Daniel and Jorge Explain the UniverseDaniel talks to Harry Cliff, author of the new book "Space Oddities", about the most intriguing unexplained particle physics experiments and what they might mean.
See omnystudio.com/listener for privacy information.
If you love iPhone, you'll love Apple Card. It's the credit card designed for iPhone. It gives you unlimited daily cash back that can earn four point four zero percent annual percentage yield. When you open a high Yield Savings account through Apple Card, apply for Applecard in the wallet app subject to credit approval. Savings is available to Apple Card owners subject to eligibility. Apple Card and Savings by Goldman Sachs Bank USA, Salt Lake City Branch Member FDIC terms and more at applecard dot com. When you pop a piece of cheese into your mouth, you're probably not thinking about the environmental impact. But the people in the dairy industry are. That's why they're working hard every day to find new ways to reduce waste, conserve natural resources, and drive down greenhouse gas emissions. How is US Dairy tackling greenhouse gases? Many farms use anaerobic digesters to turn the methane from manure into renewable energy that can power farms, towns, and electric cars. Visit us dairy dot COM's Last Sustainability to learn more.
And friends and families walking riding on passing the roads every day. Remember they're real people with loved ones who need them to.
Get home safely.
Protect our cyclists and pedestrians because they're people too, Go safely, California. From the California Office of Traffic Safety and Caltrans.
We're just days away from our twenty twenty four iHeartRadio Music Festival, presented by Capital On.
The biggest headliners in live music will be taking over to Mobile Arena, Las Vegas.
Loss some special surprises and moments you are not going to want to miss. Stream only on Hulu the iHeartRadio Music Festival.
And listen on iHeartRadio the most anticipated live music events of the year.
This Friday and Saturday, starting at ten thirty pm Eastern, seven thirty Pacific.
Hey Daniel, When they operate a big, complicated machine like the large Hadron Collider, Like, what's the worst they can happen?
Ooh, other than pressing the wrong button and destroying a ten billion dollars science experiment?
Can it get worse than that?
I guess you could make a black hole that destroys the world.
And now is that the absolute worst?
Actually? No, the absolute worst is if the whole thing runs perfectly and nothing interesting happens.
What's wrong with that?
Well, then We'll have spent like ten billion dollars and learn nothing.
And that's worse than destroying the whole planet.
Yes, learning nothing is worse. Destroying the planet would be a great outcome. We'd learned so much.
Yeah, we learned not to get physicists ten billion dollars.
You can make that decision from inside the black hole.
No, it'ld already have been too late. We would learn our lesson for a brief second before we all die.
Hi.
I'm moorheam a cartoonists and the author of Oliver's Great Big Universe.
Hi.
I'm Daniel. I'm a particle physicist at professor UC Irvine, and I'm desperate to discover something before I.
Retire, before you retire, or before you destroy the world.
One and the same.
Wait, I thought it would destroy the world. You would learn a lot, but then you would be.
Retired, exactly. I want to go out with a bang, learn something, and retire all on the same day.
You know you can do that on your own. You don't have to involve the rest of us.
I'm not so selfish. I want to include everybody.
It would be preferable if you don't destroy the world in your little personal curiosity quest.
Some people just don't know what they want until they get it. Isn't that what Steve Jobs said?
Well, I definitely know. I don't want to die in a black hole.
Wa until Apple releases a super slick black hole that nobody can resist.
Oh, I see is that the new I Die two point zero?
Yes? Better than the eyehole? I don't know what that's for.
Yeah, I want neither of those. Please, But anyways, welcome to our podcast, Daniel and Jorge Explain the Universe, a production of iHeartRadio.
In which we try to widen the gap between the moment we understand the universe and the moment we all perish. We want everybody out there to understand the nature of this crazy, beautiful, bizarre reality, and we want to enjoy that understanding as long as possible before our eventual demise. We hope that this podcast helps you bridge that gap, and until we do gain that final understanding of nature, we can fill you in on everything we do and do not understand along the way.
That's right, because it is a mysterious and confounding universe, full of interesting phenomena that we are still discovering and learning about every day. Everyday scientists are making new discoveries about how things work, how they don't work, and what is and isn't there.
And remember that research is exploration. When you think back to the story of scientific discovery, it seems like a very linear path. We discovered A, then B, then C, then D, so E and F were obvious right well back in the day, they weren't so obvious. There are lots of hints in various directions, and the path forward was not clear. Here we are on the forefront of human understanding or ignorance, and we don't know which direction science will take us. We don't know which hint will turn out to unravel our entire understanding of the universe, and which will turn out to just have.
Been a loose cable, and which one will hopefully not destroy the world. I mean that's always a good thing, right.
I mean that's the secondary consideration. But yes, I.
Think, Daniel, each episode you sound more and more like a superhero villain.
I'm working on my mad scientist cackle. I haven't had a perfect yet.
Are they going to make the large Hadron collider now be activated by like a snap of your fingers? You have to put on like a glove and you have to snap your fingers to be activated.
Yes, is that the plan? Yeah, we hired a whole team from Marvel to help us design the interface.
Oh there you go. Do that mean you wear capes as well?
It's reverse the usual. Often marvels hiring scientists to be advisors on their films, but we're actually hiring the Marvel folks to tell us how to make our installations looks super slick.
I have to make it more exciting for people. Would be nice if this podcast made some of that Marvel money, You know what I'm saying.
Yes, that's exactly the plan. This is step one.
Right now, we're just making DC money, which is not a lot.
But particle physics isn't all about the benjamins. It's about the discoveries. It's about those moments when you force the universe to reveal the way it actually works. And the most delicious moments are the ones when we understand the universe is quite different from how we expected it.
Yes, you said, science is all about exploration and following ideas and maybe promising directions, and sometimes you discover that things don't quite work the way you thought.
Sometimes those discoveries are clear and dramatic, like when we found the Higgs boson, and everybody can see the very persuasive peak in our data. Sometimes, though, the discoveries begin with little hints, little things in our data that don't quite make sense, little clues that maybe some big discovery is just over the horizon.
Yeah, although sometimes it seems like the horizon is getting farther from other away. I mean, when was the Higgs boson discovered? It was a while though, right over ten years?
Yeah, twenty twelve.
Wow, time flies. That was a huge discovery. The whole world got very excited about that. But since then there haven't been any new big discoveries from the big collider there, right.
Yeah, that's right, because research is exploration. We didn't know if there were tons and tons of new particles waiting for us around the corner, or if it was mostly just dust and rubble to be discovered. And the new particles are around more and more corners, if they even exist. That's the joy and disappointment of exploration.
So how's all that dust and rubble looking dusty and rubbing?
It gets hard to choke it down after a while, I'll be honest, Yeah.
It's hard to swallow dust and rubbles.
I mean, you always prefer to make exciting discoveries. When they landed the rovers on Mars, I'm sure they were hoping to find little squishy creatures under some of those rocks. But you know, they've also just found dust and rubble. Doesn't mean we're not going to keep looking.
But as you mentioned, science is about exploration, and so right now, even though you've only found dust and rubble for the last twelve years, there are maybe interesting things that you've discovered or noticed about the universe that maybe give you some excitement about continuing to explore.
That's right, because before we make a big discovery, we often have hints that point us in that direction. Before we've discovered how neutrinos can change from one kind into another, we saw weird things in our measurements of neutrinos in the sky. So particle physicists are always on the lookout for the next anomaly, the next discrepancy, the next thing we don't understand because it might be a hint for the next big discovery.
So to be on the program, we'll be tagling the question what are the most promising particle physics anomalies. Now, these are anomalies, right, not anemonies anominees.
These are not our enemies either.
Yeah, and we're not going to do this anonymously.
That's right.
Or to memory Okay, you push the groummar there too far. I'm not sure what the connection there.
Is anomalies and memories, homomines my moonides. I don't know.
Yeah, yeah, I think we finished this pun thread here.
The thing about anomalies is that they're indirect. They're just something we don't understand about our data. So explanations could be Wow, something super exciting we're about to discover, or it could be oops, turns out we didn't calibrate things correctly.
So what's the picture here? You're sorting third data. You're finding mostly dust and rubble, but sometimes in the dust and rubble you're like, maybe there's a little bit of rubble here. Looks a little bit different than it should look like.
Yeah, exactly, it's a promising sign that maybe there's something exciting there, but you need more data. It's sort of like fuzzy pictures of UFOs, like, ooh, that would be exciting if it really is a UFO. But the picture's too fuzzy to really know. What you got to do is get more data, crisper photos, more sensor information, something like that.
Oh boy, did you just compare particle physics to UFO spotting.
Yes, absolutely, enthusiastically.
An area fifty two is cern area fifty two for the Big Large Hadron collider conspiracy.
I may or may not have signed an NDA prohibiting me from answering that.
Question, prohibiting you from having a podcast where you talk about it.
For hours and hours, maybe or maybe not.
I think they as it's probably no sounds like.
No, no comment. The other thing about anomalies is that sometimes they go away. You know, all of our data is statistical. We can ever tell from one collision to the next whether there was a new particle or a Higgs boson or just something boring like protons glancing off of each other. And so all of our data is statistical, which means there are always little random wobbles. Sometimes those random wobbles can look like a new particle or a UFO, and then we gather more data and they just go away.
Well, as usually, we were wondering how many people out there had thought about particle physics anomalies and what they might mean or which ones are the most promising.
Thanks very much to everybody who answers questions for the audience participation Seig of the podcast, we'd love to hear your voice in the pod. Write me two questions at Danielandhorgney dot com to sign up.
So think about it for a second. What do you think are the most promising particle physics anomalies not anemonies. Here's what people had to say.
I don't think it's possible to have an unexplained result in a particle physics experiment because the theoretical physicists set it all up and tell the experimental physicists where to find it. So I don't think it's going to be a particle. I'm just wondering if maybe that bit where general relativity doesn't quite fit quantum theory. What if, say, Isaac Newton was right all along and it is all about gravity, and you've just left gravity out of the formulae on the calculations because you don't think gets big enough. But what if that proves Albert Einstein was wrong when he said that Newton was not wrong but limited.
He rewrote Newton.
What if Newton gets his revenge and Einstein's wrong, that might make the nine o'clock news.
The only thing that comes to mind is the very high energy cosmic rays that strike the upper atmosphere and result in a shower of particles, some of which reach the ground, and that baseball energy particle is coming from a blazer.
I'm not aware of any specific unexplained particle experiment results, but I guess in general terms the issue for particle physicists to work through there would be is this unexpected result something that can be explained by things that physicists are generally already aware of, or is it something new that they've discovered.
Well, I don't know that many experiments, but maybe the penguin diagram and then has a cool name too.
I don't know much about particles experiment results and what might be a real discovery.
But if you could.
Find a way to entangle my son's socks in the laundry so that when I find one, I always know where the other one is, that would be really helpful.
Thanks by I'm only aware of one unexplained particle result. It was something to do with muons, either missing muons or many muons, and either way, I'm hopeful that it spurs a discovery of something smaller or some behavior that we're not expecting, because that always opens up new questions and new avenues for learning.
I'm guessing something like doc matter particle or a graviton something of that nature.
Other than that, no idea.
Well like as that before answering that I would need to learn what are the unexplained part experimental results that have been generated? Please walk me through that.
All right, mostly clear, I've known you what you're talking about.
That surprised me a little bit because particle physics anomalies are often in the news, and they're often like way overhyped. I get emails from listeners asking me about some news story that says that we're on the brink of a complete revolution in particle physics because of some weird lips somebody saw on their computer screen.
I guess it depends where you're getting your news. Is this from the UFO newsletter? There?
No, you see this stuff covered in pretty mainstream press. Sometimes the scientists are excited about their little anomaly and they tell the PR people, and then by the time it gets to science dot org, they've transformed it into clickbait.
Well, didn't sound like any of our listeners here that recorded their answer new of any physics anomaly, So maybe the question should have been, do you know of any particle physics anomalies?
We have covered a few on the podcast because there are a few out there, a few areas where we might be on the verge of discovering something new or it could just go away when we gather more data.
M all right, well let's jump into the subject, Daniel, what do you describe as an anomaly? How do you know if something is anomalous?
Something is an anomaly if it's a deviation from what we expect, and what we expect usually is disappointment. So we have a theory of particles, the standard model, that has a bunch of particles in it and a bunch of forces in it, and we can use that to predict what we would see in experiments. So, for example, if we smash protons together, the standard model tells us how often they'll bounce off at this angle, how often they'll bounce off at that angle, how often they'll make a Z boson or a W boson or a top quark. And we do a bunch of measurements and then we compare them to the predictions from our theory. And when things are bang on, that's not anomalousts. And when there's any difference there, when what we see in our experiments collisions or cosmic rays or other kinds of experiments is different from what the theory predicted, that tells us that maybe there's something new going on. There's something happening in the universe it's not captured by our theory.
Well, I guess it's a sort of an interesting dance between theory and experiment. Like, for example, if something is a theory and you expect it to be, why did you expect it to be if you didn't prove it already before. Or is it about extending the theory to new phenomenon or to new situations.
Yeah, exactly, it's about extending the theory. Like the theory may have worked well for all previous experiments, but now we're in new territory. That's what we mean by exploration. When you turn a collider on it new energies, for example, you're creating conditions you haven't seen before. So maybe your theory is going to break down. Maybe there's a new particle that's going to be revealed that you need to then incorporate into your theory. Maybe that's a new force that's so weak you haven't seen it before, but at very high energies it reveals itself. That's why we do these experiments, hoping to force the universe to tell us how things work.
I guess that's why in science you just call everything a theory, right, because you always leave yourself open to the possibility that your theory is wrong. The more you explore the universe, or the more different situations you go out during test.
Yeah, exactly. The point of the Standard model is not to say this is definitive, this is how the universe works. It's a working project. It describes everything we know so far. It's like our current hypothesis, but we're always hoping to.
Update it, right, right, And that's why you called it the standard model. Unequivocally the way things are. That's why you called it that, right, That's.
What I called it that Yeah, it was named in a paper that came out a few years before I was born. But I'll totally take the blame for it being called the standard model.
Well, you're continuing to use it that you're complicit.
I think I heard you say it. Also, are you complicit?
How I said it?
You just called it the standard model, although derisively of course.
I said, that's why you call it the standard model.
Anyway, it's a standard model, but it's also changed over time. Right, We added neutrino masses to the standard model. So there's actually a big argument about what exactly is the standard model, which means it's not exactly standard. But the point is that we have a theory, we're developing it, we're testing it by doing these experiments, either by pushing to new energies or by looking out in space or creating conditions we've never explored before. We're hoping that one of those has an anomaly, a discrepancy from our prediction that shows us that there's something new in the universe that we need to describe with our theory.
And this generally falls into sort of the different ways that you discover something, not just in signs, but in particular in particle physics. You can either look for things directly or indirectly.
Right, Yeah, the direct way is the most convincing and the most exciting, Like if you can actually create this new particle, so it exists in the universe in your experiment, then you can sort of see it. I mean, we never actually see these things very directly, but we can see evidence of it. It was there left traces of the particles that decayed into That's how we discover the Higgs boson. That's how we discover the top quark. We have a bunch of episodes about the discovery of each of these particles that tells you the story about how it was seen, how it became convinced that it was.
The meaning like, you think that it's there in a particular spot, you go look for it there in that spot, and then you find it.
Yeah, or we're not sure exactly. We say it's somewhere in this territory, and then we look around and we find it within that range. Like the Higgs boson, we didn't know in advance how heavy it would be, how much mass it had. There was a huge range of ideas, so we had to go out and scan that whole range. But we found it in that range and we were able to measure it, and that's what we call it direct measurement. Even though some parts of those measurements, of course, are indirect.
So then what is indirect discovery?
So the distinction between a direct discovery and indirect is a little bit fuzzy because you know everything is in the end indirect. But some measurements are more indirect than others. Like, for example, if you don't have enough energy to actually create the particle to exist in your experiment, but you can still interact with the fields that are out there that could make that particle, then that's more indirect because you're never actually creating the particle, but the fields themselves can still influence your experiment. Like if your proto interact with those fields and it changes how they behave, then you don't see those fields directly, but you see the influence of the fields on the particles that you are studying.
That's not indirect, man, Like you're not looking for it, but you see some anomaly, which is sort of the topic of our discussion here.
Yeah, that's exactly right. But we use these indirect measurements as a way to catch some new thing something we're not looking for, Like, very very precise measurements of the particles we do know can sometimes reveal anomalies, which are clues that there's something out there influencing those particles. So that's why we sometimes make very very precise measurements of the particles we already know about, so we can look for little deviations that would tell us there's something there we weren't looking for directly.
So for example, like we've discovered the Higgs boson, and we sort of know where to find and what looks like and how it comes out. But maybe if you generate a whole bunch of Higgs bosons at one after the other, maybe in doing that you can discover something weird that happens that you didn't think about before, that happens really it to the Higgs boson.
And that's exactly what we're doing right now. We discovered the Higgs boson ten years ago, and since then we've made huge numbers of them, piles and piles of Higgs bosons. We've been studying them, looking for anomalies, looking to see if the Higgs boson behaves in any weird new ways, because if it does, we'll need some other element of our theory to explain that. It will be a hint that there's something else beyond the Higgs boson for us to discover.
Like instead of digging a hole in the field looking for something, you're maybe looking closer at the rock until you discover something that maybe you didn't.
Expect, Yeah, exactly. Or if you're looking for like weird new animals in the forest, like you suspect maybe bigfoot is out there, you don't know how to look for bigfoot directly, Then you can look for other signs. You know, you like look to see if there's any weird scratches on all the trees, or if any neighborhood pets are missing. You like, make measurements of the things that you can to look for weirdness, any deviation from the ways trees and pets normally behave. We give you a clue that there's something out there in the forest to discover.
M Like you would study maybe cats and pay attention to cat and you think, well, if there's no bigfoot, then cats should behave this way. And if you find that cats you avoid a certain area of forest, for example, or get really skittish, if you put on a gorilla suit or something, then you know, oh, maybe there's some evidence here or an anomaly that tells you maybe there's a bigfoot.
Exactly, and the tricky thing there is that there could be multiple explanations. Your cats could be scared of you in a guerrilla costume because there's a big foot in the forest, or just because you look scary in a gorilla costume. So the thing about indirect measurements is that they can give you a hint of for lots of new things, but also they're frustratingly indirect.
Yeah, if only you could just ask the cats, right, all right, Well, let's get into what are some famous anomalies that have led to discoveries in science, and then let's get to the most exciting and promising ones in physics. Today. We'll dig into that, but first let's take a quick break.
With big wireless providers. What you see is never what you get. Somewhere between the store and your first month's bill, the price, your thoughts, you we're paying magically skyrockets. With mint Mobile, you'll never have to worry about gotcha's ever again. When mint Mobile says fifteen dollars a month for a three month plan, they really mean it. I've used Mintmobile and the call quality is always so crisp and so clear. I can recommend it to you, So say bye bye. To your overpriced wireless plans, jaw dropping monthly bills and unexpected overages. You can use your own phone with any mint Mobile plan and bring your phone number along with your existing contacts. So dit your overpriced wireless with mint Mobiles deal and get three months a premium wireless service for fifteen bucks a month. To get this new customer offer and your new three month premium wireless plan for just fifteen bucks a month, go to mintmobile dot com slash universe. That's mintmobile dot com slash universe. Cut your wireless bill to fifteen bucks a month. At mintmobile dot com slash universe, forty five dollars upfront payment required equivalent to fifteen dollars per month new customers on first three month plan only speeds slower about forty gigabytes On unlimited plan. Additional taxi speeds and restrictions apply. See mint mobile for details.
AI might be the most important new computer technology ever. It's storming every industry and literally billions of dollars are being invested, so buckle up. The problem is that AI needs a lot of speed and processing power, so how do you compete without cost spiraling out of control? It's time to upgrade to the next generation of the cloud. Oracle Cloud Infrastructure or OCI. OCI is a single platform for your infrastructure, database, application development, and AI needs. OCI has four to eight times the bandwidth of other clouds, offers one consistent price instead of variable regional pricing, and of course nobody does data better than Oracle, So now you can train your AI models at twice the speed and less than half the cost of other clouds. If you want to do more and spend less, like Uber eight y eight and Data Bricks Mosaic, take a free test drive of OCI at Oracle dot com slash Strategic. That's Oracle dot com slash Strategic Oracle dot com slash Strategic.
If you love iPhone, you'll love Apple Card. It's that credit card designed for iPhone. It gives you unlimited daily cash back that can earn four point four zero percent annual percentage yield. When you open a high Yield Savings account through Apple Card, apply for Apple Card in the wallet app, subject to credit approval. Savings is available to Apple Card owners subject to eligibility. Apple Card and Savings by Goldman Sachs Bank USA Salt Lake City Branch Member FDIC Terms and more at applecard dot com. When you pop a piece of cheese into your mouth or enjoy a rich spoonful of Greek yogurt, you're probably not thinking about the environmental impact of each and every bite, But the people in the dairy industry are. US Dairy has set themselves some ambitious sustainability goals, including being greenhouse gas neutral by twenty to fifty That's why they're working hard every day to find new ways to reduce waste, conserve natural resources, and drive down greenhouse gas emissions. Take water, for example, most dairy farms reuse water up to four times the same water cools the milk, cleans equipment, washes the barn, and irrigates the crops. How is US dairy tackling greenhouse gases? Many farms use anaerobic digestors that turn the methane from maneuver into renewable energy that can power farms, towns, and electric cars. So the next time you grab a slice of pizza or lick an ice cream cone, know that dairy farmers and processors around the country are using the latest practices and innovations to provide the nutrient dense dairy products we love. With less of an impact. Visit usdairy dot com slash sustainability to learn more.
All Right, we're talking about the most promising particle physics anomalies, the weirdest things out there that might point to the most exciting new discoveries in the future. And we've talked about what an anomaly is, Daniel. What are some examples of anomalies and physics that have led to very interesting discoveries.
Well, one of the most famous, of course, is the measurement of how galaxies rotate. People thought they understood how galaxy spun and how much mass there was in a galaxy, and they went out there to check to say, hey, are stars rotating at the speeds we expect around the center of galaxies, And it turns out they weren't. They were rotating much much faster than people expected, and that was an anomaly. It was a discrepancy from what people predicted and expected. And to explain that, of course, is the whole idea of dark matter still to be resolved and understood in detail at the particle level. But maybe one of the biggest anomalies we've ever seen in physics.
Hmmm. And wasn't that done by a grad student or something like it's some lowly gratudent good assign the task of like, yeah, I just checked the galaxy rotations. And then that Gratson was like, wait a minute.
There's some hints early on in the century from France Wicky, and then Vera Rubin really did the most detailed analysis of galactic rotation curves. So she gets most of the credit, although she was overlooked for the Nobel Prize of course, what not a great track record on the Nobel Prize for assigning credit to women.
M And that trying to be a huge discovery, right, I mean we found that there's five times more dark matter than there's regular matter in the universe. I mean it's like five times everything that we know about that exists.
Yeah, exactly. And this is why we go out and make really precise measurements of things we think we already understand, because they can reveal things hiding under the surface, things waiting to be discovered. Mmm.
What's another famous anomaly.
Well, people tried to understand how many neutrinos are coming to Earth. So they built a big detector underground to measure the rate of neutrinos, and they compared that to their prediction for how many neutrinos are being made by the Sun and how many should arrive on Earth, and they discovered they were seeing way fewer neutrinos than they expected, and for decades people didn't understand this. Then it turns out that's because neutrinos can change their type as they fly between the Sun and here if electron neutrinos can turn into mew on neutrinos and town neutrinos, which those detectors were not spotting. That was a huge discovery which started from an anomaly.
Mmm. And did that person get credit?
Those guys won the Nobel Prize. Yes, old white dudes always get credit.
On the word guys. Yes, funny how that worried? All right, well, let's pivot now to maybe some of them was current exciting anomalies. What are some of the things that scientists have found and make them go huh.
There's a bunch of stuff going on that we don't understand. There are weird particles we see in cosmic rays from space. There are bizarre things going on with muons and their magnetic moments. There's all sorts of confusion about how the universe is expanding. There's always like five or ten of these things going on. Sometimes they fade away as we get more data, but some of these have persisted for a few years.
Well, to take a deeper dive into this topic of anomalies and audities out there in space, Daniel, you talked to another particle physicists.
That's right. I had a lot of fun talking with Harry Cliff. He's a particle physicist who works on a different experiment at the Large Hadron Collider. It's called LHCb B for studying bottom quarks, though he prefers to call them beauty quarks. And he just came out with a new book called Space Oddities, which is a really accessible and fun tour through some of these anomalies in particle physics.
Isn't that the title is like a David Bowie song or something.
Not an expert, but I hope he's publishing. How it's cleared the rights?
Yeah, otherwise you can have an anomalos a lawsuit there. All right, Well, here is Daniel's conversation with particle physicist Harry Cliff.
Okay, so then it's my great pleasure to welcome to the podcast. Doctor Harry Cliff. He's a colleague of mine and also the author of the new book Space Oddities, an excellent and fun exploration of a bunch of really weird stuff we see in particle physics. Right now, Harry, thanks very much for joining us today.
Well, thanks for having on the podcast.
Yeah.
Well, I really enjoyed reading your book. I love thinking about all the weird stuff that we're seeing and all the funky stuff on the horizons of the frontiers of physics, you know, the things that might lead to the next big breakthrough. Tell me what exactly inspired you to write this book right now?
The idea really came out of my own research.
So I work, like you on the Large Hadron Collider, this big parstical accelerator outside Geneva. So I work on an experiment called HCB, which is one of the four main detectors based around the ring and the B in LHCb stands for Beauty, which is the name of one of the quarks. So these six fundamental particles, two of which make up nuclear material in ordinary atoms, and the Bee quark is the heaviest negatively charged quark.
It is the fifth heaviest overall. So it's quite an exotic thing.
Let me just interrupt you to orient our listeners because on the podcast we often refer to this as the bottom quirk, but you're calling it the beauty quirk. Is that just because you don't like saying the word bottom in your research?
I think so that the history of this is that when the B and the T quarks were proposed, there were some people that tried to call them beauty and truth, and I think this was sort of to mirror charm and strange, which are the two second generation quarks. But physicists, I think Broady decided that was a bit too poetic, so they plumped for the more prosaic top and bottom. So most physicists call them top and botom. But there's this weird thing in what we call flavor physics that we prefer to be known as beauty physicists and bottom physicists. For us, it's beauty, but yeah, most other physicists call it the bottom cork. But they are the same thing.
Right, Because I did my PhD on the top quirk, and we had no issues calling ourselves top quark physicists or top physicists. But I can see how bottom physical.
Positive. Yeah, exactly.
Anyway, so you were working on the beauty quarks and you saw some weird stuff tell us.
Yeah, So these quarks are really interesting to study because they're very heavy. They can decay to a very wide range of different standard model particles. So when they're created, they live for a really tiny fraction of a second, about one and a half trillions of a second. That's long enough them to fly a little distance in your detector because they're going at the speed of light, and then they decay, and there are certain very rare decay modes of these quarks.
So basically that means that let's say you had a million of.
These beauty quarks created in your experiment, only around one of them would decay.
In one of these very rare ways. And these rare.
Decays are very interesting because basically, in our current theory of particle physics, the way these decays happen involves lots of complicated interactions of heavy particles, which it makes them very suppressed. But if there is say a new force of nature that exists, which may be very weak, it can actually contribute to this decay process, and it can alter the measured properties of these decays, So it might change, for example, how often the decays happen, it might change the angles the particles that come out of these beauty cork decays emerge at. So the basic game we play is you make very very precise measurements of these beautyqurk decays, you compare them to hopefully a precise theoretical prediction using the standard model of particle physics, and if you see a difference, that can be an indirect clue that something new, something beyond our current understanding, is altering these decays, and that kind of gives you an inkling to the existence of say a new force or some new heavy particle that we haven't seen before. So that's the sort of general the game we play lh to be broadly speaking, And for the last ten years, starting in about twenty fourteen, we've been seeing these anomalies in these very rare decays. So basically measurements that weren't lining up with the prediction of the standard model, and in some case is these were how often these decays was happening was different from what was predicted. Sometimes it was the angles. And what was intriguing about this is over time more and more of these anomalies emerged, and they seem to paint a coherent picture, so it looked like these were all coming from some new fundamental interactions. So the most common explanations involved, broadly speaking, some kind of new force, and that got.
Theorists very, very excited, and there was a lot.
Of theoretical work pursuing this, and then a lot of experimental work. So I kind of came into this area, i suppose about a year after this picture started to emerge in twenty fifteen, and spent several years of my career making other measurements that might give us some more clues as to what was going on. So that was really how I got interested in the whole subject of anomalies and the way that anomalies can sometimes lead us to a big breakthrough in our understanding of the universe. And that's what the book Space obviously is about. It's essentially about, you know, how anomalies shaped physics and cosmology through history, and focusing on five particularly big anomalies that have been doing the rounds in physics and cosmology in the last decade or so.
And when you're working on an anomaly at that when you see something you don't understand, tell us about what that's like. I mean, you're on the forefront of knowledge. You're like potentially standing, you know, one step away from some big revolution in our understanding. When you were working on that, do you have that sense of like this could be historic, you know that we could be writing books about these discoveries in twenty years. We could be telling people about them, you know the way I think like we pour over Einstein's notebooks now and you know, sort of stand over his shoulder. I wonder for the people making discoveries if they sort of like feel like the ghosts of the future paying attention to the sandwich they had that day in this Smithsonian. You know, like, was there that moment of excitement for you when you're working on this and you didn't yet know how it came out? Because across the ring we were all very excited. We were like waiting with baited breath to see if this was real.
Yeah.
I mean there were several moments that already exciting. There was one in Mark twenty twenty one.
When some of my colleagues who are working on one of these anomalies updated their measurement with using all the data that we'd recorded at LHCb up to that point. And I wasn't directly involved in the analysis, but I was a sort of inside observer, I suppose, watching this whole process, and there was this really exciting moment where they what you call unblinded their data. So this is common practice in physics nowadays, which is that you perform your analysis blind in the sense you can't look at the result until you've completely fixed your analysis procedure, you've done all your systematic studies, basically all the remains in the paper is essentially to put in the answer at the end. And the idea of doing this is you prevent yourself from biasing yourself or massaging the results one way or another, subconsciously or consciously. As a result of this, you have this moment where the result gets unscrambled and you see for the first time, you know what is actually happening here. And when that result was revealed in March twenty one, this anomaly had grown beyond this slightly arbitrary threshold known as three sigma, which is essentially where the experimental measurement is more than three standard deviations or three uncertainties away from your theory prediction, and that is for some reason, conventionally in physics, regarded as evidence. So at this point there's a sort of one in a few hundred chance that this would be a sort of random statistical fluke. It starts to look more convincing, more compelling as a real sign of new physics. So that was a really exciting moment, and you had this sense particularly that period in early twenty one, you had this result from LHCb, and then about a month later, another anomaly was confirmed by an experiment at Fermilab who were looking at the magnetism of a party called a muon, and that again sort of perhaps was interpreted as being evidence of some new force. So you had these kind of compiling results that were sort of suggesting that we were on the brink of something really exciting. And personally, I mean, my moment came a little bit later, and you know, all these measurements are sort of small contributions to an overall pitchure. There isn't like one moment where you go, you know, we've discovered something. And while I was working on a set of measurements with a student, they were less sensitive than the big one that came out in March. But nonetheless it was sort of we had this moment where we're on this was dury, sort of COVID times, so we weren't together, we were on zoom. We unblinded our measurements, and again our measurements lined up with the anomalies that everyone else had been seeing. So there was a real sense then of like, wow, you know, maybe there's something really going on here. So yeah, it was a very exciting time, and you did feel like you were in amongst a.
Process that could turn into something really big.
Yeah, and this is sort of like the joy and the frustration of some of these precision measurements. Right, you're looking for something weird, something different, something that's not predicted by your theory, and you're sensitive to a whole broad range of stuff. But because you're sensitive to a whole broad range of stuff, it could be anything, right. It could be new particles, it could be new forces. It could also be like, wow, your cable wasn't plugged in correctly, and so that's you know, as you say in your book, the unglamorous work of measuring some quantity or another to increasing number of decimal places can seem like a nerdy obsession. But this is also the kind of work that can really lead to exciting discoveries.
Yeah, it can, but you always have to be really careful. And I think more often than not, when you get an anomaly like this, I mean, there's usually sort of boring explanations for an anomaly. It's usually that it's a statistical wobble, you know, just basically bad luck in the data. And we saw that the LHC about ten years ago when there was this famous bump that was seen about both ATLAS and CMS, so people interpreted as evidence for some new particle outside the standard model.
And it was this crazy period.
I think it was announced just before Christmas twenty fifteen, and by Christmas there were already something like two hundred papers that had been published by theorists trying to explain what this little bump in a graph was. And lo and behold, you know, six months later, when more data was added, this bump just had melted away and it was just basically neither experiment done anything wrong. It was just a statistical wobble. And these things come and go, so that's one explanation. Sometimes it's as you say, it's a cable that's not plugged in properly, so some kind of experimental mistake that you just didn't realize was there. And sometimes actually it's also the theoretical prediction may not be totally solid, and this is maybe a sort of idea that's hard to get your head around because you kind of think, well, if you have a theory, surely you can just work out what the consequences of it are. But that's not necessarily the case. Sometimes it's particularly in particle physics when you're dealing with the theory of quarks and gluons, particularly, which are very important at the large Hadron collider. Those kinds of effects are very hard to calculate, so you might have a prediction for what you expect to see, but that prediction comes with its own set of uncertainties and assumptions that could bias it. So you kind of have to eliminate all three of those possibilities before you can say, well, this is really the sign of something genuinely new.
All right, So finding oddities in our data is a good way to make discoveries and also maybe just to find our own mistakes, and in the book you highlight a few of them. Let's take into the first one, which has to do with one of my favorite and craziest experiments, a balloon experiment looking for stuff from space. Tell us about the Inita experiment in what it's are.
So ANITA is a really cool experiment. Essentially, what it is it's the giant radio antenna. So it looks a bit like a huge tannois with all these white, gleaming horns that stick off it, and it's launched into the Antarctic stratosphere on a huge NASA balloon. So this is this incredible thing which is made of gossamer thin polyethylene filled with helium, and when it gets up to its full altitude up in the stratosphere, it's the size of a football stadium. So this vast kind of you know, translucent orb underneath which hangs on a little cable this radio antenna, and what ANITA is looking for is radio signals.
Coming out from the Antarctic ice sheet.
And essentially the reason they're doing this is they're using Antarctica effectively as a giant detector.
They're looking for.
Particularly, anita's looking for high energy neutrinos. So these are neutrinos that are produced by really violent extreme objects out there in the distant parts of the cosmos. They come in, they hit the Antarctic ice, and when they hit the ice they convert into electric charged particles. That creates a wave of radio signal that comes up out of the ice. And then by detecting these radio blasts, you can then essentially infer how energetic this new trino was and sometimes also what direction it came from. So essentially as a way of looking for these really really high and genutrinos using Antarctica as a giant detector.
I love the ingenuity of these experiments. So like we need a mile cube of ice. You can't build that, but let's just go like find it out there and take advantage of it. To me, this is like part of the real, you know, experimental cleverness of this field. People. Sometimes I think imagine that the theorists are the only ones being creative, but you know, it takes real creativity and ingenuity to come up with these ways to force the universe to reveal something to you. I love these experiments, and I'm also terrified and in awe of people who build their detector and then send it up on a balloon. Hoping that it works and it comes back and they get data from it, like, oh my gosh, how terrifying.
Yeah, I mean I spoke to the scientists who work on ANITA, and you know, the environment they're working out there in Antarctica is also really strange. There at this place called McMurdo, which is a US research based on the edge of the Antarctic constant, just on the edge of the ice sheet, and they're working at these pretty difficult conditions. You're out there at the balloon station in very low temperatures, working in this hangar, and then there's this moment where you take your instrument out onto the ice and it's attached the balloon and you're kind of watching with baited breath.
Is it all going to go off? Is it going to switch on?
In these very low temperatures, Like there's always a danger that your computer just doesn't boot up. And then the thing's launched into the air, and then they describe watching their sort of radio antenna getting small and small and disappearing, and they're sort of vanishing into the distance and communicating with it while it was still within line of sight to check it it's all working. So You're out there in this environment for a whole month, so you're rededicating. It's not a job where you just go to the office and come home. You're really like immersed in this place for a long period of time, and you're away from your friends and family. So it's also I think the length that people go to to find out about the universe is really impressive.
Yeah, every tiny little piece of knowledge you read about on your phone for like four seconds, it's like somebody dedicating their life to figuring out like why spiders, you know, live in these little nests in the rainforest, or how high energy neutrinos make it through the ice. So in this case, Anita is looking, you're saying, for super high energy neutrinos hitting the ice and then the radio waves bouncing back up into the atmosphere for us to record. And so what did they see That was weird.
So they didn't see the neutrinos they were hoping to see, but what they did see were high energy cosmic rays. So these are essentially electrically charged particles like protons or heavy nuclei that come in and hit the ice and they will also produce these sort of radio signals. But what was weird was that in amongst all the cosmic rays signals that they saw, they saw too that appeared to have come from below. In other words, these looked like particles that had come from underneath the Antarctic ice sheet and burst up into the atmosphere. And such a thing should not be possible because when you have very high energy particles, they would only be able to travel a very short distance through the Earth before being absorbed by the rock at the solid interior of the Earth. So essentially, they had these two events where you had these upward going very high energy particles, and there was no particle that we know that could produce such an effect.
Why couldn't it be a neutrino. We're always hearing that neutrinos can pass through a late year of lead without issue. Why can't they pass through the Earth and then interact in the ice.
Basically because neutrinos are very weakly interacting, and the reason for that is they only interact with ordinary matter through the weak force. Now, the reason the weak force is weak is because the particle that communicates the weak force, which is the well the W and the z bosons, they're very heavy, so they have a mass of between eighty and ninety gv, so that's sort of about one hundred times the mass of the proton. So they're very heavy particles, and as a result, essentially the heaviness of those particles is what makes the weak force weak, because it's impossible for a low engineutrina to.
Actually create a real what we call a real w or Z boson.
Instead, it has to sort of basically send a little bit of energy through the w and Z fields, but it's off resonance and it's all a bit of a mess, and so as a result, that force is very short ranged and very weak. But when you have a really high energy neutrino of the type that Anita is looking for, these are so energetic. When they collide with stuff in the physical material of the Earth, they can create a real w and Z boson. They have enough energy to make a real particle, So the weak force stops being weak and it becomes strong. For a low energineutree of the Earth is like this transparent thing which they just go straight through. For a highen engineutrino, though, it's a solid object and they can't get through it, so not even a neutrino could explain this kind of weird signal that Anita had been seeing.
So we saw these weird signals that look like they're coming through the earth. What could these things be?
You get an anomally like this, and then theorists go to town and they come up with all kinds of explanations. There were various ideas that went around. One was that this was an exotic type of neutrinos, something called a sterile neutrino. So steril neutrinos appear in quite a lot of extensions of the standard model. They're essentially even more antisocial neutrinos, so the neutrinos that don't even interact through the weak force, so they're essentially totally decoupled from ordinary matter. The only way they can interact is gravitationally. But in some theories, these steril neutrinos can mix with the ordinary neutrinos. So essentially what happens is you imagine one of these steron neutrinos. It goes through the Earth with lots of energy, but because it's a sterilic and just go stract to the Earth, that's fine. And then just by chance, when it gets close to the surface, it oscillates and converts into a normal neutrino, and then suddenly it sees the ice and it crashes into it creates.
This radio burst.
So it sort of gets through the Earth kind of disguised, did this invisible form and then turns into something visible just as by luck when it gets to the surface. So that was one possibility. Another possibility is that was some sort of supersymmetric particle traveling through the Earth. Other ideas that there was dark matter that was accumulating inside the Earth and annihilating and producing various exotic particles. One of the most crazy ideas, well crazy sounding, was this there was actually evidence of a universe made of antimatter where time goes backwards, which comes from a theory there was an attempt to sort of solve various cosmological problems, essentially to do with the Big Bang, where at the Big Bang there's two unit versus produced, one made of matter which goes forward in time and one made of anti matter that goes backward in time. So I mean all kinds of explanations for these things. There's also the mundane explanation. So one group of theorists suggested that actually, maybe what you're seeing here is not new physics, but effectively ice formations that are interfering with your measurements. So the way you tell the direction the particles come in is essentially you get this radio burst that's like a kind of wiggly line on a cilloscope.
It looks a bit like that.
And from the phase of that signal, so whether it kind of goes up then down, or it goes down then up, you can tell whether it came directly from the ice or whether it was reflected. So the particles that come from above, their radio signals are reflected back up. The ones from below they have this unreflected profile. But people suggested, well, maybe there are these subsurface features in the ice, so like subglacial lakes or layers of compacted snow that could create multiple reflections that would make something look like it came from below, when actually it had some kind of complicated bouncing around in the ice before it came back up again. So they proposed, well, what we actually need to do is a survey of Antarctica and look for new sub ice features that could explain this signal.
Now, the experiment said, well.
Actually, where we saw these two events, there's no evidence for interesting features underneath the ice, so we don't think that's an explanation.
So we don't know.
Whether it's exciting new physics or whether it is just something to do with ice.
And so help us understand why it's so hard to tell these various explanations apart. I mean they sound like totally different stories about what's happening. Is it just because we have such limited information. We don't have like the ice completely instrumented, We don't have like a picture of this interaction. I think people are probably used to imagining their minds particle experiments leading to these spectacular traces where you have all these particles you can sort of see what happened. Or do we have just less information about this? Why can't we look at this and say, oh, here's what it is and here's what it isn't.
Well, I mean essentially, all that Anita sees is this radio signal. It's essentially hearing this radio chirp with a particular profile, and you have to then work out what you based on that, and there are various bits of information. You know, the shape of the profile, whether it's inverted or not inverted, that tells you whether it's reflected or not reflected. But you don't have any other information, so you don't have a track, you don't have you know, images of particle interactions. You're really just going off a relatively small amount of information, and there's many ways that you can produce that signal that you know. In terms of all the new physics explanations, ultimately what they boil down to is, at some point in charge particle gets produced that interacts with the ice. So actually, whether it's a sterion neutrino, whether it's dark matter, whether it's an anti matter universe, they would all basically look the same.
You wouldn't be able to time the part You would then need.
Other experiments to go out and look for Well, okay, if it's the sterei on neutrino, we would expect to see this in other places, so let's go and look for it there.
So this would only be one clue.
It's like you've seen, you know, one footprint in the mud in the jungle when you're hunting for an animal. You don't necessarily know what animal it came from, just from this one depression in the soul. You've got to get more evident, so it would be a clue, but not convincing or not.
It wouldn't tell you ultimately what caused.
Necessarily, personally, I find it kind of frustrating that we're doing particle physics in an era where a single observation can't make a discoveries. You say, it's like seeing a footprint or a tuft of hair or something you haven't like identified the actual animal. And I think back on the days, you know, like when the positron was discovered, or you know, a cosmic rays or you know, the neutral current or whatever, where they saw something weird in their data and it was obvious that it was something new, that there was no other explanation other than a new particle. Why can't we do that anymore? Are we just passed the days of single event discovery because our experiments are so complex and our data are so indirect or do you think that's still something we could do?
I mean, if you go back to the positron discovery, that's a great story because you know, you have Carl Anderson with his cloud chamber and he sees this one track going through his cloud chamber which is bending the wrong way. You know, it looks like a positively charged electron. And on the basis of this one photograph that he's taken of one track, he discovers antimatter.
One day's experiment, one photograph, one Nobel price. It's a great ratio.
I suspected you probably did a few more days experimenting than just the one photo.
But yeah, I mean relatively speaking.
But I think the reason that was accepted quite quickly is because it was expected. Durrak had predicted the existence of the positron based on theory, so people were primed to see this thing. So I think that's partly why it was accepted. But also, you know, with this one image, there was no other way of explaining this. How do you get a positively charged track that looks like an electron where there's nothing that can do that, And he had ways of knowing that it wasn't electron going the opposite direction, for example, and tricking you. So when there are no other explanations, I think you can make a discovery based on a single measurement. So often though, I think nowadays in particle physics we're looking for really subtle effects, and you're often talking about if we go back to the LHC and the beauty quark anomalies. You're measuring some quantity to end decimal places and trying to compare it with your theory, and that measurement is kind of fraught with all kinds of potential systematic effects that you have to take into account. It's so rare that you just have this kind of thing that appears and it's, oh my god, you know that must be a particle.
I suppose, you know.
The closest became recently was the discovery of the Higgs boson, but that still required two years of data taking and then you see a bump. But at that point when you saw the bump again, because the Higgs was expected, people are pretty ready to say, okay, even at the time they didn't say this is a Higgs boson, but you know it's a Higgs like particle, and you know, gradually build more evidence.
But even in that case, there's no event you can look at and say, okay, this proves to me there's the Higgs. Each one could be Higgs or could be background. They're sitting on top of a huge background spectrum, and so in the end, it's all statistical and indirect right, there's no like a hey, look we found it, let's buy our ticket to Sweden, which is frustrating, but you know, it also gives us power to discover all sorts of other stuff.
I suppose.
Actually the counterexample thinking about it is gravitational wave discovery in twenty fifteen.
So that was one event.
Albeit they had to extract it from you know, their data, using these sort of template techniques and all the rest of it, but that was one signal, and they were prepared to say we've discovered gravitational waves on the basis of one interaction. That wasn't sort of you know, having to sample vast numbers, you know things. It does still happen, all right, But again I guess that that's helped by the fact that, again, you expected to see them, so you kind of knew what you should see, and then you see the thing you expect and you go, yes, okay, that's what that is.
That's gravitational waves.
All right. Well, that's really exciting, and I hope that what they have found in the ice in Antarctica is something new and weird and not just new layers of ice down there in Antarctica. I want to dig into some more of these anomalies, But first we have to take a quick break. When you pop a piece of cheese into your mouth or enjoy a rich spoonful of Greek yogurt, you're probably not thinking about the environmental impact of each and every bite. But the people in the dairy industry are. US Dairy has set themselves some ambitious sustainability goals, including being greenhouse gas neutral by twenty to fifty. That's why they're working hard every day to find new ways to reduce waste, conserve natural resources, and drive down greenhouse gas emissions. Take water, for example, those dairy farms we use water up to four times the same water cools the milk, cleans equipment, washes the barn, and irrigates the crops. How is US dairy tackling greenhouse gases? Many farms use anaerobic digestors that turn the methane from maneuver into renewable energy that can power farms, towns, and electric cars. So the next time you grab a slice of pizza or lick an ice cream cone, know that dairy farmers and processors around the country are using the latest practices and innovations to provide the nutrient dense dairy products we love with less of an impact. Visit us dairy dot com slash sustainability to learn more.
There are children, friends, and families walking, riding on passing the roads every day. Remember they're real people with loved ones who need them to get home safely. Protect our cyclists and pedestrians because they're people too.
Go safely.
California from the California Office of Traffic Safety and Caltrans.
Want the secret to your best skin yet. I've been getting a ton of compliments on my skin lately, and the secret Biosence, this award winning skincare brand, known for its science backed formulas, has been a game chain for me. The best my skin has ever looked is right after I started using these two holy grails, the biosons Omega Repair Moisturizing Cream and Marine ALGAEI Cream. These are just my personal faves. They're clinically proven products that deliver real results. Clinical trials have shown that one hundred percent of Omega Repair Moisturizing Cream users sawn increase in skin hydration after five minutes. And if you're concerned about fine lines like me, the Marine Algai Cream users sawn ninety seven percent improvement in the appearance of fine lines and wrinkles after one use. Are you ready for your best skin ever? Head tobiosons dot com and discover your next skincare obsession. And by the way, use code pod that's pod at checkout to score an exclusive surprise gift with any order that's code pod at checkout.
We're just days away from our twenty twenty four I Heard Radio Music Festival, presented by Capital On.
The biggest headliners in live music will be taking over T Mobile Arena las they get.
Plus some special surprises the moments you are not going to want to miss. Stream only on Hulu the i Al Radio Music Festival.
And listen on iHeartRadio, the most anticipated live music events up.
The year this Friday and Saturday, starting at ten thirty pm Eastern, seven thirty Pacific.
Okay, we're back, and I'm talking to doctor Harry Cliff about his fun new books Space Oddities, which tells us all about weird things that we are seeing in particle physics experiments that could be the hint of something new. Tell us about the muon G minus two experiment and what they are seeing.
So yeah, meon G minus two is a very impressive experiment.
So essentially what they're trying to measure is how magnetic an exotic particle called a muon is. So muon is essentially a heavy version of the electron. It's got a negative charge. There's about two hundred times more massive than an electron there, and they're quite unstable. They only live for a millionth of a second or so before they decay into neutrinos and an electron usually. Now, the reason that measuring the magnetism of the muan is interesting is that it's sensitive to the existence of new quantum fields in the vacuum that we haven't seen before. So to sort of introduce that ode of a quantum field for people who aren't familiar in particle physics, Actually we don't think of particles as being the fundamental ingredients of the universe.
We actually think of.
Particles as being manifestations of something more fundamental, which are these quantum fields that permeate all of space. So, for example, like an electron, we actually think of an electron as a little vibration in something called the electron field that fills the whole universe, and that means that if you take a little bit of empty space and you know, you look at it really hard, what you see is.
Actually is not empty. Even when you get rid of all the particles.
There are these fields that are still there, and we know about seventeen of them at the moment. There's you know, the quarks, the eleptons, the Higgs boson, and the force particles, glu on and photons and so on. These fields are always there, and there are certain properties of particles that are particularly sensitive to what is sitting around them in the vacuum. So essentially, you think about a muon, You have your muon, it's sitting in the vacuum. It actually interacts with all these quantum fields that are sitting there all the time. And what you actually measure is not the magnetism of the muon it's on its own, but the magnetism of the muon plus all its interactions with these seventeen quantum fields. And they can be really quite complicated, these sort of interactions back and forth between each other.
I think that's really helpful the way you're putting it. We're measuring these properties of the particles, but really they're showing us the interactions of the fields. Like even the mass of the muon is that way, right. The muon itself doesn't have a mass. It's the interaction of the muon and the Higgs field that changes how the muon field oscillates and the sort of standing waves of its vibrations, and we measure that as the mass the muon, But it tells us about the Higgs field. And so you're saying, measuring the magnetic moment of the muon also tells us about the other fields that could be out there. So it's a great example of the like indirect probe of all this stuff we might not know about.
Yeah, yeah, yeah, exactly.
And so the mun's magnetism was sort of measured back in the nineties, but then in two thousand there was an experiment at brook Haven near New York where they measured the muon's magnetism and it came out three sigma away from the predictions of the Standard Model. So you had this tantalizing anomaly that was seemed to be evidence that there was something else in the vacuum, something beyond the Standard Model that was altering its magnetism. So this could be the clue to something really new. And exciting the problem was that the experiment shut down wasn't taking any more data. So how do you kind of resolve this mystery? Is it really new physics or is it something else or statistical effect what have you. So some of the people who worked on that original Brookhaven experiment decided they were going to build a new and improved version of this muon G minus two experiment, and this involved essentially rebuilding the entire thing from scratch at Fermi Lab near Chicago. But I mean in terms of the lengths they go to. The only bit of the old experiment they recycled was this super conducting magnet ring. So essentially the way the experiment works is you fire muons into this magnetic ring. They go around the ring, and as they go through this magnetic field, their magnetic moment processes, so it kind of wobbles about in the magnetic field. When the muons decay, you can essentially measure the speed of the wobble depending on how much energy the particles that are produced come out at you get this kind of wiggle plot essentially. But this big ring, it's like, you know, thirty meters across, very expensive. They couldn't afford to get a new one from scratch. They had this whole thing shipped from Long Island down the Atlantic coastline, round Florida, through Hurricanaley, up the Mississippi River and then over then closed lads of freeways to get this huge thing to Fermi Lab. So it's insane, kind of like lengths that people go to again, so this whole process took a decade. They bring the new ring to Fermi Lab, they install it, they rebuild the entire experiment from scratch, taking real incredible care to measure every effect down to the sort of decimal place, characterize the magnetic feel beautifully. And then in twenty twenty one they announced their first measure of the NEWR magnetism there and again there's this dramatic moment where they unblind their results and.
The big question is is.
This thing going to land on top of the old measurement and confirmed anomally or is it going to land on top of the theoretical prediction. And what happens is it lands bang on top of the Brookhaven results. So this confirms the anomaly. It grows to over four sigma, and it's potentially really really exciting.
It looks like this is evidence for new physics.
But so often with these anomaly stories, there's a sting in the tale, which is that this case, the very same day that the new experiment published their result, a group of theorists produced a new prediction of the magnetism of the new one, and this prediction came out much closer to the experimental measurement. So essentially you had these two predictions, one that was performed by this big consortium of over one hundred theorists working together, and then this new technique using something technically called lattice QCD using big supercomputers.
And so you have these two rival.
Ways of predicting theoretically the same thing that we're giving different answers, and in one case there's a whacking great anomaly in new physics.
In the other case there's not much to see.
Essentially, this is another example of what you were talking about earlier, how it can be actually hard to know what our theory predicts. Just because we have a theory doesn't mean we know exactly how it predicts and experiments result will turn out right. So here we have two different groups using the same theory but getting different predictions, right, because the calculations themselves are so hard to do.
Yeah, that's right.
And in this case it all comes down to again quarks and gluons, which.
Are they are a real pain in the art basically Q.
Because the theory that describes them is very, very difficult to make calculations with the theory of what called quantum chromo dynamics. So we said that the nuance magnetism is affected by everything that's in the vacuum. Where there are quarks and gluon fields in the vacuum, they affect the magnetism. And it's been very difficult historically to calculate this term. So the way it was done earlier previously it was essentially to use experimental data where you have colliders that fire electrons and anti electrons, electrons and positrons at each other and then they produce particles made of quarks and gluons, and you can take this collider data and you can essentially say, well, an electronic positron annihilating to make quarks and gluons is basically the same as a muon interacting with clarks and gluons, and just kind of flip the process on its side effectively so you can take this data and then you can use a recipe to translate it into a prediction for the effect of quarks.
And gluons on the muon.
And that was how it was done, and this gave you this four sigma anomaly.
That's very clever. That's like saying, we don't know how to do this calculation, but we can make the universe do this calculation, and the extract that information and insert it into our calculation, sort of like using the universe as a computer. That's pretty awesome.
Yeah, exactly, Yeah, just take it from nature.
That was sort of an accepted, you know, very authority tested method. But this new approach was using this technique call lattice QCD, which I'm not going to pretend to understand, but it's basically a way of calculating these sorts of effects from first principles using the equations of the strong interaction, where you break space time up into this lattice of points and you solve the equations on these lattice points and you get your prediction. And they've sort of made a breakthrough in this method and how to sort of apply it to the case of the muon, and came up with a new calculation of this extra term in the calculation, and this shifted the result basically towards the experimental measurement. And so the big debate now is which of these two methods is right. You know, is it the experimentally driven one or is it the theoretically driven one to put it in broad terms, And that is still unresolved. We don't know yet which is right. The big sort of drama in this story now is basically theorists having to sort of juke it out and figure out what's the right way of doing this and hopefully eventually get to a point where both of these methods converge on the same answer and we can kind of agree how magnetic mwans really ought to be.
This is very frustrating for an experimentalist because I feel like we've done our job. We forced the universe to reveal the answer here, and we just need to know what it's supposed to be right, and the things like can't get their house in order and figure out like what we were supposed to have measured. It's like, you know, get it together, folks, But in this scenario, is there something we expect you were saying This is a great way to probe other fields. What other kind of fields might be out there that could be giving this effect? Is this the kind of thing that's predicted by various theories with.
Only nominally there are quite a lot of potential explanations on the market. So some involve supersymmetry, which is something that we've been looking for at the LHC for the last decade and have so far found no evidence for. But you know, it's so supersymmetry. Supersymmetric particles interacting essentially with the MU in the vacuum could produce an effect like this. Another possible a popular set of explanations involves what are known as dark forces, which sounds rather sinister, but these are essentially the idea that dark matter may not just be one particle like you know, it's often assumed it's it's a whimp or it's an axion, but perhaps dark matter as a sector is quite rich and there are more than just as in the atomic sector, there are multi particles interacting with forces. Maybe the dark sector involves multiple particles with its own set of forces. So there is one idea, is this is actually evidence of some kind of dark force field. That allows dark matter particles to interact with each other. That's subtly again altering the way that the muon behaves. So the honest answer is we don't know which of these is right yet. But again, this would be a clue. So if this anomaly was confirmed and the theorists agree on some calculation that gives this anomaly some high significance, you would then know for pretty well certain there is something new out there to find, and you can make various arguments to say, well, the new one has this certain mass, so we kind of know the energy scale that the new physics ought to show up at.
So it kind of gives experiments like the LHC.
A target where we might expect, you know, say, is find a new particle in the GeV range, for example, and then you go and search for particular signatures. So it wouldn't be the discovery of a particular new particle, but it would tell you there is a new particle there to be found, and that would drive an experimental ever to actually figure out what this thing is.
Do you think it's important that we have a theoretical idea for what we're looking for before we discover it, You said, something in your book which struck me. You said, quote, finding ourselves an unknown territory without a theoretical map to guide us has bewildered and disheartened many. Personally, I feel like, personally, I don't feel disheartened by not having a theoretical map. I feel excited. I'm like, Ooh, let's go out and explore this territory because my personal scientific fantasy is to find something unexpected, something that makes people go what that's impossible, you know, because those are the moments that unravel everything we thought we understand about the universe. You know, the photoelectric effect, the black body spectrum, this kind of stuff. Why do you feel like people are bewildered or disheartened by not having theoretical guidance, not having like tips for where to go look and what we might see.
I mean, personally, I agree with you. So I think, actually, this moment is really exciting. The idea that we're exploring the universe as we find it empirically observationally.
That's a great place to be. And I would love like you to see something new.
And unexpected that no one had predicted, because that's where you make the biggest progress. But I think it's fair to say that if you went back fifteen years before the Large Hadron Collider, there was this great sense of anticipation in terms of what we were going to find, and there were these very clearly defined targets for what people were going to look for and great optimism that some of them would show up. So the Higgs was one of them, and that did obligingly show up for us, but there was good reason to think it would because of all the success of the Standard Model decades beforehand. But then things like supersymmetry or extramensions of space. There was a lot of work going into and lots of predictions and lots of experimental searches, and none of them turned up. So I think that did leave people who had invested a lot of time and effort into exploring those ideas feeling pretty dispirited. But it sort of depends which angry you're coming at it from, I think, And it is a sort of change that I think looking at the history of particle physics particularly, there has been a change in the last ten years. I think it's probably the biggest impact in a way of the LHC is a sort of a shift from this theoretically led era back into one that is experimentally driven. If you went back to the middle of the twentieth century, that was a period where particle physics was really experimentally driven. You had all these particles appearing in cloud chambers and bubble chambers and collider experiments that no one really knew what was going on or understood, and that forced a theoretical effort to sort of make sense of this crazy zoo of particles, and out of that comes the quark model and then later the Standard Model. But since the Standard Model was established in the seventies, I think it's fair to say, broadly speaking, most of the story of particle physics has been a series of confirmations.
Of predictions of the Standard Model. It's the great triumph of what Weinberg.
And Glashow and others did, which they predicted the existence of the Wnz bosons. They were found in the eighties, the Higgs boson was found in twenty twelve. The other quarks that were sort of predicted were discovered, So it was really a series of like yep tic tick and now in twenty twelve we ticked the lark's box, and now we're like, Okay, there isn't a guide anymore. We've filled in all the boxes, but we know there's more out there, but we don't necessarily know where to go next. There's been an adjustment that people have gone through in shifting from that era where you sort of knew what you were looking for and you expected to find it, to one where you don't really know any more what you're looking for, and you're just going out and exploring and trying to design experiments and searches that are broad enough that they can capture even the things that you didn't necessarily predict ahead of time.
Yeah, I feel like there's sort of a pendulum that swings between, you know, philosophy and botany, And in the philosophical eras, it's like, you know, we know how this all works, and we can predict it, and we know what you should do and how to look for it, and then we swing into the botany era, where we're like, well, we have no idea what's going on. We're just taking data and describing all the weird stuff that we're seeing out there in the universe. And I feel like mostly we've been in the philosophy era and it's exciting to me to swing into the botany area where you know, as you say, experimentalists are on the forefront and we can go out and discover weird new stuff that nobody understands. To me, that's really exciting.
So we talk about botany. I mean, just this historical aside.
The same reaction came in the thirties when things like the mwon and the padrons were being discovered, where people like Fermi said, all these new particles are period people were quite dismas by it because they were like, it didn't fit into this neat theoretical picture. And I think it's firm you who said, you know, if I could remember the name of all these particles, I would have been a botanist.
So it's not the first time.
He says they're dismissively, But to me, that's very exciting. Yeah, So tell me how excited are people on the ground. I mean, you've done a great job of laying out these anomalies in your book and also giving us the caveats not over selling it. But you know, the people working on this stuff who are really seeing the details, are they excited? Are they betting that this is new physics or are they skeptical and jaded from all the anomalies that have come and gone.
I think it depends on who you speak to.
I mean, I think broadly speaking, I think it's fair to say that experimentalists tend to be more cautious.
I don't know if jaded is the right word, but certainly more cautious.
And theorists are are a bit more enthusiastic, and you know, and new and lomly turns up and they're like, amazing, great, and they kind of write loads of papers about what could explain this thing, and there's nothing wrong with that.
I think that's sort of two different approaches to the same thing.
I think, you know, as experimentalists, you do have to be more cautious because you're claiming to, you know, measure what nature is actually doing, and you don't want to be biasing your results based on some presupposition of what you're expecting to see, whereas in theory, you know, you come up with an explanation, there's no harm done. Really, I mean, if it doesn't turn out to be true, that's that's sort of fine. But it depends on the anomaly. It depends on who you talk to. But like with me on G minus two. I think if you speak to Lattice QCD theorists, they will say, well, there's nothing to see here because it's you know, the Lattice says that there's no anomaly. If you speak to other theorists who worked on the other method, they'll tell you, oh, no, this method solid and there's new physics.
So I think it really depends where you're coming from.
I think the one anomaly in the book that I found the most compelling, and where I think a lot of the field also believes this is something is actually not a particle physics anomaly, but one in cosmology which is anomally called the Hubble tension, which is essentially there's disagreement over how fast the universe is expanding or ought to be expanding. So you have these two methods of measuring this. One which involves looking at stuff we can see in the sky, so galaxies, measuring their distances and their speeds, and then you measure the expansion rate of the universe from that data. Another way that evolves looking at the light from the Big Bang, determining the properties of the early universe, and then using the standard cosmological model to run the clock forward and predict from that early data what the expansion rate should be now, and these two numbers do not agree with each other by over five sigma. Now, so this is a you know, pretty gold plated anomaly, and at least it would be in particle physics terms. But in that case, you know, there's been this long argument for a decade now about what is going on, and lots of people trying to find mistakes in how we measure distances, for example, in the local universe or drilling into the cosmic microwave background data that's used for this prediction. And after a decade of you know, scouring the data and multiple different ways of measuring the same things, no one's found a problem, really, not nothing that can explain the size of the anomaly that you're seeing. So I think more and more of the field is now coalescing around the belief that this is actually genuinely something profound that we don't understand. The difficulty there, I think, and this comes back to the point we were talking about earlier, is there isn't any ready made theoretical explanation for what's causing this. That there is sort of various things that can help relieve the tension a bit, but none of them solve it. So it's not like there's one sort of new thing where you say, oh, it's dark energy like you had with the accelerated universe in the nineties. It looks like to explain this thing, you need new physics, multiple different periods in the universe's history of different types. And I think that makes people uncomfortable because this principle of Oham's raiser, if you see something new, there should be some really simple explanation that just ah, right, yeah, you know, that's the answer, Whereas in this case it seems very difficult to do that. And I think it's meant that it has taken time for this anomaly to really kind of be accepted as a genuine effect because it is hard to explain.
Well, tell me a little bit about how you thought about presenting anomalies to the public, because your audience are people who can't really go through the d details and question your arguments necessarily, and so there's a responsibility when you're presenting this stuff to the public. You want to make it sound exciting, you're selling a book, after all, but you also want to be responsible and you don't want to overhype stuff. And you tell in your book a story of sort of a disastrous example of this, you know, the bicep two result. You said, quote, I can't think of a more disastrous example of scientific hubris than the sorry story of bicep two, which I thought was, you know, harsh but fair. How did you strike a balance in your book?
Yeah, And I think the way I try to put this across is that anomalies potentially can be revolutionary. They can give you this amazing new insight to something you never understood before, but they can also lead you astray. And so at the beginning of the book, I actually kind of have a whole chapter basically on how anomalies can trick you and how you can all go horribly wrong. I mean, so with the bicep two example, that was this discovery in twenty fourteen where a telescope at the South Pole found evidence for gravitational waves from inflation, this period of exponential expansion that cosmologists believed happened in the very first instant of the Big Bang.
And this was.
Presented to the world before it was peer reviewed, this big press conference, and you know this announcement that you know, essentially we'd heard the bee of the Big Bang, that we'd proven cosmic inflation, that we probe quantum gravity, you.
Know, all this talk about Nobel prizes. And then within about a month or.
Two, the whole thing was undiscovered as it was realized that they'd taken a key bit of data from a PowerPoint presentation by the Plank Spacecraft Collaboration, which was used to basically take into account the effect of dust contaminating their observations of the cosmic microwave background, and they misinterpreted this slide effectively, and when this was taken to account, the whole signal literally turned to.
Dust, so it disappeared. So I think that the.
Problem with what by step two did was not necessarily that they made a mistake, because mistakes happened. That can happen, but it's the way it was communicated. I think that it was they called a press conference, they made a big deal out of it, and before it had been really thoroughly checked by external peer reviewers. I think that was what weren't wrong there. So in the book, you know, all of the nonominies, I talk about the reason their arenomalies and not discoveries is because none of them are confirmed, and I go through each of them and say, well, you know, here's the exciting explanation, here's the boring explanation, and I think it hopefully gives readers a balanced view of, you know, what the story is with each of them. But the other way, I think that whether or not any of them actually turn into a new physics discovery, I think there's huge excitement just in the process of drilling into these things, and you know, learning about the experiments that people do, the lengths they go to to measure these quantities, the emotional rollercoaster people go through, you know, when they think they're seeing something and then they realize they haven't. One of the stories I tell in the book is my own research. So we talked about this at the beginning of the podcast, where we thought collectively in our area of particle physics, that we were seeing signs of something genuinely exciting. And what happened as I was writing the book, in fact, was that we discovered in some of our measurements there was a hidden or a missed background that.
We had not properly understood.
And this was a real moment of you know, the horror Essentially when you realize that you put measurements out into the world that have an error in them, and when this was corrected, a set of the anomalies disappeared. And essentially that you know, once you're corrected for this effect, it agree with the standard model. So what I look like you're on the brink of discovering something really big. You realize, oh, actually it's the opposite. You've made a pretty spectacular cockup.
Said trombone sound here.
Yeah, yeah, So I think it's important to see that that's how science works.
You know, when you're working at the edge of your.
Understanding, you're in real danger of making mistakes because you're in territory that you don't know where you're stepping. You know, your foothold is not secure, and you may take as much care as you can where there's always a chance that you put a foot wrong. But gradually the science is self correcting, so these mistakes are eventually, sometimes quite quickly found out, and even when the anomalies go away, you learn something new. So you may learn about how to make calculations with the standard model, for example, or you may learn about particular types of background processes that you didn't understand, and that allows you when you do another experiment or you make another prediction in the future, you're on much more solid ground. So these anomalies are kind of a grindstone where you're sharpening your scientific tools. Even when they don't lead to a big breakthrough, they are kind of equipping you for the next steps.
Yeah, well, let's hope that they lead to new anomalies that actually do turn out to be new particles. That's a lot more fun.
Yeah, wonderful.
Well, thanks very much for coming to talk to us about all the exciting hints on the edge of the particle physics frontier that might be the revolution in our understanding about the universe. And I encourage everyone to check out Harry's new Bookspace Oddities everywhere books are sold. Harry, thanks very much for joining us today on the podcast.
Thanks for having me. Great talking to you.
All Right, an interesting conversation. What's your takeaway from all of those oddities out there.
I think they're all exciting, but I'm not one hundred percent convinced that any of them really mean a new discovery, a new deep understanding of the universe.
Wait, what you're skeptical of a scientist saying, hey, let's go explore the unknown.
No, I think it's great to explore the unknown. One thing I really like about Harry's book is that he tells you why they're potentially exciting, but he also gives you a realistic sense for why they might have prosaic explanations. It might just be that the ice in Antarctica is not as simple as we thought, or that the calculations of the Standard Model are harder to do than we expect it, so we're not sure exactly what to compare it to. So stay tuned, is the final answer.
So these oddities are maybe not so odd.
We might mean that we learned something deeper about the universe, or we might just learn about the ice in Antarctica. Either way, we're going to learn something.
Yeah, and hopefully not destroy the planet, right right, hopefully hopefully question mark dot dot dot Great, and this is the part where you cackle with Danny Great, Hey, Nni Seth, can we cut off his funding now? Please? Thank you? All right? Well, another interesting reminder, there are still lots of discover out there, at least a lot of data and a lot of sciences through to look for things that we maybe didn't expect, because the history of science is that it's always surprising us.
It's always surprising, and it's always fantastic. It's stay tuned, and that's what we shouldn't destroyed. No comment.
All right, Well, we hope you enjoyed that. Thanks for joining us. See you next time.
For more science and curiosity, come find us on social media where we answer questions and post videos. We're on Twitter, Discord, Instant, and now TikTok. 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. When you pop a piece of cheese into your mouth, you're probably not thinking about the environmental impact. But the people in the dairy industry are. That's why they're working hard every day to find new ways to reduce waste, conserve natural rests, and drive down greenhouse gas emissions. House US dairy tackling greenhouse gases. Many farms use anaerobic digestors to turn the methane from manure into renewable energy. That can power farms, towns, and electric cars. Visit you as dairy dot COM's last sustainability to learn more.
Vitamin Water is from New York.
We needed a drink that could keep up with the music scene in the city.
We got to see our favorite DJ perform in Brooklyn at three am, or seeing karaoke in the.
Village also at three am. Drink Vitamin Water is from New York.
There are children, friends, and families walking, riding on passing the roads every day. Remember they're real people with loved ones who need them to.
Get home safely.
Protect our cyclists and pedestrians because they're people too.
Go safely.
California from the California Office of Traffic Safety and Caltrans
