Sep 19, 2017
How Albert de Roeck creates space by unravelling the mysteries of the universe
Happyplaces Stories (video)
When I travelled to Lausanne to film Claude Nicollier, to learn more about space from an astronaut, I thought: ‘Then I also need to understand better what space is.’ Since I had been at CERN once before, I was intrigued by what is happening there.
All the speakers at LIFT Conference were invited on the Saturday after the conference, to visit CERN and the Large Hadron Collider. When we arrived there, we first got a lecture from a bald and little grey haired old man who seemed to know everything there is to know about the subject, rushing us in an extreme high pace through a huge pile of slides. And then we had the opportunity to visit the experiment locations. Fascinating stuff. The most advanced subway station yuo ever visited, with instead of trains a blue pipe. Nothing to see really, but knowing what happens there is mind-boggling: they smash the tiniest bits of bits into one another, and through doing that try to unravel the mysteries of the universe.
Since that visit, every now an then CERN made it into the news. They found something, but then not. Then a crash. And then years later, they found that tiny invisible thing bit matter particle boson: the Higgs boson. What fascinated me was that this search has taken years, decades even. And meanwhile people from all over the world, even from countries that were or are at war, people from all religions, beliefs, cultures, backgrounds, worked together to find the seemingly impossible: something so crucial and minute that might help to have a better understanding about the universe. Might. I had to know more. And since I happened to be in the neighbourhood…
I made an appointment with Albert, who led the Higgs group for two years, also when it was discovered. We met at the public entrance, and then we had a long walk through the facility. Which was amazing. You could feel that something significant was happening there. What an amazing, but at the same time humble place. Scientists, like astronauts, have missions. They have a goal and have just what they need to accomplish that. So expect no tech-company fancy lounge areas. And big-ass machines they call experiments, big as cathedrals.
Hello. We are now at CERN, the biggest particle physics lab in the world in Geneva. My name is Albert de Roeck. I am a Belgian scientist working at CERN, and I am a so-called senior scientist. That is, I’m working on physics projects here at CERN, and particularly at experiments at the Large Hadron Collider, the biggest accelerator in the world to date. The Large Hadron Collider is a massive scientific instrument. It’s an accelerator, which accelerates particles. Particles, which are called protons, which are in fact constituents of atoms. This machine is large. It has a circumference of about 27 kilometres. It’s a machine of 27 kilometres. And it is 100 metres underground here in the area nearby Geneva.
Unravel the mysteries of the universe
In that machine, we accelerate particles at very very high energies. The highest we can obtain with this kind of machine. And we have two, what we call beams of particles moving in opposite directions the whole time. And at certain points along that ring of the Large Hadron Collider, we make these different running beams collide. Thus, protons from the one beam will collide with the protons from the other beam. What will happen then is, that due to these very violent collisions, we will transform energy into matter. We are able to create particles. New particles. Particles that we have never seen so far. One of these particles, which we have been looking for for a very very long time, is the so-called Higgs boson.
An accelerator isn’t enough. You need to surround the ear where the collisions happen with a detector, that can detect particles we create at these collisions, such as the Higgs boson. These detectors, or experiments as we call them, are very huge indeed. In fact, they’re as big as a cathedral. One is 20 metres high and 40 metres long. And the volume of the detector is filled up with sensitive detectors that see the passage of the particles we create in the directions of these proton-proton collisions which are sprayed out and then pass through our detectors. I am working on one of these detectors. There are two of them, well, there are more, but there are two big experiments which we call ‘the Higgs Hunting Experiments’ in our jargon. And they will also look at all sorts of new phenomena that will possibly come out of these collisions. So I work at one of these experiments. The experiment is called CMS, the Compact Muon Solenoid, that’s what the abbreviation stands for. For the past two years, my role in that experiment has been to lead the group of scientists to search for the Higgs boson. That requires a lot of resources. In that group, 700 people were active. 700 Scientist, starting from graduate students, post-docs and also senior scientists. All were working in trying to unravel the mysteries of the universe in these collisions that we have. In particular as a first task to try to find this long sought-after Higgs boson.
Experiments make or break theory
Here at CERN, in fact, all over the scientific world, we have been very excited by this finding of the Higgs particle. This Higgs particle was proposed as a solution to a problem 50 years ago already, by scientist, by theorists. But it has turned out to be very elusive up to date. And we didn’t know if it existed, or not. So why does it matter that we know that it exists? What makes it valuable is that it allows us to understand that we are here. We know of course that we are here, that we exist. This Higgs boson was a crucial ingredient for trying to understand where we come from.
The problem is the following: we have atoms. Atoms have a nucleus. And they have electrons going around that nucleus. And that builds most of the things that we see. It builds us. We consist of atoms, which are atoms with these atoms zapping around them. These electrons have a very tiny but non-zero weight or mass as we say in technical terms. And that is crucial. If the electrons had not any mass, they would fly through the universe at the speed of light. As a massless particle does, or a particle without weight. If that were so, atoms could not be formed. And a nucleus would never be able to capture the fast-going electrons and keep them around them to build the atoms that we have. This shows the importance of the atoms having little mass. It has been a puzzle for a very long time where the electrons get their mass from. What are the mechanisms that cause mass to elementary particles. The postulation that happened 50 years ago is that there is a field existing, a so-called Higgs field, which is all around us. We don’t see it, but the elementary particles feel it. And this field slows them down. Gives them mass, gives them weight. Makes the differentiation between a particle that has no weight and a particle that has weight. Does this field exist for real? of that we had no experimental evidence. In the end, it is always the experiment that can tell you that your theory is right or wrong.
The field itself we can’t measure. But the agent of the field, the quantum as we call it, of the field, namely a particle should exist which has the properties of that field. This is the Higgs particle or the Higgs boson. So the hunt has been on to find that particle. That particle, detecting it, would be a direct proof of the existence of that field which is so badly needed to have a consistent model and theory of how fundamental interactions occur. It tells us even, what happened at the very beginning of the universe just after the Big Bang. It teaches us that at some point in time, very shortly, a fraction, less than a million of a second after the creation of the Big Bang, that field must have come into action giving weight to the particles. So it’s a fundamental particle, this Higgs boson. And, this quest for it, started not immediately after the theory was introduced. Since there is always scepticism, there are different models around. There were different ideas around. This was one of the more elegant and economic types of ideas. But therefor not necessarily the right one. But the proof was in finding this Higgs boson.
Hunt
In the seventies, when the so-called Gauge theories became popular, and particularly some Dutch physicists Veltman and ’t Hooft have played a crucial role in making that happen, that people started to realise these theories should be taken very seriously and ultimately led to, what we call, the Standard Model of Particle Physics. At that point people started to say, well this Higgs mechanism or maybe some completely other mechanism, more complicated that we don’t know of, must be part of that model. Otherwise, we are left without particles without mass. And we are aware from experience all around us, the mere fact that we exist, that it is not the case.
The problem was that nobody really knew what this particle looked like. We identified properties it should have, but we didn’t know how heavy that particle itself was. Was is very light? Was it intermediate, something like the mass of a proton? Or was it maybe a hundred times the mass of a proton? The theory didn’t tell us. That was the experimental challenge: to find in all the debris of collisions, first at the lower energies and up to the very highest energies, to find that particle. And we also knew that this particle is also not produced very often. You need a billion collisions to create one Higgs particle. So we had to generate a lot of collisions to find a substantial number of Higgs particles actually to prove that it existed. Experiments looked for it, and they searched with the capacities they had, with the energies of the machines available.
Before the LHC there was no sign yet of the Higgs particle. It excluded that the Higgs particle was lighter than a hundred times the proton mass. The particle had to be heavier by itself. So the last best hope at this point to find the Higgs particle was the Large Hadron Collider. The machine with the highest energy in the world to date. The machine also designed with the mission status, with one of its points in the mission, to find the Higgs particle. Or proof once and for all, it didn’t exist. Then we would have to back to the blackboard and reevaluate our theories. Because then there was something we didn’t understand in the theories.
So there was a lot of anticipation building up when the experiment started in 2010. At first, the LHC just like with a new car started running but not yet at full speed. A sort of ‘running in’ for some time, that took a year. In 2011, the LHC was running smoothly, producing lots of collisions and at the end of that year, we started to see the first evidence. Something was in our data, which was a new kind of particle which was heavy, about 125 times heavier than the proton. And particularly, and that was the use of having two experiments which worked independently, and as competitors, they started to see at the same time and at the same place something happening in their data. Which were the first traces of the possible birth of a new particle.
Then came the year 2012. And the machine was running at full speed now. Like a race car that is making record laps each time it went around the circuit. So we got even more collisions. That allowed us to investigate and look at the place where we saw the first traces of something happening in the data of the year before. And indeed, we had confirmation that the significance of the signal we found was growing more and more up to the point where it reached the discovery level criteria for a new particle. Ans that was the exciting moment in 2012. We have collaborations, two collaborations. Each collaboration, in total, has 3,000 people working on it. 3,000 Scientists were working on it. And both collaborations, at the same time, observed the new particle in their data. Which at that moment looked like a Higgs particle, walked like a Higgs particle, quacked like a Higgs particle, but we weren’t quite sure entirely that it would be a Higgs particle. We needed more detailed data for that. But it looked fantastic. I think that was a big collective triumph when you have so many scientists concentrating on this goal of finding this particle.
New questions
These complicated detectors have more than a hundred million readout channels. That means that they look at signals in a hundred million small detectors, to reconstruct that back to find the decisive proof that we had a new particle. That created a lot of excitement in the world. That meant that we understood a new mechanism. In my mind, it even means that we have found a new force. Because the Higgs force is like none of the forces that we know.
But it also brought in new questions. We know now, how a particle gets mass, but what it didn’t explain quite yet is, why a certain mass of weight was given to it and why the electron is so light? Why are some of the elementary particles we know so heavy? These are the questions we are facing now. And with the additional data, which we are going to collect in the next years we’re going to tackle these problems.
But there are more questions. The particle we have found is at a very nice place, experimentally, to measure it. Because this mass is really within our reach. Within all the channels that we can study. But from the theory point of view, we know that this can not be the end of the story. A particle of that mass does not generate a stable universe as we know it. There must be new physics, new particles, heavier which are somewhere lurking around the corner, waiting to be discovered. And that is the mission now. To find these new particles, which are going to guide in the understanding of why certain particles get a certain mass and why we live in a stable universe as it is.
Very special, for a moment
I consider myself very lucky. Very fortunate to be part of this scientific adventure. To be able to play a role in it, a significant role, leading the Higgs group was very important in the past two years. It is the fascination that when we now make these collisions and analyse them, we go where nobody has gone before. We’re going into a new unchartered territory. And we can expect surprised. It was a bit like Columbus when he sailed off. He has a goal, so have we. But he ended up somewhere else. Surprisingly, but for the benefit of all. We, scientists, are driven by an enormous curiosity. Sometimes people say that scientists have never really grown up. They always kept their curiosity. And that drives us. And that is also why we have bizarre schedules. Many people here, when we have new collisions work seven days in a row. And sleep a good fraction of the 24 hours a day. Because they want to find out, want to be there when something potentially new pops up out of the data. When that happens, as that took place when we saw the Higgs boson, you feel very special for a moment. You know, especially for those of us who saw this for the very first time when we had the combined results and learned that we had a new particle, there were maybe five or ten people in the room when we opened the box and checked what the data told us. You know something. And you know you know something unique. For a short while. You know more than anyone else around you. Even more than your scientist colleagues. Then you prepare to announce it. There is no reason to keep it a secret. You just want to run out of the room and shout in the corridor: ‘We got it!’ But we are more disciplined than that. So we organise a way of releasing these results. In a way that the scientific community also has a way of scrutinising these results and maybe point out flaws if there would be any. There weren’t any. That moment between the announcement and the fact that you know it is a small circle that grows of course within the experiment over time is a very special feeling. And that makes it all worth it. That you are at that position, even for a short while.
Matter
And we would like to get there again. So we have other projects, ideas, searches which we want to pan out with the data of this machine. And we have very strong hopes and wishes that we are going to see new things that might help us to understand what the mysterious dark matter in the universe is. We as people consist of bionic matter. That is matter that builds up everything you see around us. But we are only 20% of the true matter that we know. When we study galaxies, we see that there is something extra that we don’t see with our telescopes, that we call ‘dark’ because it doesn’t emit light. That is very likely a new kind of particle, very heavy that almost doesn’t interact with us. But we hope to produce it here in the collider and to study it. We hope that this could be our next step.
Universal language of science
In daily life, we’re actually like normal people, apart from the working hours I mentioned before. We perhaps understand a bit deeper where we come from. But we go shopping, see movies, have an occasional beer, drive cars. We do what normal people do. But of course sometimes when you look up when it is a nice sky with lots of stars you can think: ‘I know where you guys came from.’ You guys came from the Big Bang; we know the processes that followed there, understand the theories, understand everything apart from the very beginning, which we still have to discover. There may be new particles and forces were at work, and this is what we hope to discover.
Another aspect is the very international character. I love that. We have collaborators from everywhere. You come into contact with a lot of cultures, a lot of people who have been raised in different conditions, who have been living under different conditions. But they are all scientists. And they are all united by this goal of unlocking the mysteries of the universe. In our case, by using the Large Hadron Collider. And it is my fascination, that all these scientists in this environment here at CERN where so many nationalities are intermixed are working with each other, through the goal they have, can work in perfect harmony to get things done. And to get things to work. In our detector, we had components which were manufactured in Pakistan, went through Italy, the US and finally arrived here at CERN to be installed. Since we use the language of science and engineering that worked fine. If you overcome differences in things like measurements, I think, you have a universal language. We have in our experiment Iran as a partner, the US, Arabic countries, Pakistan, India: it all works fine. If people have a great goal or dream to work for, then religion or politics don’t play a role. At least not in our world of scientists.
World machine
Personally, I found it to be one of the fascinating things. I consider myself as a bit of an ambassador, going around, also exploring countries and regions which are not yet in our experiment. And try to talk about the adventure that we are doing here. Which is a project we just started but will take on the next twenty years at least. And to invite countries, scientists in these countries who are interested and who are also caught by the same virus as we are, to join and come and work with us. And that worked. For example, last year we had scientists from Thailand, who now have become a member of our experiment. We had scientists from Malaysia who also became a member. And we now work with much more, also in the Arabic world. Qatar, Saudi Arabia. Countries that not yet have the tradition to do particle physics that we are doing. But they have expressed the interest. They want to talk with us to see if they could join. And we are welcoming new institutes, new countries to join this adventure because the experiment we have here is for humanity. And not for some privileged institutes or countries. It is a world machine that we have here. I take that very literally myself. It should allow scientists, wherever they come from, to work with us on unlocking the secrets of the universe.
Religion and science
What we are doing, does not conflict with religion. Yes, we are addressing questions like: ‘Where do we come from? How do things work? What are the forces between the particles or matter?’ Religion often offers different explanations for that. We have no problem for that. In my experiment I see no religious people having trouble with what we find. They say: ‘Science is based on facts. And the facts are what they are.’ Whit some exceptions, of course. I know that many of my colleagues are deeply religious. And I think that it is entirely compatible. It does not influence in any way, as far as I can see, they work. You can be religious, you can believe in a higher power. But scientists know that facts are facts. And they won’t argue about this when we find something new like the Higgs particle. Which was misnamed first, the ‘God particle’, which has nothing to do with a religious type of statement.
