Daniel and Kelly’s Extraordinary Universe - Why are neutrinos so light?

Episode Date: June 2, 2020

Daniel and Jorge talk about how the weirdest particle gets its mass Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

This is an I-Heart podcast. In the heat of battle, your squad relies on you. Don't let them down. Unlock elite gaming tech at Lenovo.com. Dominate every match with next level speed, seamless streaming, and performance that won't quit. And push your gameplay beyond limits with Intel Core Ultra processors. That's the power of Lenovo with Intel inside.

Maximize your edge by shopping at Lenovo.com during their back-to-school sale. That's Lenovo.com. 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. It? Maybe find out how it ends by listening to the OK Storytime podcast and the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. December 29th, 1975, LaGuardia Airport. 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 N. and the 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. Hey Daniel, do you think antiparticles feel bad? What do they have to feel bad about? I think antiparticles are super cool. Yeah, but, you know, who wants to be labeled anti-anything? Nobody wants to be the bummer in the room, you know? I guess that's true.

If you're a cartoonist, does that make me an anti-cartoonist? That doesn't sound very cool. What do you have against cartoons? Does that make me the anti-physicist? I don't know. I guess it's like with twins, right? There's always one evil twin. I think that's only true in soap operas, Daniel.

Maybe I'm watching too many telenovelas. But, you know, in particle physics, there is one particle like the photon, which is its own anti-particle. Really? It's its own evil twin. That's right, from the mouth of an anti-physicist. or an evil physicist. Am I a physicist or am I a pro-physicist? I guess it depends on who destroys the world first. Well, I am definitely anti-destroying the world, Daniel. I know that for sure.

I am pro learning about the universe while not destroying it. Okay. You need a while prefix. Although, you know, somebody gave you the option, like, what if you could learn all the secrets of the universe, but in doing so, destroy it? That would be a difficult choice. That would be a difficult choice?

Oh, my God. Somebody take this man's finger off the button and away from any responsibility, please. I second that. I second that. But welcome to our podcast, Daniel and Horhead, hopefully don't destroy the universe, a production of I-Hard Radio.

In which we avoid destroying the universe. Instead, take it apart gently piece by piece and put it back together in a way that makes sense to you. Yeah, we like to talk about the galaxies out there, the stars and the planets and all of the incredible nebula out there in the cosmos. But we also like to talk about the small things, the little things in life and in the universe, the things that we are all made out of like the particles. That's right.

And the things that everybody is puzzling about. We think that everybody wants to know how the universe works and you deserve an explanation that's not just the very basics, the dumbed down version, but an answer that takes you all the way to the forefront of knowledge that helps you understand what science doesn't know right now. Yeah, because scientists have this standard model of matter in the universe, this sort of collection of particles and force particles that they call the standard model of physics. Yeah, what do you think about that name, the standard model? You give that an A rating?

It's pretty standard, I guess, for physicists to claim something as standard. Yeah, I guess so. And next I'm going to tell you it's not actually standard. Great, it's non-standard. No, we have this standard model, and it has particles in it that make up stuff. Those are matter particles like electrons and quarks and that kind of stuff. And we have particles that represent forces like photons represent electromagnetism, and the W and Z particles represent the weak force, and the gluons represent the strong force.

And then in 2012, we found the missing particle, the Higgs boson. And you'll hear a lot of people describe the standard model as, finally complete. Like the Higgs boson is the cap on the top of the period. And so, and you haven't found anything new since, even though you've been like colliding particles with higher and higher energy. You haven't found anything new since 2012. Jeez, you sound like sort of demanding. Like, hey, what do you discover for me lately? Well, yeah, my tax dollars are going to your salaries. That's true. But remember that searching for new discoveries in particle physics is like exploring. We're like wandering around the surface of Mars, turning over rocks, hoping to find little green men or

weird new kinds of life. And it's true that since 2012, we have not found any new particles at the Large Hage on Collider. And that gives some people the feeling like, well, maybe the standard model is all wrapped up. Maybe that's all there is. Maybe we can just tighten the bow and move on. But there are lots of really weird little problems with the standard model. Lots of interesting discoveries we've made along the way. Yeah, it seems like a lot of big physics projects in the U.S. and internationally have sort of turned inwards to look at one particular particle in the standard model, which is the neutrino. That's right. Often described as the weirdest little particle, but not because they're rare. Really? Yeah. You call it the weirdest little

particle? Yes, in a totally positive way. In a very loving, we love you little neutrinos. No, seriously. He's so weird. We like you anyways. Is that kind of what you're saying? Yes. Physicists love the weird, the strange, the unexplained, that's where the clues are, right? That's where the hints are that tell you how to unravel the secrets of the universe. If you look at everything and it just sort of like makes sense instantly, well, that's boring. We want a puzzle. We want something strange and weird. And so neutrinos are fascinating. But again, not because they're rare. They're everywhere. There's a hundred billion neutrinos passing through my fingernail every second. But there's so much that we still don't understand about them. Really basic questions

that just don't have answers to. Yeah, we are awash in neutrinos. There's no lack of neutrinos in the world around you. But there is one question about them that still puzzles physicists, and that's the topic of today's episode. So today on the podcast, we'll be tackling the question.

Why are neutrinos so light? Not, why are they light, but not light. Why is their mass so little? That's right. It's not like they've been on a. diet. No, it's not about why neutrinos are bright or not bright. It's about why they don't have a lot of mass. It's not that they're low calorie, like Coke light. They are actually low calorie. You could eat like a cubic light ear of neutrinos and gain no weight. It just goes

right through you. That's right. There's zero points on the Weight Watchers diet. So go have your cheat day, eat as many neutrinos as you want. Maybe I should invent like a neutrino-based snack food. It sounds like Tostino's, but... It'd be a little neutral snack food, right? Neutrino. Yeah, there you go. You know, speaking about snack foods and quantum physics, we did get a hilarious email from a listener today

who suggested a really fascinating snack food-based physics experiment. Aren't all snack foods these days? Like a physics experiment? Like, how fluorescent can we make a snack? Flaming hot, glowing particles. How can we delay entropy of my... my snack as much as possible. Yeah, and it's not about flame and hot neutrinos,

though that's the snack food I want to develop. Now, this listener writes in and he says, I make a sandwich and I shoot it into deep space. Then I make a second sandwich and instantaneously, the first sandwich is converted from new sandwich to old sandwich. And so he's suggesting that this is a version of sort of quantum sandwich entanglement because the original sandwich is out there in deep space and suddenly becomes the old sandwich.

We've made the new one. Oh, man. This is funny that this is funny to you. How is this even a joke? I don't know. There's just some words that are funny. I think sandwich is one of them. I think sandwich is also.

If this was a weasel sandwich, that would be even funnier. I see. Oh, I see. There's kind of a joke about how naming things is kind of like transmitting information at the speed of light, faster than the speed of light. Yeah, exactly. Exactly. The universe recognizes that that's no longer the latest sandwich.

Instantaneously, its status is changed. Wow. It's a sandwich teleportation. Anyway, back to the topic of neutrinos. Back to the topic of today's podcast. Yeah, why are neutrinos so light? So I guess, first of all, neutrinos are light. Neutrinos are very low mass.

We identify particles essentially by their mass. We look at the particles and we say, how much mass does it have? And there's a huge spectrum of values. But neutrinos are in the very, very bottom. bottom end of it. We measure these things in terms of electron volts. And a typical value like for an electron is half a million electron volts or a muon is 100 million electron volts. How much is a neutrino? A neutrino is less than one electron volt. What? Yeah. It's like, wow. It's like a percentage of a percentage. Yeah, it's like one millionth. And they even go higher. Like quarks are

billions of electron volts, up to almost 200 billion electron. volts and you know this is weird there's a huge spectrum here from very very very heavy to very very very light and even between the leptons and the quarks the electrons and the top quark for example there's a big range but neutrinos are all on their own at the very very bottom of this scale and that looks weird that puzzles us really it's the only light particle or i guess the only low mass particle yeah because you have particles that have no mass that's right we have photons that have no mass, but neutrinos are the only fermion that have this small amount of mass. Neutrinos are matter particles, right?

And we didn't know for a long time whether they had any mass, but we recently discovered that they do have mass, but it's a very, very small amount. So zero makes sense to us. A number similar to the other masses make sense to us, but a really weird super tiny mass, that's a clue. That's like, there's something going on here that you could figure out. Right, right. Yeah.

All right. So that's a mystery. Why are neutrinos so much lighter or have so much less mass than all the other particles? And so as usual, Daniel went out there into the wild of the internet, the pandemic internet, to figure out how many people out there knew about this mystery and why they think that maybe neutrinos have such little mass. That's right. So thanks to everybody who volunteered for these person on the internet interviews and listen to these fun answers and think to yourself, Do you know why neutrinos are so light? Here's what people had to say. I'm not sure why neutrinos are as light as they are as they're like not zero, like photons.

Neutrinos get their mass, I would assume, by interacting with the Higgs field, like I think everything else is supposed to. So why they are so light would be because they interact very weakly. with the Higgs field though they do at least interact some so they have some mass now why they interact so weakly with the Higgs field is another question

I honestly don't know neutrinos are light because they interact weekly with the Higgs field because of how little they interact with the Higgs field oh man I don't know aren't they billions of them flying through space all the time

and hardly any of them interact with us big detectors on the ground filled with bleach or something like that if you remember. I'd imagine they get their mass by the Higgs field. So I think that neutrinos are made of dark matter and they are paired in such a way that they almost cancel out in each other.

That means they don't show gravitational attraction maybe something to do with inertia. All right. Some pretty knowledgeable answers here. There's a lot of references to the Higgs field? I'm like, wow. Yeah, some listeners to this podcast have learned something about the Higgs field. That's awesome. Yeah, so a lot of people say it's because it doesn't interact as much with the Higgs field. Right. And that's a totally solid answer because most particles out there, that's how they get their mass, like the top cork, the electron, the bottom

cork, the muon, all those particles get their mass by interacting with the Higgs field. It's almost like a synonym, right? It's almost like the same thing. Like how much mass you have is how much much you interact with the Higgs field. Yeah, precisely. Before we discovered the Higgs boson and understood this mechanism, we didn't really understand, like, where mass came from. Like, it was just a description. When you try to push something, this happens, that it tends to take a force in order to accelerate it. That's really what mass is, inertial mass, what we're talking about. And then we discovered this mechanism, this weird field that if it existed, would have exactly that property as you push on particles. It would mean that when you pushed on a particle, it would take a force to give it

acceleration because of the way this field interacts with those particles. So that by itself is pretty super cool to take this like very intuitive, macroscopic experience of stuff having inertia and explain it in terms of this weird microscopic particle interaction. You know, I love when you can make that connection between the big, the everyday, and the tiny the microscopic. But hey, maybe that's why I'm a particle physicist, even an evil one. All right. So maybe Daniel step us through here.

Let's talk about mass and particles and just in general. How do particles get mass? And before we can even talk about why one in particular has such little mass. Yeah. And remember, first of all, that most of your mass, the stuff that makes you up, doesn't come from the Higgs field. What makes up mass is not just the sum of all the masses of all the particles inside you, but also the energy that holds them together. Because inertial mass comes not just from those particles, but from any energy that's stored within you.

Interesting. Because E equals MCC. squared. Like, if you have energy stored, that's like having mass stored. Yeah, mass essentially is a representation. It's a feature of having energy. Any energy that's stored has inertia. It takes some force to get it up to speed. And that's not something we totally understand. We could do a whole other podcast about, you know, the mysteries of mass and how it works and whether it's connected to this whole other concept of gravitational mass, which is the force of gravity between objects.

But the thing to understand is that the mass is that mass is, this mysterious thing and most of it is stored in the energy of your bonds, but about 1% of it is stored actually in the mass of those particles. Wow. So wait, 99% of my mass, like how much I weigh and how much I'm attracted by gravity to this planet is from the energy inside of me, not from the actual particles. Yes, but you just refer to gravitational mass, right? Which is a separate concept from inertial mass. Gravitational mass is how much you're attracted by the gravitational force of the earth. Inertial mass is how much force does it take to give you an acceleration?

It's the M in F equals M.A. Right, but they're the same, right? It turns out they're the same. I mean, they're different physical concepts, right? One is inertia and the other is gravity. Turns out the number turns out to be the same. It is a whole fascinating topic we can dig into another time. But today we're mostly talking about inertial mass.

Okay, well, yeah, how hard I am to sort of move. And most of it comes from the energy I have. stored inside of me. That's right. So if I'm feeling low energy, I should weigh less. Yeah, and as you absorb energy from the sun, for example, you do weigh more. Like you go out and you sun tan, you actually gain a tiny little bit of weight. Is that true?

No. That is true. Yeah, no, it's not measurable. But every time you absorb a photon, you're getting more energy. Even though photons have no mass, you absorb a photon, you go up in mass. One more reason to wear a hat when you're out in the sun. That's right. Daniel Whiteson's Stay in the Dark Diet.

you should market that. Eating, blaming hot neutrinos, snack chips, and staying in the dark. That's the particle physics diet. It's an anti-diet. And I'm sure it'll be anti-profitable as well. That's right. I just gave it away for free anyway. All right.

So that's kind of wild to think about just that, you know, like we're like batteries almost. Like most of what makes us us is the energy we have stored inside of us. Yeah. And we talked about that a lot of times that most of what makes you, you, is not the actual nature of the particles that are used to build you, but how they're put together. And that includes the energy of those bonds, right? You're like a bunch of Lego pieces bound together really tightly. And it's all about how those Lego pieces grip together. That's what gives you most of your mass. But the Lego pieces themselves, those electrons and quarks that make you up, they also have their own mass. And that's kind of

what we're talking about here today, which is like what's the intrinsic mass by itself of the neutrino. That's right. And for electrons, for example, they get their mass by interacting with a Higgs field. And what that means microscopically is an electron can be flying along and it can emit a Higgs boson and then it can reabsorb that Higgs boson. And that's what interacting with the Higgs field means. It can create virtual Higgs bosons. Right.

We talked about virtual particles last time. Yeah. This is not like a real Higgs boson that you could ever see. Only the electron creates it and can reabsorb it. But the key thing is that in order for an electron to be able to emit a Higgs boson, It has to have an antiparticle. The electron can't do that if the positron doesn't also exist. All right, let's dive deep into these particle physics phenomena and processes.

But first, let's take a quick break. In the heat of battle, your squad relies on you. Don't let them down. Unlock Elite Gaming Tech at Lenovo.com. Dominate every match with next level speed, seamless streaming, and performance that won't quit. And push your gameplay beyond limits with Intel Core Ultra processors. That's the power of Lenovo with Intel inside.

Maximize your edge by shopping at Lenovo.com during their back-to-school sale. That's Lenovo.com. Lenovo, Lenovo. December 29th, 1975, LaGuardia Airport. 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. Well, 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. All right, so Daniel, we're talking about the neutrino and why it has such little mass. And we know that most particles get their mass from the Higgs field. You're telling me that this mass sort of comes from creating virtual Higgs particles and anti-particles. So every time my particles feel mass, you're saying they're creating anti-Higgs and Higgs bosons. It's more about the electron itself has to have an antiparticle. We'll dig into the details in a moment, but the short version of the story is that any particle that gets its mass from the Higgs boson also has to have an antiparticle. The kind of interaction that it does with the Higgs field

means that to be consistent, it also has to be possible for a Higgs to decay into the particle and its antiparticle. So if you don't have an antiparticle, this interaction can't happen and you just can't get your mass from the Higgs boson. The Higgs boson doesn't have an anti-Higgs boson. But in order for the electron to be able to emit a Higgs boson

and then later reabsorb it, it has to have an antiparticle. There has to be a positron. Why? Every particle that gets mass from the Higgs boson has to have an antiparticle. And the reason why is fascinating. The way we think about these particle interactions is three lines intersect. So for this interaction, where an electron emits a Higgs boson, you have one initial particle, the electron, that's one line, and two outgoing particles, the electron and the Higgs boson.

Those are the other two lines. So maybe make a little diagram in your mind of an electron line splitting into an electron and Higgs boson. That's like a mini-fine-min diagram. Now, to be consistent with special relativity, for this interaction to exist, then others also have to exist. If you move an incoming particle from this diagram

to the outgoing side, it becomes an antiparticle. So this little interaction means you should also have another one where the Higgs comes in and out goes an electron and a positron. But that interaction can only happen if there is a positron on nature's menu. I feel like maybe an audio podcast is maybe not the best place to use a schematic to explain something. So maybe let's break it down. I think what you're saying is that, you know, if we want an electron to be able to split into an electron plus a Higgs boson, which is kind of what happens when you try to move an electron, then that process needs to be kind of like reversible.

Or you have to be able to get that process from any sort of order. Is that kind of what you mean? Yeah, that's exactly what I mean. And some of those reversals turn electrons into anti-electrons. And so the anti-electron has to be a possibility in order for this interaction to work. It has to be like a thing that can exist. Yeah. If the electron didn't have an antiparticle, then it couldn't emit a Higgs boson.

Oh, what? Because, hmm, I see. If it didn't have, if there wasn't an anti-version of the electron, that means that the whole process has to be canceled. You can't have that process. Yes, yes, exactly, because this process also requires this other process, a Higgs boson turning into the particle and its antiparticle. But if the antiparticle doesn't exist, this process can't happen in any shape or form. It's like everything has to balance out cosmically, kind of.

That's right, because this process, an electron emitting a Higgs boson and then continuing along its path, somebody else, from another perspective, could see it differently. They could see it as a Higgs boson creating a particle and antiparticle because of special relativity. Remember, everybody can see the same. same thing from a different perspective. And so that process has to also be possible. And that actually happens in the universe, right? Like sometimes the Higgs boson will hit a, what, an anti-electron and become an electron?

Yeah, sometimes we create Higgs bosons, for example, at the large Hajron Collider, real ones, not virtual ones, and they turn into a particle, anti-particle pair, like an electron or a bottom quark and an anti-bottom cork. This totally happens. It's how we discovered the Higgs boson. Okay, so it's almost like a prerequisite for having mass is that there needs to be an anti-version of you to have mass. Exactly right.

In order to get mass from the Higgs boson, you have to have a partner. You can't dance without a partner. You want to dance with the Higgs, you have to have an antiparticle. And it doesn't have to actually exist. It just has to be possible. Yeah, it has to be sort of on nature's list,

on the menu of things that could exist. All right, yeah, yeah. I guess for me to exist, there has to be a, for me to have math, there has to be the possibility of an anti-Horhe out there, even if one doesn't exist. That's right. And so if you can get rid of the anti-Horhays,

that means that you're not going to get any mass from the Higgs boson. There's a whole other particle physics diet for you. There you go. The anti-anty, a twin diet. All right. But then neutrinos, that's kind of where the mystery of neutrinos come in because neutrinos don't have an anti-version necessarily, right? Well, that's the question.

we don't know. Either neutrinos are just like the other particles, electrons and top quarks and whatever, and they have antiparticles and they get their mass from the Higgs boson, or they're not. There's some other weird kind of particle that doesn't have an antiparticle, that is its own antiparticle. So those are the sort of the two possibilities, and we don't know currently which it is. Wait, what are the two possibilities that neutrinos don't have an antivversion, and so they're is weird and they somehow violate this, you know, sort of carmic requirement of the universe? Or like the neutrino, it's so zen with itself that it satisfies its own

anti-requirement. Well, yeah, the two possibilities are one, that it's a normal particle like the electron. It has an antiparticle and it gets its mass from the Higgs. But in that case, we don't understand, like, why does it get so little mass? The other possibility is that it doesn't have an antiparticle, so it can't dance with the Higgs, so it can't get its mass from the Higgs, and it gets its mass in a totally different way. Oh, I see.

Those are the two possibilities. Yeah, either it has an antiparticle and it gets its mass from the Higgs, or it doesn't. It's its own antiparticle, and that makes it this other weird kind of particle called a myeronafirmia. Wow. All right. Well, it sounds like two appealing options to a non-physicist, but what have we measured? Have we measured or found an antineutrina?

we haven't right we have not ever established whether anti neutrinos themselves exist we've seen neutrinos but remember that's always very indirect like neutrinos hardly ever interact this is one of the things that makes them so weird is that they mostly ignore the rest of the universe you have a hundred billion neutrinos flying through your fingertip right now and you don't notice because they don't interact with you and so it's very difficult to feel neutrinos and the reason is that they only interact via one of the forces that we know and the weakest one, the weak nuclear force. And so we have been able to see neutrinos. And the last 20 or 30 years, we've discovered that they do have mass. But you can't like get a pile of neutrinos and measure

them. You can't like say, here's a spoonful of neutrinos and put them on a scale. They're very, very light and very difficult to interact with. So we have these very subtle experiments that can't actually measure the masses themselves. They just measure the difference in masses between the kinds of neutrinos, like electron neutrinos and muon neutrinos and tau neutrinos. Oh, right, because we found different types of neutrinos. That's right. We know there are three types of neutrinos, and we've seen them change back and forth from one to the other.

We did a whole fascinating podcast episode about how neutrinos change flavor, from electron to muon to flame and hot, no, to tau neutrinos. And so what we do know is this is sort of the differences between the masses, and those are very, very small numbers. What? We only know that there are differences. We don't know they're like absolute masses. That's right.

We only know their differences. We don't know their absolute values. We've tried to measure their values and we know that they're less than some number, but we don't know what the masses actually are. But we have measured the differences between them. So we know like the difference between one and two and two and three. Oh, I see. But that doesn't even tell us like the order, like which one is heavier and which one is lighter.

We can only measure these two differences. We know that whatever they are, they're really small compared to other particles. That's right. They're really small and they're not zero. And so, for example, if they do have antiparticles and they do get their mass from the Higgs boson, then it's a question of like, why such a small number? Every particle that gets its mass from the Higgs boson gets a different amount of mass because it interacts with the Higgs boson more or less, like the top core interacts a lot with the Higgs boson.

The electron, not nearly as much. So there's just like a parameter, like a number, like a dial on the universe that says, how much you interact with the Higgs boson. And we want to know, like, why are these numbers all different? Why are the values for neutrinos so small? It's not an explanation to say, oh, neutrinos get their mass because they hardly interact with their Higgs. Like, why?

Why neutrinos different or weird or special? It's a totally unanswered question. But it could be that there's no answer, right? Like, it could be that maybe the mass with the neutrino is just a, like, a basic constant in the universe that it just is because it is. But that's not an answer. know, I find that totally unsatisfactory to say that the universe has like 19 different numbers and they just are what they are. Like, why are they that and not something else? Was there a moment in

the beginning of the universe when these were randomly chosen? Could they actually be any value? I feel like sometime in the future physics will discover a reason why these numbers are what they are. We just don't know it yet. You know, there must be some pattern, some simplification, some way that we can explain this. So it's very unsatisfying to say, well, neutrinos get their mass from the Higgs and they just don't interact with it very much for some reason we don't know. Right. That's weird and unexplained. And that's just option A. Option B is that it's a totally different kind of particle that maybe doesn't even get its mass from the Higgs. That's right. And early on in the days of particle physicists, there were two competing ideas for how particles could exist. One from

Paul Dirac, a famelish English physicist, who predicted antiparticles, and another from Etore Maerana, an Italian physicist who predicted that particles could be their own anti-partners. All right, let's get into what neutrinos could be and how that would explain, why they have such little mass. But first, let's take a quick break. In the heat of battle, your squad relies on you. Don't let them down.

Unlock elite gaming tech. Lenovo.com. Dominate every match with next level speed, seamless streaming, and performance that won't quit. And push your gameplay beyond limits with Intel Core Ultra processors. That's the power of Lenovo with Intel Inside. Maximize your edge by shopping at Lenovo.com during their back-to-school sale. That's Lenovo.com.

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. Well, 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. All right, Daniel, neutrinos. We know they're weird because. they have such little mass but we don't know if it's because that's just how they interact with the Higgs boson or whether they get their mass from a totally

different way. Is that impossible? Can you get mass from not the Higgs field? Yeah, there are other ways to get mass and the one was predicted by Mayerana and he came up with a whole different way to like think about particles. Remember most of the particles that we

think about today were envisioned by Paul Dirac. He was trying to put together a theory of quantum mechanics that worked well with relativity. And he came up with an equation called, of course, the Dirac equation that described how particles move through space. And it's when he put that equation down on paper and he looked at it. He noticed, he said, wait a second, this equation suggests not just that particles can move

through space, but that they should each have a partner. There's like a symmetry in that equation that says, if there's a particle, there should be an antivversion, a version with the opposite charge. That's where the whole idea of antiparticles came from, from this. This guy, Paul Dirac. And then, of course, we discovered electrons do have antiparticles and protons have antiparticles and all that stuff. Dirac was right, yeah. Dirac was right.

I wonder if he had come up with a second equation, what he would have called it. Or the rise of Skywalker, probably. The rise of Dirac. My second equation. Dirac strikes back. All right. So that's one way that particles can be. They can have anti-versions of itself.

But then Majorana came up with another way. Yeah, he came up with a different equation. He wrote his mathematics differently. And he thought about the way you could have quantum mechanics and relativity. And he put the math together in a different way. And he came up with a way to describe particles moving through space that didn't imply antiparticles. And it totally works mathematically. Like, there's no reason we know of why particles should be like Dirac particles instead of like myerana particles.

Wow. But it still predicts. anti-particles? No, myerrana's particles don't have antiparticles. What? Yeah, they work without antiparticles. So his equation is different. It doesn't have this symmetry. It doesn't require there to be the opposite particle. But it's still right and true? Well, it works mathematically, but we've never seen one in the universe. So before we discovered the positron, nobody knew whether every particle was like the ones described by Dirac's equation or by the ones described by myerana's equations. And then we discovered, oh, all the particles we know, they do have

antiparticles. So we'll put them on Dirac's tally. And so far, Maerana has won zero of these battles. Like every single particle we've discovered, so far has been a direct type of part. Oh, I see. But it's possible that some of them could be myerana particles. We don't know. We have no reason to understand why the universe likes direct particles and not Maerana particles. I mean, Maerana was a cool dude. All right. So then the idea is that maybe neutrinos are maybe one of these. Mayerana particles that don't have anti-versions of itself? Yes, exactly.

Neutrinos could be their own anti-particles. They could be myerana particles. So there's not like a separate particle that's the anti-electrono neutrino. And if that's the case, if they are myerona particles, this special weird kind of particle nobody's ever seen before, then there's a very nice explanation for why they would be so light, why they would have such a small mass. Interesting. Because I guess May Uranus equation kind of allows for some particles who have very little mass.

Yeah, if you take his equations and you say, well, what if there aren't three neutrinos, there are six? And three of them are super duper heavy, like cosmically heavy. Like, you know, each one weighs as much as like a planet or something crazy. Then if you do that, then because of the way the equations work out, you get three really low mass neutrinos that pop out of the equation. What? So he posits that neutrinos don't have maybe an antivirion. They just have a heavy version. Yeah.

Instead of there being three, there's like six. And three of them are super duper cosmically heavy. And it's called the seesaw mechanism because those guys like steal all the mass essentially in these neutrino fields and leave only a tiny little bit left over to the neutrinos that we know and love. And so this imbalance comes from the way the matrices are diagonalized, et cetera, et cetera, it falls out of the math. But essentially, it's a very natural, simple way to solve his equations and to get a set of very heavy and very light neutrinos. So it'd be sort of elegant.

Instead of like flipping the charges, you kind of almost flip the mass, kind of. Yeah. Yeah, that's a good way to think about it. And unlike with the Higgs boson, you don't have to just like put a number in by hand. It's like it comes out of the math naturally. If you have six of these particles and half of them are heavy, then the other ones just come out naturally to be very, very light. And that's what we look for. We look for sort of natural explanations where you don't have to say, this is just a number. I don't know what it is. I'm just

going to stick it in there and see that it works without any explanation. We look for ways that it's a natural consequence of the math. The way that antiparticles are a natural consequence of Dirac's math that tells us Dirac's math is probably right about most of the universe. But maybe Myerana's math is right about neutrinos. You know, maybe finally he can get one on his tally card. But I feel like Mayerana's equation would require there to be like these crazy particles, like a neutrino with the mass of a planet. That doesn't sound like something we found. And it's not something we found, absolutely. And it's less, Daniel. What if it's dark matter? What if the whole Earth is just one big neutrino? There you go. But it's a classic trick in particle physics to explain

something we see. You add a bunch of crazy stuff that happens with particles that are really heavy, because we can't see those particles. We can't create them in our colliders. We don't have enough energy. They're too rare. They haven't been around since the Big Bang. And so it's sort of like sweeping stuff under the rub. I see.

You know, you push up all your problems into the really heavy particles, which nobody ever sees and are never created. And so it can't be found, kind of. It can't be found, exactly. Right, because to like create a planet-sized neutrina would require a crazy particle collider. Yeah, particle collider, the size of a galaxy, probably, to create that much energy.

Or like require conditions like the Big Bang, right? Because right now, today, it would be very unlikely for us to see something like that if it existed or could exist. Yeah, essentially impossible. Nothing is technically impossible when you're talking about quantum mechanics, but essentially. But there are ways for us to figure out if neutrinos are their own antiparticles or not. All right. That would settle the question of what kind of particle neutrinos are. That would settle a question because of neutrinos have their own antiparticles,

then they're Dirac particles, and he basically runs the board and wins everything. But if they do not have their own antiparticles, if they are their own antiparticles like the photon is, then Myerana wins one. Oh, man. You know, if people get confused, we're only talking about matter particles here. There are some particles like the Higgs and the photon, which are their own antiparticles, but they're not matter particles, so they're not governed by this Dirac versus Maerana. Yeah, I feel like now there are stakes, Daniel.

Well, I really like the math of the myerrano particles, and so I'm sort of rooting for him. I also like the underdog, you know. It's like, let's give him one, guys. Come on. Throw him a bone. That's right. Let's give him one.

Also, let's give him the weirdest best, awesome. Neutrinos are fascinating. So if you have to pick one to win, it would be neutrinos. All right. So you're saying even if neutrinos are their own antiparticles, that would still put them in the Dirac column. No, if neutrinos have an antiparticle, that would put them in the direct column.

Right, right. The opposite of what I just said. Yeah, the anti, what you just said. If neutrinos are their own antiparticles, then they're in the Meyer honor carlo. Oh, I see. And we have a possibility to maybe even see this, to discover, to tell the difference

between those two hypotheses, to figure out if neutrinos are their own antiparticles or if they have antiparticles. Oh, all right. It sounds like we have an overtime penalty goal here. So maybe real quickly describe what this experiment is. Well, it involves beta decay. Beta decay is the process

where you take a neutron and it turns into a proton. And it happens all the time. It's radioactive decay. And what you get is a neutron turns into a proton plus an electron and a neutrino. This is actually how neutrinos were first discovered because we saw

the neutrons turned into protons and electrons, but there was some missing information because we can't see the neutrino itself. And so people thought, oh, well, there must be some little neutral particle carrying off some energy. That's the origin of the name neutrino. Like a little remainder.

Yeah, like a little remainder. Now, sometimes there's some nuclei that can't do this. But what they can do is they can do double beta decay. They can take two neutrons, simultaneously turn them into two protons, which should give you also two electrons and two neutrinos. So what people are looking for is neutrino-less double beta decay. the idea that these two neutrinos that are produced, one from each of the neutrons, might combine and annihilate each other.

If they are their own antiparticle, then they can do that. They can just like, slurp into each other. Disappear. Disappear, yes. But it sounds like maybe the idea is that there's an experiment in which two neutrinos are created at the same time. And if we suddenly see these two neutrinos disappear, then that means that they are their own antiparticles, and they did sort of cancel each other out. Yeah, exactly. So if neutrinos are myerona particles, then double beta decay can happen without any neutrinos flying out. It'd be like neutrino list double beta decay. And you might ask like, well, how is it possible to even tell? Like you can't see neutrinos directly. So how can you tell like if there weren't two neutrinos there. If there were or there weren't. Yeah. Well, if there's a neutrino there, it carries off some of the energy. Like that's how neutrinos were discovered. Remember, you add up the energy of everything else and it doesn't.

doesn't add up. All the energy that came out doesn't equal to the energy that went in. That's the evidence for the existence of a neutrino. So if you see this happen and there's no missing energy, no energy is lost, then that tells you that there probably was no neutrinos created and the neutrinos annihilated themselves. That you have neutrino-less double beta decay. It sounds kind of impossible, right? Or what if the neutrinos were created? They took some of the energy, but then they canceled each other afterwards. Yeah. Well, it could be that they like just go off in opposite directions, and so they do cancel each

other. It's a very hard experiment to do. So far, nobody's ever seen neutrino list double beta decay. Nobody's ever seen this happen. But it's difficult, right? To have evidence for this not happening, you have to create the situation where you think it could happen and then prove that you would see it if it did happen and then not see it. So it's a very subtle experiment.

It's hard, but a total problem. You lost me a few steps back there, but it's like you have to see something that's not there. Or you have to not see. Not see something that is there, but not there at this time. It's a very subtle experiment. And total props to the folks looking for nutrient-neutralous double beta decay. It's a fascinating question in particle physics, but it connects to this much bigger, deeper question of like, how do particles get mass? And do particles have their own antiparticles?

and, you know, why are there anti-particles anyway, which is a question I've never really wrapped my mind around. Interesting. It's like a little detailed question that's subtle, but it might sort of upend the whole basis for the standard model and our whole sort of understanding of what particles are and what's possible. Exactly. And so the discovery of the Higgs boson is not the crowning achievement of the standard model.

It doesn't put the last piece into place and answer all of our questions. We don't step back and go, oh yes beautiful we're done we've done it no we're like well there are so many weird little bits that don't make any sense hanging ugly things off the back of it that we want to try to understand and smooth over and figure out because hey we like the weird stuff not the shiny and cool stuff all right well it sounds like there's still big questions out there about our understanding of particles in the universe and um i think it's time for people to the side you know are you pro direct or anti-Niurana and is that the same thing?

And what would happen if Dirac and Maerana went to a conference together, would they annihilate each other? That's right, with the same energy and the opposite direction, would we even be having this conversation? That's right. Well, I'm on Team Meyerana because I hope that the universe is weird and then we find new stuff. If it turns out that neutrinos have anti-particles and get their mass from the Higgs, just like all the other particles, And that's much less exciting than discovering a whole new kind of particle that does something weird. So you're pro weird or anti-standard. That's right. I'm rooting for the weird model of physics, not the standard model.

All right. Well, we hope you enjoyed that. And think a little bit differently the next time you look up into the sky and realize that you're bathed in these weird, mysterious neutrinas that are maybe something totally different than the rest of the universe. And maybe they hold a clue to something even deep. about the nature of matter and reality and the whole universe. 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. Oh, come on. Why is this taking so long? This thing is ancient. Still using yesterday's tech? Upgrade to the ThinkPad X1 Carbon, ultra-light, ultra-powerful, and built for serious productivity with Intel core ultra-processors, blazing speed, and AI-powered performance. It keeps up with your business, not the other way around. Whoa, this thing moves. Stop hitting snooze on new tech. Win the tech search at Lenovo.com.

Unlock AI experiences with the ThinkPad X1 Carbon, powered by Intel Core Ultra processors so you can work, create, and boost productivity all on one device. 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 podcast on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. December 29th, 1975, LaGuardia Airport. 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 Irish. Heart Radio app, Apple Podcasts, or wherever you get your podcasts. This is an IHeart podcast.