0:00:06 > 0:00:092012 promises to be a truly historic year for science.
0:00:14 > 0:00:17Just before Christmas, researchers working at CERN
0:00:17 > 0:00:22near Geneva, announced that they had caught a tantalising glimpse
0:00:22 > 0:00:23of the Higgs boson.
0:00:26 > 0:00:28I'm Jim Al-Khalili and, as a physicist,
0:00:28 > 0:00:30I must say that following the search
0:00:30 > 0:00:34for this so-called "God particle" has been incredibly exciting.
0:00:34 > 0:00:38Sometime this year, researchers hope to be able to declare
0:00:38 > 0:00:42the Higgs finally, officially discovered.
0:00:42 > 0:00:46If confirmed, it will be the most important scientific discovery
0:00:46 > 0:00:47of my lifetime.
0:00:47 > 0:00:50It'll be evidence for one of the most
0:00:50 > 0:00:53all-encompassing ideas in physics.
0:00:53 > 0:00:55That at the heart of everything
0:00:55 > 0:00:58is the simple and enchanting idea
0:00:58 > 0:01:00of symmetry.
0:01:00 > 0:01:04The search for the Higgs takes us deep into the most important
0:01:04 > 0:01:08questions about how the universe works and how it was created.
0:01:10 > 0:01:14Horizon has been following the final stages of the hunt
0:01:14 > 0:01:18for this most important and elusive of particles.
0:01:48 > 0:01:50This is CERN, headquarters
0:01:50 > 0:01:54of the European Organisation for Nuclear Research.
0:01:54 > 0:01:57It's home to some of the thousands of scientists
0:01:57 > 0:02:00who have been doggedly hunting
0:02:00 > 0:02:03the elusive Higgs boson
0:02:03 > 0:02:07and the £6 billion experiment that they're using to do it.
0:02:07 > 0:02:10Especially built to find the one particle
0:02:10 > 0:02:14that's thought to give substance to everything in the universe.
0:02:19 > 0:02:22This is fantastic. Any one of those 40 million collisions
0:02:22 > 0:02:25happening every second could be giving us a Higgs boson.
0:02:25 > 0:02:27Could be that one right there.
0:02:27 > 0:02:30In the autumn of 2011,
0:02:30 > 0:02:32when Horizon was at CERN,
0:02:32 > 0:02:35there was already a sense that this near 50-year quest
0:02:35 > 0:02:37was reaching its final stages.
0:02:37 > 0:02:41Yeah, I think this is the end. This is the end, one way or another.
0:02:41 > 0:02:43We're definitely in the endgame now.
0:02:43 > 0:02:46I think that this time next year,
0:02:46 > 0:02:48it will be there or it won't be.
0:02:51 > 0:02:54It's a search that's dominated the careers
0:02:54 > 0:02:56of a generation of physicists.
0:02:56 > 0:03:00Personally, I got a job saying I wanted to do this in 1993.
0:03:00 > 0:03:02It's the 11th year now.
0:03:02 > 0:03:05- About ten years, me. - Yeah, and about 5 years for me.
0:03:05 > 0:03:06Since 1989.
0:03:06 > 0:03:10That's over 20 years.
0:03:10 > 0:03:13But while there are thousands of scientists in pursuit,
0:03:13 > 0:03:17only for a few will there be prizes
0:03:17 > 0:03:19and a place in history.
0:03:19 > 0:03:21The Higgs is going to win a Nobel Prize,
0:03:21 > 0:03:23so everybody wants to be a part of it. This is the goal
0:03:23 > 0:03:26of every physicist. I mean, you won't spend 20 years
0:03:26 > 0:03:28if you don't believe in something.
0:03:28 > 0:03:31There's a lot of people who are interested in this, so...
0:03:31 > 0:03:33So yeah, it tends to get exciting.
0:03:33 > 0:03:35Not sleeping very much!
0:03:35 > 0:03:37It's a big collaboration. "What did you do?"
0:03:37 > 0:03:39Everyone wants an answer to that.
0:03:39 > 0:03:42INTERVIEWER: And are you two competing or working together?
0:03:42 > 0:03:45Together. If he finds it, I'll take the credit.
0:03:50 > 0:03:53Amongst the intrepid Higgs hunters
0:03:53 > 0:03:55are Jon Butterworth
0:03:55 > 0:04:00and his colleague Adam Davison, from University College London.
0:04:00 > 0:04:03They've been drawn here, like all the other scientists,
0:04:03 > 0:04:06by the potential of the Large Hadron Collider
0:04:06 > 0:04:08to find the missing boson at last.
0:04:11 > 0:04:15It's a great opportunity for us to finally understand
0:04:15 > 0:04:17whether the Higgs exists.
0:04:17 > 0:04:19Physics won't be the same after this.
0:04:19 > 0:04:23Even a null result here will re-write the text books.
0:04:23 > 0:04:26This is it. This is where it's going to happen.
0:04:32 > 0:04:35The problem with hunting for the Higgs
0:04:35 > 0:04:39is it can't be detected in everyday conditions.
0:04:39 > 0:04:42To find it, scientists need to return
0:04:42 > 0:04:45to those at the very beginning.
0:04:45 > 0:04:49Well, almost - to the conditions just after the big bang.
0:04:49 > 0:04:54When, the theory goes, the Higgs and everything else
0:04:54 > 0:04:55was first created.
0:04:57 > 0:04:59So here we have the big bang.
0:05:03 > 0:05:05Deserves a little bit of colour, I think.
0:05:05 > 0:05:06BOOMING EXPLOSION
0:05:06 > 0:05:10And then the timeline of the universe.
0:05:10 > 0:05:11This is where we are.
0:05:11 > 0:05:15It's now, the age of the universe,
0:05:15 > 0:05:18about 13.7 billion years
0:05:18 > 0:05:21after the big bang.
0:05:21 > 0:05:23So working backwards,
0:05:23 > 0:05:27we know that a few hundred thousand years ago,
0:05:27 > 0:05:29we had the dinosaurs.
0:05:29 > 0:05:31So, here's a dinosaur.
0:05:31 > 0:05:33DINOSAUR ROARS
0:05:33 > 0:05:36Then life itself, the first DNA,
0:05:36 > 0:05:39is about 4 billion years ago.
0:05:39 > 0:05:44Before DNA, there was the Earth.
0:05:45 > 0:05:48Before that, stars.
0:05:48 > 0:05:51Before them, atoms.
0:05:55 > 0:05:56And inside atoms,
0:05:56 > 0:06:00you have the most fundamental building blocks of existence.
0:06:02 > 0:06:06The big question is where did those building blocks come from?
0:06:06 > 0:06:10The answer to all that lies in the first second.
0:06:10 > 0:06:16In this one crucial second, all the elementary particles were created.
0:06:16 > 0:06:20Including, scientists believe, the Higgs boson.
0:06:20 > 0:06:22The mysteries of existence lie within this second.
0:06:22 > 0:06:26Certainly, we understand the science, we understand the physics.
0:06:26 > 0:06:28Backwards into this second,
0:06:28 > 0:06:30but at some point we just run out of knowledge.
0:06:33 > 0:06:37The Large Hadron Collider is allowing us to see
0:06:37 > 0:06:41right back to 10 to the -12 seconds
0:06:41 > 0:06:43after the big bang.
0:06:43 > 0:06:46Beyond that, here be dragons. Or dinosaurs!
0:06:55 > 0:06:59The Large Hadron Collider's technique to transport scientists
0:06:59 > 0:07:03to the moment just after the big bang is as violent
0:07:03 > 0:07:08as it is ambitious. 100 metres underground, it takes protons
0:07:08 > 0:07:09from the nuclei of atoms
0:07:09 > 0:07:14and collides them, at almost the speed of light.
0:07:26 > 0:07:29These protons are colliding at huge energies,
0:07:29 > 0:07:30and in those collisions
0:07:30 > 0:07:34a large number of particles are produced, hundreds, thousands even.
0:07:34 > 0:07:38And trying to look at those particles that are produced,
0:07:38 > 0:07:41and understand what happened in those collisions,
0:07:41 > 0:07:43is what the LHC is all about.
0:07:56 > 0:08:00Somewhere buried in this wreckage, they hope to unearth the Higgs.
0:08:02 > 0:08:06It would be proof of the existence of a field
0:08:06 > 0:08:11that scientists believe surrounds us all the time.
0:08:11 > 0:08:14And that appeared in that first second of creation.
0:08:19 > 0:08:22As the heat and fury ebbed out of the big bang,
0:08:22 > 0:08:26so the theory goes, the Higgs field condensed.
0:08:26 > 0:08:29As particles travel through this field
0:08:29 > 0:08:32they get slowed down, like travelling through treacle.
0:08:32 > 0:08:34This is what gives them mass.
0:08:43 > 0:08:45Without gaining mass, particles
0:08:45 > 0:08:51would have continued to fly through the universe at the speed of light.
0:08:53 > 0:09:00Never clumping together to form you, me, blackboards, well, anything.
0:09:04 > 0:09:08To have deduced the presence of something as weird as the Higgs,
0:09:08 > 0:09:10just from theory and from other previous data,
0:09:10 > 0:09:13and then to find it in nature, would be a hugely exciting vindication
0:09:13 > 0:09:15of our picture of what is going on.
0:09:17 > 0:09:22Finding something that's all around us is surprisingly tricky.
0:09:23 > 0:09:26Scientists need to create a disturbance in the Higgs field
0:09:26 > 0:09:29to detect the boson itself.
0:09:30 > 0:09:36This is what the LHC is attempting to do, by colliding particles.
0:09:39 > 0:09:41It's a challenge other particle accelerators
0:09:41 > 0:09:46have tried and been unable to complete.
0:09:46 > 0:09:49Because for all scientists sense that the Higgs ought to be there,
0:09:49 > 0:09:54it has proven spectacularly difficult to find.
0:09:54 > 0:09:58The idea of the Higgs boson was first proposed in 1964.
0:09:58 > 0:10:02Which was a very long time ago, before I was even born.
0:10:02 > 0:10:05Many years of work have been leading up to this point,
0:10:05 > 0:10:08so it is absolutely exciting to be here
0:10:08 > 0:10:11at the point where the discovery might happen.
0:10:17 > 0:10:19What's made all the difference at the LHC
0:10:19 > 0:10:23are the incredible energy levels the collider can reach.
0:10:26 > 0:10:30Pushing further back in time into that crucial first second.
0:10:34 > 0:10:38This has opened up new places to search for the Higgs,
0:10:38 > 0:10:40a hunt that's defined in terms
0:10:40 > 0:10:43of what mass the Higgs itself might have,
0:10:43 > 0:10:49measured in GeV, or giga electron volts.
0:10:49 > 0:10:52So on this line of what the mass of the Higgs might be,
0:10:52 > 0:10:56we can draw on what previous experiments have tried,
0:10:56 > 0:11:00and where they have been able to exclude it from being.
0:11:00 > 0:11:05After decades of work, the LEP collider at CERN,
0:11:05 > 0:11:06a predecessor of the LHC,
0:11:06 > 0:11:11ruled out the Higgs being at the bottom end of potential masses.
0:11:12 > 0:11:16In fact, they were able to say that the mass of the Higgs is,
0:11:16 > 0:11:23with 95% confidence, 114 GeV, or more.
0:11:23 > 0:11:27So after LEP, the next major milestone in the Higgs search
0:11:27 > 0:11:32was limits set by another collider in the US called the Tevatron.
0:11:32 > 0:11:38The Tevatron was able to exclude a range here,
0:11:38 > 0:11:41around 160 GeV here.
0:11:41 > 0:11:48And by November 2011, the LHC had already radically narrowed the search.
0:11:48 > 0:11:51The LHC has been able to rule out a big region
0:11:51 > 0:11:54from 145...
0:11:55 > 0:11:57..quite far up.
0:11:59 > 0:12:01It's been decades' worth of work
0:12:01 > 0:12:06to gradually eliminate more and more of the space where the Higgs boson could be,
0:12:06 > 0:12:09and now we are finally in this regime
0:12:09 > 0:12:10where in the next couple of years
0:12:10 > 0:12:13we might be able to close this gap
0:12:13 > 0:12:16and finally know for sure whether it is there or not.
0:12:21 > 0:12:26In November, that left a region of just 30 GeV
0:12:26 > 0:12:28for the Higgs to be hiding in.
0:12:28 > 0:12:35But this last remaining energy range is also the trickiest to search.
0:12:35 > 0:12:39It is the area in which the unique signature of the Higgs
0:12:39 > 0:12:41is most deeply buried
0:12:41 > 0:12:46under the background noise of other particles created in the collider.
0:12:50 > 0:12:52Not that the Higgs hunters were deterred.
0:12:52 > 0:12:55The data is piling up and we know how to do it,
0:12:55 > 0:12:58we just don't have enough data to tell you today what the answer is.
0:13:04 > 0:13:10If I was to bet, I would probably put it at 130 GeV.
0:13:10 > 0:13:14At the moment, probably somewhere around 120 GeV.
0:13:14 > 0:13:17I would predict somewhere between 120 and 130 GeV.
0:13:17 > 0:13:23I would put the Higgs somewhere close to 114 GeV,
0:13:23 > 0:13:25because it is the most difficult place to look,
0:13:25 > 0:13:27and we haven't found it yet.
0:13:27 > 0:13:30That is a good question, because, you know,
0:13:30 > 0:13:32you are assuming it actually exists,
0:13:32 > 0:13:36which I am starting to believe it probably does not exist.
0:13:41 > 0:13:45I'm really oscillating between thinking it is clearly there,
0:13:45 > 0:13:48and then thinking, no, it's not going to turn up, is it?
0:13:48 > 0:13:50Yeah, I don't know,
0:13:50 > 0:13:53I think I have decided not to have a strong opinion.
0:13:53 > 0:13:55I keep trying not to.
0:13:55 > 0:13:57In almost every way, I think it would be more exciting
0:13:57 > 0:13:59to prove it doesn't exist.
0:13:59 > 0:14:02Yeah, it would be a longer-term bigger result, I think,
0:14:02 > 0:14:05the negative result would have a longer-term bigger impact,
0:14:05 > 0:14:08because it would really put us back to the drawing board.
0:14:08 > 0:14:11On the other hand, in the short-term, it'd be disappointing
0:14:11 > 0:14:13because a positive result is positive.
0:14:13 > 0:14:16- You'd like to see that. - I don't think that's true at all.
0:14:16 > 0:14:20I think a negative result, even in the short-term, would be more exciting.
0:14:20 > 0:14:23It's the opposite of what people expect, right?
0:14:23 > 0:14:25It's like... It'd be a lot more fun.
0:14:26 > 0:14:29The experimental physicists here at CERN
0:14:29 > 0:14:33have already put some of the ideas of their colleagues,
0:14:33 > 0:14:38the theorists, to the test, and not all the results have been positive.
0:14:38 > 0:14:41It's a whole bunch of theoretical models and papers.
0:14:41 > 0:14:44There's been a bonfire of them since the LHC started.
0:14:44 > 0:14:46There are whole swathes of potential speculation
0:14:46 > 0:14:49that are now pointless. They're obviously a dead end
0:14:49 > 0:14:51because the data says this.
0:14:51 > 0:14:55But what's at stake with the Higgs isn't just one particle,
0:14:55 > 0:15:00however elusive, or any old theory.
0:15:01 > 0:15:06The Higgs is the cornerstone for the most successful and all-encompassing
0:15:06 > 0:15:12description of how our universe works that there is.
0:15:19 > 0:15:21Working this beautiful model out
0:15:21 > 0:15:25has been one of the great achievements of theoretical physics,
0:15:25 > 0:15:29and Frank Wilczek was one of the key contributors.
0:15:31 > 0:15:35- Hi. Welcome. Come in. - Yeah, that'd be great, thank you.
0:15:42 > 0:15:47I'll show you our library, living room, trophy room.
0:15:47 > 0:15:52A lot of puzzle books, most of which I've worked through.
0:15:52 > 0:15:56I'm a big puzzle man.
0:15:56 > 0:16:03Here are the awards and trophies that have found their way here.
0:16:03 > 0:16:10- This is the Nobel Prize medal and here's one for you.- Thank you.
0:16:10 > 0:16:12Are these ones edible?
0:16:12 > 0:16:16Yes, more or less. Anyway, I intend to eat one.
0:16:16 > 0:16:19And...
0:16:22 > 0:16:24..you'll notice that...
0:16:25 > 0:16:29..not only in this room but everywhere, there are little toys.
0:16:29 > 0:16:32A lot of what I do is really just play.
0:16:32 > 0:16:35I mean, I play with the equations, ideas.
0:16:35 > 0:16:38HE LAUGHS
0:16:38 > 0:16:43And all that puzzling won Frank a Nobel prize
0:16:43 > 0:16:45for his contribution to what's called
0:16:45 > 0:16:48the Standard Model Of Elementary Particles.
0:16:49 > 0:16:51Well, what have we got here?
0:16:51 > 0:16:55It looks like an instrument of torture for the mind.
0:17:00 > 0:17:04The Standard Model is essentially an understanding of how all the pieces
0:17:04 > 0:17:08of the universe fit together, except for gravity.
0:17:08 > 0:17:10A mind-boggling project.
0:17:10 > 0:17:17This is going to be a hell of a puzzle to figure out.
0:17:17 > 0:17:21All right. Now, a promising start. HE LAUGHS
0:17:21 > 0:17:26'We think the Standard Model contains all you need,
0:17:26 > 0:17:30'in principle, to describe how molecules behave,
0:17:30 > 0:17:35'all of chemistry, how stars work, all of astrophysics.
0:17:35 > 0:17:39'Not only how things behave, but what can exist.
0:17:39 > 0:17:41'These are the rules of the game.'
0:17:46 > 0:17:52The ingredients of the Standard Model are of three basic sorts.
0:17:52 > 0:17:56There's what you might broadly call matter.
0:17:59 > 0:18:05That's sort of lumps of stuff that have a certain degree of permanence
0:18:05 > 0:18:10and these are on the one hand quarks.
0:18:10 > 0:18:13They include the building blocks of protons and neutrons
0:18:13 > 0:18:16and atomic nuclei.
0:18:16 > 0:18:18And leptons.
0:18:21 > 0:18:26The most prominent lepton in everyday life is certainly the electron.
0:18:26 > 0:18:30So those are matter particles.
0:18:32 > 0:18:36On the other side we have what you might call force particles,
0:18:36 > 0:18:38or force mediators.
0:18:42 > 0:18:46These particles are more like lumps of energy
0:18:46 > 0:18:51and they transmit the forces that bring the matter particles to life,
0:18:51 > 0:18:55like the photon, which carries the electromagnetic force.
0:18:55 > 0:18:58The gluons that carry the strong force,
0:18:58 > 0:19:01which holds the nuclei of atoms together,
0:19:01 > 0:19:04and the W and Z bosons
0:19:04 > 0:19:08that are responsible for the weak force governing radioactivity.
0:19:13 > 0:19:17Every one of these particles has now been found experimentally.
0:19:17 > 0:19:21There's just one pesky missing piece to the model
0:19:21 > 0:19:24that they're searching for so intensively at CERN.
0:19:26 > 0:19:27The Higgs.
0:19:27 > 0:19:30In order to reconcile the beautiful equations
0:19:30 > 0:19:33with the not quite as beautiful observations,
0:19:33 > 0:19:38we need to find out what that piece is
0:19:38 > 0:19:42and its properties and see if it really fits into a nice pattern
0:19:42 > 0:19:45and completes the Standard Model.
0:19:45 > 0:19:48We need experimental information
0:19:48 > 0:19:52and this is usually called the quest for the Higgs boson.
0:20:03 > 0:20:07This is why finding the Higgs is such an obsession among physicists.
0:20:11 > 0:20:16If they do, it will be the vindication of this beautiful model.
0:20:16 > 0:20:21And if not, they'll have to fundamentally rethink
0:20:21 > 0:20:24their understanding of how the universe is put together.
0:20:26 > 0:20:30In a way, finding the Higgs will be the completion of a dream.
0:20:30 > 0:20:32Not finding it will be the start of a new one.
0:20:32 > 0:20:37Imagine that the Standard Model is the car and the Higgs is the engine
0:20:37 > 0:20:40and it's running, and imagine you find a car and then you open
0:20:40 > 0:20:45and see no engine, so it might be more interesting than the car with an engine.
0:20:45 > 0:20:48If you find that the car is running without an engine,
0:20:48 > 0:20:50it's more interesting but it's kind of...
0:20:50 > 0:20:53"What did I do in the last 20 years?" You know?
0:20:53 > 0:20:57Do I believe in the Higgs? I... I think so.
0:20:57 > 0:21:00I believe there's something that we're missing
0:21:00 > 0:21:02and hopefully it's the Higgs, because...
0:21:02 > 0:21:04it fits our model very nicely.
0:21:04 > 0:21:09There are other possibilities, so I wouldn't discount those completely
0:21:09 > 0:21:11but I think this is the best explanation we have so far.
0:21:11 > 0:21:14Ask me in a year's time and I might give you a different answer.
0:21:17 > 0:21:20It's October 2011 in the Atlas Control Room,
0:21:20 > 0:21:24the nerve centre of one of two detectors at CERN
0:21:24 > 0:21:27intensively searching for the Higgs.
0:21:33 > 0:21:36Scientists here are avidly collecting data
0:21:36 > 0:21:41from the billions of collisions, to comb for evidence of the boson,
0:21:41 > 0:21:45because you can't simply spot it directly.
0:21:45 > 0:21:50Almost as soon as it's created, it decays into other particles,
0:21:50 > 0:21:53leaving just a trace of its existence.
0:21:54 > 0:21:59The only way scientists can tell if a Higgs boson was there or not
0:21:59 > 0:22:02is by looking for a statistical anomaly,
0:22:02 > 0:22:07some blip in the measurements that they can't otherwise account for.
0:22:07 > 0:22:10Seeing one picture like that isn't sufficient,
0:22:10 > 0:22:13because there are other things that can look like the Higgs.
0:22:13 > 0:22:16But if you get a bunch of them and you plot them, that's what we do,
0:22:16 > 0:22:19that's our job, we put together all these tracks
0:22:19 > 0:22:22and we say, "What mass of a particle would produce that?"
0:22:22 > 0:22:26And then we look at them all and if we see a bump,
0:22:26 > 0:22:30some little statistical anomaly there that's significant,
0:22:30 > 0:22:34then we get excited, and then we go ask the other guys, "Hey, did you guys see that?"
0:22:34 > 0:22:38Then we celebrate, but right now we've got a lot of work to do.
0:22:38 > 0:22:44In the autumn, that intensive effort was being directed at the 30GeV
0:22:44 > 0:22:48energy window that the Higgs could be hiding in.
0:22:48 > 0:22:52We've covered a lot of range, we're travelling up a river,
0:22:52 > 0:22:56we've checked all the different streams and we've narrowed it down
0:22:56 > 0:23:00to some areas where it could be, and so that's where we're focusing
0:23:00 > 0:23:03all of our energy, to look in those areas and see if we find it.
0:23:03 > 0:23:07I think we're really on the brink of discovery.
0:23:09 > 0:23:11But it's a slow process,
0:23:11 > 0:23:16because it's all about crunching vast quantities of data.
0:23:16 > 0:23:19One blip alone isn't enough, of course.
0:23:19 > 0:23:22You need to be sure it isn't an error or fluke
0:23:22 > 0:23:27and these anomalies can disappear almost as quickly as they arrive.
0:23:32 > 0:23:37For experimentalists, these false alarms happen all too frequently.
0:23:37 > 0:23:42You work on it day in, day out, so you get quite emotionally attached
0:23:42 > 0:23:45to the state of these plots and numbers.
0:23:45 > 0:23:49Especially if it's your plot. You want it to be your plot that finds the Higgs.
0:23:49 > 0:23:52I realised at some point actually that it is genuinely...
0:23:52 > 0:23:55I realised I found it genuinely stressful when plots get worse.
0:23:55 > 0:23:57Yeah, that's right.
0:23:57 > 0:24:02- So many points can do that. - When it get worse that makes me a little bit anxious and I think,
0:24:02 > 0:24:04- "This is insane."- That's right,
0:24:04 > 0:24:09- and so you live in hope and then you often hit disappointment. - Disappointed frequently.
0:24:17 > 0:24:21It was in this state of perpetual tension that the scientists
0:24:21 > 0:24:27working on the Atlas Detector met in November to discuss their latest set of results.
0:24:36 > 0:24:40- What's going on? - They've just got started
0:24:40 > 0:24:44and now we're going to get to the nitty-gritty of how things are actually going.
0:24:44 > 0:24:48We don't have enough data, the statistics are fluctuating up and down.
0:24:48 > 0:24:50You get excited about something and then more data,
0:24:50 > 0:24:52it goes away and a bit more, it comes back.
0:24:52 > 0:24:55It's all very tense at the moment, I'd say.
0:24:55 > 0:24:58- Fun.- Does it feel like there's a real atmosphere
0:24:58 > 0:25:00in terms of the search for Higgs closing in?
0:25:00 > 0:25:05It's really weird because you're working on this more or less 20 hours a day
0:25:05 > 0:25:08and it's been going on for a long time, so it becomes almost routine,
0:25:08 > 0:25:11and then you get a meeting like this where it all
0:25:11 > 0:25:14comes together and people go, "This is really exciting again."
0:25:14 > 0:25:17This isn't one of those moments where people remember why we're here.
0:25:17 > 0:25:21- Can we come in?- No.
0:25:21 > 0:25:24In fact, the guy just said, "The BBC are outside.
0:25:24 > 0:25:28"Be nice to them at the coffee break, tell them what they want to know."
0:25:28 > 0:25:32The spokesperson was in there and said, "Don't tell them anything!"
0:25:34 > 0:25:41The intense secrecy was because of the competition between the LHC's different detectors
0:25:41 > 0:25:46to find the Higgs first and the provisional nature of the results.
0:25:48 > 0:25:50What nobody was aware of at the time,
0:25:50 > 0:25:55was that a small blip in the data that Atlas researchers had seen
0:25:55 > 0:26:00would ultimately turn into something far more significant.
0:26:18 > 0:26:23The hunt for the Higgs may be the most high-profile work going on at CERN
0:26:23 > 0:26:30but the £6 billion experiment is about far more than finding one boson.
0:26:33 > 0:26:37Scientists here are using the particle accelerator to understand
0:26:37 > 0:26:40some of the other great mysteries of the universe.
0:26:43 > 0:26:47But there's one common problem that links the Higgs
0:26:47 > 0:26:52with other work happening here and that of scientists around the world.
0:27:02 > 0:27:06Many scientists hope that if the Higgs is found
0:27:06 > 0:27:09it'll help resolve the paradox within our understanding
0:27:09 > 0:27:12of the laws of nature.
0:27:17 > 0:27:19And it's a rather fundamental one.
0:27:24 > 0:27:26Science has given us a set of laws
0:27:26 > 0:27:29that describe the world so accurately
0:27:29 > 0:27:32that we can predict the motion of a coin tossed in the air,
0:27:32 > 0:27:35because we understand the law of gravity.
0:27:35 > 0:27:39We understand electromagnetism so well that we can use our GPS satellites
0:27:39 > 0:27:43to locate your car to within a few inches.
0:27:43 > 0:27:47We understand the nuclear force so well that we can predict
0:27:47 > 0:27:49the future evolution of the sun itself.
0:27:54 > 0:27:59The mathematics that's given rise to many of these great successes
0:27:59 > 0:28:01has one consistent theme.
0:28:01 > 0:28:04It's one we see around us every day.
0:28:09 > 0:28:15It characterises our faces, the natural world
0:28:15 > 0:28:22and tiny structures like viruses and even our DNA.
0:28:22 > 0:28:24Symmetry.
0:28:24 > 0:28:27In the Standard Model, symmetry rules.
0:28:27 > 0:28:33The laws are dictated really in their form
0:28:33 > 0:28:36by requiring tremendous amounts of symmetry.
0:28:36 > 0:28:38That's how we found them.
0:28:42 > 0:28:47But for all the power of symmetry in uncovering these fundamental laws,
0:28:47 > 0:28:50there's a deep paradox at work.
0:28:50 > 0:28:53If the laws of science are framed at their most perfect,
0:28:53 > 0:28:55most symmetrical form,
0:28:55 > 0:28:58then life cannot exist at all.
0:29:05 > 0:29:08There'd be no mountains, rivers, valleys.
0:29:08 > 0:29:11No DNA, no people, nothing.
0:29:16 > 0:29:20A universe created along absolutely symmetric principles
0:29:20 > 0:29:25would be in perfect balance, and would cancel itself out.
0:29:27 > 0:29:31There'd be no mass, Higgs... or matter at all.
0:29:31 > 0:29:34But here we are.
0:29:34 > 0:29:37Our world is teeming with life and complexity,
0:29:37 > 0:29:40and yet that seems to be incompatible with
0:29:40 > 0:29:45perfection in our equations. By rights, we shouldn't be here.
0:29:47 > 0:29:49This paradox about symmetry
0:29:49 > 0:29:53lies at the heart of modern physics.
0:29:53 > 0:29:56And it's crucial to understanding the significance
0:29:56 > 0:29:57of the Higgs itself.
0:30:05 > 0:30:07So what unites much of the work at CERN
0:30:07 > 0:30:12is trying to resolve this problem with symmetry.
0:30:19 > 0:30:21There's another group of scientists
0:30:21 > 0:30:23who work alongside the Higgs hunters.
0:30:27 > 0:30:29There are over 700 of them,
0:30:29 > 0:30:32and they're searching for answers to this puzzle about symmetry.
0:30:37 > 0:30:39So this canteen is very important, really.
0:30:39 > 0:30:43It's one of the main working places at CERN.
0:30:43 > 0:30:46You see a lot of big names down here -
0:30:46 > 0:30:49if you wait long enough you'll come across a Nobel Prize winner
0:30:49 > 0:30:51during the day.
0:30:51 > 0:30:54Peter Clarke is one of the scientists working
0:30:54 > 0:30:58on the Large Hadron Collider's LHCb experiment,
0:30:58 > 0:31:04along with his colleague from the University of Edinburgh, Conor Fitzpatrick.
0:31:06 > 0:31:07Their field of study
0:31:07 > 0:31:11is the weird symmetric mirror world of antimatter.
0:31:11 > 0:31:16A substance that's as real as matter, but its opposite...
0:31:17 > 0:31:19..and rather more elusive.
0:31:19 > 0:31:24The geek in everyone still feels a bit excited about the concept of working with this stuff.
0:31:24 > 0:31:28It's not something the public sees from day to day life,
0:31:28 > 0:31:32and it's one of the few things you can only see at CERN.
0:31:33 > 0:31:37Antimatter may sound like the stuff of science fiction.
0:31:37 > 0:31:41But since it was first proposed as a concept 80 years ago,
0:31:41 > 0:31:43scientists have been creating it in experiments.
0:31:47 > 0:31:50The very idea of antimatter emerged from a revolutionary
0:31:50 > 0:31:55piece of mathematics, with symmetry at its heart.
0:31:55 > 0:31:58It said that for every particle of matter,
0:31:58 > 0:32:01there should be a corresponding one of antimatter.
0:32:04 > 0:32:08Once one's thought about the symmetry of the theories,
0:32:08 > 0:32:11and realised that antimatter must exist,
0:32:11 > 0:32:14you then think it's absurd that there wouldn't be antimatter
0:32:14 > 0:32:17or the possibility to create antimatter.
0:32:17 > 0:32:21Which is why it's so surprising that the world in which we live is entirely made of matter.
0:32:23 > 0:32:25Because the theory posed a puzzle:
0:32:25 > 0:32:31when matter and anti-matter meet, they destroy each other completely.
0:32:34 > 0:32:38Equal amounts of each would leave nothing but energy.
0:32:41 > 0:32:45If the laws of science are expressed in their most perfect form,
0:32:45 > 0:32:48then life cannot exist at all.
0:32:57 > 0:33:01Clearly, all the matter WASN'T destroyed by antimatter.
0:33:01 > 0:33:06After all, we see around us far more matter than antimatter
0:33:06 > 0:33:07in the universe today.
0:33:13 > 0:33:16Just how this could have happened is something that Peter, Conor
0:33:16 > 0:33:21and the other scientists on the LHCb experiment are trying to understand.
0:33:23 > 0:33:27So they're using the Large Hadron Collider to create some
0:33:27 > 0:33:30pairs of matter and antimatter particles of their own,
0:33:30 > 0:33:32to study what could have happened
0:33:32 > 0:33:36in that crucial first second of the universe.
0:33:40 > 0:33:43We're currently in the LHCb control room.
0:33:43 > 0:33:46This is colloquially referred to as "the pit" -
0:33:46 > 0:33:49100 metres below us right now is the LHCb experiment itself.
0:33:52 > 0:33:59LHCb is one of the four detectors sited around the collider.
0:34:00 > 0:34:04When the two beams of protons meet in a head-on collision,
0:34:04 > 0:34:07recreating the energy levels just after the big bang,
0:34:07 > 0:34:10it records the particles that are formed.
0:34:10 > 0:34:13We can see antimatter being created in our detector,
0:34:13 > 0:34:17so the difference between matter and antimatter is that they're differently charged.
0:34:17 > 0:34:19So these two green tracks here,
0:34:19 > 0:34:22in a magnetic field they're going differently, so one of them
0:34:22 > 0:34:24has to be matter, and one of them has to be antimatter.
0:34:24 > 0:34:28It's kind of cool that we can see it right here in an event on the screen.
0:34:30 > 0:34:34Combing through the wreckage of billions of collisions,
0:34:34 > 0:34:39and building on the work of previous particle accelerators,
0:34:39 > 0:34:42scientists here have been in search of ways
0:34:42 > 0:34:47in which matter and antimatter behave differently.
0:34:47 > 0:34:49And they've managed to observe one -
0:34:49 > 0:34:52a crucial breaking of symmetry
0:34:52 > 0:34:55in the behaviour of matter and antimatter versions
0:34:55 > 0:34:57of particles called B mesons.
0:35:00 > 0:35:03So I'll give you one example of the way
0:35:03 > 0:35:06we observe the difference between matter and antimatter.
0:35:06 > 0:35:10This is perhaps the simplest example to visualise.
0:35:10 > 0:35:13We can observe how B mesons created in LHCb decay to particles,
0:35:13 > 0:35:17and how anti-B mesons decay to antiparticles.
0:35:17 > 0:35:19We can count the rate at which this happens,
0:35:19 > 0:35:22the number of times it happens, and we do this.
0:35:22 > 0:35:25We observe the particles decaying 7,000 times,
0:35:25 > 0:35:28and the antiparticles 6,000 times.
0:35:28 > 0:35:30And if matter and antimatter did not have this asymmetry,
0:35:30 > 0:35:32it would just be an equal number of times.
0:35:32 > 0:35:36So this difference of 1,000 is an absolute clear manifestation
0:35:36 > 0:35:39of the asymmetry between matter and antimatter.
0:35:45 > 0:35:47So far, researchers haven't been able to find
0:35:47 > 0:35:50enough instances of this asymmetry
0:35:50 > 0:35:54to explain all the matter we know IS in the universe.
0:36:00 > 0:36:03But one thing is clear. The reason we exist,
0:36:03 > 0:36:07is because the perfect symmetry scientists believe was once there
0:36:07 > 0:36:12between matter and antimatter must somehow have been broken.
0:36:17 > 0:36:22And symmetry breaking is at the heart of scientists' understanding
0:36:22 > 0:36:28of how the Higgs came to give mass to everything in the first place.
0:36:41 > 0:36:44The theory goes that there was a moment after the big bang
0:36:44 > 0:36:47when the Higgs field appeared.
0:36:50 > 0:36:53And this split apart a perfect symmetry
0:36:53 > 0:36:57between two of the fundamental forces of nature.
0:37:02 > 0:37:06And the Higgs gave the particles of these forces different masses.
0:37:10 > 0:37:16And at the same time, it gave mass to all the other particles.
0:37:16 > 0:37:21The Higgs boson and the Higgs field is basically what does this symmetry breaking.
0:37:21 > 0:37:23So the whole idea that our theories
0:37:23 > 0:37:26revolve around symmetries and broken symmetries -
0:37:26 > 0:37:28the Higgs is kind of the linchpin of that.
0:37:28 > 0:37:32It's this unique prediction of this kind of idea,
0:37:32 > 0:37:35and without it, we're back to the drawing board,
0:37:35 > 0:37:37but with it, if we see it,
0:37:37 > 0:37:40it's a stunning prediction of this idea of symmetry
0:37:40 > 0:37:44and broken symmetry somehow lying behind the way the universe works.
0:37:45 > 0:37:49The Higgs allows the symmetry in scientists' equations
0:37:49 > 0:37:53to be broken in the real world.
0:37:53 > 0:37:54Finding it would be a vindication
0:37:54 > 0:37:58of their whole approach to understanding the universe.
0:37:58 > 0:37:59That's why it's become
0:37:59 > 0:38:03such a defining quest in modern physics.
0:38:07 > 0:38:11Tuesday 13th December 2011
0:38:11 > 0:38:15was a day with the potential to change physics history.
0:38:16 > 0:38:19- NEWS:- 'Scientists at the Large Hadron Collider near Geneva
0:38:19 > 0:38:21'are expected to announce later...'
0:38:21 > 0:38:24'..are expected to present preliminary evidence today...'
0:38:24 > 0:38:28'..will confirm whether the current theory of particle physics is correct.'
0:38:28 > 0:38:33Since November, a lot more data had been crunched,
0:38:33 > 0:38:36ahead of an important meeting.
0:38:38 > 0:38:42It was the end of year report, where the experiments analysed
0:38:42 > 0:38:46the data we collected during 2011, and reported on the Higgs search.
0:38:46 > 0:38:49And I guess everyone knew that either the mass range
0:38:49 > 0:38:52the Higgs could be in was going to shrink down,
0:38:52 > 0:38:55possibly to nothing, or some kind of hint would pop up
0:38:55 > 0:38:57that there was something there.
0:38:57 > 0:39:02What was special about this meeting was that it would bring together
0:39:02 > 0:39:05data from two independent detectors at CERN.
0:39:05 > 0:39:10The data from Jon and Adam's Atlas detector,
0:39:10 > 0:39:13and a second one - CMS.
0:39:13 > 0:39:17But neither team knew in advance what the other had discovered,
0:39:17 > 0:39:21and the atmosphere on both sides was electric.
0:39:21 > 0:39:23- It was ridiculous...- Yes.
0:39:23 > 0:39:27Very, er... almost frenzy, I don't know.
0:39:27 > 0:39:29There were people having their breakfast
0:39:29 > 0:39:31in the lecture theatre at 9 o'clock,
0:39:31 > 0:39:33to be sure they'd get a seat for the seminar at 2 o'clock.
0:39:36 > 0:39:38The room holds about 600 people,
0:39:38 > 0:39:42and it was full two hours before the talk started.
0:39:42 > 0:39:44There were rumours on the internet,
0:39:44 > 0:39:46and obviously people talk to each other,
0:39:46 > 0:39:50so I think, yeah, this idea that something exciting
0:39:50 > 0:39:54- was about to happen was building in the community, at least. - All got a bit out of hand, really.
0:39:57 > 0:40:03By late afternoon, it was clear that the hunt for the Higgs had closed in.
0:40:05 > 0:40:08NEWS: 'Scientists hunting for the elusive Higgs boson
0:40:08 > 0:40:11'say they've discovered strong signals that it exists.'
0:40:11 > 0:40:15'Scientists say they've uncovered signs of the elusive Higgs boson,
0:40:15 > 0:40:17'known as the God Particle.'
0:40:17 > 0:40:21'Researchers presented results from two independent experiments...'
0:40:21 > 0:40:24'..evidence which helps them move closer to the building blocks of the universe.'
0:40:28 > 0:40:32What had emerged during the meeting was that a potential
0:40:32 > 0:40:37signal of the Higgs had been spotted in both experiments.
0:40:41 > 0:40:44And crucially, in practically the same place.
0:40:48 > 0:40:50It was very exciting.
0:40:50 > 0:40:53People were getting the Atlas data and the CMS data
0:40:53 > 0:40:56and going, "Do they really see the same thing?" and all this.
0:40:56 > 0:41:00It was a lot of fun, actually, and a major step forward.
0:41:01 > 0:41:04The results weren't definitive,
0:41:04 > 0:41:07but in the month between November and December
0:41:07 > 0:41:10the data plots had evolved significantly.
0:41:16 > 0:41:19So the announcement was that the LHC,
0:41:19 > 0:41:23with the new data from the whole of 2011, is able to expand
0:41:23 > 0:41:26the area that it can exclude the Higgs from.
0:41:27 > 0:41:32The new lower limit has risen to 115 GeV.
0:41:32 > 0:41:37And the new upper limit has dropped to 127 GeV.
0:41:37 > 0:41:41So the really exciting thing was that the reason the LHC experiments weren't able to exclude
0:41:41 > 0:41:46anything inside this remaining window, is that in fact they see an
0:41:46 > 0:41:50excess of events. The early signs of the Higgs boson, if it's there.
0:41:50 > 0:41:54And the excesses were in practically the same place.
0:41:56 > 0:42:00CMS observed one at 124 GeV,
0:42:00 > 0:42:03and Atlas one at 126.
0:42:03 > 0:42:08So this is really a tantalising hint that the Higgs boson
0:42:08 > 0:42:13might exist, and it might have a mass of around 125 GeV.
0:42:13 > 0:42:16I think a lot of people will be really interested to see what
0:42:16 > 0:42:19happens in this region when we add more data in 2012.
0:42:19 > 0:42:22That's going to be really exciting to follow.
0:42:22 > 0:42:25For all the buzz surrounding the Higgs,
0:42:25 > 0:42:28scientists can't claim to have officially discovered
0:42:28 > 0:42:31this elusive particle just yet.
0:42:31 > 0:42:34And there are some outstanding questions
0:42:34 > 0:42:37about WHY it would have this mass.
0:42:37 > 0:42:40But with such promising data so far,
0:42:40 > 0:42:43it's hard not to be enthusiastic.
0:42:45 > 0:42:48Six months ago I would have said that there probably is no Higgs.
0:42:48 > 0:42:51It's a neat idea, but what are the chances of nature
0:42:51 > 0:42:54actually doing what we think it should do?
0:42:54 > 0:42:57But now I think maybe it has. This is kind of remarkable.
0:42:57 > 0:43:02What's clear, though, is that with four times the amount of data
0:43:02 > 0:43:05expected out of the LHC next year,
0:43:05 > 0:43:09this long-standing question will finally be resolved.
0:43:09 > 0:43:13I mean, there will be a day, some time next year, where
0:43:13 > 0:43:16we will go in not knowing whether the Higgs boson exists or not,
0:43:16 > 0:43:20and we will come out... And that that will be a fact, you know -
0:43:20 > 0:43:24we will know one way or the other, and our knowledge of the universe will have expanded.
0:43:24 > 0:43:27- In a big way, as well. I mean... - Yeah.
0:43:27 > 0:43:30It may not be everyone's idea of a great time,
0:43:30 > 0:43:32but what we're seeing is physics textbooks being written.
0:43:32 > 0:43:35And to me, having studied physics for so long,
0:43:35 > 0:43:37and known what's in those textbooks, and taught people
0:43:37 > 0:43:41from those textbooks, to see new pages being written that will never
0:43:41 > 0:43:44be unwritten, this is something new we know, that we didn't know before
0:43:44 > 0:43:48that we will always know afterwards. That is really exciting.
0:43:52 > 0:43:55If the Higgs is confirmed at last,
0:43:55 > 0:43:58then it'll open a new chapter
0:43:58 > 0:44:01in our understanding of how the universe works.
0:44:08 > 0:44:12Scientists plan to use the completed standard model
0:44:12 > 0:44:17as the foundation for an even deeper description of the universe,
0:44:17 > 0:44:21one based on the idea of symmetry and its breakage.
0:44:25 > 0:44:30That could take our knowledge of the cosmos even further back
0:44:30 > 0:44:33into that crucial first second of existence,
0:44:33 > 0:44:38right to the moment of the big bang itself.
0:45:02 > 0:45:08It's long been a dream of theorists to wind the clock back to the instant of creation,
0:45:08 > 0:45:13a place, so far, no machine has been able to go.
0:45:13 > 0:45:19Here, they believed they'd find a moment of absolute symmetry.
0:45:21 > 0:45:23The state of perfect symmetry
0:45:23 > 0:45:25is very similar to the state of perfect balance.
0:45:25 > 0:45:27Think of a spinning top.
0:45:27 > 0:45:31It exists in a state of perfect rotational symmetry.
0:45:31 > 0:45:34No matter how you rotate, everything looks the same.
0:45:35 > 0:45:40Just like with the spinning top, at this instant of creation,
0:45:40 > 0:45:42everything in the universe would've been the same.
0:45:42 > 0:45:46There'd be no distinction between gravity and electromagnetism,
0:45:46 > 0:45:51light and dark, matter and forces.
0:45:51 > 0:45:53But perfection can't last.
0:45:53 > 0:45:58The slightest imperfection, the slightest little defect,
0:45:58 > 0:46:02will cause it to vibrate and fall to a lower energy state.
0:46:02 > 0:46:04Symmetry has been broken.
0:46:09 > 0:46:12Within a fraction of a second of the big bang,
0:46:12 > 0:46:19physicists believe the absolute symmetry of the universe was shattered by a tiny fluctuation.
0:46:19 > 0:46:21The forces split apart.
0:46:21 > 0:46:26The particles of the standard model became distinct.
0:46:26 > 0:46:31This fall from perfection was what allowed us to come into being.
0:46:33 > 0:46:38Everything we see around us is nothing but fragments of this original perfection.
0:46:38 > 0:46:42Whenever you see a beautiful snowflake, a beautiful crystal
0:46:42 > 0:46:45or even the symmetry of stars in the universe,
0:46:45 > 0:46:52that's a fragment, that's a piece of the original symmetry at the beginning of time.
0:46:55 > 0:46:57By unifying the fragments,
0:46:57 > 0:47:01physicists think they'll find the ultimate key
0:47:01 > 0:47:03to how the universe was born.
0:47:05 > 0:47:08The Higgs is a vital stepping stone in this mission.
0:47:08 > 0:47:11But in their quest for unification,
0:47:11 > 0:47:15theoretical physicists have taken the idea of symmetry
0:47:15 > 0:47:18to a new, extraordinary level.
0:47:26 > 0:47:29When James Gates came to study at MIT,
0:47:29 > 0:47:33he was keen to unlock the secrets of the universe.
0:47:33 > 0:47:40And he was prepared to push the boundaries of his thinking a little further than most.
0:47:40 > 0:47:44The universe and we are intricately tied together.
0:47:47 > 0:47:52This idea of unity turns out to be one of the most powerful driving themes in physics.
0:47:53 > 0:47:57And it keeps getting us to look for deeper and deeper connections.
0:47:57 > 0:48:02Ultimately, perhaps we exist because the universe had no other choice.
0:48:05 > 0:48:08He began with the standard model -
0:48:08 > 0:48:11the collection of building blocks of matter
0:48:11 > 0:48:14and the forces that hold them together.
0:48:14 > 0:48:18Could these two very different groups of particles
0:48:18 > 0:48:21be connected in some more fundamental way?
0:48:22 > 0:48:26So, when we find something in nature that doesn't have a symmetry,
0:48:26 > 0:48:28we always ask the question, "Why?"
0:48:28 > 0:48:34and then we go one step further and ask the question, "What if?"
0:48:34 > 0:48:37It was the asking of this "what if?" question
0:48:37 > 0:48:39that drove the construction of supersymmetry
0:48:39 > 0:48:44which had an incredible resonance for me when I was a graduate student.
0:48:44 > 0:48:47I saw one more beautiful balance that we could put in nature.
0:48:53 > 0:48:55James became one of the pioneers
0:48:55 > 0:48:59of a powerful new mathematical theory called supersymmetry.
0:49:02 > 0:49:07Using symmetry in equations had previously led to the discovery of antimatter.
0:49:08 > 0:49:15These new ones suggested there was a hidden world of particles no-one had suspected.
0:49:17 > 0:49:22Mathematics leads us to find things we didn't know were there before.
0:49:22 > 0:49:24Supersymmetry is an example of that.
0:49:24 > 0:49:26We know about ordinary matter.
0:49:26 > 0:49:31The maths leads you on to discover super-matter and super-energy.
0:49:34 > 0:49:38The theory took everything we thought we knew about,
0:49:38 > 0:49:40even the Higgs, and doubled it...
0:49:41 > 0:49:45..giving every matter particle a force partner
0:49:45 > 0:49:48and every force particle a matter partner.
0:49:49 > 0:49:54These heavier, supersymmetric twins were labelled sparticles.
0:49:55 > 0:49:59So, once you believe this maths that says there's more to existence
0:49:59 > 0:50:02then you have to wonder what these other things are.
0:50:02 > 0:50:05You have to name them, at the very first step.
0:50:05 > 0:50:08So, in nature, there's a thing called the electron.
0:50:08 > 0:50:12The maths says it has a superpartner called the selectron.
0:50:12 > 0:50:15Muon - there'd have to be the smuon.
0:50:15 > 0:50:18Photon - there'd have to be a photino.
0:50:18 > 0:50:21Quark - there'd have to be squarks.
0:50:21 > 0:50:24Z particle - there'd have to be zino.
0:50:24 > 0:50:28W particle - there'd have to be a wino.
0:50:28 > 0:50:30And that's how supersymmetry works.
0:50:33 > 0:50:35According to supersymmetry,
0:50:35 > 0:50:39matter and forces aren't so distinct after all.
0:50:39 > 0:50:42There's a grand symmetry between them.
0:50:42 > 0:50:46But we can currently see only one partner from each pair.
0:50:55 > 0:50:56However strange it seems,
0:50:56 > 0:51:01this theory has gained widespread support from theoretical physicists...
0:51:07 > 0:51:09..not just for the beauty of its equations
0:51:09 > 0:51:12but for what it might help explain.
0:51:12 > 0:51:16When supersymmetry began as a topic of discussion,
0:51:16 > 0:51:19no-one realised what it can do.
0:51:19 > 0:51:22It turned out that, studying the mathematics,
0:51:22 > 0:51:26we get a firm foundation for the existence of everything.
0:51:29 > 0:51:34One of the great attractions of supersymmetry is it helps to resolve a niggling problem
0:51:34 > 0:51:37with the existence of the Higgs particle,
0:51:37 > 0:51:40alleviating the need for mathematical fudges
0:51:40 > 0:51:44in the standard model to fix its mass.
0:51:44 > 0:51:48This object called the Higgs? The mass of this could fluctuate,
0:51:48 > 0:51:52except if there's supersymmetry and that stabilises the mass.
0:51:54 > 0:51:58Supersymmetry makes the mass of the Higgs more natural, more stable, less of a wild coincidence.
0:51:58 > 0:52:06It could even help explain why there's more matter than antimatter in the early universe.
0:52:07 > 0:52:10Supersymmetry is the theory that, if it were true,
0:52:10 > 0:52:14could allow the rates of matter and antimatter interactions early on
0:52:14 > 0:52:19to be great enough to explain the asymmetry we need in the early universe.
0:52:28 > 0:52:35Supersymmetry pieces together more broken fragments from that first second of existence.
0:52:37 > 0:52:39I very much want supersymmetry,
0:52:39 > 0:52:42because it's a beautiful thing, by any standard
0:52:42 > 0:52:46and would take our understanding of nature to a new level.
0:52:46 > 0:52:48So, I want that.
0:52:50 > 0:52:55But, so far, it's just a theory, with no experimental data
0:52:55 > 0:52:57to support it.
0:52:57 > 0:52:59At least, not yet.
0:53:06 > 0:53:10That's where the £6 billion experiments at CERN
0:53:10 > 0:53:14may really usher in a revolution.
0:53:16 > 0:53:19Because they're hunting for evidence of supersymmetry.
0:53:20 > 0:53:23So, here we are now, 100 metres underground,
0:53:23 > 0:53:26where the LHCB detector is installed.
0:53:26 > 0:53:31Since the accelerator is stopped now for a few days, we can actually go in and see the detector.
0:53:35 > 0:53:39Richard Jacobsson is in charge of the operation of the detector
0:53:39 > 0:53:43that may give the first clues about supersymmetric particles.
0:53:49 > 0:53:52So, this is really where the dreams of theorists meet reality.
0:53:52 > 0:53:56Theorists, they invent new ideas as they go
0:53:56 > 0:54:00and our job as experimentalists is to actually find out
0:54:00 > 0:54:03which of these theories are definitely wrong
0:54:03 > 0:54:05and which are the ones we can establish, measure,
0:54:05 > 0:54:09that actually correspond to what we measure in the experiment.
0:54:11 > 0:54:15So far, not only have they found no evidence of the photinos,
0:54:15 > 0:54:19squarks or other sparticles predicted by the theorists,
0:54:19 > 0:54:22they've even ruled out the possibility of them
0:54:22 > 0:54:26at some of the energies theorists were hoping they'd be.
0:54:26 > 0:54:31Throughout this year, we've recorded more than ten billion reactions between protons.
0:54:31 > 0:54:37By studying them very precisely, we've been able to sort of exclude certain versions of supersymmetry.
0:54:37 > 0:54:42For the theorists, this means they have to look in a different direction.
0:54:44 > 0:54:50But the first, tantalising glimpse of the Higgs will have come as an encouragement to scientists here,
0:54:50 > 0:54:52because the mass of the Higgs
0:54:52 > 0:54:55determines the mass of the sparticles.
0:54:55 > 0:55:01And if they were too heavy, the LHC would be simply unable to create them.
0:55:01 > 0:55:05Fortunately, the mass of the Higgs they have hints of
0:55:05 > 0:55:09means evidence of the sparticles should show up in this machine.
0:55:11 > 0:55:13That's IF they exist.
0:55:18 > 0:55:23JAMES GATES: LHC is up and running. So far, there's no sign of superparticles.
0:55:23 > 0:55:27If we find supersymmetry in experiments,
0:55:27 > 0:55:33for me, personally, it will mean that I have not wasted my entire research career
0:55:33 > 0:55:39because this is the one question, as a young scientist, I decided had my name on it to study.
0:55:44 > 0:55:48I'm starting to get nervous.
0:55:48 > 0:55:51You know...
0:55:51 > 0:55:52Er...
0:55:52 > 0:55:58So, there were a lot of people who predicted supersymmetry was just around the corner,
0:55:58 > 0:56:03or something else, that as soon as LHC turned on, they'd see spectacular effects,
0:56:03 > 0:56:07or that the Higgs particle would be heavy. Those were all wrong.
0:56:07 > 0:56:14So far, nothing I believed in has been proved wrong and a lot of the competition has gone up in smoke.
0:56:16 > 0:56:18But the crunch time is coming.
0:56:18 > 0:56:24They're going to be capable of seeing things I've predicted or want
0:56:24 > 0:56:30and we'll see. It's in the hands of God or CERN or something.
0:56:32 > 0:56:33Now it's make or break time.
0:56:44 > 0:56:47For the scientists involved,
0:56:47 > 0:56:51pushing the frontiers of knowledge is a roller coaster ride.
0:56:51 > 0:56:56And, with the Large Hadron Collider, the journey has only just begun.
0:56:56 > 0:57:02This machine has opened the door to physics, above this key energy scale in nature,
0:57:02 > 0:57:05where the symmetries of nature change fundamentally.
0:57:05 > 0:57:09You don't get the key, open the door, go, "Well, that was nice," then close the door.
0:57:09 > 0:57:11You see what's happening.
0:57:11 > 0:57:13That's what we'll be doing in the next many years.
0:57:13 > 0:57:15If every theory was like a room,
0:57:15 > 0:57:18it's like we looked in the first one down the corridor,
0:57:18 > 0:57:24- and already we found something exciting, so now we can't wait to look in all the others, right?- Yep.
0:57:24 > 0:57:25Yep.
0:57:26 > 0:57:29There's loads more stuff we'd like to look for at the LHC,
0:57:29 > 0:57:33like supersymmetry, extra dimensions...
0:57:33 > 0:57:34Quantum gravity.
0:57:34 > 0:57:37New fundamental forces.
0:57:37 > 0:57:40Substructure inside quarks, black holes...
0:57:40 > 0:57:44- Miniature black holes.- Think of your favourite theory and double it...
0:57:44 > 0:57:46- The possibilities are endless. - Yeah, absolutely.
0:57:49 > 0:57:52To put this into perspective,
0:57:52 > 0:57:56I think the last time we stood in such an exciting place
0:57:56 > 0:58:00was 1905, when Einstein discovered special relativity
0:58:00 > 0:58:05and announced the most famous equation in physics - E=mc2.
0:58:06 > 0:58:08Because if the Higgs is confirmed,
0:58:08 > 0:58:13it's about much more than just a spectacular discovery.
0:58:14 > 0:58:19It'll also open a new chapter in physics, ask new questions,
0:58:19 > 0:58:24setting off the search for an even deeper understanding of nature.
0:58:24 > 0:58:28But we simply can't say where THAT search will take us.