Original subtitles

Ok, welcome to CERN.

This is in fact the control room for the ATLAS experiment.

ATLAS is one of the four large experiments now going on

at the LHC, the Large Hadron Collider.

The Large Hadron Collider is a huge ring of 27km,

and that’s an accelerator

where we accelerate protons in two different directions,

and then they collide in four points.

We are just above one of those colliding points

at the ATLAS experiment.

So ATLAS is both

a large collaboration of about 3,000 people,

I'm one of them, my name is Pauline Gagnon,

I'm Canadian.

I work for an American institute, Indiana University,

and I live here in France and I work in Switzerland,

but that's just about the kind of sociology

that you have with the people here at CERN.

So it's a very mixed background,

in ATLAS alone we have people from more than 70 different countries.

There are only 38 countries participating in the experiment,

but since people like me with...

I'm Canadian and I grew up in an American institute,

so, then there are people from different countries working together.

The common language to work is broken English,

so everybody speaks it

with their own mistakes and all that, their own accent.

So... But people get along and we usually get the work done.

All this, you may wonder,

what's the purpose of all this?

Why do we go to such an extent?

So much work, 3,000 people

just to build the detector and work on it

and analyse the data that comes out of it.

Essentially, its just to increase

the knowledge about what matter is made of.

What is the universe where we live,

what is this place we are in

and where did it come from. Where is it going.

So, it's very fundamental questions,

it's nothing that puts food on your plate right away.

The food might come later on, because with research,

you never know what will come out of it.

We're going out and...

let's see what we find!

It's a bit like a mushroom hunt, you know,

you can bring back something that is really good

and you make a good dish and you might not

come back with anything suitable.

So, I was saying earlier that we have the accelerator

which accelerates the particles

and then we have the detectors

that are there just to detect what comes up.

A detector is just a very fancy camera,

so we take a snapshot of what happens

when two protons come into collision.

All the energy released in the collision

then is in one small tiny point

and it allows you to create a particle

because E = MC2, so the energy that you have put there,

you can transform it into mass.

The C squared is just the exchange rate between energy and mass.

So we can create new particles and study how they behave.

I saw in 1995 there was an opening at CERN

and LHC was due to start very soon.

And so this is why I decided it could be a good opportunity

and so that's why I jumped.

So, I think...

It's actually beautiful to be part of a...

modern cathedral's building.

That's the way I see it. It's like being a community

with a single aim and a single scope

and we're producing machines

that nobody has built before. Like a cathedral.

I'm in charge of the magnets at CERN

everything that has to do with magnets for the machines

and I arrived at CERN in 1995

after a few years of working in thermonuclear fusion.

I think I was lured here by the adventure of the LHC,

so it was at the beginning of the LHC.

In fact where we are today is the hall where we do all the maintenance,

the work, the construction and the reconstruction of the LHC magnets.

We do mostly dipoles here, and we work with quadrupoles as well

these are the main elements

that make up the superconducting cryostat of the LHC.

Well magnets are the main mass in an accelerator.

As you've seen in accelerators at CERN, magnets guide particles,

they drive them around on a circular path

so that they can go back to the real accelerating component

which is a cavity. But they need to do that thousands

and tens of thousands of times a second, like in the LHC.

So the main function of the magnet is to guide the particles back

this is what we call dipoles, and they have to focus them

onto the closed orbit of the machine, and these are the quadrapoles.

In addition to that,

the quadrapoles also squeeze the beam down to a small size,

smaller than a hair, in the experimental region.

This is the main function of the magnets.

To give you an idea of power and strength...

I think...

Let's start with electrical power that we use

because we need electrical power to run the machines.

So CERN uses roughly 160 megawatts of electrical power

only to run the accelerators and that's more or less the consumption

of a small city like Geneva.

So it requires indeed a lot of power

in spite of the fact that we use superconductors.

So the LHC itself uses about 60 megawatts and the whole complex

before the pre-injectors

uses also about 60 megawatts to inject the beam into the LHC.

As to the magnetic field,

to give you a feeling for how strong the magnetic field is,

you should imagine a magnetic field

in our magnets of 8 tesla produces forces.

These magnets are 15 meters long,

and the forces produced on the magnet

are in the order of 350 tonnes per half magnet.

So 350 tonnes per meter of magnet for every half of the magnet.

So it's a lot of weight that needs to be held

by the very strong structures that we put around them.

This is why the magnets are all encircled

in these very strong structural steel that keeps them together.

As to the magnetic field itself, the nominal field is 8 tesla.

You can compare that to the magnetic field of the earth

which you can barely see with a magnetic needle.

So here in Geneva the earth is producing about half a Gauss

and if I compare that to the magnetic field of the LHC,

which is 8 Tesla, that's a factor of 100,000 more.

So the LHC produces 100,000 more magnetic field

than that of the earth.

We are 90 meters underground,

between the Jura and the Lake of Geneva,

and this is the cavern of the ATLAS experiment.

It's the biggest experiment in high energy physics we ever built,

so it's... the cavern is huge it's 60m by 30m.

Inside there is a detector, it is 7,000 tons,

it's the same weight as the Tour d'Eiffel in Paris.

And, the cavern is fully occupied, in fact by our detector

and this is one of the detectors that has measured the Higgs-Boson,

this year and last year.

And now we are in maintenance mode so, this is the period in which we stop,

we open the detector and we work on it.

So the aim of all this is quite varied,

one of the main aims,

one which you can also find in the press

is the discovery of the Higgs-Boson.

Apart from being a particle it's a mechanism, it's a field,

and it's the mechanism which gives the mass

to all the other particles.

But this is only one of the aims of this detector.

This is a general purpose detector

and can measure several aspects of nature.

Several aspects of nature in very tiny dimensions.

And this backwards in time, the accelerator itself is a time machine.

Raising the energy allows us to go back in time

and to reach a point a tiny amount of time after the big bang.

The description of nature as we know today is at the moment...

I would say, quite complete,

especially after the discovery of the Higgs-Bosons.

But there are many, many things we don't understand, that...

For which this detector has been built for

and these for example are questions about matter

and well, there is one very basic question

that is the difference between the amount of matter and anti-matter.

Because all this... knowledge, all this building of knowledge

and building of theories tells you that...

the big bang bang and

at a certain moment in time was beginning.

And all the matter, all the matter that exists in the universe now

comes from a very small point

from where everything expanded, in a way,

to give an image.

But to have this final tiny point with this enormous amount of energy

and matter, density,

you must have a way to put all together...

and, the only considerable way you can see about this is symmetric...

a symmetric way of thinking.

That you must have the same amount of matter and anti-matter.

And then of course you can ask yourself:

so why is it not myself in anti-matter that is destroying me.

So in a way there is a tiny difference between the matter

and anti-matter that makes all this exist.

And this is certainly a mystery, there are other mysteries

like the amount of dark matter, we see that if we look...

we can look at this kind of phenomena also in space

and we can look at matter in space

and we cannot really compute totally the matter

that is in space, we can compute it but we see there is a deficit

and that is what we call the dark matter and the dark energy,

that they are not exactly the same thing to make this size of universe

and this way the matter is distributed possible.

And this is certainly a mystery.

Another mystery I would like to give you is that...

I explained to you that energy and time are correlated

and the product of energy and time has to give you a constant.

Now, if you think for a moment

that the time you're aiming at is 'zero',

then to keep this as a constant the energy has to be infinite.

So there is in itself a paradox here

and something that maybe we can't approach,

we can do our best,

but the time 'zero' is something which is difficult.

So...

What we do in research is...

sounds a bit strange, I mean, we...

on the one hand we want to

test and confirm

our present theory

and at the same time we are always looking for things which

destroy our present theories

to find something new.

You...

want me to explain the Higgs particle?

Yeah... this is... yes... I mean, the Higgs...

Higgs mechanism... I have... This is one of my...

My... I mean, the...

I have been wondering how one can

correctly and easily explain

the role of the Higgs field,

Higgs mechanism and the Higgs particle.

This is something which is difficult for me to do.

How can I explain?

Is...

Higgs-Boson has such a unique and important role,

even one that allows us to exist,

this important particle

hadn't been discovered till just one year ago.

So, in a way, this is a very frustrating situation.

We know the theory works very well,

however one of the key elements of the theory

hasn't been confirmed by experiment,

nobody has seen whether this exists or not.

Now it's very likely

this will be discovered.

So, in a sense,

the last piece of our theory has been found

and put into the jigsaw puzzle,

but in a jigsaw puzzle this would be the completion,

then you glue it and put it on the wall

or take it apart.

But in physics it doesn't work like this.

Up to this point the analogy of the jigsaw puzzle works fine,

but after that it doesn't hold anymore.

What we want to do is...

first of all, we have to confirm

if this particle is really the last piece of the jigsaw puzzle,

not something similar but it maybe something totally different.

We have a picture, a cosmological history of our universe,

nobody tells us that is the truth but within our present knowledge

this is the best we can do and indeed it does explain very nicely

everything we are able to observe.

Maybe we come up with new observation.

Remember,

what we are studying at the LHC

is matter,

so matter, well visible matter, constitutes only 4% of the universe.

All the rest is unknown, dark matter, that we know it exists

but we don't know what it is.

And something even more mysterious is dark energy.

Again we suspect it exists

cause we need it to explain

given properties of the evolution of the universe

but again we don't have any idea what it is.

So today we are in a situation

where we understand 4% of the universe

and we ignore what the rest of it is.

So the specific place where we are now,

this is ALICE experiment,

we are looking to recreate primordial matter.

Matter as it existed shortly after the big bang.

Here we are talking fractions of a micro-second

after the beginning of the universe.

At that time temperatures were extremely high,

energy density was very high

and matter was in a completely different shape than today.

So we recreate this primordial matter,

try to understand nature and properties of this matter

and then how it evolved

from its state in the early universe to the state as we know it today.

Imagine in a single collision

we are producing, about 10,000 particles,

running through the equipment

that must be identified.

So we don't see the particle itself, we take a picture of the track

a particle leaves as it passes through the detector.

Like if you look at a ski slope,

you don't see the skier

but you can identify weight, size and direction

by the traces he leaves behind.

And for a full trace of the skier

you need a big field!

We use brute force, we aren't very smart.

We use the energy from a collision

to create these new particles.

We need to bring a small particle

up to a very high speed,

close to the speed of light,

so for this we just need big machines!

Using magnets to make the particle turn and electricity to accelerate it

and a million other things to make the whole thing work!

And I think CERN is a really good example

for humanity following a common objective.

Even if we don't discover anything in science,

I think having achieved that is a major achievement.

So she recognised that they pushed the crash button?

Are we speaking about this new crash button

which we installed like a year ago in Utrecht, or not?

- I don't know. - This, I think, we have to understand.

I think we really have to understand this.

The crash button was somehow recognised as being pushed...

I think Christoph Schäfer also has to be involved.

So, that's the suspicion right now?

That someone hit the crash button?

- No. - So, that's the question.

So why did it turn off in the first place?

All the information is inclusive of an emergency stop.

So it's as if some hit the crash button?

- So... - I mean...

I don't know the meaning of emergency stop...

That's OK, that's OK.

So, the law is as if...

it's as if someone hit the crash button?

You don't think someone did,

but it's as if someone hit the crash button.

OK.

So the question is about first statement.

You looked at reprocessed versus prompt data

and you decided to stay with the prompt,

but in the reprocessed data, there are not just changes for jets,

so I find the statement a little bit...

surprising.

So, the question is, is it a quantitative measure

of these major differences, which you can see you have some...

plots also that show that.

If it's in the back-up, we can look at it later

but I don't want to kill the stream.

I'm not quite sure if I put it in the back-up or not.

Just more than a sentence

I think that's what I'll learn from the question.

OK, we can take it offline and we can go on from here.

You look frozen, are you still, you know, alive?

I think the shock of this question was too much.

He's gone.

OK, he turned invisible.

So no more questions until the end please.

Can anybody...

outside CERN still hear us?

- I can. - Oh, good.

So I can go and sit down and just wait.

In the beginning I was heavily involved in building a system

that we call 'the trigger system'.

This trigger system actually selects online,

in real time,

the interesting collisions to be recorded and analysed later.

This involved the development

of an electronic system which operates very fast.

It looks at a collision 40 million times per second,

like a digital camera,

which takes 40 million pictures per second.

It not only takes the pictures

but it looks for interesting patterns for example.

And if there are,

which is only the case a few hundred times per second,

then the trigger system recognizes these

and marks them for recording.

Like if you take lots of snapshots with a camera

but you eliminate those that you do not like.

But we do that online extremely fast.

Our first important discovery

was a particle that looks very much like the so-called Higgs particle,

which is also called God particle,

but this is a term which physicists don't really like.

We have discovered a very new particle

and now we are going to measure all its properties

and make sure it is really the long sought Higgs particle

or if it is indeed something completely new.

But actually this experiment was built for another main purpose

which was to discover if there are new forces in physics.

We all know gravity, for example,

but there are also other forces

such as electro-magnetic forces in the universe.

But maybe there are other forces we do not know about

and this could be discovered here.

We could also discover completely new spatial dimensions

which might be very small

meaning till now we haven't been able to see them,

but with a tool like the Large Hadron Collider and this experiment

we can use them like a giant microscope

and look deep into nature

and we hope to find something very new.

For example it is imaginable

that gravity becomes a very, very strong force.

Much stronger than we are used to it when we go to very small distances.

For example: when you smash 2 protons

against each other as it is done in the LHC

then you really come to very, very small distances.

And it is possible that gravity becomes very strong.

So if gravity becomes strong then we can also create mini black holes.

Microscopic black holes.

So this would be a spectacular

new signature for up to now unknown physics.

It's a constant struggle

and of course sometimes the kids complain,

'Mummy there's nothing to eat!' but I'm not alone

and one has to get all the help one can.

I think even if the family suffers, in the end

they see how enthusiastic we are

and they see that we've achieved

something really satisfying that can show new ways

and normally families understand.

But I should also say there have been lots of divorces at CERN,

mainly because of just too much work.

People are enthusiastic though,

these are not people that come at 9 and leave at 5

and look at their watch, they really like to spend the time here

and put in all the means possible to get results

and also to get personal satisfaction.

This centre is at CERN and has essentially two main and very important connections.

One connection brings us to the experiment,

so essentially the main flux of data is from the experiments to here.

So when beams collide,

the results of the collision are recorded,

filtered through different levels of filtering

and eventually they are shipped here via a dedicated network.

So this is the first connection.

Data arrives here and is stored and ready to be immediately analysed.

This is just the first part of the analysis,

we call it 'general reconstruction'.

The idea here is that

from the raw data

which we receive from the experiments

we reconstruct, for example, trajectories, from which you can

identify particles and assign them energies and directions.

This data is also shipped outside.

They are shipped directly from CERN to important computer centres,

more or less comparable to this one

which in turn redistribute data to other places

like universities or university type facilities

where the final analysis will be done

or other activities connected with analysis of the data.

I think one can visualize data coming from the experiment,

being stored, used for initial reconstruction and also distributed.

So this is the backbone of our activity.

I was born in 1964,

and, talking with people of my age,

came to the conclusion that the Apollo period

end of the 60's beginning of the 70's had a big influence on us.

Initially it was a big fascination with astronomy and astronauts

which eventually, getting older, became an interest in physics and so on.

I think there's a specific correlation between astronomy, physics

and that period of space exploration.

On one side there's astronomy with gigantic distances,

worlds you can not really visit directly, and there's particle physics

which is a kind of mirror image, you go smaller and smaller.

So you find worlds which are really fascinating, strange sometimes, bizarre

but it's clearly one of the things

which moved me to go into physics.

And now, even if I'm more in computing, there's a pride in saying

these experiments are something really interesting, really cool,

and we are making our small contribution.

I think for somebody with a physics background that CERN,

even if they move on, keeps this fascination.

It's our home.

It's our dream place.

I think it is so.

We have our own fire brigade.

We have our own emergency services.

Actually we are like a city, and this is the challenge also in my job,

because you asked me in the beginning where we are here.

I have to, we have to manage a small city,

and to give you an idea of what I mean by city

we have roughly 10,800 guest scientists

coming from all over the world,

One hundred and twenty nationalities, we have roughly 2,500 staff,

we have 500 postdocs, 500 students and apprentices.

So it's a population and needs accommodation and services

as any customer would need in a small city.

In some sense we are both an organisation like any other,

but we also provide our own legislation, if you like.

Because the convention gives us the right

and also the obligation to handle certain things ourselves.

For example, if we fix our salaries we cannot simply do it,

we have to do it according to

the rules approved by our 20 member states.

In some sense we're a kind of state in the states.

What we need is a long breath.

This is sometimes a problem if you discuss things with politicians.

They're used to working in horizons of 3 - 5 years.

They expect a return on investment which is more or less immediate.

Immediate means tomorrow.

But we have seen by the example of the world wide web

which was invented here at CERN,

you need on average at least 10 - 15 years

between the first basic ideas

and the first industrial product.

So, I'm a theoretical physicist.

My job is to come up with some ideas,

some possible explanations,

then I try to understand what are the consequences

of these ideas and how you can test these ideas using experimental result.

In particular, experimental results being obtained now in this LHC,

this big machine that has been built here at CERN

which is working pretty well at the moment.

Good ideas can come at any moment and you have to be ready.

It can be dangerous too!

If you have an idea while you're driving your car

you have to keep your ideas.

When you getting back home to take a little piece of paper

to writing down your ideas and try to finish your computation.

Most of the time you make mistakes

but from time to time you are right and you understand something new.

That's fantastic, it's a good feeling when you come home in the evening

you're feeling very good

because you know more than in the morning.

The feeling of having thought of something

nobody has done before

is what's really exciting about research.

For a few moments you are the only person on earth

who has a clear understanding of a problem.

Discovering the Higgs-Boson is not like discovering yet another particle.

What we are really after is trying to understand some fundamental laws,

some fundamental principles that govern the universe.

So for a very long time one main theme of particle physics

and theoretical physics was the Gauge principle.

So the Gauge principle is really the process that explains

how particles interact with each other with the exchange of the Gauge-Boson.

And maybe with the discovery of the Higgs-Boson we are about to discover

a new fundamental principle of nature that could really govern

how the universe is structured.

But again, we are not so much interested in new particles.

What we really want to understand is

'what is the principle behind these new particles?'

Is the discovery of the new particle

telling me something more fundamental about nature:

is there a new space-time dimension,

is there a new interaction...

a fundamental interaction between those particles.

That's really what we are about.

I mean, the fact that till now we understand interaction

as the exchange of Gauge-Bosom,

that was a really big step forward in the understanding of nature.

But still there are a few things that we don't quite understand.

For instance the fact that electro-magnetism is described

by one particular symmetry of nature, there is a weak interaction

which is described by another symmetry, there is a strong interaction,

yet another symmetry.

Why those particular symmetries?

Is there something deeper behind those symmetries,

a bigger symmetry for instance?

That will unify all those symmetries associated to the different interactions.

And, yeah, we are trying to understand these kinds of things.

We have good ideas but we still don't know if our ideas are true or not.

I mean, I'm not a physicist

and I used to say I'm here to develop the toys for physicists.

So I'm involved with the machines.

There are several people at CERN

who decide what has to be done on the physics' side

and we are responsible for developing the tools

for these people to carry out their research.

There is not really hierarchies here at CERN,

at least that’s my feeling,

there are people from the physics side

deciding what has to be done

and we're here to provide them

with the required tools to be able to investigate

what they are looking for so there is no real hierarchies,

there are different specialties at CERN

in the technical part.

Our section is MDT,

my section leader used to translate that to Making Dreams True.

People ask for dedicated tools

and we are here to try to develop these tools.

We are presently working on the new generation

of superconducting magnets using new technology,

Niobium 3 Tin (Nb3Sn) superconducting cables,

in order to reach a higher field that will be required

for the upgrade of the luminosity of the LHC.

The magnets presently installed in the LHC

are based on Niobium Titanium technology

and will reach the limit of the magnetic field that can be reached

with this kind of superconductor.

For example we're working on a new dipole

with 100mm Bohr and 13 Tesla.

And to give you a rough idea of what this represents,

the required niobium cable to produce one coil

is around 100,000 Swiss francs per coil

and we need 4 coils inside.

You only need a few seconds to destroy the cable so,

this is quite difficult to deal with.

We're working with superconductivity

so the magnets we have to test have to cool down

to a very low temperature, in this case to 4.2 kelvin

or to an even lower temperature which is 1.9 kelvin.

To do that you need a kind of thermos,

a vessel that is well insulated from the outside which is very warm

with respect to the magnet.

Basically you have a 300 kelvin difference

which would be the same as saying 300 degrees

because it's a relative number.

So then you have to make sure the heat 'inleak' is kept to a minimum.

So we build equipment

which is essentially made up of a vessel itself

in which we can put the magnet, then obviously we close it

and we can access it by liquid

which is in this case liquid helium

and cool it down to 4.2k.

Then we have to connect the power to this equipment

because obviously the power generation is on the surface

and a nominal 20 degree temperature is in the hall.

So you have to bring the current into the magnet through this vessel.

This vessel also helps us make the interface

between the magnet and outside.

And then obviously we have all the information coming out

which is in the form of wires and we plug them into

and then we have a control room behind us

where we get the information visible on computers in a graphical way,

in such a way that we can analyse it later on.

So that is essentially what we have here behind me

and basically you have three test stations of this type,

so three units, which are nearly independent one from another.

Well, my whole family is here

because I have to say my husband works at CERN,

my husband works in the same area as me, so also magnets.

And ok, that's life, we have a three year old child

and she goes to the kindergarten at CERN.

So in the morning we come as a family to CERN

and are dispatched all over the three sites:

My husband works in the French area,

I work between the Swiss part and the French part,

still in French territory,

and my daughter is on the Swiss side in kindergarten.

Yeah.

My husband also has another son,

he's in the control room.

I also have a brother-in-law

in the ATLAS detector,

so we are really all a family.

Well,

when you say we have to leave some space for the imagination,

you assume that what we are doing is enough to understand the world,

how the universe works, I'm not so sure.

I think that...

We are in a territory where we are

so close to understanding the complete picture

that it has become very, very hard to improve.

I'm not at all convinced

that the big steps we make

are big enough

to get rid of the space that remains there.

I think we're on the top but now it progresses very slowly.

I think we are still far away,

I'm not sure it will come next year

where we explain Higgs and the dream is real.

No, I think we will find elements that will bring us closer,

that's the idea, I believe,

but I'm not convinced that we will understand the complete picture.

You might know there is a principle called the Anthropic Principle

which says nature and the laws of nature

were designed only to make it possible for humans to exist.

But I doubt.

Of course, we also realize that science and physics

is only one perspective of understanding reality and nature.

I had a long discussion here with the Pope, when he visited CERN,

not the present or previous Pope, it was John Paul II,

who visited the CERN.

I discussed with him,

can there be a conflict between science, physics, and religion

and we agreed, no, there cannot be a conflict.

He agreed to that.

So I asked him, if you agree why don't you rehabilitate Galileo?

I said, look, if you have a plate, a dinner plate,

and you look at it from the top, you would say it's a circle.

If you look at it from the side, you wouldn't say it's a circle,

you would say it's a line.

So they are two conflicting perspectives and you could ask forever

'Is it a line, or is it a circle?'

So that's what religion and science does with reality,

they are looking at different projections of reality.

They see it differently

but they are two projections of the same reality.

It takes a long time to clarify a certain concept.

How do we define something.

The real imaginative nature of science is

in creating a consensus

which is necessary to find the laws of nature.

Maybe these concepts are not unique,

there might be other ways to describe nature by different concepts.