00 | |
The Higgs is the cornerstone for the most successful and all-encompassing | 0:15:01 | 0:15:06 | |
description of how our universe works that there is. | 0:15:06 | 0:15:12 | |
Working this beautiful model out | 0:15:19 | 0:15:21 | |
has been one of the great achievements of theoretical physics, | 0:15:21 | 0:15:25 | |
and Frank Wilczek was one of the key contributors. | 0:15:25 | 0:15:29 | |
-Hi. Welcome. Come in. -Yeah, that'd be great, thank you. | 0:15:31 | 0:15:35 | |
I'll show you our library, living room, trophy room. | 0:15:42 | 0:15:47 | |
A lot of puzzle books, most of which I've worked through. | 0:15:47 | 0:15:52 | |
I'm a big puzzle man. | 0:15:52 | 0:15:56 | |
Here are the awards and trophies that have found their way here. | 0:15:56 | 0:16:03 | |
-This is the Nobel Prize medal and here's one for you. -Thank you. | 0:16:03 | 0:16:10 | |
Are these ones edible? | 0:16:10 | 0:16:12 | |
Yes, more or less. Anyway, I intend to eat one. | 0:16:12 | 0:16:16 | |
And... | 0:16:16 | 0:16:19 | |
..you'll notice that... | 0:16:22 | 0:16:24 | |
..not only in this room but everywhere, there are little toys. | 0:16:25 | 0:16:29 | |
A lot of what I do is really just play. | 0:16:29 | 0:16:32 | |
I mean, I play with the equations, ideas. | 0:16:32 | 0:16:35 | |
HE LAUGHS | 0:16:35 | 0:16:38 | |
And all that puzzling won Frank a Nobel prize | 0:16:38 | 0:16:43 | |
for his contribution to what's called | 0:16:43 | 0:16:45 | |
the Standard Model Of Elementary Particles. | 0:16:45 | 0:16:48 | |
Well, what have we got here? | 0:16:49 | 0:16:51 | |
It looks like an instrument of torture for the mind. | 0:16:51 | 0:16:55 | |
The Standard Model is essentially an understanding of how all the pieces | 0:17:00 | 0:17:04 | |
of the universe fit together, except for gravity. | 0:17:04 | 0:17:08 | |
A mind-boggling project. | 0:17:08 | 0:17:10 | |
This is going to be a hell of a puzzle to figure out. | 0:17:10 | 0:17:17 | |
All right. Now, a promising start. HE LAUGHS | 0:17:17 | 0:17:21 | |
'We think the Standard Model contains all you need, | 0:17:21 | 0:17:26 | |
'in principle, to describe how molecules behave, | 0:17:26 | 0:17:30 | |
'all of chemistry, how stars work, all of astrophysics. | 0:17:30 | 0:17:35 | |
'Not only how things behave, but what can exist. | 0:17:35 | 0:17:39 | |
'These are the rules of the game.' | 0:17:39 | 0:17:41 | |
The ingredients of the Standard Model are of three basic sorts. | 0:17:46 | 0:17:52 | |
There's what you might broadly call matter. | 0:17:52 | 0:17:56 | |
That's sort of lumps of stuff that have a certain degree of permanence | 0:17:59 | 0:18:05 | |
and these are on the one hand quarks. | 0:18:05 | 0:18:10 | |
They include the building blocks of protons and neutrons | 0:18:10 | 0:18:13 | |
and atomic nuclei. | 0:18:13 | 0:18:16 | |
And leptons. | 0:18:16 | 0:18:18 | |
The most prominent lepton in everyday life is certainly the electron. | 0:18:21 | 0:18:26 | |
So those are matter particles. | 0:18:26 | 0:18:30 | |
On the other side we have what you might call force particles, | 0:18:32 | 0:18:36 | |
or force mediators. | 0:18:36 | 0:18:38 | |
These particles are more like lumps of energy | 0:18:42 | 0:18:46 | |
and they transmit the forces that bring the matter particles to life, | 0:18:46 | 0:18:51 | |
like the photon, which carries the electromagnetic force. | 0:18:51 | 0:18:55 | |
The gluons that carry the strong force, | 0:18:55 | 0:18:58 | |
which holds the nuclei of atoms together, | 0:18:58 | 0:19:01 | |
and the W and Z bosons | 0:19:01 | 0:19:04 | |
that are responsible for the weak force governing radioactivity. | 0:19:04 | 0:19:08 | |
Every one of these particles has now been found experimentally. | 0:19:13 | 0:19:17 | |
There's just one pesky missing piece to the model | 0:19:17 | 0:19:21 | |
that they're searching for so intensively at CERN. | 0:19:21 | 0:19:24 | |
The Higgs. | 0:19:26 | 0:19:27 | |
In order to reconcile the beautiful equations | 0:19:27 | 0:19:30 | |
with the not quite as beautiful observations, | 0:19:30 | 0:19:33 | |
we need to find out what that piece is | 0:19:33 | 0:19:38 | |
and its properties and see if it really fits into a nice pattern | 0:19:38 | 0:19:42 | |
and completes the Standard Model. | 0:19:42 | 0:19:45 | |
We need experimental information | 0:19:45 | 0:19:48 | |
and this is usually called the quest for the Higgs boson. | 0:19:48 | 0:19:52 | |
This is why finding the Higgs is such an obsession among physicists. | 0:20:03 | 0:20:07 | |
If they do, it will be the vindication of this beautiful model. | 0:20:11 | 0:20:16 | |
And if not, they'll have to fundamentally rethink | 0:20:16 | 0:20:21 | |
their understanding of how the universe is put together. | 0:20:21 | 0:20:24 | |
In a way, finding the Higgs will be the completion of a dream. | 0:20:26 | 0:20:30 | |
Not finding it will be the start of a new one. | 0:20:30 | 0:20:32 | |
Imagine that the Standard Model is the car and the Higgs is the engine | 0:20:32 | 0:20:37 | |
and it's running, and imagine you find a car and then you open | 0:20:37 | 0:20:40 | |
and see no engine, so it might be more interesting than the car with an engine. | 0:20:40 | 0:20:45 | |
If you find that the car is running without an engine, | 0:20:45 | 0:20:48 | |
it's more interesting but it's kind of... | 0:20:48 | 0:20:50 | |
"What did I do in the last 20 years?" You know? | 0:20:50 | 0:20:53 | |
Do I believe in the Higgs? I... I think so. | 0:20:53 | 0:20:57 | |
I believe there's something that we're missing | 0:20:57 | 0:21:00 | |
and hopefully it's the Higgs, because... | 0:21:00 | 0:21:02 | |
it fits our model very nicely. | 0:21:02 | 0:21:04 | |
There are other possibilities, so I wouldn't discount those completely | 0:21:04 | 0:21:09 | |
but I think this is the best explanation we have so far. | 0:21:09 | 0:21:11 | |
Ask me in a year's time and I might give you a different answer. | 0:21:11 | 0:21:14 | |
It's October 2011 in the Atlas Control Room, | 0:21:17 | 0:21:20 | |
the nerve centre of one of two detectors at CERN | 0:21:20 | 0:21:24 | |
intensively searching for the Higgs. | 0:21:24 | 0:21:27 | |
Scientists here are avidly collecting data | 0:21:33 | 0:21:36 | |
from the billions of collisions, to comb for evidence of the boson, | 0:21:36 | 0:21:41 | |
because you can't simply spot it directly. | 0:21:41 | 0:21:45 | |
Almost as soon as it's created, it decays into other particles, | 0:21:45 | 0:21:50 | |
leaving just a trace of its existence. | 0:21:50 | 0:21:53 | |
The only way scientists can tell if a Higgs boson was there or not | 0:21:54 | 0:21:59 | |
is by looking for a statistical anomaly, | 0:21:59 | 0:22:02 | |
some blip in the measurements that they can't otherwise account for. | 0:22:02 | 0:22:07 | |
Seeing one picture like that isn't sufficient, | 0:22:07 | 0:22:10 | |
because there are other things that can look like the Higgs. | 0:22:10 | 0:22:13 | |
But if you get a bunch of them and you plot them, that's what we do, | 0:22:13 | 0:22:16 | |
that's our job, we put together all these tracks | 0:22:16 | 0:22:19 | |
and we say, "What mass of a particle would produce that?" | 0:22:19 | 0:22:22 | |
And then we look at them all and if we see a bump, | 0:22:22 | 0:22:26 | |
some little statistical anomaly there that's significant, | 0:22:26 | 0:22:30 | |
then we get excited, and then we go ask the other guys, "Hey, did you guys see that?" | 0:22:30 | 0:22:34 | |
Then we celebrate, but right now we've got a lot of work to do. | 0:22:34 | 0:22:38 | |
In the autumn, that intensive effort was being directed at the 30GeV | 0:22:38 | 0:22:44 | |
energy window that the Higgs could be hiding in. | 0:22:44 | 0:22:48 | |
We've covered a lot of range, we're travelling up a river, | 0:22:48 | 0:22:52 | |
we've checked all the different streams and we've narrowed it down | 0:22:52 | 0:22:56 | |
to some areas where it could be, and so that's where we're focusing | 0:22:56 | 0:23:00 | |
all of our energy, to look in those areas and see if we find it. | 0:23:00 | 0:23:03 | |
I think we're really on the brink of discovery. | 0:23:03 | 0:23:07 | |
But it's a slow process, | 0:23:09 | 0:23:11 | |
because it's all about crunching vast quantities of data. | 0:23:11 | 0:23:16 | |
One blip alone isn't enough, of course. | 0:23:16 | 0:23:19 | |
You need to be sure it isn't an error or fluke | 0:23:19 | 0:23:22 | |
and these anomalies can disappear almost as quickly as they arrive. | 0:23:22 | 0:23:27 | |
For experimentalists, these false alarms happen all too frequently. | 0:23:32 | 0:23:37 | |
You work on it day in, day out, so you get quite emotionally attached | 0:23:37 | 0:23:42 | |
to the state of these plots and numbers. | 0:23:42 | 0:23:45 | |
Especially if it's your plot. You want it to be your plot that finds the Higgs. | 0:23:45 | 0:23:49 | |
I realised at some point actually that it is genuinely... | 0:23:49 | 0:23:52 | |
I realised I found it genuinely stressful when plots get worse. | 0:23:52 | 0:23:55 | |
Yeah, that's right. | 0:23:55 | 0:23:57 | |
-So many points can do that. -When it get worse that makes me a little bit anxious and I think, | 0:23:57 | 0:24:02 | |
-"This is insane." -That's right, | 0:24:02 | 0:24:04 | |
-and so you live in hope and then you often hit disappointment. -Disappointed frequently. | 0:24:04 | 0:24:09 | |
It was in this state of perpetual tension that the scientists | 0:24:17 | 0:24:21 | |
working on the Atlas Detector met in November to discuss their latest set of results. | 0:24:21 | 0:24:27 | |
-What's going on? -They've just got started | 0:24:36 | 0:24:40 | |
and now we're going to get to the nitty-gritty of how things are actually going. | 0:24:40 | 0:24:44 | |
We don't have enough data, the statistics are fluctuating up and down. | 0:24:44 | 0:24:48 | |
You get excited about something and then more data, | 0:24:48 | 0:24:50 | |
it goes away and a bit more, it comes back. | 0:24:50 | 0:24:52 | |
It's all very tense at the moment, I'd say. | 0:24:52 | 0:24:55 | |
-Fun. -Does it feel like there's a real atmosphere | 0:24:55 | 0:24:58 | |
in terms of the search for Higgs closing in? | 0:24:58 | 0:25:00 | |
It's really weird because you're working on this more or less 20 hours a day | 0:25:00 | 0:25:05 | |
and it's been going on for a long time, so it becomes almost routine, | 0:25:05 | 0:25:08 | |
and then you get a meeting like this where it all | 0:25:08 | 0:25:11 | |
comes together and people go, "This is really exciting again." | 0:25:11 | 0:25:14 | |
This isn't one of those moments where people remember why we're here. | 0:25:14 | 0:25:17 | |
-Can we come in? -No. | 0:25:17 | 0:25:21 | |
In fact, the guy just said, "The BBC are outside. | 0:25:21 | 0:25:24 | |
"Be nice to them at the coffee break, tell them what they want to know." | 0:25:24 | 0:25:28 | |
The spokesperson was in there and said, "Don't tell them anything!" | 0:25:28 | 0:25:32 | |
The intense secrecy was because of the competition between the LHC's different detectors | 0:25:34 | 0:25:41 | |
to find the Higgs first and the provisional nature of the results. | 0:25:41 | 0:25:46 | |
What nobody was aware of at the time, | 0:25:48 | 0:25:50 | |
was that a small blip in the data that Atlas researchers had seen | 0:25:50 | 0:25:55 | |
would ultimately turn into something far more significant. | 0:25:55 | 0:26:00 | |
The hunt for the Higgs may be the most high-profile work going on at CERN | 0:26:18 | 0:26:23 | |
but the £6 billion experiment is about far more than finding one boson. | 0:26:23 | 0:26:30 | |
Scientists here are using the particle accelerator to understand | 0:26:33 | 0:26:37 | |
some of the other great mysteries of the universe. | 0:26:37 | 0:26:40 | |
But there's one common problem that links the Higgs | 0:26:43 | 0:26:47 | |
with other work happening here and that of scientists around the world. | 0:26:47 | 0:26:52 | |
Many scientists hope that if the Higgs is found | 0:27:02 | 0:27:06 | |
it'll help resolve the paradox within our understanding | 0:27:06 | 0:27:09 | |
of the laws of nature. | 0:27:09 | 0:27:12 | |
And it's a rather fundamental one. | 0:27:17 | 0:27:19 | |
Science has given us a set of laws | 0:27:24 | 0:27:26 | |
that describe the world so accurately | 0:27:26 | 0:27:29 | |
that we can predict the motion of a coin tossed in the air, | 0:27:29 | 0:27:32 | |
because we understand the law of gravity. | 0:27:32 | 0:27:35 | |
We understand electromagnetism so well that we can use our GPS satellites | 0:27:35 | 0:27:39 | |
to locate your car to within a few inches. | 0:27:39 | 0:27:43 | |
We understand the nuclear force so well that we can predict | 0:27:43 | 0:27:47 | |
the future evolution of the sun itself. | 0:27:47 | 0:27:49 | |
The mathematics that's given rise to many of these great successes | 0:27:54 | 0:27:59 | |
has one consistent theme. | 0:27:59 | 0:28:01 | |
It's one we see around us every day. | 0:28:01 | 0:28:04 | |
It characterises our faces, the natural world | 0:28:09 | 0:28:15 | |
and tiny structures like viruses and even our DNA. | 0:28:15 | 0:28:22 | |
Symmetry. | 0:28:22 | 0:28:24 | |
In the Standard Model, symmetry rules. | 0:28:24 | 0:28:27 | |
The laws are dictated really in their form | 0:28:27 | 0:28:33 | |
by requiring tremendous amounts of symmetry. | 0:28:33 | 0:28:36 | |
That's how we found them. | 0:28:36 | 0:28:38 | |
But for all the power of symmetry in uncovering these fundamental laws, | 0:28:42 | 0:28:47 | |
there's a deep paradox at work. | 0:28:47 | 0:28:50 | |
If the laws of science are framed at their most perfect, | 0:28:50 | 0:28:53 | |
most symmetrical form, | 0:28:53 | 0:28:55 | |
then life cannot exist at all. | 0:28:55 | 0:28:58 | |
There'd be no mountains, rivers, valleys. | 0:29:05 | 0:29:08 | |
No DNA, no people, nothing. | 0:29:08 | 0:29:11 | |
A universe created along absolutely symmetric principles | 0:29:16 | 0:29:20 | |
would be in perfect balance, and would cancel itself out. | 0:29:20 | 0:29:25 | |
There'd be no mass, Higgs... or matter at all. | 0:29:27 | 0:29:31 | |
But here we are. | 0:29:31 | 0:29:34 | |
Our world is teeming with life and complexity, | 0:29:34 | 0:29:37 | |
and yet that seems to be incompatible with | 0:29:37 | 0:29:40 | |
perfection in our equations. By rights, we shouldn't be here. | 0:29:40 | 0:29:45 | |
This paradox about symmetry | 0:29:47 | 0:29:49 | |
lies at the heart of modern physics. | 0:29:49 | 0:29:53 | |
And it's crucial to understanding the significance | 0:29:53 | 0:29:56 | |
of the Higgs itself. | 0:29:56 | 0:29:57 | |
So what unites much of the work at CERN | 0:30:05 | 0:30:07 | |
is trying to resolve this problem with symmetry. | 0:30:07 | 0:30:12 | |
There's another group of scientists | 0:30:19 | 0:30:21 | |
who work alongside the Higgs hunters. | 0:30:21 | 0:30:23 | |
There are over 700 of them, | 0:30:27 | 0:30:29 | |
and they're searching for answers to this puzzle about symmetry. | 0:30:29 | 0:30:32 | |
So this canteen is very important, really. | 0:30:37 | 0:30:39 | |
It's one of the main working places at CERN. | 0:30:39 | 0:30:43 | |
You see a lot of big names down here - | 0:30:43 | 0:30:46 | |
if you wait long enough you'll come across a Nobel Prize winner | 0:30:46 | 0:30:49 | |
during the day. | 0:30:49 | 0:30:51 | |
Peter Clarke is one of the scientists working | 0:30:51 | 0:30:54 | |
on the Large Hadron Collider's LHCb experiment, | 0:30:54 | 0:30:58 | |
along with his colleague from the University of Edinburgh, Conor Fitzpatrick. | 0:30:58 | 0:31:04 | |
Their field of study | 0:31:06 | 0:31:07 | |
is the weird symmetric mirror world of antimatter. | 0:31:07 | 0:31:11 | |
A substance that's as real as matter, but its opposite... | 0:31:11 | 0:31:16 | |
..and rather more elusive. | 0:31:17 | 0:31:19 | |
The geek in everyone still feels a bit excited about the concept of working with this stuff. | 0:31:19 | 0:31:24 | |
It's not something the public sees from day to day life, | 0:31:24 | 0:31:28 | |
and it's one of the few things you can only see at CERN. | 0:31:28 | 0:31:32 | |
Antimatter may sound like the stuff of science fiction. | 0:31:33 | 0:31:37 | |
But since it was first proposed as a concept 80 years ago, | 0:31:37 | 0:31:41 | |
scientists have been creating it in experiments. | 0:31:41 | 0:31:43 | |
The very idea of antimatter emerged from a revolutionary | 0:31:47 | 0:31:50 | |
piece of mathematics, with symmetry at its heart. | 0:31:50 | 0:31:55 | |
It said that for every particle of matter, | 0:31:55 | 0:31:58 | |
there should be a corresponding one of antimatter. | 0:31:58 | 0:32:01 | |
Once one's thought about the symmetry of the theories, | 0:32:04 | 0:32:08 | |
and realised that antimatter must exist, | 0:32:08 | 0:32:11 | |
you then think it's absurd that there wouldn't be antimatter | 0:32:11 | 0:32:14 | |
or the possibility to create antimatter. | 0:32:14 | 0:32:17 | |
Which is why it's so surprising that the world in which we live is entirely made of matter. | 0:32:17 | 0:32:21 | |
Because the theory posed a puzzle: | 0:32:23 | 0:32:25 | |
when matter and anti-matter meet, they destroy each other completely. | 0:32:25 | 0:32:31 | |
Equal amounts of each would leave nothing but energy. | 0:32:34 | 0:32:38 | |
If the laws of science are expressed in their most perfect form, | 0:32:41 | 0:32:45 | |
then life cannot exist at all. | 0:32:45 | 0:32:48 | |
Clearly, all the matter WASN'T destroyed by antimatter. | 0:32:57 | 0:33:01 | |
After all, we see around us far more matter than antimatter | 0:33:01 | 0:33:06 | |
in the universe today. | 0:33:06 | 0:33:07 | |
Just how this could have happened is something that Peter, Conor | 0:33:13 | 0:33:16 | |
and the other scientists on the LHCb experiment are trying to understand. | 0:33:16 | 0:33:21 | |
So they're using the Large Hadron Collider to create some | 0:33:23 | 0:33:27 | |
pairs of matter and antimatter particles of their own, | 0:33:27 | 0:33:30 | |
to study what could have happened | 0:33:30 | 0:33:32 | |
in that crucial first second of the universe. | 0:33:32 | 0:33:36 | |
We're currently in the LHCb control room. | 0:33:40 | 0:33:43 | |
This is colloquially referred to as "the pit" - | 0:33:43 | 0:33:46 | |
100 metres below us right now is the LHCb experiment itself. | 0:33:46 | 0:33:49 | |
LHCb is one of the four detectors sited around the collider. | 0:33:52 | 0:33:59 | |
When the two beams of protons meet in a head-on collision, | 0:34:00 | 0:34:04 | |
recreating the energy levels just after the big bang, | 0:34:04 | 0:34:07 | |
it records the particles that are formed. | 0:34:07 | 0:34:10 | |
We can see antimatter being created in our detector, | 0:34:10 | 0:34:13 | |
so the difference between matter and antimatter is that they're differently charged. | 0:34:13 | 0:34:17 | |
So these two green tracks here, | 0:34:17 | 0:34:19 | |
in a magnetic field they're going differently, so one of them | 0:34:19 | 0:34:22 | |
has to be matter, and one of them has to be antimatter. | 0:34:22 | 0:34:24 | |
It's kind of cool that we can see it right here in an event on the screen. | 0:34:24 | 0:34:28 | |
Combing through the wreckage of billions of collisions, | 0:34:30 | 0:34:34 | |
and building on the work of previous particle accelerators, | 0:34:34 | 0:34:39 | |
scientists here have been in search of ways | 0:34:39 | 0:34:42 | |
in which matter and antimatter behave differently. | 0:34:42 | 0:34:47 | |
And they've managed to observe one - | 0:34:47 | 0:34:49 | |
a crucial breaking of symmetry | 0:34:49 | 0:34:52 | |
in the behaviour of matter and antimatter versions | 0:34:52 | 0:34:55 | |
of particles called B mesons. | 0:34:55 | 0:34:57 | |
So I'll give you one example of the way | 0:35:00 | 0:35:03 | |
we observe the difference between matter and antimatter. | 0:35:03 | 0:35:06 | |
This is perhaps the simplest example to visualise. | 0:35:06 | 0:35:10 | |
We can observe how B mesons created in LHCb decay to particles, | 0:35:10 | 0:35:13 | |
and how anti-B mesons decay to antiparticles. | 0:35:13 | 0:35:17 | |
We can count the rate at which this happens, | 0:35:17 | 0:35:19 | |
the number of times it happens, and we do this. | 0:35:19 | 0:35:22 | |
We observe the particles decaying 7,000 times, | 0:35:22 | 0:35:25 | |
and the antiparticles 6,000 times. | 0:35:25 | 0:35:28 | |
And if matter and antimatter did not have this asymmetry, | 0:35:28 | 0:35:30 | |
it would just be an equal number of times. | 0:35:30 | 0:35:32 | |
So this difference of 1,000 is an absolute clear manifestation | 0:35:32 | 0:35:36 | |
of the asymmetry between matter and antimatter. | 0:35:36 | 0:35:39 | |
So far, researchers haven't been able to find | 0:35:45 | 0:35:47 | |
enough instances of this asymmetry | 0:35:47 | 0:35:50 | |
to explain all the matter we know IS in the universe. | 0:35:50 | 0:35:54 | |
But one thing is clear. The reason we exist, | 0:36:00 | 0:36:03 | |
is because the perfect symmetry scientists believe was once there | 0:36:03 | 0:36:07 | |
between matter and antimatter must somehow have been broken. | 0:36:07 | 0:36:12 | |
And symmetry breaking is at the heart of scientists' understanding | 0:36:17 | 0:36:22 | |
of how the Higgs came to give mass to everything in the first place. | 0:36:22 | 0:36:28 | |
The theory goes that there was a moment after the big bang | 0:36:41 | 0:36:44 | |
when the Higgs field appeared. | 0:36:44 | 0:36:47 | |
And this split apart a perfect symmetry | 0:36:50 | 0:36:53 | |
between two of the fundamental forces of nature. | 0:36:53 | 0:36:57 | |
And the Higgs gave the particles of these forces different masses. | 0:37:02 | 0:37:06 | |
And at the same time, it gave mass to all the other particles. | 0:37:10 | 0:37:16 | |
The Higgs boson and the Higgs field is basically what does this symmetry breaking. | 0:37:16 | 0:37:21 | |
So the whole idea that our theories | 0:37:21 | 0:37:23 | |
revolve around symmetries and broken symmetries - | 0:37:23 | 0:37:26 | |
the Higgs is kind of the linchpin of that. | 0:37:26 | 0:37:28 | |
It's this unique prediction of this kind of idea, | 0:37:28 | 0:37:32 | |
and without it, we're back to the drawing board, | 0:37:32 | 0:37:35 | |
but with it, if we see it, | 0:37:35 | 0:37:37 | |
it's a stunning prediction of this idea of symmetry | 0:37:37 | 0:37:40 | |
and broken symmetry somehow lying behind the way the universe works. | 0:37:40 | 0:37:44 | |
The Higgs allows the symmetry in scientists' equations | 0:37:45 | 0:37:49 | |
to be broken in the real world. | 0:37:49 | 0:37:53 | |
Finding it would be a vindication | 0:37:53 | 0:37:54 | |
of their whole approach to understanding the universe. | 0:37:54 | 0:37:58 | |
That's why it's become | 0:37:58 | 0:37:59 | |
such a defining quest in modern physics. | 0:37:59 | 0:38:03 | |
Tuesday 13th December 2011 | 0:38:07 | 0:38:11 | |
was a day with the potential to change physics history. | 0:38:11 | 0:38:15 | |
-NEWS: -'Scientists at the Large Hadron Collider near Geneva | 0:38:16 | 0:38:19 | |
'are expected to announce later...' | 0:38:19 | 0:38:21 | |
'..are expected to present preliminary evidence today...' | 0:38:21 | 0:38:24 | |
'..will confirm whether the current theory of particle physics is correct.' | 0:38:24 | 0:38:28 | |
Since November, a lot more data had been crunched, | 0:38:28 | 0:38:33 | |
ahead of an important meeting. | 0:38:33 | 0:38:36 | |
It was the end of year report, where the experiments analysed | 0:38:38 | 0:38:42 | |
the data we collected during 2011, and reported on the Higgs search. | 0:38:42 | 0:38:46 | |
And I guess everyone knew that either the mass range | 0:38:46 | 0:38:49 | |
the Higgs could be in was going to shrink down, | 0:38:49 | 0:38:52 | |
possibly to nothing, or some kind of hint would pop up | 0:38:52 | 0:38:55 | |
that there was something there. | 0:38:55 | 0:38:57 | |
What was special about this meeting was that it would bring together | 0:38:57 | 0:39:02 | |
data from two independent detectors at CERN. | 0:39:02 | 0:39:05 | |
The data from Jon and Adam's Atlas detector, | 0:39:05 | 0:39:10 | |
and a second one - CMS. | 0:39:10 | 0:39:13 | |
But neither team knew in advance what the other had discovered, | 0:39:13 | 0:39:17 | |
and the atmosphere on both sides was electric. | 0:39:17 | 0:39:21 | |
-It was ridiculous... -Yes. | 0:39:21 | 0:39:23 | |
Very, er... almost frenzy, I don't know. | 0:39:23 | 0:39:27 | |
There were people having their breakfast | 0:39:27 | 0:39:29 | |
in the lecture theatre at 9 o'clock, | 0:39:29 | 0:39:31 | |
to be sure they'd get a seat for the seminar at 2 o'clock. | 0:39:31 | 0:39:33 | |
The room holds about 600 people, | 0:39:36 | 0:39:38 | |
and it was full two hours before the talk started. | 0:39:38 | 0:39:42 | |
There were rumours on the internet, | 0:39:42 | 0:39:44 | |
and obviously people talk to each other, | 0:39:44 | 0:39:46 | |
so I think, yeah, this idea that something exciting | 0:39:46 | 0:39:50 | |
-was about to happen was building in the community, at least. -All got a bit out of hand, really. | 0:39:50 | 0:39:54 | |
By late afternoon, it was clear that the hunt for the Higgs had closed in. | 0:39:57 | 0:40:03 | |
NEWS: 'Scientists hunting for the elusive Higgs boson | 0:40:05 | 0:40:08 | |
'say they've discovered strong signals that it exists.' | 0:40:08 | 0:40:11 | |
'Scientists say they've uncovered signs of the elusive Higgs boson, | 0:40:11 | 0:40:15 | |
'known as the God Particle.' | 0:40:15 | 0:40:17 | |
'Researchers presented results from two independent experiments...' | 0:40:17 | 0:40:21 | |
'..evidence which helps them move closer to the building blocks of the universe.' | 0:40:21 | 0:40:24 | |
What had emerged during the meeting was that a potential | 0:40:28 | 0:40:32 | |
signal of the Higgs had been spotted in both experiments. | 0:40:32 | 0:40:37 | |
And crucially, in practically the same place. | 0:40:41 | 0:40:44 | |
It was very exciting. | 0:40:48 | 0:40:50 | |
People were getting the Atlas data and the CMS data | 0:40:50 | 0:40:53 | |
and going, "Do they really see the same thing?" and all this. | 0:40:53 | 0:40:56 | |
It was a lot of fun, actually, and a major step forward. | 0:40:56 | 0:41:00 | |
The results weren't definitive, | 0:41:01 | 0:41:04 | |
but in the month between November and December | 0:41:04 | 0:41:07 | |
the data plots had evolved significantly. | 0:41:07 | 0:41:10 | |
So the announcement was that the LHC, | 0:41:16 | 0:41:19 | |
with the new data from the whole of 2011, is able to expand | 0:41:19 | 0:41:23 | |
the area that it can exclude the Higgs from. | 0:41:23 | 0:41:26 | |
The new lower limit has risen to 115 GeV. | 0:41:27 | 0:41:32 | |
And the new upper limit has dropped to 127 GeV. | 0:41:32 | 0:41:37 | |
So the really exciting thing was that the reason the LHC experiments weren't able to exclude | 0:41:37 | 0:41:41 | |
anything inside this remaining window, is that in fact they see an | 0:41:41 | 0:41:46 | |
excess of events. The early signs of the Higgs boson, if it's there. | 0:41:46 | 0:41:50 | |
And the excesses were in practically the same place. | 0:41:50 | 0:41:54 | |
CMS observed one at 124 GeV, | 0:41:56 | 0:42:00 | |
and Atlas one at 126. | 0:42:00 | 0:42:03 | |
So this is really a tantalising hint that the Higgs boson | 0:42:03 | 0:42:08 | |
might exist, and it might have a mass of around 125 GeV. | 0:42:08 | 0:42:13 | |
I think a lot of people will be really interested to see what | 0:42:13 | 0:42:16 | |
happens in this region when we add more data in 2012. | 0:42:16 | 0:42:19 | |
That's going to be really exciting to follow. | 0:42:19 | 0:42:22 | |
For all the buzz surrounding the Higgs, | 0:42:22 | 0:42:25 | |
scientists can't claim to have officially discovered | 0:42:25 | 0:42:28 | |
this elusive particle just yet. | 0:42:28 | 0:42:31 | |
And there are some outstanding questions | 0:42:31 | 0:42:34 | |
about WHY it would have this mass. | 0:42:34 | 0:42:37 | |
But with such promising data so far, | 0:42:37 | 0:42:40 | |
it's hard not to be enthusiastic. | 0:42:40 | 0:42:43 | |
Six months ago I would have said that there probably is no Higgs. | 0:42:45 | 0:42:48 | |
It's a neat idea, but what are the chances of nature | 0:42:48 | 0:42:51 | |
actually doing what we think it should do? | 0:42:51 | 0:42:54 | |
But now I think maybe it has. This is kind of remarkable. | 0:42:54 | 0:42:57 | |
What's clear, though, is that with four times the amount of data | 0:42:57 | 0:43:02 | |
expected out of the LHC next year, | 0:43:02 | 0:43:05 | |
this long-standing question will finally be resolved. | 0:43:05 | 0:43:09 | |
I mean, there will be a day, some time next year, where | 0:43:09 | 0:43:13 | |
we will go in not knowing whether the Higgs boson exists or not, | 0:43:13 | 0:43:16 | |
and we will come out... And that that will be a fact, you know - | 0:43:16 | 0:43:20 | |
we will know one way or the other, and our knowledge of the universe will have expanded. | 0:43:20 | 0:43:24 | |
-In a big way, as well. I mean... -Yeah. | 0:43:24 | 0:43:27 | |
It may not be everyone's idea of a great time, | 0:43:27 | 0:43:30 | |
but what we're seeing is physics textbooks being written. | 0:43:30 | 0:43:32 | |
And to me, having studied physics for so long, | 0:43:32 | 0:43:35 | |
and known what's in those textbooks, and taught people | 0:43:35 | 0:43:37 | |
from those textbooks, to see new pages being written that will never | 0:43:37 | 0:43:41 | |
be unwritten, this is something new we know, that we didn't know before | 0:43:41 | 0:43:44 | |
that we will always know afterwards. That is really exciting. | 0:43:44 | 0:43:48 | |
If the Higgs is confirmed at last, | 0:43:52 | 0:43:55 | |
then it'll open a new chapter | 0:43:55 | 0:43:58 | |
in our understanding of how the universe works. | 0:43:58 | 0:44:01 | |
Scientists plan to use the completed standard model | 0:44:08 | 0:44:12 | |
as the foundation for an even deeper description of the universe, | 0:44:12 | 0:44:17 | |
one based on the idea of symmetry and its breakage. | 0:44:17 | 0:44:21 | |
That could take our knowledge of the cosmos even further back | 0:44:25 | 0:44:30 | |
into that crucial first second of existence, | 0:44:30 | 0:44:33 | |
right to the moment of the big bang itself. | 0:44:33 | 0:44:38 | |
It's long been a dream of theorists to wind the clock back to the instant of creation, | 0:45:02 | 0:45:08 | |
a place, so far, no machine has been able to go. | 0:45:08 | 0:45:13 | |
Here, they believed they'd find a moment of absolute symmetry. | 0:45:13 | 0:45:19 | |
The state of perfect symmetry | 0:45:21 | 0:45:23 | |
is very similar to the state of perfect balance. | 0:45:23 | 0:45:25 | |
Think of a spinning top. | 0:45:25 | 0:45:27 | |
It exists in a state of perfect rotational symmetry. | 0:45:27 | 0:45:31 | |
No matter how you rotate, everything looks the same. | 0:45:31 | 0:45:34 | |
Just like with the spinning top, at this instant of creation, | 0:45:35 | 0:45:40 | |
everything in the universe would've been the same. | 0:45:40 | 0:45:42 | |
There'd be no distinction between gravity and electromagnetism, | 0:45:42 | 0:45:46 | |
light and dark, matter and forces. | 0:45:46 | 0:45:51 | |
But perfection can't last. | 0:45:51 | 0:45:53 | |
The slightest imperfection, the slightest little defect, | 0:45:53 | 0:45:58 | |
will cause it to vibrate and fall to a lower energy state. | 0:45:58 | 0:46:02 | |
Symmetry has been broken. | 0:46:02 | 0:46:04 | |
Within a fraction of a second of the big bang, | 0:46:09 | 0:46:12 | |
physicists believe the absolute symmetry of the universe was shattered by a tiny fluctuation. | 0:46:12 | 0:46:19 | |
The forces split apart. | 0:46:19 | 0:46:21 | |
The particles of the standard model became distinct. | 0:46:21 | 0:46:26 | |
This fall from perfection was what allowed us to come into being. | 0:46:26 | 0:46:31 | |
Everything we see around us is nothing but fragments of this original perfection. | 0:46:33 | 0:46:38 | |
Whenever you see a beautiful snowflake, a beautiful crystal | 0:46:38 | 0:46:42 | |
or even the symmetry of stars in the universe, | 0:46:42 | 0:46:45 | |
that's a fragment, that's a piece of the original symmetry at the beginning of time. | 0:46:45 | 0:46:52 | |
By unifying the fragments, | 0:46:55 | 0:46:57 | |
physicists think they'll find the ultimate key | 0:46:57 | 0:47:01 | |
to how the universe was born. | 0:47:01 | 0:47:03 | |
The Higgs is a vital stepping stone in this mission. | 0:47:05 | 0:47:08 | |
But in their quest for unification, | 0:47:08 | 0:47:11 | |
theoretical physicists have taken the idea of symmetry | 0:47:11 | 0:47:15 | |
to a new, extraordinary level. | 0:47:15 | 0:47:18 | |
When James Gates came to study at MIT, | 0:47:26 | 0:47:29 | |
he was keen to unlock the secrets of the universe. | 0:47:29 | 0:47:33 | |
And he was prepared to push the boundaries of his thinking a little further than most. | 0:47:33 | 0:47:40 | |
The universe and we are intricately tied together. | 0:47:40 | 0:47:44 | |
This idea of unity turns out to be one of the most powerful driving themes in physics. | 0:47:47 | 0:47:52 | |
And it keeps getting us to look for deeper and deeper connections. | 0:47:53 | 0:47:57 | |
Ultimately, perhaps we exist because the universe had no other choice. | 0:47:57 | 0:48:02 | |
He began with the standard model - | 0:48:05 | 0:48:08 | |
the collection of building blocks of matter | 0:48:08 | 0:48:11 | |
and the forces that hold them together. | 0:48:11 | 0:48:14 | |
Could these two very different groups of particles | 0:48:14 | 0:48:18 | |
be connected in some more fundamental way? | 0:48:18 | 0:48:21 | |
So, when we find something in nature that doesn't have a symmetry, | 0:48:22 | 0:48:26 | |
we always ask the question, "Why?" | 0:48:26 | 0:48:28 | |
and then we go one step further and ask the question, "What if?" | 0:48:28 | 0:48:34 | |
It was the asking of this "what if?" question | 0:48:34 | 0:48:37 | |
that drove the construction of supersymmetry | 0:48:37 | 0:48:39 | |
which had an incredible resonance for me when I was a graduate student. | 0:48:39 | 0:48:44 | |
I saw one more beautiful balance that we could put in nature. | 0:48:44 | 0:48:47 | |
James became one of the pioneers | 0:48:53 | 0:48:55 | |
of a powerful new mathematical theory called supersymmetry. | 0:48:55 | 0:48:59 | |
Using symmetry in equations had previously led to the discovery of antimatter. | 0:49:02 | 0:49:07 | |
These new ones suggested there was a hidden world of particles no-one had suspected. | 0:49:08 | 0:49:15 | |
Mathematics leads us to find things we didn't know were there before. | 0:49:17 | 0:49:22 | |
Supersymmetry is an example of that. | 0:49:22 | 0:49:24 | |
We know about ordinary matter. | 0:49:24 | 0:49:26 | |
The maths leads you on to discover super-matter and super-energy. | 0:49:26 | 0:49:31 | |
The theory took everything we thought we knew about, | 0:49:34 | 0:49:38 | |
even the Higgs, and doubled it... | 0:49:38 | 0:49:40 | |
..giving every matter particle a force partner | 0:49:41 | 0:49:45 | |
and every force particle a matter partner. | 0:49:45 | 0:49:48 | |
These heavier, supersymmetric twins were labelled sparticles. | 0:49:49 | 0:49:54 | |
So, once you believe this maths that says there's more to existence | 0:49:55 | 0:49:59 | |
then you have to wonder what these other things are. | 0:49:59 | 0:50:02 | |
You have to name them, at the very first step. | 0:50:02 | 0:50:05 | |
So, in nature, there's a thing called the electron. | 0:50:05 | 0:50:08 | |
The maths says it has a superpartner called the selectron. | 0:50:08 | 0:50:12 | |
Muon - there'd have to be the smuon. | 0:50:12 | 0:50:15 | |
Photon - there'd have to be a photino. | 0:50:15 | 0:50:18 | |
Quark - there'd have to be squarks. | 0:50:18 | 0:50:21 | |
Z particle - there'd have to be zino. | 0:50:21 | 0:50:24 | |
W particle - there'd have to be a wino. | 0:50:24 | 0:50:28 | |
And that's how supersymmetry works. | 0:50:28 | 0:50:30 | |
According to supersymmetry, | 0:50:33 | 0:50:35 | |
matter and forces aren't so distinct after all. | 0:50:35 | 0:50:39 | |
There's a grand symmetry between them. | 0:50:39 | 0:50:42 | |
But we can currently see only one partner from each pair. | 0:50:42 | 0:50:46 | |
However strange it seems, | 0:50:55 | 0:50:56 | |
this theory has gained widespread support from theoretical physicists... | 0:50:56 | 0:51:01 | |
..not just for the beauty of its equations | 0:51:07 | 0:51:09 | |
but for what it might help explain. | 0:51:09 | 0:51:12 | |
When supersymmetry began as a topic of discussion, | 0:51:12 | 0:51:16 | |
no-one realised what it can do. | 0:51:16 | 0:51:19 | |
It turned out that, studying the mathematics, | 0:51:19 | 0:51:22 | |
we get a firm foundation for the existence of everything. | 0:51:22 | 0:51:26 | |
One of the great attractions of supersymmetry is it helps to resolve a niggling problem | 0:51:29 | 0:51:34 | |
with the existence of the Higgs particle, | 0:51:34 | 0:51:37 | |
alleviating the need for mathematical fudges | 0:51:37 | 0:51:40 | |
in the standard model to fix its mass. | 0:51:40 | 0:51:44 | |
This object called the Higgs? The mass of this could fluctuate, | 0:51:44 | 0:51:48 | |
except if there's supersymmetry and that stabilises the mass. | 0:51:48 | 0:51:52 | |
Supersymmetry makes the mass of the Higgs more natural, more stable, less of a wild coincidence. | 0:51:54 | 0:51:58 | |
It could even help explain why there's more matter than antimatter in the early universe. | 0:51:58 | 0:52:06 | |
Supersymmetry is the theory that, if it were true, | 0:52:07 | 0:52:10 | |
could allow the rates of matter and antimatter interactions early on | 0:52:10 | 0:52:14 | |
to be great enough to explain the asymmetry we need in the early universe. | 0:52:14 | 0:52:19 | |
Supersymmetry pieces together more broken fragments from that first second of existence. | 0:52:28 | 0:52:35 | |
I very much want supersymmetry, | 0:52:37 | 0:52:39 | |
because it's a beautiful thing, by any standard | 0:52:39 | 0:52:42 | |
and would take our understanding of nature to a new level. | 0:52:42 | 0:52:46 | |
So, I want that. | 0:52:46 | 0:52:48 | |
But, so far, it's just a theory, with no experimental data | 0:52:50 | 0:52:55 | |
to support it. | 0:52:55 | 0:52:57 | |
At least, not yet. | 0:52:57 | 0:52:59 | |
That's where the £6 billion experiments at CERN | 0:53:06 | 0:53:10 | |
may really usher in a revolution. | 0:53:10 | 0:53:14 | |
Because they're hunting for evidence of supersymmetry. | 0:53:16 | 0:53:19 | |
So, here we are now, 100 metres underground, | 0:53:20 | 0:53:23 | |
where the LHCB detector is installed. | 0:53:23 | 0:53:26 | |
Since the accelerator is stopped now for a few days, we can actually go in and see the detector. | 0:53:26 | 0:53:31 | |
Richard Jacobsson is in charge of the operation of the detector | 0:53:35 | 0:53:39 | |
that may give the first clues about supersymmetric particles. | 0:53:39 | 0:53:43 | |
So, this is really where the dreams of theorists meet reality. | 0:53:49 | 0:53:52 | |
Theorists, they invent new ideas as they go | 0:53:52 | 0:53:56 | |
and our job as experimentalists is to actually find out | 0:53:56 | 0:54:00 | |
which of these theories are definitely wrong | 0:54:00 | 0:54:03 | |
and which are the ones we can establish, measure, | 0:54:03 | 0:54:05 | |
that actually correspond to what we measure in the experiment. | 0:54:05 | 0:54:09 | |
So far, not only have they found no evidence of the photinos, | 0:54:11 | 0:54:15 | |
squarks or other sparticles predicted by the theorists, | 0:54:15 | 0:54:19 | |
they've even ruled out the possibility of them | 0:54:19 | 0:54:22 | |
at some of the energies theorists were hoping they'd be. | 0:54:22 | 0:54:26 | |
Throughout this year, we've recorded more than ten billion reactions between protons. | 0:54:26 | 0:54:31 | |
By studying them very precisely, we've been able to sort of exclude certain versions of supersymmetry. | 0:54:31 | 0:54:37 | |
For the theorists, this means they have to look in a different direction. | 0:54:37 | 0:54:42 | |
But the first, tantalising glimpse of the Higgs will have come as an encouragement to scientists here, | 0:54:44 | 0:54:50 | |
because the mass of the Higgs | 0:54:50 | 0:54:52 | |
determines the mass of the sparticles. | 0:54:52 | 0:54:55 | |
And if they were too heavy, the LHC would be simply unable to create them. | 0:54:55 | 0:55:01 | |
Fortunately, the mass of the Higgs they have hints of | 0:55:01 | 0:55:05 | |
means evidence of the sparticles should show up in this machine. | 0:55:05 | 0:55:09 | |
That's IF they exist. | 0:55:11 | 0:55:13 | |
JAMES GATES: LHC is up and running. So far, there's no sign of superparticles. | 0:55:18 | 0:55:23 | |
If we find supersymmetry in experiments, | 0:55:23 | 0:55:27 | |
for me, personally, it will mean that I have not wasted my entire research career | 0:55:27 | 0:55:33 | |
because this is the one question, as a young scientist, I decided had my name on it to study. | 0:55:33 | 0:55:39 | |
I'm starting to get nervous. | 0:55:44 | 0:55:48 | |
You know... | 0:55:48 | 0:55:51 | |
Er... | 0:55:51 | 0:55:52 | |
So, there were a lot of people who predicted supersymmetry was just around the corner, | 0:55:52 | 0:55:58 | |
or something else, that as soon as LHC turned on, they'd see spectacular effects, | 0:55:58 | 0:56:03 | |
or that the Higgs particle would be heavy. Those were all wrong. | 0:56:03 | 0:56:07 | |
So far, nothing I believed in has been proved wrong and a lot of the competition has gone up in smoke. | 0:56:07 | 0:56:14 | |
But the crunch time is coming. | 0:56:16 | 0:56:18 | |
They're going to be capable of seeing things I've predicted or want | 0:56:18 | 0:56:24 | |
and we'll see. It's in the hands of God or CERN or something. | 0:56:24 | 0:56:30 | |
Now it's make or break time. | 0:56:32 | 0:56:33 | |
For the scientists involved, | 0:56:44 | 0:56:47 | |
pushing the frontiers of knowledge is a roller coaster ride. | 0:56:47 | 0:56:51 | |
And, with the Large Hadron Collider, the journey has only just begun. | 0:56:51 | 0:56:56 | |
This machine has opened the door to physics, above this key energy scale in nature, | 0:56:56 | 0:57:02 | |
where the symmetries of nature change fundamentally. | 0:57:02 | 0:57:05 | |
You don't get the key, open the door, go, "Well, that was nice," then close the door. | 0:57:05 | 0:57:09 | |
You see what's happening. | 0:57:09 | 0:57:11 | |
That's what we'll be doing in the next many years. | 0:57:11 | 0:57:13 | |
If every theory was like a room, | 0:57:13 | 0:57:15 | |
it's like we looked in the first one down the corridor, | 0:57:15 | 0:57:18 | |
-and already we found something exciting, so now we can't wait to look in all the others, right? -Yep. | 0:57:18 | 0:57:24 | |
Yep. | 0:57:24 | 0:57:25 | |
There's loads more stuff we'd like to look for at the LHC, | 0:57:26 | 0:57:29 | |
like supersymmetry, extra dimensions... | 0:57:29 | 0:57:33 | |
Quantum gravity. | 0:57:33 | 0:57:34 | |
New fundamental forces. | 0:57:34 | 0:57:37 | |
Substructure inside quarks, black holes... | 0:57:37 | 0:57:40 | |
-Miniature black holes. -Think of your favourite theory and double it... | 0:57:40 | 0:57:44 | |
-The possibilities are endless. -Yeah, absolutely. | 0:57:44 | 0:57:46 | |
To put this into perspective, | 0:57:49 | 0:57:52 | |
I think the last time we stood in such an exciting place | 0:57:52 | 0:57:56 | |
was 1905, when Einstein discovered special relativity | 0:57:56 | 0:58:00 | |
and announced the most famous equation in physics - E=mc2. | 0:58:00 | 0:58:05 | |
Because if the Higgs is confirmed, | 0:58:06 | 0:58:08 | |
it's about much more than just a spectacular discovery. | 0:58:08 | 0:58:13 | |
It'll also open a new chapter in physics, ask new questions, | 0:58:14 | 0:58:19 | |
setting off the search for an even deeper understanding of nature. | 0:58:19 | 0:58:24 | |
But we simply can't say where THAT search will take us. | 0:58:24 | 0:58:28 |