So thanks a lot. It's really a pleasure to be here and to talk this morning on the Standard Model and the Large Hadron Collider and the Higgs boson.
So let me begin the first part of my talk to review something that most of you will know about, which is the start of particle physics.
I, in connection with previous lectures of this morning that you have had, so James mentioned the quantum field theory, right?
The standard model is perhaps the greatest success of this very important theory, which is quantum field theory.
So first of all, let me mention that this is really an extremely exciting time to be a particle physicist.
Right? So in the last years, particle physics had to be in the headlines several times.
And this is fully justified by the discovery of the Higgs boson at the Large Hadron Collider in thousand 12 is the most
important discovery in our field in the last 25 years because it completes the extremely successful standard model.
But at the same time, it opens a large number of crucial questions for our field that we need to answer.
And the Large Hadron Collider will play a central role in exploring this high energy frontier for the last for the next 20 years.
So what is this? I'm not a modest I'm not a model,
is the theory which explains a wide variety of microscopic phenomena into a single unified framework, which is quantum field theory.
It describes all elementary particles and their interactions with the only exception of of gravity.
So what is the standard model composed of? First of all, in this matter, right.
It describes a protons and electrons and also other of the particles.
Its content is composed, organised in quarks,
which experience the strong interaction and leptons which they only experience a weak electronics electromagnetic interaction.
There are six quarks. They are called up, down, strange bottom and top.
There are also six leptons, six from the electron familiar with, but it also has two headed counterparts, the new and under and the Lepton.
And also there are three neutrinos which are massless electron neutrino, neutrino and neutrino.
And then there are the interactions which relate these particles among them.
And these forces are governed by the exchange of the so called a force carriers, and that is one force carrier for each of the interactions.
The electromagnetism is based on the exchange of photons.
These you are familiar with the strong interaction, as I will explain, is characterised by an exchange of gluons.
And then the weak force is defined by the interaction, by the exchange of divergence at bosons.
And the last ingredient, which was found only three years ago, was the Higgs boson,
which is really essential because it's the way in which all the particles in this field can acquire mass,
because this mass is forbidden by the symmetries of the Lagrangian.
So let me begin by recalling where all this comes from, right?
So let's go to the early thirties. And after a number of very important discoveries, the electron, the proton,
the neutron and the positron, we have more or less a complete understanding.
I can read the scripture of particle physics. I do have the atom we had.
We understood the atom as composed by atomic nuclei of protons and neutrons, and then of the electron electron layers.
So it seems that more or less things were in place.
Of course they were important questions, but some people thought perhaps there are minor issues.
However, the discovery of the moon of 37, which is a heavier electron, basically was completely unexpected.
Like nobody expected the the moon, as some people put it for that.
Why do we need to have the electron? What does this state in the scheme of things and to make things worse then a plethora of newer,
strongly interacting particles called pions chaos was soon discovered.
So as you can see in this time and here. So by 33 we had the neutron, the positron, but then we had the mean pions cones and then,
you know, a large array of other particles, lambdas, obstinance.
And the question is, can we make sense of this really [INAUDIBLE] situation?
And moreover, many important conceptual questions were left unanswered.
For example, if you have protons together in the atomic nuclei, they have Coulomb repulsion, right?
So they should be atomic nuclei should explode. Why? Atomic nuclei are stable.
What close together protons in the nucleus. What is the origin of weak interactions?
Which are the life radioactive decays so why we atoms decay radioactively we had no theory to explain this.
Moreover, all these particles are fundamental. They are composite.
They didn't have any structure.
And even more important, which is a suitable mathematical language to describe particle physics is quantum mechanics is something else.
This was not clear to many people. Now, let me begin with the first thing that actually this is quantum quantum electrodynamics.
This was well, this is it is the quantum version of electromagnetism.
So electromagnetism was discovered by many people in the late 19th century, and it describes the interactions of charged particles.
We had exchange of of photons, however,
making sense of quantum thermodynamics so making sense of electromagnetism once we called
quantum mechanics was extremely challenging y because you had to apply multiple infinities.
When we try to compute corrections, quantum corrections to electromagnetism, we encounter infinities and how to deal with these infinities.
What have theoretical thought? The force, which took ten years until the formulation of quantum electrodynamics was achieved?
I'm sure these are very beautiful theory because starting from simple rules, which are called the Feynman rules,
we can compute any terms as an expansion in power based on the weak coupling.
The electromagnetic coupling is basically the electron chatter square.
So these are small number.
So you can compute the leading term and then subsequently add more and more complicated attempts, each of which will be in principle.
It's my of the others. They can achieve an arbitrary position, make computing more and more complicated diagram.
So if I put together all these lines and all these vertices and I do the entire in principle,
I can achieve arbitrary accuracy in any any process and actually some of the most precise.
Nations that we have never done have been done with quantum electrodynamics, for example.
These are quantitative, which is called the anomalous magnetic moment of the moon,
which equity is known to an accuracy better than one part in 1 billion.
Imagine this we can compute something with this incredible precision and attack this with experiment.
It's really a major success of quantum theory. Of course, this is not an easy task.
We'll have to compute extremely complicated diagrams which involve complex interest.
But in principle, starting from these rules, everything else is fully, fully predicted.
Now, what about the poor? How they were just how they were discovered?
Well, in the beginning of the century, there were experiments discovered in internal structure of of atoms.
How this this was discovered. Well, so that was the experiment.
There was a theme, a theme for love of God. And then you had this was bombarded with alpha particles, which basically helium nuclei.
And we looked at a ruler for look at the reflection of this of these of these alpha particles.
Right. And by looking at the scattering angles of these alpha particles,
after interacting with their with atoms, they realised that the atom is not like a pancake.
The atom is really odd.
The all the positive charge is constituting a very small volume, which is the atomic nuclei, and then the electrons are around these nuclei.
So this was, of course, our impressive discovery.
Very interestingly, 70 years later, the very same technique was used to discover quarks.
What did we do? Well, in this case, instead of using alpha particles against atoms, we use very energetic electrons and we bombarded a protons.
Right. And by looking at how the electrons were deflected, whereas when they scatter with a product,
we discovered that in the proton the charge is also point, like it's concentrated in small volumes.
And this what is what led to the discovery of of of quarks in there in the proton by the same
mechanism as the discovery of the atomic nuclei by their in their order for experiment.
Of course, the concept, of course, had been known for a while.
Right. Since it seems since the sixties we had the Constitution Park model, which allowed to describe all the all the others as composed by this.
This. Hypothetical particles, which are called the quarks, like example,
the proton can be understood as as composed by two apart and one network and the neutrons one upward to the quarks.
However, these works were very peculiar, right? To begin with, they had fractional charge.
So they tell us either two thirds or minus one set. And we have never seen a particle fractional, fractional charge.
So many people was a sceptic and they thought that perhaps this is just a mathematical trick to organise hadrons by physical existence.
However, after the experiments that I mentioned here, people realised that they are able to play a good mathematical description.
They are really they have a physical existence and describe their. The structure of Aladdin's soap with just up down a stretch we could describe.
Essentially all known. No. So again, we had the very interesting surprise winning the 73 to 77.
Two new, heavier quarks were soon discovered, the Champ Quark, with a mass of about 1.5 and the bottom quark with almost about five g.
So this is there in this spot here, you can see that their discovery of their channel.
So how these things were discovered, we had an electron positron collision.
Right. And we've vary the mass, the energy of the collision.
And at some point we see that there's a peak. Right?
This peak is indicating that in this collision there is a particle which has been formed with Hamas around three TB.
This particle was called the jape site, which corresponds to a mass of our time.
And so this was the discovery of the Templars in 73 and there is an even heavier support of 475 times.
The proton mass is it's a single particle which is almost 200 times heavy on the proton.
Had to wait until 1995 to be discovered because it's being so massive.
We need very high energy colliders to be to be able to. To detect it now.
So I've thought about quantum electrodynamics, this activity spectra.
But if I can compute terms because the coupling is small, I can just compute 10% expansion in orders of this coupling.
So this, of course, makes a theory very predictive. I thought my Feynman ephemeris I can draw diagrams for any process.
I can compute the corresponding cross-sections. However, the atoms interact strongly.
Right? The interaction is characterised by if like it's coupling is something which is very strong.
So it seems that the model of QED is of, of affirmative quantum field theory is not applicable and that we need something else.
And people working this are extensions of like a theory or its matrix.
However, a breakthrough came in in 1973 when it was realised that there was a theory that could describe the strong interaction.
At the same time, the attractive theory is called quantum thermodynamics, and quantum computing has a very peculiar feature,
which is the following, which is the strength of the strong interaction.
So this is the value of the QCT coupling as a value, as a function of the energy right in the remains able quantum of series,
the value of the couplings around this with the energy. This is the three romanisation group equations.
Now, if you look at low energies, for example, well below the proton mass,
this coupling is very large and the theory is strong, interacting as all the data suggested.
However, once we look at very high energies, for example, 100 times the proton mass,
the theory becomes quickly weakly coupled because alpha is a small number.
And in this regime, what I'll face is a small.
We can just exactly the same techniques as what QED to do to computer, to compute predictions for physical observables.
And this was verified to very, very high accuracy.
So again, quantitative theory is the right language to describe not only the electromagnetism, but also the strong interaction.
So the strong interaction, say, QED, has the photon. In the case of a you see we have the gluon,
which is the particle that made this interaction and is responsible of binding together the quarks in there in the proton.
And this you can understand that easily. So we see that the strong interaction is something that the coupling but also with the energy.
Right. We know that even in quantum mechanics growing with the energy, so it's more energy to correspond to larger distances.
Now, imagine they have two quarks and they have they are very close together.
If they are close, it corresponds to basically large energies.
So the copying is small, but if I tried to pull them together, so I pulled them apart.
Sorry, their distance will increase. At this point, these correspond to lower energies and they will become a strong.
So the fact that the coupling is large is large. A small energies for large distances implies that we cannot have quarks isolated.
They will always be bound together because this coupling is very large.
Now, the gluon was also discovered but also verified experimental its existence in 1977 and this is called three jet events.
So the theory of the strong interaction predicts that if we collide electrons and positrons,
some of the events that we will see in our detector will have kind of mercedes's shape.
You have to quirks here. And then there's a gluon recoiling and this is exactly what was seen.
So this would be awkward yet quartette the yet.
So again this provided an extra evidence that electricity was the right theory for the strong for the strong interactions.
Now going to the interactions with interactions are something that was having known for
a while because it's allowed to explain the idea of metallic metallic of of nuclei.
Now, in the 1930s, Fermi explained the metallic of nuclei by full body interaction.
So basically you have a neutron and these news on the case into a proton and neutrino and the electron in out for body interaction.
So therefore the atomic number of this nucleus would change by what one unit as modified in better metallic experiments.
So it seems that these are also very different from the strong, from the it from QED, right?
Yeah. There is no particle mediating this force.
So what's it is possible to describe the weak interaction in the framework of this quantum field theory?
And the answer is yes.
And the point is that as opposed to the blue one and the photon, which has no mass, they are massless the carriers of the weak interaction,
which are the WS and their bosses, they have a very massive they have a mass of almost 80 GBPS, so 80 times the proton mass.
Therefore, if you look at weak interactions at low energies, you would never resolve the mass with just a point interaction as once you hear.
But if you go to very high energy,
you will see that actually there is a particle propagating like just like the photon or it, but that is very massive.
So in the standard model, the weak interaction of Fermi can be seen as here.
So we have this ah neutron composed down, up, down.
These are proton composite, right down, up, up. And then the down emits the larger you boson so transforms into an output and it will
give us some indication for the electron unable to do so exactly as s as Fermi had.
But now in the context of that, nobody is able quantum theory.
So also in this in the seventies, the fact that this theory was the right explanation of the interactions was verified.
So, for example, the discovery of neutral currency neutrino scattering.
So you have high energy beams of neutrinos which you point to some target, and then you try to reconstruct the results of this collision.
Now, one of the predictions of this was that the neutrino there would be neutral patterns in the sense
that the neutrino will interact via the neutral particle that and then hadrons would be formed,
but no other charge that happens. So these the neutrino these are the traces of the of the evidence for the collision, but there's no charge at level.
So you have neutral currents. And then you also mentioned that the analysis of this kind of images was done among other places.
Know what we are speaking now, which had a crucial role in the discovery of that of the neutral currents.
So we have seen the electromagnetism, the strong interaction and the weak interaction.
What is the only missing piece? This is the the Higgs mechanism. Right.
So what's the problem? Well, Julia will talk much more about this.
Let me just explain it briefly. So the problem is that in the standard model, its symmetries don't allow to have mass in the Lagrangian.
Right. So in particular, we have a electroweak.
A Electroweak theory has a asymmetry between left handed and right handed particles, which for beat the particles.
So what is the Higgs mechanism? These are very clever trick to bypass the restriction, because in the Higgs mechanism the laws are still symmetric.
But the configuration that nature has chosen is not symmetric. Right.
Is this is the famous Mexican hat potential.
Right. If you look at this potential, this potential exploitation, asymmetric, right.
Any direction looks the same. However, the point where the Higgs field just has to be is not is not traditional
symmetric is just one point of all the possible end points of the of the minima.
So these are spontaneously symmetric breaking that laws asymmetric.
However, the specific configuration of the vacuum is not.
So it's actually a mechanism that all the particles in the standard model can operate en masse.
And it's a crucial product. If the energy of interaction is high enough, we can excite the Higgs field.
And excitations of this Higgs field are the Higgs particle which can be produced.
And that's the ultimate test, that this explanation is the right one,
that the Higgs mechanism is correct description of the mass, and the model is the discovery of the Higgs boson.
So it was predicted more than 50 years ago,
but it took an impressive and impressive effort from theories that experimentalists to be able to develop the calculations
and the machines to be able to finally vindicate this prediction and was discovered two years ago at the Lateran Collider.
Okay. So this is the standard model. Let me move to the second part of my thought.
How can we explore the high energy frontier? And this is the best machine we have nowadays to explore the frontier.
Is there a Large Hadron Collider?
So, first of all, why do we care about high energy colliders, what they are suitable to explore really nature at the smallest possible distances.
But we know from the Heisenberg Principle this is there was a question here that if we want to prove something which very small resolution,
we need to have a proof which is very energetic. Right.
So if we want to resolve an object to very small scale, we with a particle which is very energetic, if not, it will be impossible.
So a rule of thumb is to convert distances in energies is the following.
If I have a particle with one GV, this corresponds to roughly a distance of a .8.42 ten to the minus time into a matter of 50 metres.
It's called 0.2 pendulums. This conversion sets the energy that we need to more or less use to explore smaller and smaller objects.
Like, for example, a an atom has a length of about 10 to -8 centimetres, right?
So we need energy of the earth at about 2.5 million to exploit a structure.
If we want to prove the structure of an atomic nucleus, this is an object of about ten to the -40 metres.
We energies of the order of 200 amoebae, which makes sense because these are typical energies which are that are relevant for nuclear processes.
If we want to go to even smaller distances in particular to to prove the structure of the proton, we need a particle has energies in the GBE range.
And this was precisely by the experiments in like a ten GB because this is right energy to be able to resolve the internal structure of the proton.
If we want to go further and explore, for example, if electrons or quarks have a further structure,
then we need to prove energies because a quad is known to have our radius of a smaller than 10 to 16 centimetres.
So with energies of of two TB right. So if we want to reach really the smallest possible distances, there is no other option.
But going to that to these wide the LHC collider that is bring the escape.
No high energy carriers have been around for a while.
Right. The first collider was there, the Lawrence cyclotron in Berkeley.
And as you can see, by the standards that we are now used to, it is just, you know,
it's almost at that point, right, is only 1.5 metres and the energy seems very small at 15 maybe.
But this was really crucial, right? Because this was the first time that in a controlled setup,
you could accelerate particles and restore its results without a with without the collider.
What is the problem? And we want to use we can only use cosmic rays, for example, or, or that natural process.
So we cannot control in detail which are the settings of our collision.
And this is of course not good for extend our point of view.
We want to control everything. And in the case of our cyclotron, we have all the activities that we want to to control the energy of the collisions.
And then these are very clean proof of air. Of our experiment.
So they have many other colliders being built. And then I would just highlight three of them.
One of these is it's like this the Stanford Linear Collider with a length of three kilometres.
This is in in California. And an edge of 98 is a linear collider, which means that I collide electrons with positrons.
These are very clean experiment. However, it switching energies limited.
There's also the collider in Amber, which was the first and only electron proton collider ever built.
So we have a high energy beam of electrons colliding with a high energy team of protons, the length of six kilometres and the energy of 210 GB.
And then there was the platinum collider in Chicago, which was before the energy was the highest energy collider of the world,
which is a proton collider in a tunnel of six kilometres.
And the energy you have out to TV. Each of these experiments has provided us crucial information of the standard model.
But since a some years, some years ago, we have the Large Hadron Collider really and is an impressive machine.
Right? It's the most powerful accelerator ever built by mankind.
They taught it at CERN in Geneva, which is the sun, is the European Laboratory for particle physics.
So it's composed by a massive 27 kilometre long tunnel with four gigantic detectors in them.
So this is the this is a photo taking of the LHC area.
So this is the Geneva Airport for those of you that nobody at the Geneva.
This is where seven is located. So my office used to be here for three years.
And then underneath all this area, there is a Large Hadron Collider. So these are the SPS.
And then this is the LHC tunnel that goes almost from the airport to the lake.
And then today I'm on the other side of the lake.
And identity of the protons attacks had the highest energies ever approved with the goal,
as I was mentioning, to explore the laws of nature, the smallest distances ever achieved.
So in the LHC there are four massive detectors.
They are called Atlas CMS, satellite TB.
You can see, you know, by comparing with the size of a of a of a person, they are really they're really massive.
They are like six, seven, eight story buildings of an amazing technology.
I'm always impressed that these things even managed to work. Right. You have something which is huge as a building.
Everything wires and detectors. And, you know, it manages to work on two quite impressive measurements.
I think that's the technological is an impressive achievement.
So I say, well, I also wanted to mention that Oxford has played the central role both in building
these detectors and now in operating them and extracting the most of that information.
The galaxies are an impressive machine, right?
But without its detectors, which are able to explore, you know, and able to extract information from the collisions, then it would be useless.
So we thought the detector, having very energetic protons, is not very useful.
So let me show how articulation looks like. So these are nice video done by their Atlas collaboration.
So this is the LHC tunnel. Right. So here you have there we have that protons, which are actually a very, very high energies.
Right. So let's go inside the beam. This is the proton composed by in this video by three quarks.
And the proton is six and eight of them. At some point the beams will cross.
Right, and they will cross in the interaction points whether that they are located.
So we have their proton beams, they get close to each other, and then eventually they collide.
And what the detector does is by reconstructing the traces of the collision, reconstructing the hadrons, the leptons, the most, the missing energy,
that the aim is to reconstruct what has happened in this interaction point, because this interaction point is that collision of very high energies.
So therefore, here is precisely what we are calling nature at the smallest distances.
So let me mention some facts about the LHC, which I think are quite interesting.
So first of all, LHC is one of the coldest places in the universe in order to keep it in magnets.
So it is based on semiconductor superconducting magnet in order to keep these magnets operating with very, very low temperatures.
So the LHC will have a 30 kilometres tunnel just kept at only two degrees above absolute zero, which is, you know, it's called the interstellar space.
Another interesting fact is this is one of the empty space in the solar system.
Why? Because if in the beam where we have the problems running, there is even a very small density of air particles.
The problem we've had with these particles and we will not be able to explore the in the detector.
So we with really a very, very high vacuum like us.
Another interesting fact is that it's one of the hottest places in the galaxy.
So, for example, when we collide, heavy ions like for example, that in the LHC,
the temperature that we generate is an example of these collisions are billions of times larger than in the sun.
Right. Which is the conditions similar to those in the very, very early universe.
And also a final score. They think it's really impressive is the amount of information that we extract from the LHC in just one second.
The LHC in principle could record one third of out of data just per second.
Right. So this is like having to record 10,000 sets of Encyclopaedia Britannica per second.
So it is it's an impressive technological challenging to be able to efficiently skim all this huge amount of information for the relevant events.
So what bility has has what have we learned fertility up to now?
So the first result has been that rediscovery of this model.
What do you mean by rediscovery? Well, in the previous slides I mentioned the discovery of the deep sea obsidian as a particle.
The very first thing that DDT had to do is to check that everything was still there.
And this might seem obvious, but it is not because this machine is technologically very complex.
So first of all, we have to validate that everything is in place, that the detectors went to the detectors, its performance.
And also, we need to check out our calculations, which have been tested before at lower identities.
Also hold high energies, because we are these are very largely average.
That's increasing the energies. So the in this book here by this collaboration, this is a plot of the.
This is proton proton collisions into the news in this case.
And each time we see a peak, it means that there is a new particle has been produced in this collision.
So, for example, if we look at around three, three gbps, we see a peak.
This is a site discovered in 73. If we look at above at 1022, we see the epsilon.
This is bottom 90, both the mission discovery in 77 and then at around 100 GB that does have mass, right.
It was very nice to see that no ability.
We can quickly rediscover the oldest under model and test our calculation with a very high degree of accuracy.
And this is very important because predicting the standard as well as just passing predicted processes with
very high accuracy could be the key to discover new physical reality in there in the following years.
Of course, the biggest achievement of the LHC has been the discovery of the Higgs boson.
In this video here, I'm showing a collision in which a Higgs boson candidate is being is being formed into four into four leptons.
So each of these four lines is are four leptons,
which is one of the cleanest channels of the production of the K and Julia know talk about this later.
And this is a extremely challenging measurement, right? Because it requires to disentangle a very small signal from of a large background
and to try to to convey the message of how challenging these measurements are.
Let me show you an extended mission by the Atlas collaboration. So how we discovered the Higgs from the practical point of view.
So we begin without any data, right? And we want to measure two things.
One, to measure the masses of default numbers so the Higgs can decay into pairs of photons.
So if we look at beta photons and compute the mass, if we see a peak, that would be a discovery of the Higgs boson.
The same the Higgs can be came to four letters.
So if I compute the mass of four atom events, which is not in this model, will be evidence for the Higgs.
Right. So let me begin to take data. So slowly I began to accumulate data.
But here there's nothing, just a flat line. So just background. But with more and more data, right?
Something will appear. What will appear? There's a structure forming here, right?
And what is this structure? This is a peak around 25.
TV is very interesting because this is this could be the mass of the Higgs boson.
Now, is it really the Higgs boson could be something as a statistical fluke?
Well, what we do is to go to the other process, which is going to four leptons and also big data here.
Right. So I'm taking data in the Higgs into four letters to begin with.
I don't have anything. So I need to more and more data. Everything looks under model no Higgs.
But eventually there are some events here that hey, they are their mass 125 GV and they are not they are not.
Some said that for example, this could be a Higgs.
And the crucial thing is that this signal here has a peak at exactly the same mass as they're wanting today for the channel.
These are very strong. Check that this feature here, this feature here correspond to the same logic like this,
that the Higgs boson and actually at the at the LHC, these two channels, two forms, four letters.
What are the ones that we are able to proclaim our discovery in July 2012.
So it really this is why after this massive exercise, we can be happy because we found the Higgs boson.
No. Okay. However. Some of our models is an impressive success and we should be really proud of.
It is one of the greatest success of modern science.
However, despite its successes and discoveries, Higgs boson, there are many crucial questions which are still left open.
For example, the stability of the Higgs Mass. Why the Higgs Mass is what it is and not the mass of the mass at very, very high energies.
What is the nature of dark matter or that cannot see those forces unify into a single one?
So our strong interactions with interactions and explanation aspects of the same force or they are not.
Is there a theory of everything? What is the role of gravity? Because the gravity doesn't fit in a standard model, right?
What is the origin of the matter? Anti-matter asymmetry.
So there are many questions which are really crucial that have been not that are left open by another model.
And the interesting thing is that there are many theories that go beyond the standard model, and many of these can be tested at the LHC.
So the LHC is a unique tool to scrutinise these theories, which will try to attempt some of the limitations of the standard model.
One popular example that you might have heard about is called supersymmetry.
So in supersymmetry, each particle has a super partner. So we have talked about quarks, neutrinos, the force carriers and the Higgs boson.
So in supersymmetry, we have the standard model and we have another copy of all the particles with the spin the force by one half.
So you have the force which had us no fermions anymore.
We have this leptons and then we have the the best symmetric version of the case, Boston Dynamics of the Higgs, which is called the Higgs.
And among all the things that have been predictions of supersymmetry,
it predicts that all the free forces are strong with magnetic, if you will, two very high energies.
They become just a single, single force.
So this what is called a force unification, which is, of course, a very attractive theory out of a fundamental theory of nature.
However, as of today, there are no hints of yes in physics ability.
However, in just a few months, data will have started even higher energies and will have ten, 15,
20 years to keep exploring the high energy frontier and try to understand all these pressing and very important questions.
So I think that it is very likely that we have many new breakthroughs and we are on the corner.
Okay. So in the last 5 minutes, I want to mention what's next, right?
What's what's beyond reality? And this is important because in high energy physics, building these facilities,
since it's really at the cutting edge of technology, it takes long timescales.
Right. Both from the civil engineering to a technology to or to the physics,
say something that even if we are only at the beginning of the LHC problem, we have to begin to think what comes next.
So this is the scale of the LHC for the next 25 years.
So I'll say what's amazing, they deliver a huge amount of interesting results, but we are just at the very beginning of the problem.
Right. So we have seen how they can data for three years at seven TV and a TV reality has some that are going along shut down of two years.
And now we are here. We are about at the beginning of day, which is called rental, where the energy has increased from eight TV from 13 to 14 TV.
So there will be a period of about eight years of running for TV and then there will
be a very important upgrade in which the LHC will be turned into the high luminosity.
LHC What's a high luminosity?
It's only the number of collisions per bunch crossing will be increased substantially, so increasing the chances of finding interesting events.
So we have half work for the next 20 years to really try to explore the high energy frontier.
And the LHC is the best machine that we have for this. And something which is crucial, especially in the lack of any evident signal of BFM theory,
is to try to sharpen our understanding of the weak interactions, electromagnetism, because this would be the key of new discoveries.
New discoveries would appear as a subtle deviation from some normal prediction.
So the better you can compute things with high precision, the closer could be to a new discovery.
At the Large Hadron Collider. And of course, it's essential to have a very close interplay between theory and experiment.
Right. And two of the central ingredients of the LHC program for the next 20 years.
Well, first of all, precision measurements of the Higgs couplings. And Julia will talk about this in her talk.
And then the search for dark matter. The LHC and Woolly again will tell us about this.
So as I was saying in about 2022, we have to upgrade the LHC and turn it into our high luminosity machine.
What's the high luminosity, as it was mentioning, is now in the municipality.
The number of collisions that a bunch of crossing would be much higher, which means that the chances of finding interesting events will be larger.
Of course this has challenges because if you have more collisions, you have more single events,
but also many more background events like these because this looks extremely messy.
We have to extract interesting signal in a in a collision where we have almost 200 collisions, literally a background noise and need to be removed.
So this requires a complete upgrade of the LHC detector.
And also here, Oxford is studying a central role, in particular in the case of Atlas in building the new Atlas Atlas Silicon Tracker.
And so let's try to think even bigger. So what comes in the next 20, 30 years?
Well, as I was mentioning, the planning of these facilities is always an expression of very long timescale.
Right. Because we are at the cutting edge of technology, of civil engineering.
You know, there are problems that these machines are planning the solution.
So we to think we are out of time. So in particular now we are discussing whether the next peak machine would be 100 TV.
Collider So seven times higher than the Large Hadron Collider.
Also, we have electron positron, an electron proton model. This is called tentatively Future Collider and this is the plan of a possible site.
This would be again in Geneva. So is the LHC tunnel.
This would be the 100 kilometre long tunnel where this could be built.
So you see that it's quite impressive that as compared to the FCC, it's very small, despite being an incredibly large machine.
Also sites China is very interested in this kind of projects. And there's a proposal for the FCC in China.
And now in the context of of working groups,
there is a worldwide effort trying to understand both the technical feasibility and the physics motivation of this of this proposal.
There are also other ways that we could explore the hydrogen from the earth.
For example, there are plans to build a linear collider where you have electrons and positron collisions at very high energies.
For example, there is the plan of having click in Geneva.
It would be a linear, linear tunnel that goes from the French part of the French area to almost all given crossing all the Geneva area.
These are cleaner machines because electrons are fundamental constituents, so there is less background noise.
However, they have greatly reduced reduce friction.
In. So I think that I've tried to convey that this is really a fascinating time to be in particle physics,
that this has been an incredibly successful theory and that it will be the
best tool we have to explore the high energy frontier for the next 20 years.
I think that you should really stay tuned for news for the LHC because I'm sure that
there will be very interesting results from us and you will be happy to have them about.
So thanks for your attention.