Fundamental Particles – A Myth

Some of the earliest machines used to probe the atom were bubble chambers, that produced exquisite pictures of fundamental particles at the heart of matter.

Fundamental Particles
Particle Explosion

And now, behind these doors, Joachim Mayer has a machine that gives us the best possible view.

Professor Andy Parker “What you see here is a sudden explosion of particles from nowhere in the liquid of the bubble chamber and that is because a neutrino has hit an atomic nucleus there and smashed it to pieces, and we see the particles flying off. And that’s anti-matter being created from pure energy. So this is the map or a part of the map, of what nature can do. So it’s part of the map of the universe.”

But now, after 80 years of smashing, the map is complete. In the summer of 2012 scientists at the LHC, announced the discovery of the famous Higgs boson particle. It’s the final piece of what’s called the Standard Model – a set of 17 fundamental particles including quarks and electrons that make up everything we know.

Professor Andy Parker
Professor Andy Parker

But for physicists like Professor Andy Parker it’s not the end of the story.

Andy Parker “Everyone’s heard about the Higgs boson but the story goes much beyond that. In fact my main interest is beyond the Higgs boson.

Like any great explorer, Andy Parker is not satisfied that this is the end of the journey.

Andy Parker “OK so we’re in the ATLAS main control room, this is where the experiment crew, shift crew here are sitting taking data today. Collisions are happening 40 million times every second.”

And as the energy of the collisions increases, Andy will be able to look on smaller and smaller scales, even delving inside the so-called fundamental particles.

Professor Andy Parker

ATLAS Control Room
ATLAS Control Room

Andy Parker “Fundamental particles is a myth, I think. It looks at the moment as if quarks and electrons are point-like particles. We can’t see any size to them but that is just because we haven’t been able to measure very short distances around them. What I’d like to see this what’s going on inside them. So we’re looking for the innards of the quarks by smashing them together as hard as we can.”

In the search for the smallest piece of the universe, part of the problem may be knowing when to stop. Each new layer reveals great secrets. But does this search have an end?

Or within every small thing, is there another… and another?

Perhaps the best known of all the fundamental particles is the electron. It underpins much of our modern lives, from computers to streetlights to televisions. But for theoretical physicist Professor Jeroen van den Brink, the electron might not be as fundamental as we think.

Professor Jeroen van den Brink

Professor Jeroen van den Brink
Professor Jeroen van den Brink

Professor Jeroen van den Brink “The more fundamental things are, the nicer it is to look inside them. Physics it’s always that something appears to be fundamental, and just because we believe it is fundamental we take the next step and try to look what’s inside it.”

Jeroen’s idea was that, rather than smashing electrons into pieces, he could find a different way to split its properties… the very properties that make it so useful.

Jeroen van den Brink “So the electron has three fundamental properties, charge, spin and orbital and theoretically it’s definitely possible to split those three parts of the electron. If you do the mathematics there is no problem in doing that. If you do the quantum mechanics, it’s completely allowed. So in principle you can split the electron, at least you can do it on paper.”

The Swiss Light Source

Swiss Light Source
Swiss Light Source

If you want to do it in practice, you need this… the Swiss Light Source; a million watt light bulb.

Andreas Ludeke “This is an in vacuum undulator.”

The Swiss Light Source is in fact the Swiss X-ray Source. Inside the ring, under the care of Dr Andreas Ludeke, a beam of electrons creates the ultimate x-ray laser.

Dr Andreas Ludeke

Andreas Ludeke “This is a superconducting cavity.”

It’s one of the most powerful, highly focused, narrow x-ray beams in the world.

Andreas Ludeke “We have a high intense magnetic field in the middle.”

The perfect tool for probing down to the size of an electron. Jeroen’s partner in electron splitting, the man he devised and runs the experiment, is Dr Thorsten Schmitt of the Paul Scherrer Institute.

Dr Thorsten Schmitt

Dr Thorsten Schmitt
Dr Thorsten Schmitt

Dr Thorsten Schmitt “So here we are in the so-called optical hutch, where all the crucial optical elements – mirrors which are optimised for x-rays and which are used for shaping the beam quality are sitting.”

Jeroen van den Brink “So when I come here I go to the equipment, I look at it, I admire it and then I go back and sit behind a computer or take my pen and paper and start to do the mathematics. I do not really understand what the stuff out here is exactly doing and I believe, I’m sure Thorsten does and they do the experiments.”

Thorsten Schmitt “We have x-rays, which are coming in and hit a sample, and we will then in the end analyse the x-rays, which are re-emitted or scattered off from the sample.”

Spinons, Orbitons and Holons

Spinons, Orbitons, HolonsWhen the x-ray beam strikes, the electron split into new quasi-particles. These particles, called spinons, orbitons and holons, carry the properties of the electron, and can travel off in different directions.

Jeroen van den Brink “This is actually the picture that tells the whole story. The most important part is here, the red part, what’s important is that it’s wavy. And this waviness tells us that what happened in this experiment is that the electron was split into spinons and orbitons. So this is the picture that is the experimental proof that the electron has been split. So the electron can be split into these three different particles, but, really, what can you do with those particles when you have them? I don’t have a good answer to that.”

The electron has, in one sense, been split in three. But it’s a measure of just how weird things are down here that it still considered to be fundamental. Down at this scale, we just have to accept that the rules become deeply strange. And if we reach down even further, we may have to throw out the rule book altogether.

External Links

Higgs boson particle – Wikipedia Page

Fundamental Particles or Elementary particles – Wikipedia Page

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