0:00:08 > 0:00:12Five days ago, hundreds of the world's brainiest people
0:00:12 > 0:00:15descended on a hotel in Chicago.
0:00:19 > 0:00:21Good morning, ladies and gentlemen.
0:00:21 > 0:00:24They have come to hear news from particle physicists
0:00:24 > 0:00:26working at CERN.
0:00:27 > 0:00:30Last year, researchers there had started running
0:00:30 > 0:00:34the Large Hadron Collider at the highest energy ever...
0:00:36 > 0:00:38..and a rumour quickly emerged.
0:00:38 > 0:00:42They were on the brink of a huge discovery.
0:00:42 > 0:00:45We started hearing these mysterious noises
0:00:45 > 0:00:48about something going on at CERN.
0:00:48 > 0:00:51This may be what I have been spending an entire lifetime
0:00:51 > 0:00:53waiting for.
0:00:53 > 0:00:57A strange bump on a graph suggested that they might have discovered
0:00:57 > 0:00:59a brand-new particle...
0:01:00 > 0:01:03..that could revolutionise physics...
0:01:04 > 0:01:07Right here, right now at CERN, in 2016,
0:01:07 > 0:01:10is THE most exciting time and place in the history of science.
0:01:10 > 0:01:15If you want, really, to change the conditions of humanity,
0:01:15 > 0:01:18then you need breakthroughs.
0:01:18 > 0:01:23..and could change our understanding of how everything works.
0:01:23 > 0:01:27The discovery of a new particle may mean a complete rethinking
0:01:27 > 0:01:31of the conceptual basis of the physics world.
0:01:31 > 0:01:34For the last eight months,
0:01:34 > 0:01:38it looked like the universe was about to be turned upside down...
0:01:40 > 0:01:44..and Horizon has been inside CERN following the story.
0:01:44 > 0:01:47I doubt that it will be named after me,
0:01:47 > 0:01:51but I can think of it like this, that it might be!
0:01:53 > 0:01:56There was a short circuit on a circuit-breaker developed
0:01:56 > 0:02:00which arced and damaged the nearby equipment.
0:02:01 > 0:02:03Two teams of physicists...
0:02:05 > 0:02:07..one massive machine...
0:02:07 > 0:02:09and a dream.
0:02:09 > 0:02:12Was the bump was just a glitch in the data,
0:02:12 > 0:02:15or the biggest physics discovery in over a century?
0:02:15 > 0:02:18A Nobel prize is possible.
0:02:47 > 0:02:49Bonjour. Bienvenue a CERN.
0:02:51 > 0:02:57This is the European Organization for Nuclear Research - CERN.
0:03:00 > 0:03:03CERN is home to half of the world's particle physicists...
0:03:05 > 0:03:09..and the biggest particle-hunting machine that has ever been built.
0:03:11 > 0:03:14The Large Hadron Collider, or LHC.
0:03:16 > 0:03:20Inside this pipe, two beams of protons
0:03:20 > 0:03:23are sent hurtling around a 27km loop
0:03:23 > 0:03:25before being smashed together
0:03:25 > 0:03:28to create subatomic particles.
0:03:31 > 0:03:34In November 2015, researchers here got
0:03:34 > 0:03:38a tantalising glimpse of what they thought might be
0:03:38 > 0:03:39a brand-new particle.
0:03:41 > 0:03:44A particle that could transform our understanding
0:03:44 > 0:03:46of how the universe works.
0:03:50 > 0:03:52Now they're trying to find it.
0:04:00 > 0:04:06The Large Hadron Collider has been hunting for particles since 2009...
0:04:08 > 0:04:12..and it's the job of British physicist Mike Lamont
0:04:12 > 0:04:13to keep it running.
0:04:17 > 0:04:20Today, it's having one of its off days.
0:04:22 > 0:04:24This is not a cock-up.
0:04:24 > 0:04:26We stop because,
0:04:26 > 0:04:27as you can see,
0:04:27 > 0:04:30there's a huge amount of stuff down here -
0:04:30 > 0:04:32big systems, cooling, ventilation,
0:04:32 > 0:04:34cryogenics, etc,
0:04:34 > 0:04:38and this stuff needs a bit of periodic tender loving care.
0:04:38 > 0:04:43With over 4,000 miles of cabling and 100,000 processor cores,
0:04:43 > 0:04:48the LHC is one of the most complicated machines in the world.
0:04:48 > 0:04:51She is not a simple beast to operate,
0:04:51 > 0:04:55and a lot of time we spend wrestling it under control.
0:04:55 > 0:05:00We need very powerful magnets to bend the beam around in a circle,
0:05:00 > 0:05:03so basically, these are superconducting magnets,
0:05:03 > 0:05:07they're cooled with superfluid helium at 1.9K.
0:05:07 > 0:05:09The fact that this actually works at all
0:05:09 > 0:05:14is a real testament to an awful lot of hard work, modern technology,
0:05:14 > 0:05:19planning, precision on a completely remarkable scale.
0:05:19 > 0:05:23With the hunt on for a potential new particle,
0:05:23 > 0:05:26Mike and his team are trying to run the LHC
0:05:26 > 0:05:28at its highest ever energy,
0:05:28 > 0:05:32and it's making their job more challenging than usual.
0:05:33 > 0:05:35We had a very interesting month,
0:05:35 > 0:05:38with a number of fairly major technical problems,
0:05:38 > 0:05:40including the famous weasel,
0:05:40 > 0:05:42which took us out for about six days,
0:05:42 > 0:05:45but from now on, after this maintenance period,
0:05:45 > 0:05:48it's pedal to the metal for two or three months.
0:05:54 > 0:05:56To try and find new particles,
0:05:56 > 0:06:01the LHC does something that was once completely out of our grasp.
0:06:03 > 0:06:09It recreates the conditions that existed just after the Big Bang.
0:06:10 > 0:06:14The Big Bang was an explosion that happened
0:06:14 > 0:06:17at the beginning of the universe, when all matter was created.
0:06:17 > 0:06:20So, this is the year zero, and if we draw a line...
0:06:20 > 0:06:23From this point, the universe expanded,
0:06:23 > 0:06:27getting cooler, its energy dispersing.
0:06:27 > 0:06:30..to where we are in the universe now, where humans exist,
0:06:30 > 0:06:32that's 14 billion years.
0:06:34 > 0:06:38We know that when the universe was 9 billion years old,
0:06:38 > 0:06:39the sun was formed,
0:06:39 > 0:06:42and over 8 billion years before that,
0:06:42 > 0:06:45the first stars were born,
0:06:45 > 0:06:49but the LHC is able to look even further back in time
0:06:49 > 0:06:53to when all that existed were the fundamental building blocks
0:06:53 > 0:06:55of the universe - particles.
0:06:55 > 0:06:58So, in a way, the Large Hadron Collider
0:06:58 > 0:07:00is like a time machine,
0:07:00 > 0:07:03trying to create the conditions that happened
0:07:03 > 0:07:06just in the few millionths of a second after the Big Bang
0:07:06 > 0:07:10to see what particles existed when the energy density
0:07:10 > 0:07:13of the universe was really, really high.
0:07:13 > 0:07:16To do this, the LHC makes use of
0:07:16 > 0:07:20one the most famous scientific discoveries ever made.
0:07:22 > 0:07:26What we're doing is using the very high energy of the protons
0:07:26 > 0:07:32in the collision using Einstein's equation E = mc2...
0:07:34 > 0:07:39..which tells us that mass and energy are equivalent,
0:07:39 > 0:07:43so we have protons and they're going round and round the LHC,
0:07:43 > 0:07:45and we have one set of protons going round this way
0:07:45 > 0:07:47and we have another set of protons
0:07:47 > 0:07:49which are going around in the opposite direction,
0:07:49 > 0:07:52getting faster and faster, closer to the speed of light,
0:07:52 > 0:07:54and more and more energetic.
0:07:54 > 0:07:56Then we get one proton beam
0:07:56 > 0:07:59and the other proton beam
0:07:59 > 0:08:01going at the highest energies,
0:08:01 > 0:08:03and then we smash them together.
0:08:06 > 0:08:08At the moment of collision,
0:08:08 > 0:08:10the energy is converted into mass
0:08:10 > 0:08:12in the form of thousands of particles.
0:08:15 > 0:08:17Although most will be ones we already know about,
0:08:17 > 0:08:22the hope is that undiscovered particles might also be created
0:08:22 > 0:08:25that could help explain some of the mysteries
0:08:25 > 0:08:28of how the universe was formed.
0:08:33 > 0:08:35SHE BLOWS
0:08:36 > 0:08:40But creating particles is just the beginning.
0:08:41 > 0:08:42Detecting them requires
0:08:42 > 0:08:46some of the most sophisticated machines in the world.
0:08:46 > 0:08:50I come into the cavern hundreds of times in a year
0:08:50 > 0:08:51and every time I walk in,
0:08:51 > 0:08:54my jaw still drops a little bit when I see ATLAS.
0:08:54 > 0:08:57We built this thing. We REALLY built this thing.
0:08:57 > 0:09:00Dave Charlton runs the snappily named
0:09:00 > 0:09:05A Toroidal Large Hadron Collider Apparatus, known as ATLAS.
0:09:05 > 0:09:09It's the largest particle detector on the LHC circuit.
0:09:09 > 0:09:13The collisions take place right in the centre of the experiment,
0:09:13 > 0:09:16about 30 metres away from where we're standing.
0:09:16 > 0:09:19ATLAS has seven different detecting systems
0:09:19 > 0:09:22arranged in layers around the collision point.
0:09:22 > 0:09:25They're poised to capture evidence of the particles
0:09:25 > 0:09:28that have been produced.
0:09:29 > 0:09:34Dave hopes that ATLAS will lead the hunt for the potential new particle,
0:09:34 > 0:09:36but he's not the only one
0:09:36 > 0:09:40with a giant particle detector at his disposal.
0:09:43 > 0:09:47There's another massive detector on the LHC circuit -
0:09:47 > 0:09:50the Compact Muon Solenoid.
0:09:50 > 0:09:52CMS.
0:09:54 > 0:09:58It's run by Italian physicist Tiziano Camporesi.
0:10:03 > 0:10:06The croissant has become something almost associated to me
0:10:06 > 0:10:10because I've grown into the habit of bringing croissants every morning
0:10:10 > 0:10:13to the crew which is working at the experiment.
0:10:13 > 0:10:15So now, if I show up without croissants,
0:10:15 > 0:10:17they are disappointed.
0:10:17 > 0:10:21No, actually, I like this... I like this habit.
0:10:21 > 0:10:23You know, when you have a ritual,
0:10:23 > 0:10:27you don't want to change it because it will bring bad luck.
0:10:31 > 0:10:35Tiziano's machine, CMS, is very similar to Dave's.
0:10:36 > 0:10:42CMS is big. It's a 14,000-tonne object...
0:10:44 > 0:10:47..which basically is five storeys high
0:10:47 > 0:10:50and something like 26 metres long.
0:10:50 > 0:10:52But ATLAS is slightly bigger.
0:10:52 > 0:10:55Look at the size of it. As you can see,
0:10:55 > 0:10:56it's really a huge experiment.
0:10:56 > 0:10:5825 metres high, 45 metres long.
0:10:58 > 0:11:02These detectors are purposefully designed
0:11:02 > 0:11:05to do the same thing in two different ways.
0:11:07 > 0:11:09You could see it as an oversized camera,
0:11:09 > 0:11:12something like a 100-megapixel camera.
0:11:12 > 0:11:16Nowadays, a digital camera might be 25 megapixels, 25 million channels,
0:11:16 > 0:11:20but we're able to read out our 100 million channels
0:11:20 > 0:11:2240 million times a second.
0:11:24 > 0:11:26The idea is that new particles
0:11:26 > 0:11:29will be seen by both detectors independently.
0:11:29 > 0:11:32It can help ensure their findings are valid,
0:11:32 > 0:11:35but that doesn't stop both teams
0:11:35 > 0:11:38wanting to be first to make a discovery.
0:11:39 > 0:11:43We understand that there is some healthy competition
0:11:43 > 0:11:46between us and ATLAS, so we are convinced that CMS is better.
0:11:46 > 0:11:48HE CHUCKLES
0:11:48 > 0:11:51There IS a rivalry between the experiments.
0:11:51 > 0:11:53We don't want to lose.
0:11:59 > 0:12:04If CMS and ATLAS detect a new particle,
0:12:04 > 0:12:09it could be the most important physics discovery in over 100 years.
0:12:11 > 0:12:15Ah, you've made it! Come on in. We can talk about some physics.
0:12:15 > 0:12:17It's going to be fun.
0:12:19 > 0:12:22By the beginning of the 20th century,
0:12:22 > 0:12:25particle physicists like Professor Jim Gates
0:12:25 > 0:12:29had ascertained that milk, bowls, glasses -
0:12:29 > 0:12:32in fact, everything we see around us -
0:12:32 > 0:12:34is made from atoms...
0:12:35 > 0:12:41..and that atoms themselves are made of even smaller subatomic particles.
0:12:48 > 0:12:52From the 1950s, hundreds of particles were discovered...
0:12:53 > 0:12:57There was this strange quark -
0:12:57 > 0:13:00and this was not the order in which they were discovered -
0:13:00 > 0:13:02and then the top quark...
0:13:02 > 0:13:05and the most familiar particle of them all, the electron.
0:13:05 > 0:13:08All of our electronics come from this.
0:13:08 > 0:13:10And so we kept discovering particles -
0:13:10 > 0:13:15neutrino, gluon...
0:13:15 > 0:13:19But the influx of new particles did little to help explain
0:13:19 > 0:13:21how the universe really behaved.
0:13:22 > 0:13:25So, this is the state of knowledge about particles
0:13:25 > 0:13:27in the 1950s, '60s and '70s.
0:13:27 > 0:13:31It was a zoo of particles jumbled about -
0:13:31 > 0:13:33confusion, no order.
0:13:33 > 0:13:36It was only by studying their characteristics
0:13:36 > 0:13:38that physicists could begin to understand
0:13:38 > 0:13:41how these particles worked together.
0:13:42 > 0:13:46It turned out that the electron, in fact, has another particle
0:13:46 > 0:13:48very similar to it called the muon.
0:13:49 > 0:13:53This family of particles was called the leptons
0:13:53 > 0:13:57and they were soon joined by another - the quarks.
0:13:57 > 0:13:58Quarks are really important,
0:13:58 > 0:14:02because they are what you need to construct protons and neutrons.
0:14:02 > 0:14:05And now, with protons, neutrons and the electron,
0:14:05 > 0:14:07you can construct atoms.
0:14:07 > 0:14:13From atoms, you can construct cells, molecules, compounds
0:14:13 > 0:14:14and, ultimately, us -
0:14:14 > 0:14:17so these guys are really, really important.
0:14:19 > 0:14:22This group are the known as the fermions -
0:14:22 > 0:14:24they're particles that make matter -
0:14:24 > 0:14:28but you can't build a universe with fermions alone.
0:14:31 > 0:14:32They're held in patterns
0:14:32 > 0:14:36and interact through particles known as force carriers.
0:14:37 > 0:14:40One of them is the photon, the particle of light.
0:14:40 > 0:14:43It is the carrier of the electromagnetic force -
0:14:43 > 0:14:45so, we're going to put that up here.
0:14:45 > 0:14:49Then there are other forces in nature beside the electromagnetism -
0:14:49 > 0:14:51there's a weak nuclear force.
0:14:51 > 0:14:56It has carriers - we call them the W and the Z particle.
0:14:58 > 0:15:01This family is completed by the gluons
0:15:01 > 0:15:04that hold matter together inside an atom,
0:15:04 > 0:15:10and the Higgs, responsible for giving the other particles mass.
0:15:12 > 0:15:16And now we have the modern Standard Model,
0:15:16 > 0:15:18born around 1973,
0:15:18 > 0:15:22where the fermions are all sitting here divided into two families
0:15:22 > 0:15:24of quarks and leptons,
0:15:24 > 0:15:26and these guys are the force carriers.
0:15:26 > 0:15:30It is the best-tested, most tested piece of science
0:15:30 > 0:15:32that has ever been constructed.
0:15:32 > 0:15:36It literally explains tens of thousands of observational facts.
0:15:36 > 0:15:39It is just an amazing triumph
0:15:39 > 0:15:42that almost nobody has ever heard of, outside of physics.
0:15:43 > 0:15:47The Standard Model has served as a map to our understanding
0:15:47 > 0:15:51of the particles in the world around us for over 40 years...
0:15:52 > 0:15:56..but physicists have hoped, for almost as long,
0:15:56 > 0:15:58that it's not the end of the story -
0:15:58 > 0:16:02that other particles will also exist
0:16:02 > 0:16:04that could help explain
0:16:04 > 0:16:07some of the more troublesome mysteries of the universe.
0:16:09 > 0:16:12The problem is finding them.
0:16:28 > 0:16:30I'm not going to disturb these guys.
0:16:30 > 0:16:32These guys are doing serious work!
0:16:32 > 0:16:34Fixing the chair, yeah! Fixing the chair!
0:16:34 > 0:16:36THEY LAUGH
0:16:36 > 0:16:39At CERN, it takes hundreds of researchers
0:16:39 > 0:16:42writing millions of lines of computer code
0:16:42 > 0:16:45to scour collisions for signs of new particles.
0:16:49 > 0:16:51This thing is a raw image,
0:16:51 > 0:16:54as they come in, basically unfiltered,
0:16:54 > 0:16:59from the collisions which are happening 100 metres below ground,
0:16:59 > 0:17:01under our feet.
0:17:01 > 0:17:05What makes the job even harder is that undiscovered particles
0:17:05 > 0:17:08will only exist at very high energies
0:17:08 > 0:17:10like those inside the LHC -
0:17:10 > 0:17:14and almost as soon as they're created, they decay
0:17:14 > 0:17:18into the stable particles that we're familiar with.
0:17:18 > 0:17:20So, I'd like to change this 60...
0:17:20 > 0:17:23Let's say... Make it 1, or...?
0:17:23 > 0:17:26So the teams aren't looking for the particles themselves,
0:17:26 > 0:17:30but for the trails they leave behind.
0:17:30 > 0:17:31This is detective work,
0:17:31 > 0:17:35because, basically, you are seeing fragments of the disintegration,
0:17:35 > 0:17:39you are trying to understand from the behaviour of the fragments
0:17:39 > 0:17:41how the particle was to start with.
0:17:41 > 0:17:45It's a task for some of the brightest minds in physics
0:17:45 > 0:17:46working around the clock.
0:17:48 > 0:17:51What we really like is a young brain, I have to tell you!
0:17:51 > 0:17:54Because, I mean, these guys are amazing.
0:17:54 > 0:17:57I lived through that, I know what it means -
0:17:57 > 0:18:01once you become in my position,
0:18:01 > 0:18:04the level of stress becomes a different one.
0:18:07 > 0:18:09Towards the end of last year,
0:18:09 > 0:18:12it looked like all the hard work would pay off.
0:18:19 > 0:18:2428-year-old Dr Livia Soffi is an analyst for CMS.
0:18:26 > 0:18:30She was once a European artistic roller-skating champion.
0:18:33 > 0:18:37I really like to relax, to stay a little bit under the sun
0:18:37 > 0:18:39without staying in the office.
0:18:41 > 0:18:43I really like the lake,
0:18:43 > 0:18:45because when I was younger, I used to go to the sea -
0:18:45 > 0:18:47now we cannot go to the sea,
0:18:47 > 0:18:50but we have the lake, it is nice, as well.
0:18:50 > 0:18:52Then we can take an ice cream -
0:18:52 > 0:18:54there is an Italian ice cream place close to here,
0:18:54 > 0:18:55so it's very nice.
0:18:57 > 0:19:01Last November, Livia found something unexpected in the data
0:19:01 > 0:19:03coming from the CMS detector.
0:19:05 > 0:19:09What she saw was a mysterious bump on a graph.
0:19:10 > 0:19:15So, basically, the idea is that if you do not have anything new,
0:19:15 > 0:19:18you will see the dashed line,
0:19:18 > 0:19:23and if the solid line, here, the observation,
0:19:23 > 0:19:26is inside these two bands,
0:19:26 > 0:19:28this means that everything is quiet,
0:19:28 > 0:19:30then the fluctuation is not interesting.
0:19:30 > 0:19:35When the fluctuation goes outside the bands,
0:19:35 > 0:19:38this means that your expectation and what you observe
0:19:38 > 0:19:41are not so compatible.
0:19:41 > 0:19:43It might not look like much,
0:19:43 > 0:19:45but the bump indicates that,
0:19:45 > 0:19:49at the energy of 750 giga-electronvolts,
0:19:49 > 0:19:54the LHC is producing unexpected bursts of photons.
0:19:56 > 0:19:58We have two possibilities.
0:19:58 > 0:20:01Either our detector is not working - but this is not the case,
0:20:01 > 0:20:04because we know that it is well performing -
0:20:04 > 0:20:07or we have observed something.
0:20:09 > 0:20:12I have never seen something like this in my life.
0:20:12 > 0:20:16This could be evidence of a brand-new particle.
0:20:18 > 0:20:21A particle that disappears into a pair of photons
0:20:21 > 0:20:23almost as soon as it's created.
0:20:30 > 0:20:32And what made the bump even more exciting
0:20:32 > 0:20:35was that it wasn't just seen in CMS.
0:20:39 > 0:20:42James Beacham is an analyst at the other detector, ATLAS.
0:20:45 > 0:20:48To my mind, right here, right now at CERN, in 2016,
0:20:48 > 0:20:52is THE most important time and place in the history of science,
0:20:52 > 0:20:55because we have just pushed forward, as a species,
0:20:55 > 0:20:58into an energy regime where we have never been.
0:20:58 > 0:20:59No-one's ever looked here.
0:20:59 > 0:21:01APPLAUSE
0:21:01 > 0:21:05On the 15th of December, both ATLAS and CMS
0:21:05 > 0:21:07presented their findings.
0:21:08 > 0:21:14We, of course, observed a little bump at 750 GeV...
0:21:14 > 0:21:17It was in this seminar that the science community learnt
0:21:17 > 0:21:20that the mysterious bump was being seen
0:21:20 > 0:21:23by both the CMS and ATLAS detectors.
0:21:23 > 0:21:27It was an extremely exciting seminar that we had here at CERN,
0:21:27 > 0:21:28and, to me, watching, you know,
0:21:28 > 0:21:30and then, suddenly, he shows this little thing,
0:21:30 > 0:21:32and I'm like, "This is very intriguing."
0:21:32 > 0:21:34The implications of such a little bump,
0:21:34 > 0:21:39if it turns into, potentially, a new particle, are super-huge.
0:21:39 > 0:21:42This is completely uncharted territory.
0:21:42 > 0:21:46The excitement quickly spread out into the physics world.
0:21:46 > 0:21:50Within weeks, 300 papers had been written by theorists
0:21:50 > 0:21:55trying to determine what this potential particle might be.
0:21:55 > 0:21:57When the result was announced,
0:21:57 > 0:22:02the whole theory group was just crazy -
0:22:02 > 0:22:03crazy with discussion,
0:22:03 > 0:22:05crazy to understand what it was...
0:22:05 > 0:22:07Er... That's it!
0:22:07 > 0:22:11This was the moment, it seemed.
0:22:11 > 0:22:14We started hearing these mysterious noises
0:22:14 > 0:22:17about something going on at CERN,
0:22:17 > 0:22:22and it had a very prosaic name - the 750 GeV bump.
0:22:22 > 0:22:23It sounds like a dance, to me.
0:22:23 > 0:22:27I thought it was a joke - but then I began to look more carefully,
0:22:27 > 0:22:30thinking that, "Oh, my goodness, this may be
0:22:30 > 0:22:34"what I have been spending an entire lifetime waiting for."
0:22:40 > 0:22:42By the beginning of this year,
0:22:42 > 0:22:46the race was on for ATLAS and CMS to gather more collision data
0:22:46 > 0:22:49to see if the mysterious bump would reappear,
0:22:49 > 0:22:52or if it was simply a statistical fluctuation.
0:22:54 > 0:22:55The fact that the two experiments
0:22:55 > 0:22:59seem to see a hint of something in the same place is fascinating,
0:22:59 > 0:23:01but the statistics are too low with the current data sample
0:23:01 > 0:23:03to get too excited.
0:23:03 > 0:23:05It's more potential excitement, at this stage,
0:23:05 > 0:23:07for the experimentalists
0:23:07 > 0:23:10rather than cast-iron established excitement.
0:23:12 > 0:23:15For the bump to be confirmed as a new particle,
0:23:15 > 0:23:17the two teams work independently,
0:23:17 > 0:23:19both trying to collect enough data
0:23:19 > 0:23:23to reach a level of statistical certainty known as 5-sigma.
0:23:25 > 0:23:27I mean, to give you a feel for the scale of the statistics
0:23:27 > 0:23:29for the Higgs discovery,
0:23:29 > 0:23:31we had a few tens of events
0:23:31 > 0:23:34that were identified as being signal-like Higgs events,
0:23:34 > 0:23:39but we had looked in a million billion events.
0:23:39 > 0:23:42So, that's the complexity of the science that we do.
0:23:42 > 0:23:43It's really...
0:23:43 > 0:23:46I mean, people talk about a needle in a haystack,
0:23:46 > 0:23:48but it's a needle in a haystack of haystacks of haystacks!
0:23:48 > 0:23:50A grain of sand in an ocean.
0:23:51 > 0:23:53It's a huge task,
0:23:53 > 0:23:56but with the physics world desperate for news,
0:23:56 > 0:23:57the teams have just three months
0:23:57 > 0:24:01to announce if they really have found a brand-new particle.
0:24:02 > 0:24:06The big thing is our conference in Chicago.
0:24:06 > 0:24:10The first week of August. By that time, we should have...
0:24:12 > 0:24:17..I think at least doubled the data which we took last year.
0:24:17 > 0:24:18As you know...
0:24:18 > 0:24:22MUSIC: A Kind of Magic by Queen plays in background
0:24:22 > 0:24:25This is specific to our experiment.
0:24:25 > 0:24:31You have to realise that the guy who designed our architecture here
0:24:31 > 0:24:35for taking data, he is a Queen fan,
0:24:35 > 0:24:39so all of the change of states of the machines,
0:24:39 > 0:24:42or of the experiments, are basically announced
0:24:42 > 0:24:44by a snippet of a Queen song.
0:24:44 > 0:24:50Everybody has become aware of the meaning and of the Queen songs!
0:24:50 > 0:24:53"It's a kind of magic" means that you have managed to start the run.
0:25:02 > 0:25:07The last time particle physicists were this excited, prizes were won.
0:25:11 > 0:25:16This is the Nobel medal which I received in 2013.
0:25:16 > 0:25:22I think it had something to do with some work I did in...
0:25:22 > 0:25:25When was it? 1964.
0:25:28 > 0:25:30Make way, please.
0:25:32 > 0:25:35On the 4th of July, 2012,
0:25:35 > 0:25:38Peter Higgs arrived at CERN for an announcement.
0:25:39 > 0:25:43On the day itself, I found myself
0:25:43 > 0:25:46being besieged by crowds of physicists
0:25:46 > 0:25:49who had more or less camped out overnight
0:25:49 > 0:25:52in the hope of getting into the lecture theatre,
0:25:52 > 0:25:56which was really already fully booked.
0:25:57 > 0:25:59So good morning...
0:25:59 > 0:26:03Fabiola Gianotti, who is now Director-General of CERN,
0:26:03 > 0:26:05was part of a team from ATLAS.
0:26:07 > 0:26:10The atmosphere was absolutely amazing,
0:26:10 > 0:26:12it was a big, big emotion.
0:26:12 > 0:26:15So you can see here some beautiful events,
0:26:15 > 0:26:17selected by our pic search.
0:26:17 > 0:26:20We were working days and nights,
0:26:20 > 0:26:23nourished and pushed only by adrenaline,
0:26:23 > 0:26:27because we didn't have the time to sleep, to eat - it was fantastic.
0:26:27 > 0:26:30So this channel has a tiny rate...
0:26:30 > 0:26:34At this conference, CMS and ATLAS confirmed that they had found
0:26:34 > 0:26:40a particle predicted by Peter nearly half a century earlier.
0:26:40 > 0:26:46..extremely clean, except one big spike here, in this hadron here.
0:26:46 > 0:26:50An excess, with a local significance of 5.0 sigma,
0:26:50 > 0:26:54at a mass of 126.5 GeV - thank you.
0:27:01 > 0:27:05It was 48 years from the time that the theory was formulated
0:27:05 > 0:27:09as something which might be useful in particle physics,
0:27:09 > 0:27:11to the discovery of the particle.
0:27:11 > 0:27:13So it was a long wait.
0:27:15 > 0:27:18I think we have it. Do you agree?
0:27:18 > 0:27:21LAUGHTER AND APPLAUSE
0:27:21 > 0:27:25Everybody cheered and got up, it was rather like the end of
0:27:25 > 0:27:28a football match, rather than a scientific seminar.
0:27:34 > 0:27:38Then I went into hiding again and had some lunch and escaped.
0:27:38 > 0:27:41Fly home before anybody else tried to capture me.
0:27:44 > 0:27:47The Higgs boson was the final piece needed
0:27:47 > 0:27:49to complete the maths of the Standard Model.
0:27:53 > 0:27:57But an unpredicted new particle, like the 750 GeV bump,
0:27:57 > 0:27:59could be even more significant.
0:28:01 > 0:28:06If the bump which has been seen recently is genuine,
0:28:06 > 0:28:09that is opening up a new era.
0:28:09 > 0:28:10So it's very exciting.
0:28:14 > 0:28:18The hope was that if it really is a new particle,
0:28:18 > 0:28:23the bump could help physicists answer some of life's big questions.
0:28:25 > 0:28:28Like, "How stable is our universe?
0:28:28 > 0:28:31"Does it have hidden extra dimensions?"
0:28:33 > 0:28:38And an old bugbear - "What is the universe actually made of?"
0:28:42 > 0:28:47In the 1930s, evidence emerged that the luminous matter,
0:28:47 > 0:28:52the matter which forms the stars, it cannot be sufficient
0:28:52 > 0:28:56to justify the dynamics of what we observe in the sky.
0:28:56 > 0:29:00There should be something else that gives a gravitational pull.
0:29:01 > 0:29:06Physicists faced the rather disturbing realisation that
0:29:06 > 0:29:09they don't really know what makes up most of the universe.
0:29:12 > 0:29:16So 95% of what is around in our universe
0:29:16 > 0:29:20is not the ordinary matter that we are used with,
0:29:20 > 0:29:23and that the Standard Model explains.
0:29:24 > 0:29:27This is very frustrating for particle physicists,
0:29:27 > 0:29:31but particle physicists always look on the bright side,
0:29:31 > 0:29:33and they see that there is an opportunity.
0:29:37 > 0:29:42This unidentified stuff has been called "dark matter"
0:29:42 > 0:29:44and "dark energy".
0:29:44 > 0:29:46And the bump could bring us a step closer
0:29:46 > 0:29:48to finding out what it actually is.
0:29:55 > 0:29:59The 750 GeV particle cannot be the dark matter,
0:29:59 > 0:30:03because we know that it decays very quickly into two photons,
0:30:03 > 0:30:07meaning that if it were around in the cosmos, it would have
0:30:07 > 0:30:10disappeared very quickly, so we know that it cannot be.
0:30:10 > 0:30:14However, there has been speculations that the 750
0:30:14 > 0:30:18must be part of a bigger family.
0:30:18 > 0:30:19Inside this family,
0:30:19 > 0:30:21there could be one particle
0:30:21 > 0:30:24that plays the role of the dark matter.
0:30:24 > 0:30:27So, even if the 750 is not dark matter,
0:30:27 > 0:30:30it could be related to the particle giving rise to the dark matter.
0:30:30 > 0:30:32This may have a lot of implications
0:30:32 > 0:30:36in understanding the structure of the universe,
0:30:36 > 0:30:39understanding how this dark matter was formed
0:30:39 > 0:30:43and understanding its role in the universe.
0:30:46 > 0:30:49A new particle could well have a profound effect.
0:30:50 > 0:30:53But first, they had to find it.
0:31:01 > 0:31:03It's the middle of May at CERN.
0:31:04 > 0:31:08And with just over two months until the important summer conference,
0:31:08 > 0:31:10the mission to gather data continues.
0:31:13 > 0:31:15So we are just getting ready to go to work.
0:31:15 > 0:31:16My boyfriend is hiding.
0:31:16 > 0:31:19SHE LAUGHS
0:31:19 > 0:31:20You can come out.
0:31:21 > 0:31:23If he wants to.
0:31:26 > 0:31:30The LHC has been providing an unprecedented amount of collisions
0:31:30 > 0:31:32for the teams on the detectors.
0:31:32 > 0:31:37We had the longest fill in the history of the LHC.
0:31:37 > 0:31:40And this happened over the weekend, so basically,
0:31:40 > 0:31:45starting from Friday and then continuing through Saturday.
0:31:46 > 0:31:49Dr Magda Chelstowska is part of the ATLAS team,
0:31:49 > 0:31:53and it's her job to clean up and format the data as it's collected.
0:31:56 > 0:32:01I think of myself as a person who gives birth to the data.
0:32:01 > 0:32:05So I feel that it is my child, it is my kid.
0:32:05 > 0:32:09Because I prepare the data and I polish it and massage it
0:32:09 > 0:32:15and make it into something which then can go out and be on its own.
0:32:15 > 0:32:18The race is on to see which team will be first to gather
0:32:18 > 0:32:21enough data to find out if the bump is back.
0:32:21 > 0:32:25When we know that we are very close to making
0:32:25 > 0:32:29a major breakthrough in physics,
0:32:29 > 0:32:32we of course want to do it as soon as possible,
0:32:32 > 0:32:37because we don't want the experiment on the other side to beat us to it.
0:32:40 > 0:32:44ATLAS and CMS are working blind, accumulating and processing the data
0:32:44 > 0:32:48without actually being able to see what it's showing.
0:32:50 > 0:32:53It means the two teams can't influence either their own
0:32:53 > 0:32:55or the other's results.
0:32:55 > 0:32:57THEY CHUCKLE
0:32:57 > 0:33:00And with a discovery of this potential significance, for ATLAS,
0:33:00 > 0:33:05it is up to Dr Marco Delmastro to make sure nothing is left to chance.
0:33:05 > 0:33:10It's always difficult to see whether this excess is a new particle
0:33:10 > 0:33:14or not, because nature is behaving in a sort of stochastical way.
0:33:16 > 0:33:19We will be spending days and nights, basically,
0:33:19 > 0:33:21going through all the stuff,
0:33:21 > 0:33:25from the current that we measure inside the detector
0:33:25 > 0:33:28to the piece of software that transforms current to energy,
0:33:28 > 0:33:31and then tell us where the things are in the detector
0:33:31 > 0:33:34and how they are constructed, to the very end.
0:33:35 > 0:33:38In the back of my head, there is always a small devil
0:33:38 > 0:33:40sitting on my shoulder, saying,
0:33:40 > 0:33:42"Are you sure you checked everything?
0:33:42 > 0:33:46"Are you sure that there is nothing wrong in what you're doing?"
0:33:47 > 0:33:51That is my worry, and still is my worry, so yeah,
0:33:51 > 0:33:54I think it is going to stay there for a while.
0:34:03 > 0:34:05As the teams crunch the data,
0:34:05 > 0:34:10speculation about what the new particle might be is rife.
0:34:13 > 0:34:16Jim Gates hopes it could prove a theory known as supersymmetry.
0:34:19 > 0:34:24He has been studying this idea for nearly 40 years.
0:34:24 > 0:34:27For a long time, the idea of supersymmetry was pooh-poohed.
0:34:27 > 0:34:30In fact, I remember all throughout graduate school,
0:34:30 > 0:34:32I had colleagues working on other things that were considered
0:34:32 > 0:34:35"good physics", and there I was in the corner,
0:34:35 > 0:34:39the only student in my team working on this supersymmetrical stuff.
0:34:41 > 0:34:45The idea of supersymmetry was born when physicists started
0:34:45 > 0:34:50questioning why the Standard Model wasn't mathematically more balanced.
0:34:50 > 0:34:54So here is the triumph of the study of the standard models.
0:34:54 > 0:34:57And many of us who were studying physics then looked at this,
0:34:57 > 0:35:02and we noticed that there is a lack of balance here, a lack of symmetry.
0:35:02 > 0:35:05To make this obvious, let me put some lines on the table.
0:35:08 > 0:35:11And you can see that there are
0:35:11 > 0:35:14two quadrants here that are empty.
0:35:14 > 0:35:18Physicists are very sensitive to the lack of symmetry or balance.
0:35:18 > 0:35:21And we can ask the question,
0:35:21 > 0:35:23"What would the world look like if it were balanced?"
0:35:23 > 0:35:26And we ask the question with mathematics.
0:35:27 > 0:35:30Supersymmetrists found that the Standard Model
0:35:30 > 0:35:33could be given balance if a mirror image
0:35:33 > 0:35:37of each of the particles also existed.
0:35:38 > 0:35:42They were called "superpartners" or "sparticles".
0:35:45 > 0:35:47So if the universe is supersymmetric,
0:35:47 > 0:35:49there must be another particle
0:35:49 > 0:35:52on this side that we call the selectron.
0:35:52 > 0:35:55And also, that has to occur for its neutrino,
0:35:55 > 0:35:58which we would call a sneutrino.
0:35:59 > 0:36:02For the muon, there's another particle called the smuon.
0:36:04 > 0:36:08We physicists, when we make great triumphs, are so happy
0:36:08 > 0:36:12that we get giddy, so we name things in a silly manner.
0:36:12 > 0:36:15The idea is deceptively simple.
0:36:15 > 0:36:17Each ordinary matter particle
0:36:17 > 0:36:21has an undiscovered supersymmetric force partner.
0:36:21 > 0:36:23And each force particle,
0:36:23 > 0:36:27an undiscovered supersymmetric matter partner.
0:36:29 > 0:36:32Once we've made this change we are looking at
0:36:32 > 0:36:36not the Standard Model but a supersymmetric extension
0:36:36 > 0:36:40of the Standard Model, where we get a balance on both sides -
0:36:40 > 0:36:42there's a balance of the superpartners
0:36:42 > 0:36:44to the ordinary matter...
0:36:44 > 0:36:46There's a balance for the super force carriers
0:36:46 > 0:36:49to the ordinary force carriers.
0:36:49 > 0:36:51And this is what we've been wondering about for
0:36:51 > 0:36:53over 30 years -
0:36:53 > 0:36:56is it just mass or is it the universe we look at?
0:36:58 > 0:37:02Devotees of supersymmetry believe that their theory solves
0:37:02 > 0:37:05one of the most worrying mysteries of our universe.
0:37:07 > 0:37:13At the smallest scales, the universe is in a constant state of flux...
0:37:13 > 0:37:17seething with particles popping in and out of existence.
0:37:19 > 0:37:22The best way to understand it is to try to understand
0:37:22 > 0:37:25something about what's going on inside of a teapot.
0:37:25 > 0:37:28We can see the water is boiling, there's bubbles coming out,
0:37:28 > 0:37:30some are big, they explode, they disappear.
0:37:30 > 0:37:33So if you imagine that this surface is the universe,
0:37:33 > 0:37:36the bubbles popping in and out are actually virtual particles,
0:37:36 > 0:37:38they're virtual electrons and photons -
0:37:38 > 0:37:40all the particles that make up our universe,
0:37:40 > 0:37:43they pop into existence and then they disappear.
0:37:48 > 0:37:52This state of chaos is known as the quantum vacuum.
0:37:53 > 0:37:57And Jim thinks that without supersymmetry,
0:37:57 > 0:37:59it might make the universe unstable.
0:38:02 > 0:38:05I'm going to use a set of quarters to represent our universe.
0:38:07 > 0:38:10And...with a little bit of work I can get it to balance.
0:38:10 > 0:38:13With the particles of the Standard Model, there's actually
0:38:13 > 0:38:16a preponderance of one type of particle over the other.
0:38:16 > 0:38:19And now let's follow what happens
0:38:19 > 0:38:23if you let this preponderance work for a while.
0:38:23 > 0:38:25It's as if you are pressing on the stack of coins,
0:38:25 > 0:38:27but because of the preponderance
0:38:27 > 0:38:29you are always pressing in one direction.
0:38:29 > 0:38:32And what you find is that we are very close to being
0:38:32 > 0:38:35in a situation where the universe might collapse.
0:38:37 > 0:38:40Now, supersymmetry can help solve this problem.
0:38:44 > 0:38:47So, if you have particles - all the ones we know about,
0:38:47 > 0:38:51as well as the sparticles - they press, but they press
0:38:51 > 0:38:53in opposite directions.
0:38:53 > 0:38:57And our universe is a much more stable place.
0:38:57 > 0:39:00And I know I would sleep much more quietly at night
0:39:00 > 0:39:02knowing I live in a stable universe.
0:39:06 > 0:39:10The problem is that in 30 years of research...
0:39:10 > 0:39:12no sparticle has ever been found.
0:39:13 > 0:39:15But is that finally about to change?
0:39:17 > 0:39:22The 750 GeV bump might actually be one of these particles
0:39:22 > 0:39:25that we've predicted by the mathematics of supersymmetry.
0:39:25 > 0:39:29And if that's the case, it becomes the herald for supersymmetry.
0:39:29 > 0:39:33For me it will mean several things. Emotionally it will be a great high.
0:39:33 > 0:39:36I have been a supporter of the idea of supersymmetry
0:39:36 > 0:39:41since I was 25 years old, first learning theoretical physics.
0:39:42 > 0:39:47The dream was to find a magical piece of mathematics.
0:39:47 > 0:39:51Simultaneously, an accurate description of something in nature.
0:39:51 > 0:39:53It will be a source of intense joy.
0:40:14 > 0:40:17With the hopes of theoretical physicists around the world
0:40:17 > 0:40:23at stake, the pressure is on the LHC to keep providing collisions.
0:40:24 > 0:40:27But running this machine at such high energy...
0:40:28 > 0:40:31..is putting a huge strain on all its systems.
0:40:34 > 0:40:37When it's running well, it runs well,
0:40:37 > 0:40:40but there are a lot of things that can go wrong and do go wrong.
0:40:40 > 0:40:42So it can get quite stressful.
0:40:44 > 0:40:48Today, one of the accelerators that provides the LHC with protons,
0:40:48 > 0:40:52the Proton Synchrotron - or PS -
0:40:52 > 0:40:54has broken down.
0:40:54 > 0:40:56This is one of the veritable workhorses of CERN,
0:40:56 > 0:41:01and really is like the beating heart of the complex,
0:41:01 > 0:41:03and at the moment the line is flat.
0:41:05 > 0:41:09So we are in some of the oldest parts of CERN here.
0:41:09 > 0:41:11The PS has been with us since 1959,
0:41:11 > 0:41:14so there's some really old kit around here.
0:41:19 > 0:41:23And...this beast here is what we call the rotating machine,
0:41:23 > 0:41:26if you like, it's a kind of temporary energy storage system
0:41:26 > 0:41:31which we use to power and de-power the PS machine,
0:41:31 > 0:41:33the main bending magnets of the PS.
0:41:33 > 0:41:38It was retired a few years ago, it was pressed back into service
0:41:38 > 0:41:41because we've had a problem with the new version.
0:41:41 > 0:41:45Unfortunately, last week a problem developed on this -
0:41:45 > 0:41:48there was a short-circuit on a circuit breaker
0:41:48 > 0:41:53developed downstairs, which arced and damaged the circuit breaker
0:41:53 > 0:41:55and some nearby equipment.
0:41:58 > 0:42:02Thanks to the failure of this near-50-year-old power supply,
0:42:02 > 0:42:07the world's most expensive science experiment is just an empty pipe.
0:42:10 > 0:42:13There's a huge experimental community on the LHC out there
0:42:13 > 0:42:16really looking forward to getting as much data as they can this year.
0:42:16 > 0:42:18And of course, there's a lot of pressure to get the complex
0:42:18 > 0:42:20back up and running properly.
0:42:21 > 0:42:25I still can't believe it says 1967 on there, actually.
0:42:27 > 0:42:32If the LHC isn't running again soon, the worry for the experimentalists
0:42:32 > 0:42:35is that they won't be ready for the August conference.
0:42:36 > 0:42:38Another day that it's not coming in,
0:42:38 > 0:42:41it's a bit frustrating. I like to wake up in the morning
0:42:41 > 0:42:43to see how much data we took...
0:42:45 > 0:42:49..overnight. But lately I haven't had any good mornings!
0:42:53 > 0:42:57In the very beginning, there was a loss of 1.7 inverse picobarns
0:42:57 > 0:43:00because of a problem. And then at the end of the run...
0:43:00 > 0:43:04But the teams are determined to find a way around the problem.
0:43:05 > 0:43:11So, we are considering suppressing our technical stops.
0:43:11 > 0:43:18Which basically will put us on track for our goals of achieving
0:43:18 > 0:43:22basically something like three times the statistics
0:43:22 > 0:43:25which we have accumulated last year...
0:43:25 > 0:43:29in time for the summer conference in Chicago.
0:43:41 > 0:43:45At the University of Maryland near Washington, DC,
0:43:45 > 0:43:48Professor Raman Sundrum has great expectations
0:43:48 > 0:43:50about what the bump might be.
0:43:52 > 0:43:53His hope is that it could be
0:43:53 > 0:43:57a hypothetical particle that has near mythical status.
0:44:00 > 0:44:04A force carrier particle of gravity -
0:44:04 > 0:44:07known as an extra-dimensional graviton.
0:44:09 > 0:44:13The discovery of a graviton could help solve a puzzle
0:44:13 > 0:44:17that has baffled physicists for a long, long time.
0:44:17 > 0:44:20Gravity seems strong, it seems like it's the first force that,
0:44:20 > 0:44:23you know, cavemen would have known about, right?
0:44:23 > 0:44:25It's the thing that dominates most of our lives,
0:44:25 > 0:44:27just being pulled down to the Earth.
0:44:27 > 0:44:29But we can sort of see why physicists
0:44:29 > 0:44:32think that gravity is in fact the weakest force.
0:44:32 > 0:44:35And a quick way to demonstrate that is to just take a simple object,
0:44:35 > 0:44:37like a paperclip.
0:44:37 > 0:44:38Watch gravity act on it.
0:44:39 > 0:44:43But we can act on this paperclip with this magnet,
0:44:43 > 0:44:47which seems much smaller, and perhaps much weaker than the Earth.
0:44:48 > 0:44:53The entire gravitational pull of the planet can be easily overcome...
0:44:55 > 0:44:56..with just a small magnet.
0:44:58 > 0:45:02If you work this out you actually find that electromagnetism is
0:45:02 > 0:45:07by far and away stronger than the force of gravity.
0:45:07 > 0:45:11It's basically one followed by about 30 zeros times stronger than
0:45:11 > 0:45:14the force of gravity.
0:45:14 > 0:45:16That's how weak gravity is to a physicist.
0:45:18 > 0:45:20Raman believes there is one mind-blowing way
0:45:20 > 0:45:23to explain this puzzle -
0:45:23 > 0:45:29the existence of a tiny, invisible extra dimension in our universe.
0:45:31 > 0:45:34We're used to living in three dimensions of space -
0:45:34 > 0:45:37we can travel forwards and backwards, left and right,
0:45:37 > 0:45:39and up and down.
0:45:39 > 0:45:42If you just look at the vast expanse of the grass,
0:45:42 > 0:45:44it looks fairly flat,
0:45:44 > 0:45:48and so you'd say, effectively, for my purposes, it's two-dimensional.
0:45:49 > 0:45:53But if you're small, you can go places humans can't.
0:45:55 > 0:45:57And the grass looks rather different.
0:45:59 > 0:46:00From the bug's point of view, the grass
0:46:00 > 0:46:04does not look that two-dimensional. Doesn't look that flat.
0:46:04 > 0:46:07If it really gets in there, it can go up and down these clovers,
0:46:07 > 0:46:09or up and down a blade of grass,
0:46:09 > 0:46:12so it's really in there with the third dimension,
0:46:12 > 0:46:13the vertical dimension.
0:46:13 > 0:46:17The grass looks 2D to humans because we're so big,
0:46:17 > 0:46:21and perhaps the same applies to our apparently 3D universe.
0:46:23 > 0:46:26It might be that for human-size creatures like us,
0:46:26 > 0:46:30we live in something that looks effectively three-dimensional.
0:46:30 > 0:46:32And yet, there's another dimension -
0:46:32 > 0:46:35a very small dimension that's sort of hidden to the naked eye.
0:46:35 > 0:46:39But if you are a microscopic, subatomic particle,
0:46:39 > 0:46:41you might be a little bit like that bug.
0:46:42 > 0:46:46If an invisible extra dimension exists, it could mean
0:46:46 > 0:46:49that gravity appears weak because we're only seeing
0:46:49 > 0:46:54part of its strength. The rest is hidden - in the extra dimension.
0:46:56 > 0:47:00And the discovery of a graviton in the LHC
0:47:00 > 0:47:02could help prove this extraordinary theory.
0:47:06 > 0:47:09That's part of what the LHC is doing when it collides protons.
0:47:09 > 0:47:14The collision is incredibly energetic and that energy provides
0:47:14 > 0:47:20the kind of quantum mechanical magnifying glass for these particles
0:47:20 > 0:47:24to look inside the extra dimension and report back in an indirect way.
0:47:25 > 0:47:30If it is a graviton, then that has very great significance.
0:47:40 > 0:47:43It's the middle of June at CERN.
0:47:43 > 0:47:47For the last four weeks, the LHC has been running so well
0:47:47 > 0:47:51that the team from ATLAS have finally gathered enough data
0:47:51 > 0:47:53to see if the bump is back.
0:47:56 > 0:47:59The machine has been working over the clock and produced
0:47:59 > 0:48:04a lot of collisions and now we have almost as much data as we got
0:48:04 > 0:48:10in 2015, so it's kind of exciting times because the day has arrived
0:48:10 > 0:48:15to look at this data and to see if there's something there or not.
0:48:15 > 0:48:17I am VERY optimistic!
0:48:17 > 0:48:21Well, last time, I was actually quite pessimistic
0:48:21 > 0:48:25cos I didn't think that we would get enough data at this point,
0:48:25 > 0:48:30so now my optimism is going up and up with each day!
0:48:30 > 0:48:33My gut feeling - I...
0:48:33 > 0:48:38Oh, I'm really oscillating, I would say, and, erm...
0:48:38 > 0:48:43Yeah, I still hope there is something there.
0:48:47 > 0:48:51The results will be revealed in an ATLAS team meeting.
0:48:52 > 0:48:55You have to stay outside.
0:49:04 > 0:49:08The secrecy is because ATLAS have beaten CMS to it
0:49:08 > 0:49:11and they don't want them to know their conclusions.
0:49:17 > 0:49:22An hour later, Marco and the team are out. The results are clear.
0:49:24 > 0:49:29750 is here, so you will expect to see a bump somewhere here.
0:49:29 > 0:49:31The data is the data, so unless we made
0:49:31 > 0:49:35a very bad mistake in processing the data,
0:49:35 > 0:49:39you can see by eye that there is no evident excess there.
0:49:39 > 0:49:42It's very flat. There is no bump there.
0:49:45 > 0:49:48Data that we have looked at from this year,
0:49:48 > 0:49:51we haven't seen anything yet, which is a bit disappointing,
0:49:51 > 0:49:57to be honest, but that's actually how most of our searches turn out.
0:49:57 > 0:50:00We don't allow ourselves to hope, but, of course,
0:50:00 > 0:50:02we are humans and we were probably
0:50:02 > 0:50:07unconsciously hoping for something more and we're not seeing it.
0:50:07 > 0:50:10It might simply mean there was a fluctuation
0:50:10 > 0:50:13of the background noise in 2015 that has gone away,
0:50:13 > 0:50:16so it's a bit disappointing, honestly,
0:50:16 > 0:50:19and, of course, we are not in the position
0:50:19 > 0:50:21to draw a definitive conclusion,
0:50:21 > 0:50:25but, yeah, it could have been a more exciting day.
0:50:26 > 0:50:28The only hope for the bump
0:50:28 > 0:50:32is that it's been found by the other team, CMS.
0:50:34 > 0:50:39They don't know about the ATLAS results and, three days later,
0:50:39 > 0:50:42they're ready to look at their data.
0:50:44 > 0:50:47I am very excited.
0:50:47 > 0:50:49At least in my life, working life,
0:50:49 > 0:50:51it's the most exciting moment.
0:50:57 > 0:51:01So now we're going to open the reports.
0:51:02 > 0:51:05And there's nothing.
0:51:06 > 0:51:08So, no bump.
0:51:10 > 0:51:11Nothing is there.
0:51:11 > 0:51:16We just see something that is compatible with the expectations.
0:51:17 > 0:51:20There was just... There have been many times in the past.
0:51:20 > 0:51:22It will happen in the future.
0:51:22 > 0:51:25Too bad. Of course, you are hopeful that somebody finds something
0:51:25 > 0:51:28cos that's basically why we do the job,
0:51:28 > 0:51:32but it basically tells everybody now that we don't need to be excited
0:51:32 > 0:51:36because the fluctuation we saw for the moment is gone
0:51:36 > 0:51:41and now we have to wait for the rest of the data.
0:51:43 > 0:51:47So, I'm looking at it and, er...
0:51:49 > 0:51:51And...
0:51:51 > 0:51:54there is nothing.
0:51:57 > 0:52:01The results are shared with the rest of the team at the weekly meeting.
0:52:04 > 0:52:06Can you hear me?
0:52:07 > 0:52:14The 750 bump now doesn't look very healthy, put it like this.
0:52:14 > 0:52:21So, I'm going to report on the status of the analysis.
0:52:23 > 0:52:30I would give it 95% probability that it was fluctuation
0:52:30 > 0:52:35and in fact we always said that and we tried to keep very cool about it.
0:52:35 > 0:52:40Obviously, I would have preferred that nature had surprised us
0:52:40 > 0:52:44because it was a real surprise, this 750 thing.
0:52:44 > 0:52:47On the other hand, if this thing had been real, it would have really
0:52:47 > 0:52:53meant a complete change of the way we interpret nature,
0:52:53 > 0:52:56so it has always been in the back of my mind
0:52:56 > 0:53:00that this thing could be a fluctuation.
0:53:00 > 0:53:04We got permission to look at data over the weekend
0:53:04 > 0:53:05and now if we look at data,
0:53:05 > 0:53:11what we can see is the observed 750 is not confirmed.
0:53:11 > 0:53:14But in the next months, we'll get four times more statistics
0:53:14 > 0:53:19so by that time, one will be able to tell for sure.
0:53:48 > 0:53:50It's the 5th of August.
0:53:50 > 0:53:54Tiziano and Dave are in Chicago for the conference.
0:54:02 > 0:54:05The time has come for them to share the results of their hunt
0:54:05 > 0:54:10for the 750 GEV bump with the rest of the physics world.
0:54:15 > 0:54:18It's a great pleasure to be here today to talk about the first half
0:54:18 > 0:54:22of the highlights from the LHC and the way we've organised this...
0:54:22 > 0:54:25Further data has confirmed what the teams feared.
0:54:25 > 0:54:27But then, as you will have heard,
0:54:27 > 0:54:29we were looking at the 2016 data
0:54:29 > 0:54:31and I'm afraid to say in the 2016 data,
0:54:31 > 0:54:36there is no clustering around the 730-750 GEV region
0:54:36 > 0:54:39and so there's about four times more data and so, from this,
0:54:39 > 0:54:41we have to conclude that the 2015 excess
0:54:41 > 0:54:44was most likely a statistical fluctuation.
0:54:44 > 0:54:48The dream of the 750 GEV bump is over.
0:54:50 > 0:54:51It would have been a revolution.
0:54:51 > 0:54:55Yep, we would have broken the Standard Model of particle physics.
0:54:55 > 0:54:59It would have sent a lot of theories back to the drawing board.
0:55:01 > 0:55:05The bump was just a fluctuation in the data.
0:55:05 > 0:55:10That it was seen by both detectors was a highly unlikely coincidence.
0:55:10 > 0:55:14The bump was a cruel statistical fluke.
0:55:14 > 0:55:20It's simply the kind of thing which can happen because basically
0:55:20 > 0:55:22when we're dealing with statistics, it's like,
0:55:22 > 0:55:26you know, flipping a coin five to ten times,
0:55:26 > 0:55:27you can always get heads.
0:55:29 > 0:55:31And the disappointing news
0:55:31 > 0:55:34quickly reaches the rest of the physics world.
0:55:36 > 0:55:40We'd have vastly preferred that it WAS there because it would have
0:55:40 > 0:55:44definitely heralded a much richer particle physics
0:55:44 > 0:55:47that would play out, guaranteed, in the next few years.
0:55:47 > 0:55:51Scientists are human and so we have feelings just like everyone else.
0:55:51 > 0:55:54I guess, in my case, I would say disappointment
0:55:54 > 0:55:58but not discouragement, and so we have to look a little bit harder.
0:56:01 > 0:56:05The 750 GEV bump didn't live up to anyone's hopes.
0:56:08 > 0:56:11But the quest to understand the mysteries
0:56:11 > 0:56:13of the particle world are far from over.
0:56:18 > 0:56:21Back at CERN, the hunt for particles goes on
0:56:21 > 0:56:24and they're certainly not giving up.
0:56:27 > 0:56:29We are clever beings.
0:56:29 > 0:56:34Human beings are clever beings, so our intrinsic wish
0:56:34 > 0:56:36and our intrinsic duty and right
0:56:36 > 0:56:40is really to be intelligent, clever beings.
0:56:40 > 0:56:46Today, the LHC is operating at the highest capacity it's ever achieved.
0:56:48 > 0:56:52The machine is performing exceptionally well at the moment.
0:56:52 > 0:56:55We really are somewhere where we didn't expect to be.
0:56:55 > 0:56:58Things aren't breaking down very often and we're sitting there
0:56:58 > 0:57:03for 24 hours at a time with stable beams continually producing
0:57:03 > 0:57:06these high rates of collisions to the experiments
0:57:06 > 0:57:08and nothing's going wrong.
0:57:08 > 0:57:12These bottles have come from ATLAS and CMS. We had a small celebration.
0:57:12 > 0:57:15We actually reached design luminosity a couple of weeks ago.
0:57:15 > 0:57:19This was actually a quite profound achievement for the LHC.
0:57:19 > 0:57:22The Large Hadron Collider is the most ambitious
0:57:22 > 0:57:25scientific experiment ever undertaken.
0:57:25 > 0:57:28For now, it's holding on to its secrets,
0:57:28 > 0:57:30but the teams working there
0:57:30 > 0:57:34still hope that they will be the ones to unlock them.
0:57:34 > 0:57:38One day. Oh, there's a huge amount more in the LHC.
0:57:38 > 0:57:41We've barely started the journey at this point, clearly.
0:57:41 > 0:57:44We have another 20 years of data-taking
0:57:44 > 0:57:47and we will have huge, huge data samples
0:57:47 > 0:57:51and lots of sensitivity to new particles if they're there.
0:57:51 > 0:57:53I'm excited about the future.
0:57:53 > 0:57:56The one thing where I would not be ready to bet
0:57:56 > 0:57:59is whether the discovery's going to happen in the next six months,
0:57:59 > 0:58:02the next three years or the next ten years.
0:58:02 > 0:58:06It all depends on how kind nature is going to be with us.