Daniel and Kelly’s Extraordinary Universe - The Sticky Story of the Gluon's Discovery

Episode Date: November 26, 2020

What is the gluon and how was it discovered? Daniel and Jorge take us through the dramatic events. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

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Hey, Daniel. Is science as dramatic as they make it out to be in the movies? You mean like, do we all wear white lab? coats and go, aha, while making discoveries in the shower? I don't want to know if you wear a lap coat in the shower, but isn't that dramatic? No, it's not usually so exciting. You mean you don't storm into a room with a piece of definitive evidence on a piece of paper and claim some amazing discovery all the time?

I'm waiting for the day I have a chance to do that, but so far, nothing. Really? That doesn't happen in particle physics? Not usually, but there was this one time... In which you wore a lap coat in the shower or in which you had definitive evidence? I'm not going to answer that question. I'm Jorge. I'm a cartoonist and the creator of PhD comics. Hi, I'm Daniel. I'm a particle physicist and I love storming into rooms with definitive evidence. How often do you get to do it, Daniel?

Never, almost never. I'm desperate for an opportunity. How do you know you love it if you've never done it? I dream about it. You simulate it in your head. It's funny when I talk to young students who are interested in particle physics and they read about big discoveries and amazing revelations about the universe and then I tell them that, you know, we don't make discoveries every day.

It's not like that on a day-to-day basis, unfortunately. Really? You throw cold water into their optimism and enthusiasm? I do. I don't want to mislead them. And then I show them all the fun puzzles that we do get to solve on a day-to-day basis, which is more like, why is my code not working and less like what is universe made out of? And then they walk out of your office, or are they hooked by the small puzzles?

You get some of both. You get some of both. Well, welcome to our podcast, Daniel and Jorge, explain the universe, a production of iHeard radio. In which we try to hook you on the puzzles of the universe, the big questions about how the universe was made, how it all fits together, why it works at all, and whether we can understand it. Yeah, because science is a process. It's real people asking questions about the universe and trying to figure out how to answer those questions. Because it's not always clear.

That's right. It's people pushing forward individually with their curiosity on the boundary of knowledge, trying to figure out, is this the way things work? Is that the way things work? Does this particle exist? How about that other weird particle? And sometimes there are dramatic days of discovery, though those are few and far between. Usually it's more subdued, you would say, you know, more about, you know, slow discoveries or slow consensus of discovery. Slow discoveries, you know, these days the particles we're discovering take more information to find them. You don't have like a single picture of an event where you say, oh, look at this new weird particle that nobody's ever seen before. It's more statistical. But back in the early days of particle physics, you really could.

You could, like, have a cloud chamber. You could see a particle decay in a new way that nobody'd ever seen before. So you could have this, like, single event discovery. But those days are behind us. Do you think those people would also describe it as exciting and dramatic? Or maybe I wonder if it was still a slog for them, you know, like, if it was incremental and slow for them. I think there were a lot of boring days in between the dramatic days of discovery. But those individual days must have been pretty exciting.

I think about the way archaeologists, like, dig for human bones. And sometimes you hear about like a 25-year career that finally they found a jaw bone. And I'm thinking like, why did they keep digging after 22 or 23 years? That takes a lot of determination. They were waiting for someone to throw them a bone to their career. And then it happens. And it does happen. And that's why I think these stories of discovery are useful because they help inspire the next generation of scientists to remember that we don't make discoveries unless somebody keeps pushing forward.

At least it helps get them into your office. office, at which point you discourage them and tell them the real truth about research. I tell them the real truth to encourage them because there's lots of different ways to do science. Some people like to do science by writing programs. Some people like to do science by tweaking lasers in the basement. There's lots of different ways to do science. The most important thing is to find the way that you find fun. Well, it is fun to discover new things. And so today we're going to be talking about a very specific discovery that was done in particle physics. And Daniel, this is a bit of a sticky story. It is a bit of a sticky story. And it's part of a series of episodes we've had

on how we understand the standard model. We know that everything is made out of particles, but how do we know that those particles exist? Are they just theoretical ideas? What experiments did we do to really reveal them? And for me, this is really fun because it reminds people that all these concepts about how the universe works came out of individual experiments. Things people saw, weird stuff that happened when we smash stuff together that reveal the nature of the universe. And by standard model, you mean sort of like our collection, our idea, our survey of all the particles that make up the universe, right? Yeah, we've been building it for decades now, our understanding of what is out there, what kind of particles can be used to make up the universe, not just what particles are used to make up the universe, not just what particles are used to make up me and you and hamsters and llamas and ice cream, but also what kinds of particles are

possible. And that gives us a sense for like how the universe is organized and what the patterns are and gives us access to some of those really interesting, fundamental and basic questions. But we find these one at a time, bit by bit, sometimes after years of painful work. Yeah. So you call this list or this, I guess it's more like a table or like a like a grid of particles. You call that the standard model. Yeah. The standard model is sort of like our current consensus list of particles we found and what we know about them. And so it's filled with a bunch of particles, about 12 of them, right, so far? Yeah, there are 12 matter particles, the kind of particles that make up me and you and all sorts

of stuff. And then there are other kinds of particles that represent forces, the way the things push against each other and pull themselves together. And so there's a handful of those extra particles as well. Yeah. And so today we'll be talking about one that, I mean, you could literally say it's the nucleus of all the things that we're made out of, right? That's right.

It holds all of us together. Yeah. So to the end of the program, we'll be asking the question. How was the gluon discovered? And the gluon is one of my favorite particles because it has such an awesome name. I wonder what that meeting was like. They're like, we got this new particle and it's really sticky. I can't get it off my fingers.

You know, I did a little informal survey here in my household just a few minutes ago. I asked my kids, I said, if I said the word glue on to you, what do you think that means? And my daughter said, I don't know, something particle physics-y, maybe, but it sounds kind of sticky. And so I thought that was a pretty good guess. Yeah, I think having a particle physics dad might have influenced their answer. That could have been a clue, yes. Yeah, so this is one of the fundamental particles, and it's pretty important. right? It's definitely very important. Without the glue on, we would not be here.

Nuclear would not hold together. The universe, as we know, it would look totally different without the glue on. But it took a while for us to find it. It's a pretty interesting story. And so we'll jump into that. But first, we were wondering how many people out there know about, I guess, first of all, the glue on. And second of all, how it was discovered. So as usual, Daniel went out there into the wilds of the internet and asked people to send in their answers without looking it up to what they thought. What was the process in which the gluon was discovered? That's right. And so if you'd like to volunteer to answer hard physics questions with no preparation and no Googling, please write to us to Questions at Daniel and Jorge.com.

We'd love to put your baseless speculation on the podcast. So think about it for a second. How would you answer the question? What is the gluon and how was it discovered? Here's what people had to say. I don't know how the gluon was detected, but like the rest of the Daniel and Jorge community, I would imagine it happened at the LHC and its discovery as an epic tale

that changed the fundamental understanding of the universe. Maybe by firing lasers at protons and then protons explode and you can measure gluons flying away. It was about time. He was hiding for a long time. Probably was a sting operation there.

I think gluon is what holds quarks together. So my guess is when quarks were discovered, we wanted to find out well, what connects these quarks? What's the strong force that holds these things together? And that might be how gluons were detected. I think that it's likely that some physicist or scientist

discovered it by a happy accident. I think like everything else in particle physics, you take normal matter, you smash normal matter, normal metal goes boom, and all that is left is some weird stuff. All right. A lot of people want to give you credit. They think it came from the LHC at CERN. That's right.

Everybody just gives all the credit for particle discoveries to the latest, hottest, biggest, sexiest collider. Yeah. Well, you guys have taken up a lot of headlines, at least in the last 10 years. Yeah, well, that's true. That's because it takes a while to build a collider. So you don't get like a new one every year or so. So when you build a collider, it sort of takes up the popular imagination for a couple of decades. Well, there are a lot of answers here about it holds nuclear together.

It involves quarks and laser. So, step us through this, Daniel, I guess, first of all, what is the glue on? And does it dry really quickly or do you have to wait like 24 hours? Well, first of all, I have to say, I wish that I had more lasers to play with in my job. Mostly it's just tapping on a keyboard. I don't get a fire laser basically at anything ever, which is too bad. Well, you probably have a laser in your mouse, right? But you have a little, like, a laser, that's how your mouse probably reads where it is.

Yeah, that's true. There are lasers everywhere. I have a laser my laser pointer, which I used to use for lecturing when I gave lectures in person, but no more. Anyway, a glue-on is a really fun particle, and it's a really important particle, and it's connected to the strong nuclear force. And it has sort of the same relationship to the strong nuclear force that the photon does to electromagnetism. Electromagnetism, you remember, is the force that gives us, like, electricity and magnetism. It's, you know, the thing that gives us lightning and electricity and all that good stuff. And that force is carried by the photon.

Like, anytime you have an electromagnetic interaction, you have photons flying around carrying that information. Really? So it's sort of like the transmitter particle, the photon. Yeah, exactly. We break up particles into two kinds, matter particles, which are like electrons and quarks and that kind of stuff, the stuff that makes up matter and stuff. And then the force particles, and that's how the particles talk to each other. And you can think about two electrons coming near each other. How do they bounce off each other?

They don't have like physical edges that touch the way your elbow touches the table. What happens is they shoot photons at each other to talk to each other and bounce off each other? Even like a fridge magnet or like if I take two magnets and they repel each other, they're actually shooting photons at each other? Yeah. And it can get a little hairy to think about what the actual photons are. Really what we're talking about are wiggles in the fields between them. So every magnet has a magnetic field, and when it moves, it changes that magnetic field. And information about the changing field is what we call a photon.

These aren't always the same kinds of photons that hit your eyes. They can have very low frequency, very high frequency, or sometimes they're even virtual particles, not particles that live a very long time. We have a whole fun podcast about what it means to be a virtual particle. It is just sort of the name you give to the wiggles when, two particles talk to each other. Yeah, exactly. The way they talk to each other is sort of action at a distance. You know, people wondered for a long time, like, how do things push on each other without touching? And the answer is that they have these fields, right? An electron,

for example, has an electric field around it, and that field is what pushes on the other electron. A totally equivalent way to think about that field is to think about it as a bunch of particles. So you can either think about it as fields or particles. For now, we think about it as particles or think about those particles as the wiggles in the fields. It's really all equivalent. Right. And so the gluon is the one that transmits the force for the strong nuclear force. So that's one of the four fundamental forces. Electromagnetism and gravity are two of them. A third one is the strong nuclear force. That's right. Exactly. And we spent a lot of time understanding electromagnetism. The first theory of quantum fields was by Feynman and quantum

electrodynamics. It was the understanding of how electrons use photons to talk to each other. And then we thought, well, can we also use this for the other fields and the other forces? And so like the strong nuclear force is a very important one. So people were thinking if electromagnetism has a particle that's used to go back and forth between electrons, what's the particle that goes back and forth between quarks when they interact using the strong nuclear force? And so that's the idea of the gluon. That's why we thought maybe there is a gluon in the universe. And I guess maybe just to recap the strong nuclear.

It's not a force that we feel on an everyday basis, like you don't sort of need to know about it. But it is sort of what's keeping the nuclear of your atoms together, right? Like that's pretty much the sort of the main place where it acts. Yeah, it's a very short range force. And so it likes to hold things together very, very tightly. It's very, very powerful. And so it's mostly balanced out. Like anything that's imbalanced on the strong nuclear force very rapidly, that force will

realign so that everything gets like smoothed out and balanced out. and that you don't feel the force anymore. And so it operates mostly very short distances like the size of the proton. It ties those quarks together into a proton and hold it together. And what you feel on a normal everyday basis is mostly electromagnetism. Like when you push against the wall,

it's the electromagnetic force of the bonds of the electrons to the atom that are keeping the atoms from passing between each other. Right. But it's very short range in that, like if I have a quark here and a quart meter away, they're not going to feel the strong nuclear force, right? It's only when you get them really close to each other,

but they then snap together. Yeah, actually, you can't have a quark by itself because the strong nuclear force is so powerful that as soon as you create a quark by itself and give it like any distance at all, the energy stored in the strong nuclear field is so powerful that other quarks will just be created out of the vacuum to surround it. So the situation you just described,

having like two quarks a meter apart, is essentially impossible in our universe because so much energy would be stored in the strong nuclear force between them, that it would just create a shower of other matter in between them to surround them with other quarks. Wow, that's wild. All right. Well, so that's the gluon, but it's different than the photon. That's the gluon, exactly.

And it's different from the photon. Like, it's the force particle for the strong nuclear force. And the strong nuclear force is also pretty different from electromagnetism in lots of other ways. Like, it's not just that it's a short-range force and it holds a nucleus together. It's different because it's more complicated. Like electromagnetism has positive and negative charges. And photons only interact with things that have positive and negative charges. Like if you're neutral, like a neutron or a neutrino, then you can't interact with a photon.

The photon ignores you. It only interacts with things that have positive and negative charges. But the strong nuclear force is really weird. It doesn't just have two charges like positive and negative. So you can't like line them up on a number line and think about like plus one plus two, zero, minus one, minus two. It has three different charges, three different directions. So you need like three axes to think about instead of just two. Like it has a plus and minus and an X.

Yeah. And so instead of lining them up on the number line, we actually think about them in terms of colors. We think about them in the red axis, the green axis, and the blue axis. And that sort of works mathematically because if you add them all up together, you end up in the middle, we call that white or like colorless. And so we try to make this analogy to how we know colors mixed together to help us think about these color charges. These are not electric charges.

They're charges for the strong nuclear force. They're color charges. And I guess maybe your question is how do we know about these different charges? Like it's such a strange concept. It's really weird. And it was a cool discovery, actually, in the 60s and 70s because when we first started understanding that particles are made out of quarks, you know, that protons have quarks inside. them. We found all these other particles that were different mixtures of corks. We found this really weird one, the delta plus plus particle. And it was made of three upcorks. It was just like

three upcorks combined. Gives you this doubly charged delta plus plus particle. But there's a problem with that because we think that quarks are fermions. That means that like electrons, you can't have two of them in the same state. Like you know how if you have an atom, you put an electron around it. The next one has to go up in the next energy level. Can't like. hang out together. Firmions don't like to be together in the same quantum state. And so the problem with a delta plus plus is that it has three of these quarks, but they should be interchangeable. Like, how can you have three fermions all in the same quantum state together in a particle seem to violate this basic principle? And so somebody thought, well, maybe they're not the same. Maybe they all have

like a different color charge. One is red, one is green, and one is blue. And that would explain it. And so that was sort of the origin of the idea. And so I guess maybe quartz can have any one of these three charges, like an up quark or a down quark can be red, green, or blue. Yeah, exactly. The way like an electron and positron are related because they have opposite electric charge, but they are a different particle. A quark can be a red quark or a green cork or a blue cork. We don't call a different particle. But the truth is that there are three different kinds of up quarks.

They really are different particles. Green upcork is different from a red up quark. or a blue up quark, the same way an electron is different from a positron. All right, so that's the gluon. The gluon is what transmits the strong neuterforce and which therefore holds all the quarks inside of your protons and neutrons together, which is kind of important. Without it, you would just fall apart. You totally would because remember that these quarks also have electric charges.

Like a proton has two up quarks in it and a down quark. And the charges, they were totally blow it apart if the gluon wasn't there to hold it together. So thank you, gluon. Thanks. Thanks for sticking with us and sticking us together. All right, so it's super important and people theorize that it might exist, just like the photon existed. But the discovery of it was pretty interesting and pretty dramatic.

So let's get into that. But first, let's take a quick break. Parents hauling luggage, kids gripping their new Christmas toys. Then, at 6.33 p.m., everything changed. There's been a bombing at the TWA terminal. Apparently, the explosion actually impelled metal, glass. The injured were being loaded into ambulances. Just a chaotic, chaotic scene.

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Oh, wait a minute, Sam. Maybe her boyfriend's just looking for extra credit. Well, Dakota, it's back to school week on the OK Storytime podcast, so we'll find out soon. This person writes, my boyfriend has been hanging out with his young professor a lot. He doesn't think it's a problem, but I don't trust her. Now, he's insisting we get to know each other, but I just want her gone. Now, hold up. Isn't that against school policy? That sounds totally inappropriate. Well, according to this person, this is her boyfriend's former professor and they're the same age. And it's even more likely that they're cheating.

He insists there's nothing between them. I mean, do you believe him? Well, he's certainly trying to get this person to believe him because he now wants them both to meet. So, do we find out if this person's boyfriend really cheated with his professor or not? To hear the explosive finale, listen to the OK Storytime podcast on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. Your entire identity has been fabricated.

Your beloved brother goes missing without a trace. You discover the depths of your mother's illness, the way it has echoed and reverberated throughout your life, impacting your very legacy. Hi, I'm Danny Shapiro. And these are just a few of the profound and powerful stories I'll be mining on our 12th season of Family Secrets. With over 37 million downloads,

we continue to be moved and inspired by our guests and their courageously told stories. I can't wait to share 10 powerful new episodes with you, stories of tangled up identities, concealed truths, and the way in which family secrets almost always need to be told. I hope you'll join me and my extraordinary guests for this new season of Family Secrets. Listen to Family Secrets Season 12 on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. All right, so we're talking about the discovery of the global.

glue on, which was not a simple or easy discovery, apparently, Daniel. Yeah, and it was a dramatic race, actually, between two different groups of folks, the Europeans and the Americans, both trying to build a collider capable of discovering the glue on and racing against each other. Wow, that does sound dramatic. So I guess people knew that it probably existed, right, because something must be transmitting the strong nuclear force. But I guess maybe just the question was, like, nobody had seen it, right? Nobody had seen it on like a piece of paper or an experiment. Yeah. So this is like the late 70s.

And at that point, we had found all the quarks, the up, the down, the charm, the strange, the bottom, but not yet the top cork. People were pretty sure the top cork was out there, but it was going to be another 15 years or so before it was discovered. And we knew about the photon and electrons and stuff. But all the other force particles that we now know that glue on the W and the Z, those had not yet been discovered. And so we really only had evidence for one force particle, the photon. And so we were pretty sure the gluon existed, but it was kind of a big extrapolation. And so it was going to be really nice to say, like, wow, it really existed actually out there. It was sort of a big question for particle physics, whether this whole like forces as particles moving between other particles thing was real.

You know, the same way like we think maybe gravity has a graviton, but nobody's ever found it before. We could be totally wrong. Maybe gravity doesn't work by exchanging particles. So it was really a big open question. It's easy to look back on these things and say, oh, yeah, that was obvious. But at the time, there was a lot of uncertainty about whether this whole picture of particles talking to each other by passing other particles back and forth was really valid. We didn't know if the idea would stick together. So I guess maybe, you know, it's interesting because a photon, you can sort of see, right?

Like you can literally see a photon. It'll hit your eyeball in the back and you'll see it. But can gluons do that too? Can you see an individual glue on? Like can it float out into space and hit your eyeball? Well, a glue on like a cork can't be by itself. And that's because it's colored. Not in the sense that it like is red, green or blue,

but in the sense of the strong nuclear charge. And anything that has a strong nuclear charge has so much energy bound up in that force that immediately creates a spray of particles. So if you had a gluon flying through the air somehow, what would happen is they would create other corks around it to balance out that color charge. So what you'd get is a stream of particles.

Wait, so a gluon has charged, but like a photon doesn't have charge. A photon is neutral, right? Like light doesn't have positive or negative charge, but gluons do have charged. Yeah, and that's one thing that makes the strong force very different from electromagnetism. You totally put your finger on it. Photons don't talk to each other. Like photons pass right through each other. They don't have electric charges.

Photons can only talk to things that do have electric charges, but they don't talk to each other. So like two rays of light don't bounce off each other. But gluons, you're totally right. They have color. They actually carry two colors, each of them. And because of that, they can interact with each other. And so two gluons, like shooting at each other would totally, like, form a little particle.

In fact, we're searching for that. We can talk about that later. It's called a glue ball when you combine two gluons into a particle. Glue ball. Nice. All right. So there was a race to detect the gluon. So we sort of had an idea of it and maybe a theory about it,

but nobody had actually seen it until people were smashing things together, hoping that one would pop out or that, you know, evidence of one would pop out. Yeah, the idea was that you needed enough energy to make them. What we had done already was smash particles together and see pairs of quarks. So you can smash, for example, an electron and a positron together. And those will annihilate it and turn into a little ball of energy like a photon. And sometimes that photon will turn into two quarks, like a torx, like an up quark and an anti-up quark.

When you get then, there's two corks flying out, but because of what we talked about earlier, how corks can't be by themselves, each one turns into like a stream of particles. We call this a jet of particles. What do you mean a stream? Wouldn't that mean that they're like one in front of the other? Wouldn't they stick together?

Well, you have two corks coming out a really high energy back to back. So like one with a lot of energy in one direction and the other going in the other direction with a lot of energy. And so they don't stick together because they have too much energy. They're flying apart. So it happens to say they create new particles out of that energy and turn that energy into mass.

And so instead of one cork flying one way and an anti-cork flying the other way, you get like 10 quarks in a decorks in one direction and 10 flying the opposite direction. Like one in front of the other? They come together because quarks don't like to be by themselves. And so they form other particles. So you never actually see a quark. What you see are particles made from corks. You see protons and caons and pions and mazons and all sorts of crazy stuff. So when you create a quark and an anti-cork, you create these two jets of particles.

Each one has particles inside of it that are made of corks. Okay. But I guess you don't actually see the individual gluons then. You just see kind of like the gluon after it's created friends for itself. Yeah, so people had already done that. They had seen pairs of quarks. And the idea was, what would happen if you put more energy into the collision? You poured more energy into this electron-positron pair.

then there might be enough energy for a gluon to be created. So not just create the cork and anti-cork, but also in addition, create this glue-on. Because just like an electron can give off a photon, if it has a lot of energy, a cork can give off a gluon. It can radiate a gluon if it has enough energy because there's just so much energy flying around that you might occasionally randomly create one

and send it off in a new direction. In that case, you would see three of these jets, not just two back-to-back, but three in sort of like a Mercedes pattern, each flying off in a different direction. But we hadn't yet done that. We hadn't built a collider with enough energy to create these gluons.

So the idea was build a bigger collider, smash particles together, higher energy. Maybe instead of just seeing two quark jets back to back, you'd see two cork jets with a gluon jet coming out the side. Right. But you wouldn't see the glue on. The glue on jet would just be, again, more quarts. Yeah, exactly.

You wouldn't ever see the glue on directly. So it's frustrating sometimes in particle physics because these detections are never like perfect little pictures. It's not like we went hunting for a unicorn and we have a picture of the unicorn and it's indisputable. They're always sort of indirect. And here with cork and gluons, you never catch them by themselves. You just sort of see the evidence for what they made. You just see the hoof prints and the sparkles.

Yeah, it's more like you look for a celebrity and instead you see like the paparazzi around them. Because these corks and gluons create these whole streams of particles, which you can see. You can't actually see those. Anyway, so there was this race between the Americans, and they were building a collider at Slack. And then the Germans were building one at this collider at Daisy, which is a lab outside of Hamburg. I see.

So it was Americans versus Germans. Slack is the one at Stanford, right? Stanford linear accelerator complex center? Club. Collider. That's right. And so it was the late 70s, and everybody was trying to build their collider to get there first.

And the Germans turned to sort of a. unusual source to build the materials and the facilities for their collider. They had a revolutionary idea to hire manufacturers that used to build refrigerators. What? To build their collider. Yeah. And so they subcontracted out to this refrigerator company. And that company would like able to ramp up really quickly and deliver the parts needed for this accelerator. It's called Petra, P-E-T-R-A. And it may be the first collider ever in the history of particle physics to turn on ahead of schedule and under budget. What?

It was also the first one to have an ice dispenser conveniently. Somehow they snucked it in. But why fridge manufacturers? Just because the equipment was similar or they're just good German engineers? Yeah, both. You know, we use a lot of refrigeration in particle physics, but mostly we're building, you know, high precision machined objects. You need these vacuum tubes.

You need the struts. And they were in a race and they said, hey, look, this company says they can do it. Let's give them a try. And so they gambled a little bit and won. So they were able to build their collider and come in ahead of the Americans. Wait, so this one and Slack were being built at the same time? We're being built at the same time, yeah. And then, unfortunately, the Americans went with a toaster manufacturer,

which had a lot of delays. Is that what happened? They spent all their money on avocados, also in anticipation of the toast, and then they went bad. Those Californians. Too far out. All right, so the Germans build it first, and so did they find it first, or what happened when they turned it on? So they found it first, and they crank this thing up.

And, you know, these days, our colliders are very, very high energy. You know, the LHC, for example, works at 14 terra electron volts, which is 14,000 billion electron volts. Back then in the day, in the late 70s, it was a big deal to have like 13 billion electron volts. And so this collider turned on first at 13 giga electron volts. and cranked its way up to like 27 giga electron volts in the spring of 1979. And the cool thing about particle physics discoveries is that once you have enough energy, it can come pretty quickly. Like the barrier to creating these particles really is just having enough energy in your collisions.

And so once you turn it on and you have enough energy, you really only need a little bit of data to actually find something. Because I guess things are quantum, right? So like you need to hit a certain threshold of energy before. certain particles will be created because you can't make half of a glue on, right? That's right. You can't make half of a glue on. What you can do is make a low energy glue on.

And so what you need to do is put enough energy into this collision that the glue on can grab enough the energy that it can fly off by itself and make that third jet. So people have seen events with two cork jets in them, but nobody ever seen a glue on come off and make that third jet. So as you crank up the energy, you expect to get more and more energy into the glue on, And then the glue one should have enough energy sort of like fly off and be on its own

so you can actually see its own third separate jet. All right. So then how much further ahead were the Germans? Like were they years or months ahead of the Americans? It was just months ahead. And there was a conference in the middle of the summer in 1979 that everybody was aiming for. And the Germans were hoping to turn their machine on and to see this and to deliver decisive results at that June conference. They were hoping to have some pretty.

cool result to freeze out the Americans with their fridge collider. They were going to stick it to them. Yeah. All right. Well, let's get into the actual discovery of it because apparently it was pretty significant and interesting to finally get to that big drama moment. But first, let's take a quick break. The holiday rush, parents hauling luggage, kids gripping their new Christmas toys. Then, at 6.33 p.m., everything changed. There's been a bombing at the TWA terminal. Apparently the explosion actually impelled metal glass.

The injured were being loaded into ambulances. Just a chaotic, chaotic scene. In its wake, a new kind of enemy emerged, and it was here to stay. terrorism law and order criminal justice system is back in season two we're turning our focus to a threat that hides in plain sight that's harder to predict and even harder to stop listen to the new season of law and order criminal justice system on the iHeart radio app apple podcasts or wherever you get your podcasts my boyfriend's professor is way too friendly and now I'm seriously suspicious.

Wait a minute, Sam. Maybe her boyfriend's just looking for extra credit. Well, Dakota, it's back to school week on the OK Storytime podcast, so we'll find out soon. This person writes, my boyfriend has been hanging out with his young professor a lot. He doesn't think it's a problem, but I don't trust her. Now, he's insisting we get to know each other, but I just want her gone. Now, hold up. Isn't that against school policy?

That sounds totally inappropriate. Well, according to this person, this is her boyfriend's former professor and they're the same age. And it's even more likely that they're cheating. He insists there's nothing between them. I mean, do you believe him? Well, he's certainly trying to get this person to believe him because he now wants them both to meet. So, do we find out if this person's boyfriend really cheated with his professor or not?

To hear the explosive finale, listen to the OK Storytime podcast on the Iheart radio app, Apple Podcasts, or wherever you get your podcast. Your entire identity has been fabricated. Your beloved brother goes missing without a trace. You discover the depths of your mother's illness, the way it has echoed and reverberated throughout your... life, impacting your very legacy. Hi, I'm Danny Shapiro, and these are just a few of the profound and powerful stories

I'll be mining on our 12th season of Family Secrets. With over 37 million downloads, we continue to be moved and inspired by our guests and their courageously told stories. I can't wait to share 10 powerful new episodes with you, stories of tangled up identities, concealed truths, and the way in which family secrets almost always need to be told. I hope you'll join me

and my extraordinary guests for this new season of Family Secrets. Listen to Family Secrets Season 12 on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. All right, Daniel, we are in, In the late 70s, right now, 1979, and the Americans are competing with the Germans to discover the glue on. And so finally, the Germans build it first, their collider and discovered it.

Was it that simple or was it kind of a hard discovery to make? It was a little bit tricky, and that's because this is the first era of colliders where we really had a lot of data coming in. Like you're doing collisions many times per second. and then you need some sort of computer assistance to sift through all these collisions and find the most exciting ones. These days, everything we do is on the computer, like at the large Hadron Collider, you know, there's millions of collisions per second and the computers sift through them before we ever look at them. In the early days of particle physics, you had stuff like, well, you had a collision, took a picture, you looked at it, and you looked at the next one. This is the first time we really had filtered the events and the collisions by the computer. But, you know, it's the 1970s.

And so the computers back then are like much, much slower and less powerful than the computer that's literally in your refrigerator today. Wow. Yeah, they took up whole rooms and you needed punch cards, right? Yeah, they had to be really careful and clever. And so they had to be really careful and clever about how they're going to use these computers. There's not a lot of memory in them. You can't just, you know, write whatever computer program you want and be sloppy about it. So there were a bunch of folks who wrote some really clever computer algorithms to try to isolate these events where you had three,

different sprays of particles and they wrote this code to like figure out on what was the best angle to look for these three prongs and to isolate the events that were most likely to look like this. And so not only did they build this accelerator ahead of schedule, but they had this cool new snazzy computer software to help them sift through all the collisions to find the one they were looking for. They're like, see this little paper cardboard card? That's my awesome new algorithm. It's pretty funny. Actually, I remember. my dad writing his master's thesis in engineering and using punch cards and, you know, feeding them into the computer and then, oh, it doesn't work and he's going to go to the back

of the line and wait his turn again to feed them in. It was pretty crazy. Wow. I guess you need a computer because how are you getting all this data? Like you're getting this data through detectors or like are they recording these events by hand? These are definitely from detectors. And so just like at the LHC, the collision point, The point where the electron and the proton smash into each other is surrounded by layers and layers of detectors that image particles that come out. So the electron and positron collide together in the heart of the detector and then, you know, whatever happens happens and things fly out.

Then we have these layers of detectors that say, oh, a particle passed me or a particle passed over here. And then we use that to sort of try to get an image of what happened. You can think of as sort of like a 3D camera that makes a picture of everything that's flying out from the detector and where it went. All right. So then they ran it and they found the gluon. Did they find like one event of the gluon or whole like millions of events? What did the data look like?

Did they have to sort of like sift through sand or was it like one big like boom? They did actually have to sift through a lot because gluons are not that common at those energies. Most likely you're just going to have two corks back to back and it's two jets. So they had to sift through a lot of events to find one. But then they did and they turned it on. And this is like in June of 1979, they're like, you know, a week before the conference and they find one. Their computer says, ding, ding, ding. We found one that's interesting.

Take a look. They print this thing out. They like, you know, lay it flat on a piece of paper so they can see what it looks like. And it's very clear. There's like three of these sprays of particles, not two like you expect to see from two corks, but there's three. There's definitely this whole third jet that's flying out the side. And they looked at it and they just knew. They were like, this is it.

And they went and they brought, like, that transparency to this conference in Bergen and, like, slapped it up there during the presentation and showed it. And that was it. Like, everybody was like, okay, that's it. You have found the glue on. We're convinced. Wow. Just one event. Like, they didn't wait to get two. After that, they collected a lot more data. And, you know, one event was enough to convince people, this is coming. They didn't actually write the science paper until they had a few more events to support it and other detectors at the same. Accelerator had seen it, et cetera, et cetera. But that one event really broke people's skepticism. That one event told them, yeah, this is real.

The backup data is coming, but now we know it's here. So that was sort of a famous event. People who were at that conference or in the field know that one event. They know what that picture looks like. Have you talked to anyone who was in the room when they, did they actually slap the transparency down on the overhead? They stormed in white lab coat flaring behind them. You know, here it is.

boom but this is sort of what i imagine like this is the moment of discovery this is sort of the thing that we all hope for that you're trying to crack a problem in the universe in particle physics trying to understand how things work and then it's just revealed to you you like see it there's the answer gluons are real this kind of event this three jet event just couldn't exist without gluons really it couldn't be like noise in the system or some kind of fluke or some kind of i don't know some weird other thing that could have happened with the equipment yeah you know there's a possibility of that. It's very unlikely for it to just be some weird noisy fluke, but it's a possibility. And so, of course, they cross-checked their results and other people

saw similar things. And so eventually the data was just indisputable. But that first event will always be the one that really heralded the age of the gluons and also opened up this whole era where we think about forces as transmitting particles. This really showed us that this picture of sending particles back and forth as the way forces work was not just limited. to electromagnetism, it also worked for the strong force, and it led to other discoveries a few years later. All right. Well, then what have we learned about gluons since then?

Like, what makes them extra special or weird? Well, gluons are weird because, as you say, they can talk to each other. Like, each gluon carries colors with it. And that means that it can talk to other gluons. And potentially, they can even, like, hang out together. There's this idea that if you get two gluons in the right configuration, they can even form a particle just made out of gluons. This should be like a thing that's pure glue.

Right, because they, like if you get three of them with different charges, wouldn't they just naturally stick together? Yeah, and there's lots of complicated math of ways you can combine gluons to make a color neutral object. You can also just do it with two gluons. They can have the opposite colors of each other. Now, nobody's ever seen this before. We call this a glue ball.

And there are experiments out there. One of them is called glue X that's looking for exactly this. kind of thing. So we don't know if it's real sort of in the realm of things. People have predicted calculations we've done. We don't know if we will see it. If it does exist, it's not going to be that heavy. It's just like about the mass of a proton or so.

But it's pretty tricky to spot because if it does exist, it's going to look a lot like other stuff. Right. It sounds more like a playground game, glue ball. Like, hey, let's play glueball. Yeah, exactly. So we're looking for these particles made out of just four. particles. Now, is there any president for that? Like, you can't make a particle out of photons,

right? No, the strong force is the only one where the force carrier actually feels the force. You can't make a particle out of two photons. And a few years later, we found other force particles. There's the W and the Z bosons. These are the ones that correspond to the weak nuclear force. And they also, they don't feel the weak nuclear force, right? So you can't make a particle just out of W's and Zs. So the strong nuclear force is definitely weird. It's weird in lots of ways. It's weird because it's three charges. It's weird because the force carrying particles feel their own force. And in fact, just like there are three kinds of quarks because of the colors, there are actually eight different kinds of gluons. Eight. What do you mean eight?

I thought there were only, there was only one with three colors to it. Well, the quarks have one color, but the gluons each carry two colors. What? I guess because they have to match. to the two quarks or what? Exactly, right. And so, for example, a gluon can be like red, anti-blue, or it can be green, anti-red, or whatever. There's lots of different combinations. And so it turns out there are eight individual different kinds of gluons.

We have one photon for electromagnetism, but there are eight different gluons because of all the colors. And it makes you realize, like, there's a lot going on inside these particles that we can't see or even really imagine, and that most of the particles out there are actually colored particles. because we think of them as like one cork and one gluon, but really there's eight gluons and three of each kind of quark.

Wow. They sound strange enough to be their own matter particle, but they're not matter particles. They're not matter particles, but if you could make a glue ball, that would be sort of like a kind of matter just made out of forces. That would be really strange. We've never seen that before.

Totally fascinating if we could create it and study it. Well, it sounds like maybe you guys did pick a pretty good name because gluons are so strong. sticky. They even stick to themselves. They do. Exactly. They're like that cling wrap that's not supposed to stick to itself, but it does. All right. So that's a discovery.

1979, that's when we discovered Goulant. And that's how we knew how the nucleus of your atoms stay together. Yeah. And that really powered the generation of discoveries that came next. Like in the 80s, we discovered the W and the Z bosons. And we had a lot of confidence that they existed because we

understood that a lot of these forces really were mediated by these force particles. And so it was a pretty exciting moment for the field. And it gives everyone who has a rich company hope that they can maybe build the next great particle collider. You should always put your bid in because you never know when the government will come back and say, yes, actually we want you to do this. All right. Well, that was pretty interesting, pretty dramatic and very fundamental, you know, without this particle, we, none of us would be here. I mean, the universe could go on, but we, like, as beings held together, wouldn't be here to talk about it.

Me and you, we have lots of glue-ons inside us. It's sort of weird to be searching for a particle that we know is an inherent part of who we are and how we operate. But sometimes it takes a while to reveal its shy nature. But yeah, you and me and stars and everything around us has glue-ons inside of it. All right, well, we hope you enjoyed that. Thanks for joining us.

See you next time. Thanks for listening and remember that Daniel and Jorge Explain the Universe is a production of IHeartRadio. For more podcasts from IHeartRadio, visit the IHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows. The holiday rush, parents hauling luggage, kids gripping their new Christmas toys. Then everything changed. There's been a bombing at the TWA terminal, just a chaotic, chaotic scene. In its wake, a new kind of enemy emerged, terrorism. Listen to the new season of Law and Order Criminal Justice System on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts.

My boyfriend's professor is way too friendly, and now I'm seriously suspicious. Wait a minute, Sam. Maybe her boyfriend's just looking for extra credit. Well, Dakota, luckily, it's back to school week on the OK Storytime podcast, so we'll find out soon. This person writes, my boyfriend's been hanging out with his young professor a lot. He doesn't think it's a problem, but I don't trust her. Now he's insisting we get to know each other, but I just want her gone. Hold up. Isn't that against school policy? That seems inappropriate. Maybe. Find out how it ends by listening to the OK.

Storytime Podcasts on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. I'm Dr. Scott Barry Kaufman, host of the Psychology Podcast. Here's a clip from an upcoming conversation about how to be a better you. When you think about emotion regulation, you're not going to choose an adaptive strategy which is more effortful to use unless you think there's a good outcome. Avoidance is easier. Ignoring is easier. Denials easier.

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