Can neutrinos explain why we have matter?

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Speaker 1: Okay, Orr, Hey, I have a physics game for you. Is that all physics is to you? Daniel game? I thought he took particles in black holes seriously. Well, this is a game about taking things seriously. It's called would you worry? Oh man, I'm worried. Already sounds like a meta game. All right. Would you worry if cern created a black hole? Yes, even after all those times I told you not to worry. I mean, you said it's unlikely that they would create a bad black hole. But if you ask me if I'm concerned that they created a black hole? Yes, all right. Would you worry if we shot a beam of high energy particles through your backyard? Yes? Also, yes, high energy particles can never be good that kids playing in that yard. What if we shot it through the yard is in like underground. They won't come up, and they will not come up. But I'm still a little bit worried because you know, why would you do that? Why not? Hi am or Hey, I'm a cartoonists and the creator of PhD comics. Hi, I'm Daniel. I'm a particle physicist, and I don't shoot particles at your children, not usually, only if they're in your lawn. Is that what happens only if they're deep deep underground your lawn. You have a little particle shooter in your porch. Well, you know, sometimes particle physicists build accelerators underground. And in the US you own the land all the way to the center of the earth, and so you have to get permission from people to build underneath their land. But in other countries, like in Europe, you only own the earth down to like fifty below your land, so the government can build whatever accelerated they want under your property. What are you telling me that I own my land all the way to the center of earth, that all the way down to the center of the earth. US lands law says that you are the owner of that entire what is it cone or pyramid of Earth? Wow, I should build the biggest bunker humanity has ever seen, very long, very thin bunker with very low gravity near the center, multi tiered pools. You know, be a great apocalypse. But anyways, welcome to our podcast Daniel and Jorge Explain the Universe, a production of Heart Radio in which we take you all the way down to the center of the Earth to understand what's going on underneath your feet are there bunkers down there are particle physicists doing experiments you aren't aware of. And we zoom out to the wider universe to help you understand why we're here, what we're doing, and what the future holds. That's right, all the way to the far corners of the universe, to explore all the things that we can barely see, and we can see and we would that we might one day see. And we also take you down to the very core of you, to your atoms and to your particles, and to all the things that make you who you are. That's right because we think the biggest game in town is trying to understand what the world is made out of. You look around and you have to wonder, why is the world this way and not some other way? One are the basic rules that make everything up? How do they explain the reason why cats are so weird and dogs are so friendly? In the end, it has to all come down to the tiny little particle. That's right, and the even deeper question, why are we made of the particles that were made out of Why aren't we made out of other particles? That's right because scientists have discovered lots of really weird symmetries. We have a certain set of particles, but there are other possible particles out there, particles that you can create in high energy collisions, but you just don't see very often. And some of those particles are weird reflections of the particles we are made out of. We're made out of matter, but it's also possible to create antimatter. Yeah, because we we have the standard model, right Daniel, that explains or that maps out all the particles that we know about, and so there's a big question of whether or not that model is like done, is it wrapped up that all the matter there is? You know, now that we found the Higgs boson, what's left to learn about the particles that make up matter in the universe? But there's still sort of one unanswered question about it, right, That's right. I got more than one unanswered question. I only have one. What is this podcast about? But you're right, there sometimes the perception that because we have the standard Model of physics, and for a long time we said there was one missing piece, the Higgs boson, And that's true. We thought that piece existed and it was missing, and then we did find it. But that doesn't mean that questions are over. We don't just tie a bow on it and walk away and say that's it, we're done. We look at it and we ask questions about it, and we say why is it this way and not some other way. We look at things in our universe that don't have explanations, like why is there so much matter and not antimatter. That's something we can't currently explain using in the complete Standard Model of particle physics. Yeah, it's a very big question that basically determines everything, because the whole universe could have gone the antimatter way, right, Everything could have been made out of anti matter. But somehow, for some reason, everything is made out of matter, not antimatter, and so a big question is whether or not we can explain that with some of the particles that we have, namely the new trino. That's right, one of the least explored areas of the Standard Model are these weird new trinos. You might have heard of them, because the Sun is pumping them out at an incredible rate, and there's like a hundred billion of them passing through your fingernail every second. As we sit here on the surface of the Earth and they can do a bunch of really weird stuff. They come in three different flavors, they turn from one into the other. But their mysteries are only beginning to be cracked, and they could have the answers to some of these really big questions that are still open in particle physics. Yeah, why didn't trinos only come in three flavors? Is it like vanilla, chocolate and strawberry? Can you make neopolitan neutrinos Neopolitan ice cream from Italy? Also, that's where neutrinos were discovered or named at least, so many connections being made today. But you know, if there were only three flavors in the world, would you want them to beat chocolate, manilla, and strawberry? No, because I'm allergic to strawberry. But that's that's probably the only reason. To be honest, be careful what you wish for that man, I would be like chocolate, darker chocolate and super dark chocolate and pure chocolate chocolate. Forget the ice cream part. I just want to block of chocolate. We need cream and ice just just delivery mechanisms. But yeah, we don't know why neutrinos come in three flavors. And in the last twenty years we learned some weird things about neutrinos, like sometimes they're made in one flavor and they can while flying through space turn weirdly into a different flavor, which isn't something other particles can do. They have these really tiny little masses, not zero, they definitely have some masks. They're not like photons, but they're are much smaller than anything else we've ever seen, if a very subtle flavor neutrinos. But yeah, that's the question for today is whether or not neutrinos could you know, explain one of the biggest questions in particle physics. And so today on the podcast we'll be answering the question, are neutrinos the reason why we have matter and not antimatter in the universe. That's a big question, Daniel. It's a big question to hang on on one little poor particle, I know, and we often think like, well, neutrinos hardly have any matter to them. I mean, there's almost no mass there, so how can they matter so much? But remember that there are lots of them right There are billions and billions of them in every cubic centimeter of our solar system. So even though there are very few of them, they really add up, you know, they're like votes. Every neutrino counts. Yeah, And right now, there's a big experiment, right Daniel, that's trying to answer this question. And it has a pretty cool name, at least if you're a sci fi fan or a fan of SAND. I'm a fan of science fiction and SAND, so I love this experiment. Because the United States has made a sort of political strategic choice to not try to have the highest energy collider in the world anymore. We've sort of given up and let cern take over instead. The United States communities decided we're going to focus on neutrinos. We think neutrinos are the place to discover the new secrets of the universe. So the biggest particle physics experiment in the United States right now is not a huge collider to smash particles together at the highest energy has ever seen. But instead it's a new trino experiment to try to understand the mysteries of these neutrinos. And it's called Dune d U and Deep Underground Neutrino Experiment, and it's outside of Chicago Infirmulab. Right, that's right. It actually stretches part of the way across the country. Yes, we'll get into all of that, but it shoots neutrinos from one part of the country through a bunch of backyards to another part of the country. It's pretty amazing, all right. Well, we were wondering how many people out there in the Internet that had heard of this experiment, the dune experiment. And again it's not it has nothing to do with the spice or giant worms. You don't know that they could discover giant worms. They are on the ground, aren't they. Who knows what's out there. You've got to keep an open mind every time you do an experiment. It could be a giant water reservoir down there. But anyways, we're wondering how many people out there had heard of this, So as usual, Daniel went out into the wilds of the Internet to ask this question. So thank you to everybody who volunteered to answer these random questions. If you would like to hear your random speculation on our podcast, please volunteer two questions at Daniel and Jorge dot com. So before you listen to these answers, think about it for a second. Have you heard of the Dune experiment. Here's what people had to say. That's another one, unfortunately I have not heard of, unless it's referred to the novels by Frank Herbert. I don't know if this is an acronym, and I'm not sure what the letters stand for. But since I'm in the microbiology field, I'm going to say that it involves testing for some kind of extraterrestrial microbes in sand or soils from other planets. So I don't I'm blank on that one. I live five miles from Fermilab, and I take advantage of their lecture series and things, so I know the Done experiment. Fermilab is shooting streams of neutrinos and anti neutrinos through the Earth to a detector in a mile deep in South Dakota. I no idea what the Done experiments is. Maybe I should know this, but I hope that they will answer everything. Well. I've definitely never heard of the Doune experiments. I hope that they would be looking for a spice to extend human life and make space travel more feasible. So mostly blanks on that one, except for that one person who lives is near it. I guess they're probably pretty aware of it and maybe a little concern. Who knows. They did sound very concerned. They sound more happy with themselves to have heard of it. But I like the one that's suggesting that maybe it was looking for a spice to extend human life. That would probably get more funding more easily. Yeah, let's fund every science fiction novel as a particle physics experiment. There you go, lightsabers and transporter beams. So let's get on at Daniel, send me the money. I'll get started. All right, Well, let's step through this. What is Dune the Deep Underground Neutrino Experiment. So this is a really awesome new massive experiment. It's being built right now. It's not finished yet, it's gonna be finished in the next five ten years, and it's going to try to unravel some of these mysteries, try to understand the relationship between neutrinos and anti neutrinos and help us understand how they could potentially give us a clue about how antimatter all got disappeared from the universe. And it starts at Fermilab, which is this collider facility outside of Chicago. It's actually where I did my PhD work. It's out in the suburbs of Chicago, near Naperville and Batavia. Interesting and then nothing bad happened to you, at least not if you count of PhD R. Yeah. Well there were some adventures there, but not appropriate for this podcast. Well maybe they are actually. Like, for example, the first year that I worked at Fermilab, it was Halloween and I thought, hey, Fermilab is a cookie place. Probably everybody shows up at work in costume, right, So I showed up a work in a clown costume, the only person in the entire facility to wear a costume to work on Holloway makeup, wig, the whole thing, makeup, wig, the whole thing. That was pretty goofy. And so ten minutes in when I realized nobody else is wearing a costume. You know, I pulled out the bits that I could washed off the makeup, but I was still walking around all day in oversized blue shots. Oh man, did you become famous on campus for that? Infamous? I thought, Really, my academic career had tanked at that point. I would have thought that would he paid attention to you? You think it blend in, but you know, among the khaki shorts and stained T shirts that really did kind of stick out. Well, that sounds like a pretty upprovid story. But um, yeah, so what so you guys start smashing new trinos catching neutrinos, you're looking for a new trinos. What's involved in the experiment. Well, what they're doing is they're making a beam of neutrinos at Fermi Lab and then they're shooting it into a detector. And Fermi Lab used to be the place where you had the highest energy collisions in the world back in two thousand. It was the energy frontier. There were no higher energy collisions, and it was smashing protons and anti protons together. But then it sort of lost the race discern and it's been repurposed and they're taking that beam of protons and they're turning it into a neutrino or an anti neutrino being or you specause if you don't know what's coming out. No, they do both. They have like a knob. They can produce a beam of neutrinos or a beam of anti neutrinas. Yeah, I'm confused because I thought neutrino's words own anti neutrinos. Well, we don't know right, we can produce neutrinos, and we can produce anti neutrinos. We don't know if they're the same particle or not. What I guess, how do you know you're making anti neutrinos. We don't know if they're the same thing as regular neutrinas. Yeah, that's a great question. Well, Typically neutrinos, which are matter, are produced from decays of other matter, and anti neutrinos, which are antimatter, are produced from decays of other antimatter. And in these collisions, we can make both kinds, and we can select for matter or we can select for antimatter, and then we can just sort of let it decay. So the way it works is we smash protons at some target, which makes a big mess. You get lots of crazy particles out pions and kons and all sorts of stuff, and that stuff usually has electric charges. So we can separate using a mac we can say, all right, the positive ones over here and the negative ones over here, So that gives us like mostly matter or mostly antimatter that travels through a long space where the kaons and pyons they all decay into lighter particles like neutrinos that we're looking for, and then also electrons and muons, and the Earth absorbs all of it except for the neutrinos. And so we don't specifically produce neutrinos or anti neutrinos. We produce stuff which turns into neutrinos or stuff which turns into anti neutrinos, and then we just let the Earth filter it all away. And so that's the knob you can dial. You can dial like smash matter or smash antimatter, like we can produce antimatter that well, we can produce antimatter absolutely. You just smash protons into a big heavy block of matter graphite in this case, and you get a huge spray of stuff, both matter and antimatter. I mean a proton smashing into graphite. It starts out with just plus one electric charge right because of the proton. Then you've got a huge bunch of particles. But you can get like plus five hundred electric charge over there and minus four electric charge over here, So you've got a combination of matter antimatter. Oh I see the antimatter has like the negative charge. Yeah. In some cases in the same way, for example, of photon can turn into an electron and oppositron, right, so it can turn into matter and antimatter, and then you could you can separate them and say, oh, give me all the matter or give me all the antimatter. And so that's what you do here. And the super cool thing is that you're not interested in any of it except for the new trinos. So you've got to filter everything out like a sieve where you want to get everything out of the way except for the new trinos. Neutrinos the only thing you basically can't bend or turn or stop. So the way you get everything else out of your beam is you just slam it into the earth and let the earth absorb all of it except for the new trinos. Interesting, so you you produce them at Fermulab, but then you catch them somewhere else, Like you don't catch them right away, that's right. We produce them a Fermulab, and we're interested in how these neutri change over time, like do they turn mule neutrinos into electron neutrinos or into town neutrinos or into anti neutrinos or what do they do? So we've got to get them time to do that, So we want to watch this beam. We take a snapshot of it immediately as soon as it's measured to get a sense for what was in there, and then we take a snapshot that's kilometers away in South Dakota. What. You shoot them in Chicago and you catch them in South Dakota. Yeah, they're made in the cybutse of Chicago. And then they're just aimed through the earth like the Earth curves, and we shoot them in a straight line, sort of under the curve of the Earth. So they come into this mine in South Dakota. What and nobody cares like you can just shoot stuff through the earth like that, You can just shoot stuff under people's property because you know, neutrinos do nothing. You know, you're not gonna give anybody cancer shooting neutrinos under their house, you know, of we know, that's right. It's sort of amazing because usually when you make a beam of particles, you very carefully shoot it through a vacuum because you don't want to lose any of your particles. Like the beam that's at the LHC at the Large Hadron Collider is through a very very low vacuum tube. But here you specifically shooting neutrinos through rock and rubble and all sorts of crazy stuff to get rid of all the other particles. So it's sort of awesome. Wow. All right, let's get into why we're shooting this beam of natrinos to South Dakota and what we're going to learn from them. But first let's take a quick break, all right, Daniel, So about trillion and the natrinas per second are being shot out of Chicago and they're being caught in South Dakota, so that these are going how far underground are these trina's going like underneath me? How far would I be able to catch them? When they hit in South Dakota, they're about a mile underground about halfway through their trip there even further because the courage to the earth piles above them. So they're producing in Chicago and they're just above ground there where they're made, and their shot into the earth, and then they go deeper and deeper and deeper, and then the curvage of the earth sort of curves back towards them. But they end up about a mile underground where there's a mine, an old mine that was used for you know, mining and has now been taken over by particle physics experiments where people want to look for really rare stuff, and they do these experiments underground so that they're not constantly drowned out by the noise from cosmic rays particles from space that would otherwise feel your experiments. And you're telling me earlier that you know I technically on the ground underneath me from my house down to the core of the Earth. So did the US get permission from everyone along the way or did they just did it? Nope, they just did it. They can't build a facility the under your house because you own it, but they can shoot particles through it underground. Really that was a loophole. Yeah, they don't need your permission to send cell phone signals through your house, for example, or radio waves. It's the same deal. I guess did they slip that in under the same regulations like that the FTC approved this experiment. SEC. I don't know if SEC or the SC or the POC or anything approved this, but they're doing it. And you know, remember the neutrinos, they hardly ever interact like they'll go through a light year of lead and have a fifty percent chance of interacting so there are trillions of neutrinos produced per second, but only a handful of them are seen, and it takes a really really specialized, very sensitive detector to see any of them. All right, So tell us about that. What's on the other side in South Dakota in that mind, is it like a big detector or a little detector? What's there? It's ridiculously big detector, right, because to see neutrinos you have to have something very very quiet, because neutrinos are really shy. They hardly ever interact with the detector and they're very light. So when they do interact, all they do is they like bounce off a nucleus, maybe kick off an electron or so. But that happens all the time. Like if you just look for electrons being kicked off of nuclei, you would see it all the time around you from cosmic rays and from other processes. So to see it from neutrinos, you have to get a very quiet environment where nothing else is happening, and then listen for these little buzzes from the electrons, and you want to see it as often as you can, so you get a really big volume. So what they have is like basically a big bath a very cold liquid. They use liquid argon. Argon is a noble gas that doesn't interact very much. It's very quiet, and if you chill it down to like minus a hundred and eighties six celsius, it turns into a liquid. And they have these enormous containers of this liquid argon just sitting there waiting for neutrinos to fly through them. Interesting and when they flies through, do they create like a ping or like an image because they used to measure these with images, right like you might see the trail of bubbles that the particles mad. But I'm guessing these don't use that. These use are very cool new technology. Older neutrino experiments like the ones in Japan may have seen those. They're like a huge cylinder of water surrounded essentially by cameras, photo multiplier tubes, and those used charenk Off light, Like a neutrino comes in and turns into a mule on which gives off this cone of light that's then image on the side of the detector. These are even fancier because there's an electric field that's put through the liquid argon, so when autrino comes in, it actually can kick off a bunch of electrons, and you can get the whole trail of the neutrino. You can get like a track of the neutrino because you can pull off those electrons from deep inside this detector. The electric field like sucks out any of these electrons and registers of them sort of on the side. So it's like single electrons, single electrons exactly, And so it has to be very quiet and very clean, but it also has to be really big, and so experimentally that's a big challenge, right, Like, you can build something small that performs really well, but to scale it up is really difficult. And these tanks have ten kilo tons of liquid ar gone, Like, these are not small devices. Well, I guess my question is why shoot them through the earth. Wouldn't that you know, kind of corrupt signal or you know, damp in the signal. Why not shoot them kind of straight into a detector. Well they do that also, so they have detector immediately after the neutrinos are produced to sort of sample the beam. They're like, well, what did we make? Do we make mostly electron neutrinos? Do we make mostly mule neutrinos? Etcetera. But then you also want to see them change, And that's really the question we're asking. It's like, do we understand how neutrinos change from one kind into another? That's the thing that's going to help us connect to this question of antimatter and the deeper questions of the universe, and even you know, maybe understand some things about exploding stars in far Way Galaxy. The key is to understand how the neutrinas change from when they're created to further down the road. So you want to sort of corrupt them. You want them to interact, to change in flight, to do the things they're going to do, the weird stuff they can do, so then you can catch them having done it down the roof. But w don't you want a clear line aside? Why would you want it to go through rock? Wouldn't that, you know, give you a lot of things that could have happened or unexplained phenomenon along the way. Well, if you discover that somebody's, for example, build a bunker all the way down to the central of the Earth, that could really like corrupt your measurements with all their cascading pools and demando plantations and stuff. Yeah, what if a giant sandworm like wat's right into the beam. The first thing is you want all that earth there to filter out all the other particles. You need to get rid of all the muans and the chaons and all the other stuff, so you have a pure neutrina beams, So you need the earth there for that also. But then you want it to interact, and you might be thinking, well, usually particle physicists they like things to be simple, like let's interacted with a block of graphite or a perfect cube of argone or something. Right, and rock and dustin rebels seems sort of messy, But we're not very sensitive to the details of like is it, you know, marble or is it graphite or is it dense or is it loose? Because we're integrating over like hundred miles of stuff, and so we're not very sensitive to like exactly what happens where We're not going to get like a picture of the center of the Earth. We just want to the neutrinos to do something and have to pass through matter in order that. All right, Well, I guess the question is what are we going to learn from this experiment? And how does this how do you relate in neutrinos to matter and antimatter because I guess, you know, you hear the word neutrino, you think they're neutral, they don't care, but maybe they do care, and maybe they had a lot to do with the fact that we have matter. Yeah, well, this this deep question, right, like why is there matter not antimatter? And we think that in the beginning of the universe. We suspect that matter and antimatter were made at the same rate. We don't know why would be anything different, And that's just an assumption, like we could be at the very beginning of the universe there was just more matter made than antimatter for some weird, other deep reason we don't understand. But we assume, because we like to make simple assumptions, that it was made in a symmetric way, and that something exists that can turn matter into antimatter. There's some process, something that prefers to create matter over antimatter, because I guess in the equations that we have now, there's nothing in them that says, oh, obviously matter is more likely to be made. There's nothing like the equations. They're totally equal, just opposite, They're not equal like for a long time we thought they're totally equal. Obviously things have to be symmetric, and there's this principle charge conservation that says, if you see a process in nature, you should be able to flip all the charges, all the particles at up particles and see exactly the same thing happen. It should be exactly the same. But then we discovered that didn't actually hold true, that's not really true, that there are some asymmetry. Interesting for example, the weak nuclear for breaks this rule, and especially when you combine it with this other rule about putting things in the mirror, so together it's called CP violation, charge and parity. You flip the charges of something and you put it in the mirror, you should see the same effect, but you don't. Often we have a whole podcast episode digging into discovery CP violation. But this CP violation, it does give you a reason to have more matter than antimatter, but not nearly enough. It explains it by like one percent of it. So there are some asymmetries. The equation do predict that you get more matter than antimatter, but it's not big enough to explain what we see. Interesting, what does that mean like the violation means that it's one percent more likely to get matter than antimatter from like a random, you know, explosion of energy. We've calculated how much I balance you need between matter and antimatter in order to get the universe that we have now. Right, if they're exactly matched, then you get no matter left or antimatter left over in the universe because they all annihilate into nothing. You need some process which will create matter more often than antimatter in order to get extra matter left over. So when all the annihilation happens, you have matter, which is the universe that we have now. And so we've calculated, like how much of that do you need to happen? And we can explain about one percent of that process. So it's not like any given particle has a one percent chance of turning into antimatter. But we're looking for, you know, a way a channel for this to happen, and we found a few, but they're really small. They've explained just like one percent of what we need to explain the universe we see, So there's a big missing process. Something out there really prefers turning antimatter into matter rather than matter into antimatter and we don't know what it is, and maybe it's new trina. Well, so then the idea is that like matter turns into antimatter, but not symmetrically. That is that kind of what you just said, Yeah, exactly. So you have these processes where matter can turn into antimatter and antimateric and turn into matter. Most of the time it's symmetrics. So stuff just slashes back and forth and you don't overall change the balance. But there are a few things that preferentially produce matter that prefer to go from antimatter to matter, and we've seen and then they don't go back as easily, I guess exactly. They don't go back as easily so that you don't get an equalibrium and gradually build up an excess of matter. But they don't explain what we've seen. You need more processes. We're looking for the rest of them. We've seen CP violation, these processes that produce more matter than antimatter. We've seen it in chaons, we've seen it in b masons. But those are very very small. They're like not big enough. It's like we're panting for gold and we know there's a lot of gold in the stream, but we just keep getting dust, and we know that there are big nuggets out there, all right, And so is the picture then that you know, we had the Big Bang and a whole bunch of both matter and antimatter got made equally. But then over time somehow everything flipped over to matter. Is that kind of the what we're looking for. That's the scenario we're trying to figure out. Yeah, and not everything flipped over to matter, just like some fraction of it flipped over to matter, and then you had more matter than antimatter. But you know, the anti matter all annihilated with matter. But since you had more matter than antimatter, some matter was left over, all right, And that's where we came from. That's us. We are the matter that's still here. All right. Well, let's get into then how neutrinos could explain this in balance and also what it means for astrophysics. But first let's take another quick break, all right, Daniel, So how would neutrinos explain the fact that we have more matter than antimatter? Well, there's so many open questions about neutrinos and antimatter, like, for example, as you said earlier, we don't even know if neutrinos are their own anti particle, or if there are two different particles there, Like is a neutrino and anti neutrino different. It's so hard to tell because neutrinos hardly ever interact. Like for a neutral particle, what does it mean to have an antiparticle. It's like they're both charged zero right electric charge neuero, But they and neutrins have other charges right exactly in terms of the quantum charge exactly. Neutrinos, like every other particle, have charges for every single force. You have a charge for the electromagnetism, you have a charge for the strong force, and you have a charge for the weak force. And sometimes those charges are zero, like the electron is a minus one charge for electromagnetism but has no strong charge. We call that color. But neutrinos, the only charge they have is for the weak force, and so the antiparticle would have the anti charge. But the weak force is so weak that's very difficult to study, and that's what makes these experiments so difficult. And Dune doesn't measure neutrinos turning into anti neutrinos directly. Instead, what it does is ask whether muon neutrinos turned into electron neutrinos the same way that anti muan neutrinos like to turn into anti electron neutrinos. So it flips the whole process and measures the antimatter version of it. These effects are very subtle. You can't like look at one particle and see what's happening and to build it up over time. It takes a lot of experiments before you can actually see these effects because it's the weak force. Because it's the weak force. What is the weak force charge called, It's called the weak hypercharge. Okay, so then neutrinos have a charge, a weak hypercharge. And so if there are anti neutrinos, then what are you saying those would be flipped or those would not be flipped, or we don't know. We don't know. If they are their own antiparticle, they wouldn't be flipped. If they aren't. If there is a separate anti neutrino, then it would be flipped. And what we're interested in is how do neutrinos turn into anti neutrinos and back If there's a big asymmetry there, if anti neutrinos like to turn into neutrinos more than neutrinos like to turn into anti neutrinos, if they even are as every particles confused, You're you're asking, like, could an anti neutrino trend too neutrino? If and and I turned neutrino is not the same as a neutrino. There's so many things we don't understand about this. It's like a big black box. We don't know what's going on inside. And because we don't know what's going on inside, it gives us a lot of options for things that could explain, like if they are not the same, so matter and antimatter are not the same for neutrinos, and anti neutrinos like to turn into neutrinos more than neutrinos like to turn into anti neutrinos. That could account for why we have more matter than anti matter. It could have been essentially that a bunch of neutrinos are being made and then neutrinos can turn into other kinds of matter, like a neutrino can turn into an electron and a w boson what so like we could have come from neutrinos. Yeah, absolutely. Some of our particles certainly did come from neutrinos. I always thought there was a little italianan, just a little bit one percent your your j All right, Well, I guess what I don't standard is, you know, does have hypercharge for the week fours? You know, why can't I just flip that charge and call it an anti neutrino, Like it's possible. Why would you think that flipping the hypercharge would make it the same thing. Well, we don't know necessarily what the universe thinks about this symmetry. We don't know that the opposite particle can exist. Why is there an opposite to the electron. It's not like you're allowed to demand that every opposite particle exists, Like we see the opposite particle for the electron, and for the proton and for quarks, but we don't know why they exist. So it's not like we can claim that every particle should have its antiparticle. And we're doing these experiments to try to figure out, Like we do a whole different set of experiments called neutrino lists double beated decays, where they try to see neutrinos and anti neutrinos annihilating or not. So I guess you're asking, like, if I make neutrinos from antimatter, doesn't make the same neutrinos as regular matter or does it make like the one with the hard flipped exactly? Can we tell any difference? And that's why they do this experiment in two modes where they produced neutrinos and then they look to see what happens, and then they produce anti neutrinos and they look to see what happens. And one thing they're curious about is do they see any difference. Do neutrinos and anti neutrinos turn into different stuff as they fly through the Earth or do they act exactly the same way. And the exciting thing is that there were some experiments done in Japan that saw a hint, that saw a clue that suggested maybe there was a difference. Really, what did they see. They saw that neutrinos do like being a matter, not antimatter. Yeah, they saw a hint of exactly this, and they weren't powerful enough to really detect it. It It was just like a little glimmer, or it could have been a fluctuation. But this is a sort of similar experiment in Japan where they produced neutrinos in a collider and then they send it underground to this other experiment, which which originally was looking for neutrinos from the sun, but now they're piling neutrinos into it through the Japanese bedrock. And that experiment where they have a big heavy water container surrounded by by cameras looking for flashes from the neutrinos turning into muans or electrons or whatever. And they saw a hint and it was not significant, like they didn't have enough data to really say they found it, but they had enough data to suggest that it might be real. And that's the kind of motivation you need when you're spending you know, a billion dollars on an underground experiment in South Dakota. All right, So if we find that neutrinos like matter more than antimatter, or becoming matter more than antimatter, then that would explain the whole universe, right, It totally could, because there are so many matrinos in the universe that might explain why because we have more matter than antimatter. That's right, because it all came from neutrinos who would like more matter than antimatter, that's right, and the other particles would like to make matter versus antimatter. The kons and the bees, they just do it a tidy a little bit. It could be the neutrinos do it a lot, like all the time, like they really heavily prefer making matter versus antimatter. So it could be a mass of effect. It's exciting because we really just don't know, like we don't know what the answer is going to be. It could be a very small effect and explain nothing. It could be zero, it could be huge. You could be like, what these things are all turning into neutrinos all the time, and anti neutrinos aren't even really a thing. So it's exciting for us as particle physicists when we don't know the answer. It's much less exciting when like the theorists tell us, here's the Higgs boson. We know what it looks like, go find it. We know what to do, and we didn't do it. It's like box checking, you know. Oh man, So when the Higgs post found, you're like, I hate it when you're right out of principle, I will not support this. Well, you know, there was a lot of drama and political intrigue and uncertainty in the quest for the Higgs boson, which will dig into soon in an episode, but a little bit. Yeah, it's would have been more exciting to not see the Higgs and to see something else crazy, which made the theorist go, what So as an experimentalist, it's more fun to discover something unexpected. So it's nice here when we don't know the answer and we've got to go and measure it, because to me, that's the excitement, right, That's what's interesting about being an experimentalist. You're exploring the universe, you're asking you questions, and you don't always know what the answer is going to be interesting. All right, Well, let's take this conspiracy theory to the next level. Dannual and as could neutrinas even be responsible for dark matter? How do you tie those two together? Well, you know that dark matter is something that's out there. It's massive, there's a huge amount of it. It's like an explanation for all the gravity that we see out there that we can't explain. Otherwise, there's no mass that can explain all the gravity that we see. So naturally, people thought for a long time well, what if it's just a bunch of neutrinos, Like we know they're neutrinos everywhere, we can hardly see them. They're basically dark, and there's a lot of them. What if there's just like a huge, ridiculous amount of neutrinos and that would be enough to explain the dark matter, right, or not just a lot of netrinas, but maybe like really really massive netrinas. Yeah, So originally people thought, what if it's just a lot of the vanilla neutrinos, the strawberry neutrinos, the ones we're familiar with, right, But they ruled that out because neutrinos are very very light and move away too fast, and so they can't explain all the structure we see in the universe. To see how galaxies formed and stars get pulled together, we need the gravity from dark matter to be sort of slow moving. It can't be zooming everywhere in the universe, or we just would have spread everything out. So we know that if it is a neutrino, that has to be a new kind of neutrino, like a weird, new heavy neutrino, like very massive neutrino, like pure chocolate neutrinos, like just the chunk of chocolate. Are you saying that chocolate are not a good weight loss technique. If so, then I'm in trouble over here. I'm saying dark matter could be dark chocolate new theory. What are you doing, Daniel, I'm just eating dark chocolate to get an ideas for a dark matter, right, it's it's research, filling myself up with the potential hypothesis. There you go, that's right, it's intellectual food. So yeah, it could be that there's a new kind of neutrino, like a fourth mind of neutrino. We currently know about electron mule and town intrinos, but there could be another kind out, a heavy one that we don't even know about. We don't know about as we haven't seen and there are a few other places in physics where we've seen hints that suggests maybe there is one, but they're not conclusive. Like there was an experiment in Los Almos, actually my hometown, that saw neutrinos sort of disappearing in a way that we couldn't explain, and they explained it in terms of a weird new sterile neutrino that it's really hard to make, and it's very heavy, and very occasionally neutrinos sort of disappear into that sector. Interesting. And so an experiment like this, like Dune that very precisely makes a huge number of neutrinos and studies them and their antimatter. If Starren neutrinos are a thing and are possible, then they could see some of these neutrinos sort of disappearing into the dark sector, you know, because they can count the number of neutrinos they expect to see, and if they see too few, then they might be evidence that these things are turning into something else, something invisible to them. Interesting. It's basically like a really fancy and upgraded neutrino gun. Yes, it's a neutrino gun and a neutrino camera, and they point the gun at the camera and it's the more powerful gun than anybody's ever built and a more sensitive camera than anybody's ever built. And so we're gonna get a new window into neutrinos. And another cool thing is that we're not the only people who have built neutrino guns. Like it turns out that the universe is filled with neutrino guns and this new power maybe and this new powerful neutrino camera will let us see neutrinos produced by other sources, not just you know, conspiracy theories in Chicago. Interesting, So the same camera under South Dakota a mile down could see neutrino bursts from other things in the universe, like like supernova as you were telling me, Yeah, supernovas are these amazing events where an entire star collapses and then explodes, and we really want to understand how that happens, and do they turn into black holes and how often and you know, the details, the blow by blow of what happens in those events, and there's a lot of mystery because we can't see them very directly. They're very far away. And one big problem is that they're complicated, and so like light is produced in the first moments of the supernova, but then it gets reabsorbed, so you don't see it, and it takes a while for the light to sort of like make it out through the shock wave before it comes to us. But neutrinos are a great way to see supernovas because supernovas make a huge number of them, and they're not reabsorbed by the supernova. They come right through. They shoot right out from the heart of that event, that crazy cosmic collapse, and tell us about the very first few moments of what's happening in the supernova. We can use this neutrino camera basically to take pictures of the insides of supernovas well. Do you have to like point it to the supernova? We're not pointing this ten kill a ton of liquid argne at anything, dude, That's what I was asking, Like, I guess it's it easier to move Earth then, Like, do you you rotate the Earth in a different way or what he did? Yeah, we've got a nob over here. We can just turn the Earth anyway. We like, it's in a pivot, right, I'm sure. Yeah. When you're late with a deadline, you're just like, could you just stop the Earth at please? You don't do anything like that. You just sort of like, look, what you do is you turn off the neutrino gun at Fermi Lab and you just let the experiment be quiet. So basically, any time the beam is not on, you can use it to observe the universe and you can't point it at anything. But we think that these sources come from everywhere, and we're shielded by a mile of rock that prevents anything but neutrinos from getting down through the earth to this camera. And so you just you know, basically point your camera up at the sky, straight up and see what you see. All right, Well, it sounds like neutrinos could hold the key to the universe somehow, and conveniently that's where a lot of our funding is going in physics in the US. But when it's this experiment gonna go online, Daniel, Well, they're building it now and they hope to have the first part of it done in four has ever built one this big or this complicated before. So they built like a mini version of proto version, which worked well. But they think the first full scale piece will be done in and the whole thing will be complete, and then you have to run it for a few years. So like we might be looking at an answer in like and it's an exciting place to look, mostly because it's a hard place to look. And that's also the reason why it's still a place to look. You know, we look for obvious answers. We do the easiest things first. Neutrinos are the hardest things to study and that's why they still have these mysteries because they're sort of shrouded, and so we had to up our game and like figure out ways to see them and to study this deep, dark, hidden sector of the standard model to see if it has any of the secrets, any of the answer to these open questions. Now, I guess my question is, even neutrinos turned out to be the key to the matter and antimatter mystery, which means that they're not neutral, do you have to rename them, Daniel, Well, they could, because they're not neutral anymore. They're still neutral from the point of the electromagnet to them. But you're right, they're not totally neutral. I mean, they do even have mass, which gives them an effect, a gravitational charge. But neutrina is such a cute word that if we're going to rename any of the particles, it's not it's got a special place in your heart. How about the spice, We could call it the spice, the chocolate spice, chocolate spice ones. All right, Well, we hope you enjoyed that. And maybe as you look up and imagine those trillings and neutrinos going through you right now, maybe they have the key to understanding why we're here and why the universe is the way it is. That's right, and we're always interested in exploring something we have not yet looked at, because under every rock we haven't turned over could be the answer to an open question in physics, or it could be something else, something new, something totally unexpected. The history of science is filled with people building an experiment to answer one question, but accidentally stumbling over the answer to a totally different question they might not have even known to ask. Either way, it's fun and we learned a lot about as right, and it gives the US particle physics community something to do, because you don't want them pointing any other kinds of particle guns at anybody else's backyard. That's right, Your children are safe, all right. Well, thanks for joining us, See you next time. Thanks for listening, and remember that Daniel and JORGEG Explain the Universe is a production of I Heart Radio. For more podcast for my Heart Radio, visit the I Heart Radio app, Apple Podcasts, or wherever you listen to your favorite shows.