Teilchenzoo: Quarks - Bausteine der Atomkerne

Now it's about quark. It's about quarks. Of course. But how does a particle get such a strange name? The theoretical physicist who came up with the name quarks, his name was Murray Gell-Mann, he found them exotic and said we need to come up with a new exotic name. So he called them quarks. He was inspired by a novel by James Joyce called Finnegan's Wake. Quarks appear as people in it who behave a bit strangely. But I think they're good. My quarks are just like that. Even though these strange quarks came from the book, they always form the interior of an atomic nucleus. So if you keep asking what matter consists of, what is the interior of matter, then you get to atoms and atomic nuclei and then you get to quarks. And then you realize we're all made of quarks. In fact, 99.99% of the mass consists of these quarks. However, it's not just about one and the same quark. In fact, our accelerators have a total of six different quarks. They all have great names. There's the up and the down quark, meaning up and down in English. Then there's one called strange, meaning strange. And then there's one called charm, meaning charming. And then there are two that are heavy. There's the bottom, like bottom, and top, like top. The top is also very sharp, meaning it's a great particle. You can see that physicists have fun inventing new particles. You can always choose a name. So there are six different quark types, all of which like each other very much and are very sociable. Because a single quark is never to be found. You can create quarks. Here, for example, we did that. Here's an accelerator. And this tube up here is our quark thrower. We took quarks and accelerated them. That's relatively difficult, because you can't take out a single quark. Quarks always stick together. They can only pop up together. There can only be two or three quarks that form a bound particle. There's no single quark. And that's what the so-called gluon is responsible for. It comes from the English word to glue, which means to glue these quarks together. And that's a very funny force. So if you have three quarks and they're very close together, then the force is relatively small. But if you try to pull out a quark from this band, then these gluons act like rubber bands. That is, the stronger I pull on it, the stronger the force becomes. If I try to get the single quark out, I have to pull in more and more force. And what happens is that I don't even free the quark, but I destroy the whole particle that consists of the quark and create new particles that now again consist of quark groups. That is, no one has ever seen a single quark. You know from the electric charge that there is a positive charge and a negative charge. There are two. But to explain these forces that hold quarks together, you need three states of charge. And the physicists were creative again and said, plus, minus, we need something third. Come on, we'll take colors. There are red quarks and green quarks and blue quarks. That means you can take a red up quark and then you can, for example, build an atomic nucleus. This was found, among other things, here at the particle accelerator HERA at DESY in Hamburg. Up here in this accelerator we have accelerated quark packets, protons, particles that consist of quarks, and brought them into collision with other particles, with electrons, which are elementary. And with these electrons, you shot deep into the proton and then shot quarks out of the proton, and quark alone does not work, but it immediately produces new particles. And that's how we really saw what's actually going on in the proton, that it's a bubbling soup of quarks and gluons and what's not what, and that it's the proton. So it's much more complicated than we may have imagined 30 years ago. So who knows how the particles will continue to open up in the next 30 years.