How was the Higgs boson discovered?

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Speaker 1: Hey, Daniel, did you celebrate July fourth? Of course, it's a really important day in history. July fourth, two thousand and twelves two thousand twelve. You mean seventy right, American Independence Day? Oh? I mean, yeah, that's important too, But two thousand and twelve was a much more important day, more important than the founding of our country. Yeah, this is like cosmically important, all right, I'll buy what happened on July four, two thousand and twelve. July four, two twelve is the Higgs Dependence Day. It's the day we announced the discovery of the Higgs boson. Did we beat the British to it? Or it was our reunion with Britain? We did it together. Hi am Jorge. I'm a cartoonists and the creator of PhD comics. Hi. I'm Daniel Whitson. I'm a particle physicist, and the only particle I've ever helped discover was the Higgs boson. Oh nice, I've discovered lots of particles. There's plenty of dust particles in my house, none of which are particularly interesting. Some of them are big, but not Higgs. But welcome to our podcast. Daniel and Jorge explain the Universe, a production of I Heart Radio in which we talk about all the crazy and amazing things that we find in our universe. We take you to the forefront of knowledge where scientists are trying to figure out how everything works, and we show you how you can understand it to how your curiosity is the same as theirs. Yeah, and we like to talk about not just the things that scientists discover and what we understand about them, but we also like to talk about how they were discovered because we think this it's a very important part of understanding science and how science works, and what science knows and what it can know. That's right. Sometimes particle physics is presented is like a grand edifice that we've put together all at once, But really it's sort of like a sloppy house of cars that we've been building bit by bit over the last hundred years, and each piece was added painfully and with great effort due to lots of theorists and experimentalists working hard. And usually there are fun, juicy political dramas along the way. I guess it's made out of particles, the house of particles. Everything's made out of particles. Man Or Field, you did a TV series called House of Particles. There's definitely enough drama in particle physics to fuel a whole soap opera. Hopefully nobody gets pushed into a train or anything like that. But more than that, we want you to understand that this idea of particle physics, these things that we understand, are not just some theoretical concept, but they're slowly built up from actual discoveries, experiments. We've done, things that we forced the universe to reveal, and it's those experiments, those actual discoveries, those confrontations with nature that formed the foundation of that understanding. Yeah, because I think it's easy, once you know something to just forget that you at some point didn't know something. You know, like, think back when you're a kid and you didn't know about the universe or galaxies or planets. What were you thinking, Like, what was your view of the world. That's right, Like, before I knew that bananas were gross, I thought like, hey, maybe they were okay, But now I can never go back to a universe in which bananas could be digestive. Hey more bananas for me, Man, Mandy that you don't like them, it all works out, But you know, sometimes I like to imagine like alternative universes in which discoveries were made in different orders and different things were weird or puzzling, because you know, the reason that things seem weird is only because we haven't seen the whole picture. It's like when you're doing a jigsaw puzzle and you don't know like where these pieces go or what's that's going to reveal. The nature of the questions comes from the past you haven't found yet, But in some sense that's just due to luck. You know, we found this before, we found that, We stumbled over this before we stumbled over that. So the history of these discoveries is really important for you to understand why we're asking the questions we're asking now. Yeah, so to be on the program, we are covering some pretty recent history of physics wise, and we're probably the most famous particle I think in culture these days and maybe in physics. That's right, and that's not something I'm grumpy about. I mean, I think the Higgs Boson deserves its role, is the most famous particle. It plays a really a central role in our theory, and it's a really epic struggle to find it. The search for it goes over many billions of dollars and many different particle colliders and many decades. Yeah, so to be on the program, we'll be asking the question, how was the Higgs boson discovered on a Tuesday? Right, wasn't it or a Wednesday? You know, it was no single moment. I think that's the short answer to the question. It's not like we came into work one day and boom, there was a Higgs boson in our email inbox. You know, We're like we found one in the center of the lab, or there was just one moment when the results were like boom, there we have it in sort of a slow build, the gradually accumulation of data, a very gentle, gradual reveal, not like an exciting plot twist at the end. I guess it wasn't discovered with the bang. It was more like with twenty three Brazilian bangs. A second. It's like somebody very slowly drawing back the curtains so you can see more and more and more of the drama builds slowly, but then you know you need to have a date. You need to have a moment where you say, okay, this is it. We've decided we've discovered it, so that's officially the moment of discovery. You guys picked your life four. Yeah, that's just sort of random, just so a fun coincidence. And that's why we get to call it Higgs Dependence Day because we depend on the Higgs. I guess we all depend on the Higgs. Really, the whole universe depend on the The whole universe does totally depend on the Higgs. If it wasn't for the Higgs boson, our universe would be totally different. And also, the Higgs boson is sort of precariously balanced. It's in this weird high energy state, and it's the reason that particles have certain masses, and if that changed, then the universe would totally change. It would collapse into something unrecognizable to us. So thank Gosh for the Higgs boson doing what it does. He's saying it rules by fear. We must more worship, but otherwise it's gonna have destory the universe. I think the Higgs boson would rather be feared than loved. Yeah, it should be called the Machiavelli particle, not the God particle. All right, Well, it's a very important particle and it was discovered recently, and there's a bit of drama about it and a lot of interesting twists of the stories. So we'll get into that today, but first it's usually we were wondering how many people out there had heard of the story or know about the details of how the Higgs boson was discovered. That's right, So I asked people to volunteer to answer random science questions on the Internet, not knowing anything about what I would ask them, and no googling allowed to Thank you to everybody who participated, and if you'd like to volunteer your voice for future random science questions, please write to us two questions at Daniel and Jorge dot com. All right, so before you listen to these answers, think about it for a second. What do you remember about July fourth? Here's what people had to say. The Higgs boson was discovered, You thing the lhc um some sequence of particle the case was detected that backed up the theory existing on the Higgs. I know where its cern large hydron collider, but how most likely shooting and colliding particles of the Higgs boson was discovered in the large HYDRONI the Higgs boson was predicted by Peter Higgs and others, and then it was discovered in two thousand twelve in the Large Head Dround Collider. It was discovered in the Large Hadron Collider, and it was by zooming around hydrogen or helium electrons very close to the speed of light. I think it was discovered with the Large Hydron Collider, But as to how, I don't know. I know that Higgs boson first discovered. In theory, we knew that every force has an acting party ill and for gravity, we called that particular Higgs. Physicists, even someone like I'm son, figured out that there was something missing, and they kept looking forward, looking for and it was my understanding that Higgs was the one that came up with the idea of how it might might exist. If the Higgs boson gives mass two particles, I'm going to suggest that they started with a particle with known mass. I think I heard in one of you guys podcasts that they were discovered by the Large Hadron Collidas, so I'd assume that tell it was discovered. I'm not sure, though, I feel like I should know that one, and I think maybe we were smashing some particles together and found some extra energy that we couldn't account for. All Right, some pretty knowledgeable answers here. You guys did a pretty good job of educating the public. Yeah. I think it's also a good pr by the LHC team because it's sort of the particle collider that's in people's minds. I mean, I don't know if you remember where we also asked people how the top cork was discovered, and the answers were basically the same by the Large change on collider, even though that one was actually discovered by the previous collider. So I think that this is a win for the l a C as being the particle collider that's in the forefront of people's minds and the tips of their tongues. You're like the Kleenex of physics experiments. You know, pretty soon they're going to call all colliders. That's right, I blow my nose in the LHC. Alright, So let's step us through the history here, Daniel. We're going to get into how it was discovered and how can we know that it's actually there. So take us back to before. What do we know and why do we think the Higgs boson existed? So The Higgs boson is one of these particles that has a long history because we thought it existed before we discovered it. There are a lot of people who suspected it was there, and there is a grand tradition of this and particle physics of like looking at the patterns of the particles that we see and seeing something missing, or you know, not having a question answered and finding a missing piece that answers that question. It's just like with the jigsaw puzzle or with the periodic table, if there's a hole in the periodic table, you wonder like, why is that hole there? Wouldn't this make more sense if there was something else there. So people spent a lot of time thinking about the patterns of the particles that we had seen and wondering about some things about them they didn't understand, and using that to predict the existence of this Higgs boson and also this Higgs field. But in this case wasn't really a pattern because I know, for the like some of the other courts, it was sort of based on a pattern, But here wasn't it more like about the math and looking at the equations and like, oh, it's missing some field here to make it all balanced out. Yeah, Actually it was a lack of a pattern. You see, in the second half of this last century, people had understood that there was a deep connection between electromagnetism, you know, thing responsible for electricity and magnets, and the thing that gives us the photon, and this other force, the weak nuclear force, the one responsible for radioactive decay, and that force has three particles, a Z particle and two W particles, and people that understood that actually these two different forces were just parts of the same force, the electro weak force, and the photon belonged with sort of a gang. It was actually not just like one photon over here and three week particles over there. They're part of this gang of four particles. And mathematically it fit together beautifully. It's just like a missing part of the jigsaw puzzle finally clicked into place and you could understand why things look the way they looked. It was just really gorgeous. Like from the group theory point of view, it satisfied lots of symmetries, but there was one problem. The problem is that the photon is really different from these other bosons in an important way that you mentioned, and that it has no mass, whereas the other ones are really heavy, And so what made us think that they were all together in a gang? You know, like, is it because they all transmit the same force kind of or do they behave in a similar way. They do kind of behave in a similar way. I mean, electrons very familiar particles. They like to interact with photons, but also with the weak bosons, the ws and disease and that's it. Electrons don't interact with anything else. That's all they interact with, and so it feels sort of natural to connect all the particles that electrons and also muons and taws talk to and look for a pattern among them to see if they fit into like a larger grouping. It's like when you put electricity and magnetism together. Electricity is a bunch of different phenomena that you observe and magnetism are a bunch of different phenomena that you observe. But you notice that sometimes electric charges cause magnetism and sometimes magnetism can induce electricity, and so it makes more sense to think of them as one thing. I mean, there are different phenomenon, right, It's not like magnets are electrical, but there really makes more sense. It's simpler just to think of it as part of a larger combination. The Yeah, it's like they're two sides of the same coin. And so you get this beautiful connection if you plug the photon in with these other three particles in the same way as if you merge electricity and magnetism, you get these beautiful symmetries. And particle physics is all about symmetries, about finding these patterns. And we don't know why the universe has symmetries. We don't know why it has patterns, but we have found that when you look for patterns, typically those things are clues there, hints. They show you how the universe works, Like everything needs to do somehow balance together, or it would be weird if it wasn't symmetry. Yeah, precisely. And here we have a really beautiful symmetry electroweak symmetry. These particles all fit together in this really nice way. And specifically you can like rotate your way through this four dimensional space. You have four particles there. If the symmetry works, you can rotate between them. And so like the photon and the z should play the same role, you should be able to rotate between them. But the problem is the symmetry was broken. It didn't quite work because the photon is very very light as no mass, and the z was very very heavy. So it's like an almost symmetry. It's like it's like a hint, like this almost works, but what about this one piece and that piece sort of stuck in physicist I for a long time. It's like looking in the mirror and it's seeing kind of a different image of yourself. You're like something's going on here, yeah, and it's like almost right, but not quite. And so they wanted to understand, like is this symmetry just flawed and we throw it out the window, or is there a reason why it's broken? Is that a clue? Does that explain something else? Because the symmetry was too good to abandon, you know. On the other hand, there's lots of times in the history of physics when we thought we've had a beautiful idea and had to throw it away because it just didn't work. Like mathematically it works, but nature says no. So sometimes that happens. But sometimes you know, it's just a clue that like you need to refine it or tweak it or twist it. And so that's what the Higgs boson was. It was a refinement of this theory to help it work. Right, Although I feel like it's weird because I feel like you physicists started wanting things to be symmetric, but nowadays they accepted some things are not symmetric. Yeah, well, you know, the universe doesn't know is obey these symmetries. You know, we'd like to see symmetry because it's like beautiful and pretty. But then the universe says, yeah, that's nice, but I don't follow those rules. And so then we got to figure out why, like what are the real symmetries, you know, or how do we break these symmetries in the smallest possible ways? So our theories are still pretty right, I guess. I mean, like we had known back then that some symmetries can be broken, would you still have looked for the Higgs boson or come up with the Higgs boson or would you have just said, oh, well it's not to meat. That's a great question, I think. So, I mean, there's just so much evidence that suggests that the weak force and electricity magnetism are connected. You have to find some way to connect them. So I think it's too tempting to avoid, So okay, So then that's how they came up with the Higgs field. It's like, hey, let's put a number here to make it all balanced out, and let's call that the Higgs field. Yeah, because you can't just say I'm gonna make these particles massive, I'm just gonna put in by hand some numbers and make the W and the Z massive because that breaks the kind of symmetry that you're trying to protect. It's called the local gauge symmetry of electroweak symmetry lets you rotate these particles between themselves. So if you put the masses in, it just breaks that symmetry. So they found another way to give these particles mass. It's like, don't put the mass on the particle itself. Instead give it mass from its environment. So the mass is no longer like something that belongs to the particle itself. It's an after effect. It's an emergent phenomena from interacting with its environment. Like maybe it doesn't come from the photon, but maybe there's just something about space or the universe that somehow we're not seeing. But magically balances out the equations. Yeah, we talked about this on another podcast about renormalization. How for example, the actual charge of the electron all by itself is like negative infinity, and it's only an interaction with the complex vacuum of space that it gets brought up to minus one. And in the same way, the masses of these particles by themselves, like the Z and the w all by themselves and an empty universe would have mass zero, but you put them in our universe with a complex vacuum with particles and fields, whenever they look like they have this heavier mass, and that's because they interact with the Higgs boson. So it's a clever way to effectively give mass to these particles without actually putting it on them, so you don't break this symmetry. It's like a clever little mathematical trick. I guess the idea is that it's not a property of the particles, but it's more like a property of interacting with something, and that's different. That's different. Although all we can do is measure our interactions, and so it's a bit of a philosophical difference, Like we talked about in the case of the renormalization episode, like, what does it really mean for the particle to have no mass in an empty universe. It's never gonna be in an empty universe. It's always going to be in our universe. And so it's a bit of a mathematical philosophical distinction, but it lets us keep this symmetry because we think the symmetry deals with like the bear the pure particle by itself. All right, pretty cool. Let's now get into how we actually found this magic or not magic particle that gives everything mass and what the search for it was like. But first let's take a quick break. All right, Daniel, we're celebrating Higgs Dependence Day, the day that we learned of our deep dependence on the Higgs boson, which was July four, a little over eight years ago. So how do we actually find this Higgs boson. It's important to understand that the first idea was not for Higgs boson, but for Higgs field. This is some new quantum field that fills the universe and has this effect that gives the Z and the W mass and not the photon. But one prediction of the field is that, like all other fields, if you give them a little blob of energy if you excite them. If you get a little packet of excited field, then that looks like a particle. So there's a prediction also for a new particle, the Higgs boson. So the field and the part cool have the same relationship as other particles and fields. But what we found was not directly the Higgs field. We look for the Higgs boson, which is the particle from that could could you have a field without a particle, could you know, think the Higgs field but not the Higgs boson, or when you predict the Higgs field, you automatically predict the Higgs boson. Well, that's a great question. I think that every quantum field has to have a particle. I can't think of an example of a quantum file it doesn't have a particle, and I think that your interaction with it in terms of perturbation theories always described in terms of particles. But you know, I'm not sure that's a that's a really fun question. We'll smoke some banana peals and think about that deep question someday. But I guess it was. So it's all sort of together, like when Peter Higgs came up with this idea of like playing this in to make the equations, where he must have known right away that meant that there was a particle involved too. Yes, absolutely, and you know, Peter Higgs sort of wins the race to get his name put on this, but there were lots of other people coming up with very similar ideas at the same time, and they submitted papers like within weeks of each other, and so there's still a lot of bitterness. And in some parts of the world it's not called the Higgs Boson, it's called the b. E. H Boson because there's two other guys, Brout and Englert, who have their names on it. Also, so depending on like where your conference is, it's called the b. E. H Boson or the Higgs Boson or really you have to like code switch when you go between conferences. Yeah, precisely. And there's a whole group of Americans who are totally left out of the Nobel Prize and the naming and they're grumpy and all their friends call it after them, and so yeah, you totally have to switch. Oh man, But you know, I like the Higgs name. I feel like it's better than you feel like it best sounds like you burped or something, right, Yeah, but Higgs sounds pretty well if I'm insulting like all of Europe right now, mostly just Belgium. Actually, well they don't get insulted, so they're just drinking Belgian. Well, they have good fries and waffles anyway. So what we do is we look for the boson, not the field, And like with other particles, the way you make it is you use a collider and you smash particles together to try to make enough energy in a tiny little spot that the universe can make heavy particles. Most of the universe is like dilute and cool, and so there isn't enough energy to make anything except for very light stable particles like electrons and quirks that we're made up. But if you want to find new stuff, you've got to collide particles that really high energy and create those little packets of energy. The nature can then turn, sometimes very rarely, into an excitation of the Higgs field and give you a Higgs boson. I guess one question I have is, you know, it seems like the Higgs field is so pervasive and so integral to all particles, and it's like it's always there, Like, why is it so hard to make it BLib you know, Like, if it's right there, why does it have such a big threshold for us to find it. Why couldn't we have found it earlier with lower energy collider. Yeah, that's a great question, And the key is the mass. The prediction from Peter Higgs was there is this field, and therefore there is this particle. But he couldn't predict what the mass of that particle was. It could have been very very very light, in which case it would have been discovered just a few years after he predicted it, or it could have been super heavy so that we hadn't even discovered it yet, And so he didn't know how heavy it was. And like with all things in collider world, the heavier it is, the more energy you need to make it, and so the bigger your collider has to be, and so the more expensive it is, and so it just took time to build a big enough collider to find it. I guess you need energy to make it, but I guess, you know, it's sort of a weird thing to think about the Higgs boson having mass, because isn't isn't that what it does to give mass to things. Yeah, it's weird. It also has self interactions and interacts with itself, and that's the thing that gives it mass. And Higgs field didn't predict how strong that self interaction would be, and so we didn't know, and so people started looking for pretty much right away and not finding it all right, So then, yeah, you build a collider. You've smash protons together, and you hope that a Higgs comes out every once in aime, that's right, And protons have inside them quarks and gluons. The gluons hold the quirks together, and which you hope for is two of those gluons actually collide together with enough energy to give you a Higgs boson. And the Higgs boson doesn't last for very long. So you can't just like take a picture of it. You can't see it and say, here's our Higgs boson, in which case you only would have need to have made one of them and you could put it on your wall and that's your discovery. The problem is that it lasts for ten to the minus twenty three seconds and then it turns into other stuff. That's what you gotta do is look at that other stuff and figure out if it looks like it came from the Higgs boson or something else. I guess what made you think that it could even had mass? Like, couldn't have been like a photon or would that not help you with the symmetry of the equations. Yeah, in order to have the effect that it has, it has to have a non zero mass, otherwise it wouldn't have this weird symmetry breaking effect. But we didn't know it could have been ten times heavier than it turned out to be, were ten times lighter. You know. That's one of the frustrating things about the theories that we didn't quite know where to look. And that means you don't know how big to build your accelerator or how it will decay, because all those things change based on how heavy it is. Really, it can have any kind of mass, Like you know, what, do we have a very different universe of the Higgs boson was really big and massive. No, you could have the much heavier Higgs boson and basically have the same universe. Really, like if the Higgs was really massive, would in that I don't know affact how things have mass or anything like that, because it doesn't matter most things get massed through their interaction with the field. It doesn't matter how heavy the particle itself is, alright, so they're really fast collisions, and the Higgs doesn't last for very long. So how do you actually detected, Like, how do you know it existed if it only exists for ten to the minus twenty three seconds, and so we can never say for sure. What we do is we look at a collision and we look at the patterns of the stuff that came out, and we say, okay, this looked like this collision had, for example, two photons in it. We can add up the energies of those photon and say, okay, the total energy that came out of this collision, how much was it? And if higgs boson was there, then the total energy that came out of the collision should add up to the mass of the Higgs boson. So we look for a lot of events like that, a lot of collisions that turn into two photons. We add up all their masses and we make a plot of it like a histogram, and we look for a bump. We look for a bunch of collisions that led to photons that all have the same mass. Because if the Higgs boson is real, it will make more of those events happen. And you have to know for sure that those two photons couldn't have come from any other thing. We can never know that for sure. There are other ways to make two photons photons, two same photons, but they don't tend to make two same photons that add up to the Higgs mass. They tend to make random masses. And so the background, the things that mimic your signature that also give you two photons, just give you random numbers. Whereas photons that came from the Higgs always end up at about the same place. So if you do it often enough, you notice like a pile of them accumulating at this place. With the true mass of the Higgs, you look for this, basically, this bump over this background spectrum, right, and I imagine you see other bumps, but they're probably due to other like interactions. Right. Yeah, Well, bumps are pretty exciting because they almost always mean some particles. There are some heavy particles there and it decayed, and so basically every bump is a Nobel prize. You know. It's sort of like you're draining a swamp and you're seeing features in the lake, and everyone is something fascinating and interesting. And the bigger you're collider, and the longer you're running, the more you're able to like pump water out of that lake and see all the hidden features. And so we're constantly doing this way. This is why we run the collider over and over and over again, because we're looking for smaller and smaller and more subtle bumps. The more collisions you make, the more you can see these little bumps emerge from the fog. So I guess it's all statistical, right, because you you run us a bunch of times, I mean, and if you see it's kind of like an unexpected high incidence of you know, collisions in this mass range, that must mean that the Higgs was there. Yeah, it's all statistical, and we can't point to one event and say this one was definitely a Higgs. We just say, well, these fifty events all have about the same value, and there's more close to this value than any other value, and so we think it's very likely that it's there. But it's a little bit frustrating because you can't like take a picture of it or say conclusively this collision was a Higgs Boson. It it's in the end of purely statistical thing. You only see the leftovers or the footprints in the snow. You never actually like take a picture of it. Yeah, it's like you're looking for Bigfoot and you have tracks, and you have spore and you have you know, lots of other evidence that convince you that it's not just random nonsense, but you don't actually have the Bigfoot itself. You see a lot of poop in one place that more than usual, you're like something, something was here, and something likes to keep coming back here. Yeah, precisely. All right, Well let's get into now how we actually founded and what that discovery meant. But first let's take another quick break. All right, we are talking about the discovery of the Higgs Boson, which was an important date in history, at least physics history. And step us through Daniel. What was it actually like to like look for this thing and to find this thing where people confident they would find it or was it kind of a big shot in the dark. It was a very long and sometimes painful process, full of excitement and disappointment, and it was another one of these transatlantic rivalries where the Americans took the lead, and then the Europeans took over, and then they didn't find and then the Americans took over again and had a chance, and then finally the Europeans. Really like a race, Yeah, it really was. It's like an arms race in science, and it's constantly this like race for who's got the highest energy colliders. It's a bit of like nationalism and prestige. It's a lot like the space race, you know, except without the threat of i cb MS raining down on you who had the biggest rocket kind of yeah, and it started with the Americans. So there's a long history of looking for the Higgs boson a very low masses and other colliders which didn't see it. But once we understood like this thing was going to be pretty heavy, we knew it needed a big collider. And so the Americans had a big idea. They were going to build the super Conducting super Collider, awesomely named and it was gonna be the most powerful. I thought you were just using iproberly, No, they used hype of beliefs. Actually call this what is this super super conducting super collider. It's a pretty supername. It's like we made Superman. We're gonna we're gonna use super as much as possible, exactly. And this thing was going to have so much energy. It was going to have thirty three Tara electron bolts. Now Tara electron bolts, it's thirty three trillion electron bolts. That's a whole lot of energy. And it was gonna be the biggest collider ever. And they started building it. It was gonna be in Waxa Hatchie, Texas, and they started building it. They started wearing a hole. They cut like twenty kilometers of tunnel underground in Texas. They spent billions of dollars, and then they canceled the project. What happened? And well, and this one is interesting because it wasn't a ring, right, like I think it's like a straight collider. Now, this one was going to be a ring, but they never finished the ring. But it's still like a partial tunnel underground in Texas. And it just sort of lost political support and became a scapegoat for like, you know, excessive government spending, Like what are you spending five billion dollars on this thing? Is ridiculous? We scoffed at five billion dollars for the search for the ultimate particle I know. And it was especially ridiculous because they spent like two billion dollars digging a hole and then like another three billion dollars like closing up shop and filling it in. So there was so much waste of money. And there's a funny story there because the guy who was the director of CERN at the time, and CERN was preparing to build their own collider to look for the Higgs Boson, he came to the US and testified in front of RIS that it was a big waste of money to build the super conducting super collider because by the time it's finished, CERN would have already discovered the Higgs Boson. Sabotage. So Carlo Rubia, the same guy who in the top Cork history made that false claim to discovered the top word, he's sabotage. He totally knife in the back to the super conducting stugree with his confidence. He's just like, I don't even bother. He like totally psyched us out. He totally plucked us out. And of course his prediction with Bologna, because the Europeans didn't discover the Higgs boson with their next collider. And it's such a tragedy because that collider would have taught us so much about the universe. Thirty three terror electron bolts is three times as powerful as our best current collider, the large Hadron collider. This is like better, even better, three times better than the one we have now thirty years ago. So particle physics was set back like several decades by that funding decision because of this on moved by this person who had ambition to be the first one to discover it. Yeah, and you know, also the vaguaries of American electoral politics and shifting priorities in the house and all this stuff. But you know, it was sort of like particle physics aimed too high and flew too close to the Sun and then came crashing down. I see, like maybe they had only spent two billion dollars for twenty two tera electronic wal collider, maybe they would have made it through. Maybe. And you know a lot of people left their positions at academia to go work for the super conducting SuperCollider Lab, and their careers greater after that. And so it was really a big tragedy for American particle physics, all right, so then then the Europeans took over or what happened, Yes, and then the Europeans took over, and the super conducting super collider was going to collide protons, and protons are very powerful, but the Europeans took a different strategy. They decided to collide electrons and positrons. And these things are much cleaner because they don't have the strong interaction, and so the collisions are just simpler and more powerful and easier to understand. The trick is not as easy to get them up to high speed because protons are easier to accelerate to high speed because they have more mass. Counterintuitively, right, but this is still not This is not the LC. It's the l EP, the Large electron positron collider, call it LEPP. And this thing was like much much less than even one terra electron vault. It was zero point two is a fifth of a terra electron bolt. Doesn't sound so big compared to thirty three. Yeah, exactly. It was much smaller. But you know the good thing about having electron colliders, you got to use all the energy in the electron. When you collide protons, you only get part of it because you're really just using like one cork or glue on inside the proton. But when you collide electrons and positrons, you get all the energy, so you don't need as much energy in an electron positron collider. All right, Well, i've never heard of the LP, so I'm guessing it didn't discover the Higgs boltson. It didn't, but it almost did. And they turned this thing on and they ran it for a while and they didn't see the Higgs, and they didn't see the Higgs, and they didn't see the Higgs. And then the last summer that they were and have this thing turned on the summer of two thousand, they're supposed to shut down so they could tear it apart and build the Large Hadron Collider. There's gonna be the big upgrade. That last summer is in the same place, in the same place, in the same tunnel, right, So this same tunnel where the Large Electron Proton Collider was is the same tunnel we use now for the LHC. So you couldn't run both of them at once. Oh what, there's the same size tunnel, same size tunnel, just stronger magnets and so that's how they saved a bunch of money to build the LHC is that they put it in the same place as the original collider, but that meant that they couldn't operate both at the same time. So to build the LC they have to turn off the l E. So what happened right before they closed? Yeah, so right before they closed. It's a summer of two thousand and you know in Europe, in like July and August, everybody goes on vacation. It's ridiculous. It doesn't matter what's going on. Everybody takes like a month of vacation. Month I've heard of six weeks is the normal, and you're a month of the minimum. Every just sort of like slides down the continent to the beaches on the mediterrane Union. And so some people stayed behind, didn't take vacation. And a good friend of mine, Maroumi, who was a post doc in the time, he was there in the control room and it was like the last few weeks this collider would even run, and he's sitting there looking at the data, and all of a sudden, boom, there's a collision that comes in that looks exactly like a Higgs Boson. It's like beautiful, it has exactly everything you would expect. It's gorgeous. You know. It has a certain mass at about a hundred and fifteen g ev, which is like right on the edge of what the L e P could discover. And he thought, wow, that's pretty, but you know whatever, It's one event, and then later that same afternoon, boom, there's another one exactly the same mass, and he's like, wow, maybe this is like the moment, Like I'm here by myself, everybody else is on vacation. Maybe like nature is talking to me with an incredible moment for him, why would it start now and not before? Well, they were turning up the energy, so they were cranking up the energy bit by bit. They were like squeezing out as much energy as they could, and so it might be that they had just crossed the threshold to be able to create it, right, And was it real? It turned out it wasn't real, but it was tantalized. It was not it was not. And in the end he had six events. So everybody came back from vacation. He was like, guys, while you were on the beach, here's what I found. And he showed these events and it's set the whole community on fire. People are like, oh my gosh. The problem was they didn't have enough events to prove it. They didn't have like conclusive evidence that had a hint, right, So they wanted to run longer. But then everybody's also waiting to build the LHC. So they petitioned to the management of certain They said, please delay the LHC and let's run this collider for another six months or another year to get like conclusive evidence, right, just to get more hits. Yeah, because across the pond, the Americans were building their collider, the Tevatron outside Chicago, and if they turned off the l A P would take them, you know, eight or ten years to build the LHC. In the meantime, if it really was there a hundred and fifteen, the Americans would find it. And so it seemed like a really dangerous bet turn off the l EP where you had this like exciting hint that maybe it was right there, and to build the LHC. So they actually turned it off. Yea. They said no. The certain director said no, I don't think that the evidence is conclusive, and the LHC should be our priority, and so he shut it down. He gave them like an extra couple of weeks and he shut it down. What did they find in those extra weeks? Not much. You know, they had four experiments around the ring at the l e P and the one that my friend was on saw six events that looked like a Higgs boson, and a couple of the other experiments saw one or two, but some of them saw nothing, and so it was like it was tempting, It was tantalizing, but it wasn't really that strong. It was sort of like a last ditch effort to maybe maybe see it there, but it wasn't really conclusive. And so the certain director made a really tough choice, Well what do we think now, do we think that it was or that it wasn't for sure? We think it was just a fluctuation, because if it was there, if it really was the Higgs boson at a hundred and fift g V, the tevatron, the neck accelerator would have found it. And now, of course we know with the benefit of history, that's not an hundred fifty. It was found later at one. So that was just a fluctuation, you know, you flip a coin a hundred times. Sometimes you'll get weird distributions, and and that's what happened here. And the folks were like desperate to find that. They were so excited to see it that they got really excited about what, in the end was just a few random events. All right. So then I guess while they were building the L A C. Then the Americans had kind of like this window for them to do it, to find it with the teletron. Yes, so we built a collider outside Chicago at Fermulab and it was colliding protons and anti protons at two TV, so there's ten times the energy of the collider at left. Although you don't get to harness all that energy because remember the proton is like a bag of particles that has corks and gluons in it, which you're colliding are those corks and gluons, They don't have the full energy of the proton. But still it's really powerful, and you're right, they had like ten years to look for it. But you know, protons are messy because you're colliding a whole bag of particles and it makes a big, messy splash, just not as clean and pure as colliding electrons and positrons, so it's harder. So they had more energy, but it was always going to be tough for the tevatron to find it. The only chance they had is if it was very very light, if it was at one fifteen, they could have found it, but not but not higher because they can go up to two TV. They can go up to two TV. They could have found it like below one fifteen. And also there's a window between around like one fifty and one eight where it does a very special thing. It turns into w bosons that the tepatron would have been very good at finding. So they were just you know, rolling the dice. If it was low mass or if it was in this one window, they totally would have found it. The tevatron would have found the Higgs boson. So then what happened. Then they gave up while they ran as long as they could, and then once the l C turned on, then they gave up. They said, all right, well there's no point anymore. Really, yeah, what because I guess they weren't finding it. And so they're like, all right, somebody has a better machine. Yeah, And the LEDC is you know, ten times as powerful as the tevatron has higher energy and more collisions per second TV, So the LEDC is about five times is powerful. It's collisions they varied from seven TV the start up to now thirteen TV, so about an order of magnitude more powerful. But also they have more collisions per second, and so the tevatron knew that. You know, as soon as it turned on it was going to find it pretty quickly. There was no point to continue because but the tevatron to find it would need like two and a half times more data, need to run for like another five or ten years. But you know there are people in the fields who are like, no, we should keep running, we should keep going because they might stumble, right, yeah, they might crash right, Like the machine is hard to get it to work. Yeah, And you know when they turned the machine on the LHC after ten years they had been quiet building this thing. They turned it on in two thousand and eight. It only ran for like nine days before there was a big disaster. So they did stumble. They did stumble exactly, and there was an electrical fault. One of the things hadn't been wired correctly, and it's short at out and released like tons of liquid helium. There's this big alarm. And I was actually at the LHC that day. I was on shift in the control room, which is normally a very boring thing. You sit there, you look at a bunch of panels, they're all green lights. You're trying not to fall asleep. But sometimes something crazy happens. And that happened while I was there. Really, like the lights turned red with the big horns, like, yeah, exactly. Wasn't just like a computer like a window popping up you just clicked Okay, You're like, wait, wait, wait, what what did I say? No, it was a big disaster. You know. There were fires and like really heavy equipment got like shoved around inside the tunnel, and so it was a big disaster. We got to hit the big red button finally to you know, shut everything down. It was exciting, but of course it was also disappointing because it took like fifteen months to fix it. This stuff is super cold, and so to fix it you have to warm it up very gradually, fix it, and then cool it down very gradually, which takes months and months. So maybe the Teva try should have been going, you know, so the Tabatron kept going during that window. They were like, oh, we got one more little chance at this. They were watching the L A C stumble yes exactly, and so they were like, keep going, everybody, maybe we'll see it. And so they pushed a little harder, one last gasp, because again nobody knew where it was. It could have been like just around the corner in the window that tabatron could have found it. But in the end, the LC turned on, and then people turned off the tabatron because they figured they were not going to find it was time to let the LC do its thing. And pretty soon after it turned on, you guys found it. Like it like, it didn't take a long time. It didn't take a long time. You know. We turned on again in like two thousand and ten and started analyzing data. And you know, it takes a little bit of time because you have to get enough data. And these colliders, when you turn them on, they work and fits and spurts until the engineers figure out like how to kick it and how to tweak this knob, and you know, on tuesdays you gotta elbow it this way and really get it, you know, humming. But eventually the data started pouring in and then we were doing that thing. We were like pulling the water out of the swamp and seeing the features, and you know, there were wiggles in the data early on that people got excited about. And people didn't know, is it there? Is it not there? Where are we going to find it? Nobody really knew where to look. So finally, one day, uh not on July four, they actually started getting the data and and it started to point to having found the Higgs. But you know, was there a moment I imagine you told me that maybe there wasn't, But I wonder if there was a moment when like some grad student or some physicists, you know, pulls out the data and they're like, huh, what is this little bump? Well, you know there was a moment for me in the summer of two thousand and eleven. Both experiments saw bumps, but they saw bumps in different places. Like ATLAS saw bump, but it was at around a hundred and forty five g V. Cmsaw bump around a hundred and twenty g V. So you knew that they were just random because it didn't agree. Now, these are two different experiments, ATLAS and CMS, two different experiments at different points around the ring independent data, and so you expect them if the Higgs is real, to see bumps at the same place. It's a very important cross check. And also the two groups. There's a whole group of thousands of experimentalists working on ATLAS and thousands of experimentalists working on CMS. They're not supposed to talk to each other. It's supposed to keep each other separate. It's supposed to keep these secrets so that the work can be independent. The problem is, of course, all these people know each other. We're all friends. Sometimes you got like a married couple where one is on one experiment, the others on the other experiment. You know, they're talking to each other. So there's no way that any secrets are really being kept. And so there was a moment in like late two thousand eleven. I called up a friend of mine on the other experiment. I said, hey, um, you know we have a bump. Where's your bump? Had a bump like I found? I found a lump? What no, no, no, I mean sharing information like that is strictly against the rules. I would never do that. Did I say it was me? I mean, I'm in It was a colleague of mine who talked to his friend and then and told me about it. I mean, you must have misheard me. I would never do that. You tainted the results. We had this bump, and I was curious about whether they had a bump, And it turns out they had a bump in the same place. And that's the moment. And you figured that out on the phone. At the moment I started to believe when I thought, you know what, I think this is it. I think we actually did find this. Daniel, why did you do that? I think you mean my colleague who broke them and your friend also broke it because he told or she told you where the bump was. Again, this is a story about a colleague of mine who broke these rules. Everybody was breaking the rules. Man, these were the worst kept secrets at certain Oh man, I have less confidence now, Daniel in the Higgs Boson. Well, I was not directly involved in producing that plot, so it couldn't influence me in neither was he. Oh so you were like literally a league like he learned some secret and you you phone the other team again, this unnamed colleague of mine, he was we saw bumps in the same place, and so that's the moment I started to believe it. And then we just kept collecting were more data, and the bumps got bigger and bigger, and they lined up right on top of each other. And then in late June we had enough events, enough collisions at all the same place that we could say, statistically it was very, very unlikely for this to be random chance. Random chance can produce anything, but the odds were like one in millions that just random chance could produce all these bumps that exactly the same place. So that was the day we said, all right, we decided that now we have discovered. And that was July four, And that was j and there was big announcement at CERN, and everybody knew it was gonna be the announcement the next day. So starting like July three, everybody at CERN was like standing in line to get into that auditorium and sleeping in line, like camping out. You know, this is like Comic Con, but Nerd edition at CERN and super conducting super Nerds exactly, And people really wanted to be in that room. And they invited Peter Higgs and he was there and the director sir and give a tall talk, and you know, for the people in the audience. We are knew the results, we have been involved in producing them and preparing them. But it was just a moment we all got together and basically said, all right, let's high five and declare that we have found this thing after decades and decades of searching email. The rest of the world is like the Higgs What wait, do you have a collider in Geneva? Nobody told us about this. You know, the team at certain is really good at PR. They are very good at popularizing the science and making people understand it. And that's why I think the Higgs boson is one of the most famous particles is because it's been well sold to the public as an exciting discovery. Also, it was the Obama years. You know, we were we were happy about all good years. That's right, and we believed scientists. That's right. Then that gets us to today. So now these days, we know that the Higgs field exists, and that the Higgs boson exists, and it makes all the equations balance out, and and now we have a more complete picture of the yeiverse and the particles in it. That's right. And now we know where the Higgs is. It about a hundred and twenty five GV and number we didn't know before we measured it, and we can study all of its properties. We can see it turning into this kind of particle in that kind of particle, and we can try to measure its properties in great detail and see is this the particle that Higgs predicted or is it a weird version of it? Are there more Higgs bosons out there? And so the search doesn't stop just because we found it. Now we're studying in gory detail and trying to see if it has any more secrets to reveal. All right, well, again, also pretty exciting and a good insight into how signs works little by little through competition and friendly breaking of the rules. And anybody on the Atlas Experiment who heard that, please forgive me breaking the rules. But I bet you did too. You're like, hopefully nobody's listening to this podcast, not a couple of hundred thousand or ten thousand people. Well, I'm sure you know there's like you know, podcast hosts, podcast listener confidence reality. Absolutely, I mean we assume that, so I'm trusting you with that story, folks. All right, Well, thanks for joining us, Thanks for telling us a story. Daniel We hope you enjoyed that. See you next time. Thanks for listening, and remember that Daniel and Jorge Explain the Universe is a production of I Heart Radio or more podcast For my heart Radio, visit the I heart Radio app, Apple Podcasts, or wherever you listen to your favorite shows.