Into the Impossible With Brian Keating - How Strange Anomalies Lead to World-Changing Discoveries with Harry Cliff

Episode Date: February 16, 2025

Please join my mailing list here 👉 https://briankeating.com/list to win a meteorite 💥 If we look back at the history of physics, many of the biggest discoveries were triggered by strange anomalies that sparked curiosity in the minds of great scientists.  But how do anomalies drive scientific discovery? What are some anomalies that are currently reshaping our understanding of the universe? And are we on the brink of discovering new physics?  Here today to shine a light on this fascinating topic is none other than Harry Cliff. Harry is an experimental physicist at CERN and renowned science communicator who recently published “Space Oddities: The Mysterious Anomalies Challenging Our Understanding of the Universe.” In it, he examines a catalog of weird phenomena that simply can’t be explained by our long-established theories of the universe. Are these anomalies just accidents, or are they pointing us to new discoveries like they did many times in the past? Find out in our exciting conversation! — Key Takeaways:  00:00 Intro 00:34 Judging a book by its cover  02:25 From anomalies to discoveries  05:03 Understanding sigma and confidence in science  13:30 Muon g-2 and its implications  19:18 Neutrinos and the search for new physics  21:58 Hubble tension and the future of cosmology  24:58 LHCb experiment  33:37 The matter-antimatter asymmetry problem  37:39 Harry’s gut feeling on dark matter 42:10 The role of anomalies in scientific discovery  46:10 Black hole information paradox 46:57 The importance of skepticism  49:13 Outro — Additional resources:  ➡️ Learn more about Harry Cliff: 💻 Website: https://www.harrycliff.co.uk/  📚 Space Oddities on Amazon: https://a.co/d/eV4xhAv ➡️ Follow me on your fav platforms: ✖️ Twitter: https://twitter.com/DrBrianKeating  🔔 YouTube: https://www.youtube.com/DrBrianKeating?sub_confirmation=1  📝 Join my mailing list: https://briankeating.com/list  ✍️ Check out my blog: https://briankeating.com/cosmic-musings/  🎙️ Follow my podcast: https://briankeating.com/podcast  — Into the Impossible with Brian Keating is a podcast dedicated to all those who want to explore the universe within and beyond the known. Make sure to follow/subscribe so you never miss an episode! Learn more about your ad choices. Visit megaphone.fm/adchoices

The people that have the instinct to follow those little clues that often make the biggest discoveries, whether that's Penzias and Wilson and their microwave buzz or it's Rutherford and his blurry alpha particles. It's those little strange things that you really need to pay attention to. It's very rare that discovery reveals itself in a big flash in the way that maybe we've imagined through the kind of popular tellings of the history of science. Harry Cliff, welcome back to your second appearance on The Into the Impossible podcast. So good to see you. Correct to me back, Brian. And you've written a book about David Bowie this time, space audit. No, space So I was very pleased. I didn't have to pay for the advertisements. But there's two of my experiments mentioned in this wonderful new book, new in paperback, I should say. I listened to it. I read the hard copy and I bought the audible. But now the paperback is out. So double congratulations there. As is our want, I want you to take us through the cover, the title, the artwork, but also the subtitle. I always love subtitles because that's the one thing that the author has some control over. So take it away. How did you come up with this very,

man who fell to Earth type cover. I knew I wanted to write a book about anomalies, but it was trying to come up with a title that was going to grab people. And I was basically going through a conversation with my US editor, Yaniv Soha, who was a double day then. Basically, it splurged a list of just random ideas at him, including, and Space Audities was one of them. Because, you know, it's a bit of a fudge,

because a lot of the anomalies in the book are really about particle physics. And there's a couple there are astronomical cosmological anomalies. But he was like, it's got to be that one. That's got to be the one. So I was like, okay, well, I guess we're, can live with the fact this only sort of addresses about half the stories in the book. So that's where space oddities, David Bowie is like my favorite musician of all time. So it works from that perspective. In terms of the subtitle, which is the mysterious anomalies challenging or understanding

of the universe, I mean, I think that sort of speaks for itself really. It's basically about these strange observations, results that we've been seeing back when I was writing the book that were several of them looking like they might be the sign of something beyond our two standard models of particle physics and cosmology. And as for the artwork, I mean, this was come up with by the publisher, the US publisher, Doubleday. This is actually a UK cover, but the UK edition just takes the same image. So I think they were just trying to come up with something that was unusual. So they've got this kind of weird sort of infinity slash Mobius strip symbol on the cover with a little earth and a moon next to it. So I guess that kind of says space, but also there's something odd. And I quite like

the yellow. I guess it jumps out on the bookshelf for sure. You can't miss it. So when I read the book and I think about these kind of anomalies, it's really the anomalies that provide our deepest insights. People think of symmetry and beauty, our friend Brian Green, kind of elegance and beauty. But actually, the universe is pretty hideous and thankfully so. You point out in the book, if we had a perfect symmetry between, say, matter and antimatter, well, we wouldn't be we, right? So isn't it true that, as Leonard Cohen said, that it's really the anomalies, the cracks, as he called them. So famous, song called Anthem. Ring the bells that still can ring. Forget your perfect offering. There's a crack, a crack in everything. That's how the light gets in. So isn't it true that most of what we know about physics comes from the things that aren't perfect, the cracks, the imperfections? I think that is true. And if you look, you can look back in a history of physics and so many of the biggest discoveries began with something that was just a bit weird that people didn't really understand. I mean, one example I don't even give in the book is actually the very famous discovery

that took place more than 100 years ago of the atomic nuclear. That discovery came from Ernest Rutherford, who was the sort of leading nuclear physicist of the era and Hans Geiger, were working in Manchester. And they basically had this, they were building an early version of the Geiger counter. They had this tube of gas and they were firing alpha particles through it, these red particles that come out of radioactive atoms. And what they expected was that these particles were from a very sharp dot on a photographic plate at the end of this long tube of gas. Because they are like bullets. They should go through the gas without getting deflected.

And what they saw instead was this kind of like fuzzy image, this kind of like, it was a bit smeary. And Rutherford had this amazing ability to go, oh, that's just, that's a bit strange. And that kind of little clue led through a series of further experiments and steps to the discovery that the atom, the picture of the atom that we had in the early 20th century was wrong. And that it wasn't this kind of diffuse thing that Thompson had imagined, but had this nucleus in the middle with electrons going around the outside. That's just one example. At the other end, I mean, probably, I think this is what. the story I mentioned at the end of the book, probably the most momentous discovery of the 20th century, which is the cosmic microwave background, which your listeners are well familiar with,

which is the real clinching evidence that the Big Bang really did happen and persuaded most of the remaining doubters, not Fred Hoyle, but most of the others. And that again came from this noise and an instrument. It was this irritating buzz that was thought at one point to be pigeon droppings in their radio antenna. And that turns out, again, it's following that little clue, And that leads you to this incredible revelation. You discover something completely new and it shifts your view of the world. So I think you can find these kinds of strange anomalies and underpinning so much of what we know in both physics and cosmology and astronomy.

It's really amazing how these commonalities between the very smallest scale physics, particle physics, accelerator physics and anomalies there connect with the largest anomalies in the universe, literally the whole universe, my favorite story, of course, Bicep 2. and the subject of my first book, Losing the Nobel Prize, has the Bicep story. It's featured heavily in your book. But most of the anomalies,

like most of the big claims, often turn out not to be confirmed. And I think it would be good for my audience, who's not only the most brilliant audience in the known multiverse, but to have a little bit of a glimpse into what the technical details of a non-anomily,

a discovery, if you will. You talk a lot about Sigma, confidence. We talk about that, not in the context of charisma, But tell us, what is Sigma? What is confidence? What are these things? And how should a layperson kind of interpret whether or not something is a true discovery if they hear about some fascinating discovery on page one of the New York Times like Bicep? And then they never find out until many years later. Oh, actually, that wasn't confirmed. And so many people are left with the impression. These things are still on the hunt. So tell us, what is Sigma, what's confidence. What do they mean to scientists and to lay people? Broadly speaking, what we talk about Sigma. What we're really talking about is uncertainty. So any scientific, measurement or observation comes with some uncertainty. And that uncertainty can be to do with the amount of data you have. So if I want to know what's the average height of a man in the UK,

if I take two men and I measure their heights, I'm going to get a pretty inaccurate estimate of the average height of all men. If I want to absolute, the right answer, I have to go and get all 35 million men and measure all their heights. But the more men we measure, the more precise our average value gets. And the uncertainty on that average value gets smaller and small. And it's the same if we're measuring the mass of a fundamental particle. The more of these fundamental particles we produce, the more times we measure the mass, the more precise our measurement gets. You have this sort of statistical uncertainty, which is an expression of how well we think we know

this thing, within some range, basically. The other side of it, you also have a systematic uncertainty, sort of a much more of a black art, but they're an attempt to express the things you don't understand about your experiment. Do we really know the resolution of our telescope as well as we think? What happens if we make a different assumption? What does that do to our result? So these things come together basically to give us a sort of a range, which we say, okay, we think the value is here, but there's this range around that value,

which it could fall within with a pretty high degree of likelihood. So one sigma, what we call the sort of one sigma band is where basically if you did the experiment 100 times, 68 times it would fall, the result would fall within that band, broadly speaking. So that's what we mean by sigma. And then in physics, well, I think it began in particle physics and it's now spread to other areas of physics, we have this sort of slightly arbitrary scale of how we define whether a measurement is in tension with, say, your theoretical prediction. So let's say, you have your

theory. It could be your standard cosmological model and it predicts some quantity, say the Hubble constant, how fast space is expanding. You go and measure the Hubble constant. Then what you want to do is compare your experimental measurement to your theoretical prediction and you look how many units of uncertainty away are these two observations. And if it's within one or two sigma, say, well, that's fine. That's basically agreement. You know, that's kind of what you'd expect. When it gets to three sigma, around three sigma, there's a kind of one in a thousand-ish chance that you would get two values deviate by that much by random chance, just by dumb luck. So in other words, if you did the experiment a thousand times, only one of them would end up in that much

tension just by statistics. So at three-sigma people, it's completely arbitrary, but people call that evidence. So when we say we have a three sigma tension, that is the evidence that there may be something interesting going on, but we can't really be sure. And the reason we say, well, three sigma just evidence, but it's not confirmed, is that we make loads and loads of measurements, particularly say at the Large Hadron Collider, where I'm, where I do my research, we put out, I mean, we put out thousands of papers in the last 10 years. So if you make thousands of measurements, then some of them are going to be in three sigma tension just by pure statistics, regardless of whether you've made a mistake in your experiment or not.

So that's why we don't trust three sigma results. They're intriguing. People might go, okay, well, at three sigma, we're going to look into this. We're going to investigate this a bit more. But no one's going to book a flight to Stockholm for a three sigma result. Then we get to five sigma, which has now become this sort of gold standard. If you get to five sigma tension, that is what we call now an observation or a discovery. So when the Higgs boson was discovered, for example, in 2012, the thing that convinced

everyone was both, you had these two experiments, two detectors at the Large Hadron Collider, both saw a new particle at 5 Sigma. So 5 Sigma above the background, basically. And at 5 Sigma, you're talking parts in a million chance of it being a statistical fluke. While we make thousands of measurements, we don't make millions. So if you have a thing that's parts in a million, it's, there's something happening. And hopefully there's something is in new physics. It could also sometimes be some systematic that you've just missed. That also can happen. And that also can happen. But that's the kind of the thresholds that we use, three-sigma evidence, five-sigma discovery, barring the fact you haven't made any mistakes anywhere.

Many of the anomalies that you talk about and describe in the book are later shown not to be anomalies. And you speak of that being disappointing. It's always disappointing, even though we know going into it, the odds of the standard model. I think Nima Akani, Ahmed, who promised to come on the podcast four years ago, but still has not gotten pinned down yet. But anyway, he said the standard model is a strong.

than Diamond. It's very hard to break the standard model. And he's referring to the standard model of particle physics. But now we're talking about astrophysics cosmology, and the book ends with a description of Hubble tension. Do we give more slack, as it were, to cosmology or particle physics, compared to particle physics, and that we're willing to accept things that seem to be 5-sigma, and then they literally turn to dust in the case of Bicep 2? Do we give more kind of leeway to cosmology, astrophysics, than we do to particle physics? And if so, why do you think that is. It seems like we're very strict, harsh judges of particle physics and maybe give a little bit more leeway to the astrophysicist. Yeah, I don't know about if I put it that way exactly. I mean,

certainly from talking, actually, I'm not an astrophysicist or a cosmologist, but like speaking to you and your colleagues, like my sense is that people are more willing to take anomalies seriously in cosmology because the Lambda CDM model, the standard model of cosmology, the two things that are in the name of it, Lambda, Dark Energy, CDM, Cold Dark Matter, we don't know what they are, right? We have very little information about what these things are. So you have this model which is based on general relativity, which I think most people would believe is pretty solid, but the actually ingredients of the theory, the energies and forms of matter are completely unknown. So it's really, it wouldn't be that surprising if land a CDM is wrong. If dark matter interacts with itself,

for example, or if there are multiple types of dark matter, or if dark energy is dynamic, then, you know, that the theory needs modification. So I think it's easier to believe that you may be seeing something that does challenge your standard model in cosmology. In particle physics, though, you've got this model that's been around for half a century and this wealth of data, like high precision experimental data, a whole range of international experiments that, you know, the standard model agrees with beautifully. So if you find an anomaly, it has to, and you want it to be new physics, you've got to somehow introduce new physics in a way that doesn't break everything else. Because your new theory, whatever it is, your extension of the standard

model still has to have all the same successes of the standard as the standard model and explain your anomaly. So in those cases, I think people probably say, well, the prior is the standard model is so good and so precise. And it works in so many different regimes and different particles, different sorts of processes that you really have to do the work to convince anyone that an anomaly is worth taking seriously. And I think it's fair to say that there are no particle physics anomalies on offer at the moment that reached that threshold. For a while, I think there was a sense we were getting close with some of B quark anomalies that maybe we'll talk about in a bit. But as we'll see, that's now been a more ambiguous state again.

We don't really know quite what's happening there. There was a tweet that I think it was John Butterworth or another of my colleagues put out when there was a load of news around some of these B anomalies that were coming out of the LHC. And it was a picture of a huge ship labelled standard model and like a little tiny boat that it was crashing into called the anomaly. And I think that's a nice way of thinking about how it is in particle physics. Yeah, let's go through some of the particle physics anomalies.

that you talk about. You start with muon g-minus 2, which was not only heralded as some abstruse corrections at the 12th decimal place to lattice QCD, but actually is heralding the existence of a fifth force. So what do you make of these kind of overreaching statements? Even though the experimental result seemed to be quite strong, it didn't hold up to scrutiny. This episode is brought to you by Netflix. Most valuable promotions in Netflix are hosting a Blockbuster triple headliner Saturday, May 16th. Rhonda Rousey returns to face fellow woman's MMA pioneer Gina Carano in the main event. Plus co-main's Nate Diaz versus Mike Perry.

And the best heavyweight in the world, Frances Ngano versus Felipe Lins. Watch Rhonda Rousey versus Gina Carrano, live only on Netflix. Saturday, May 16th at 9 p.m. Eastern Center time, 6 p.m. Pacific time. I think the challenge is how do we actually get the word back out to the public that these things are disconfirmed or ambiguous once the kind of horse is out of the barn, so to speak. So talk about the status of G-minus-2, why that's so important, and what would it mean to really have a fifth force? What would that do to physics, even to the philosophy of science? Just to explain what G-minus-2 is for the benefit of anyone who doesn't know, there's this particle

called the muon, which is a heavy version of the electron, doesn't exist normally, but we can create it in experiments. And it has, it behaves like a little bar magnet. So the muon spins, just like an electron and because it's charged, that angular mentum comes up with an associated magnetic field. And the strength of the magnetism of the muon depends not just on the muon, but on the contents of the vacuum around it. So in particle physics, the vacuum is not empty. It's full of these things called quantum fields. And these quantum fields interact with the muon. And so in order to know the magnetism of the muon, you have to calculate with the standard model of particle physics, the influence of all these different fields.

And if you do that, you get a very precise number to 12 decimal places or whatever it is now. And what we'd been seen more than 20 years ago was this tension between a very precise experimental measurement of this little bar magnet that the nuance carries around with it and the standard model prediction at the time. As a little sort of forewarning, Chris told me that when he was a student, there was actually this moment when they first started running the original experiment in Brookhaven, where very quickly they were in three sigma tension with the standard model. And what they discovered was that the theory prediction, there was a sign error in their calculation.

So somewhere, one of the terms, someone had flipped a plus for a minus. And that created the illusion of this tension. So once they fixed that, it went away. They took more data. And by I think it was around 2001, they were back in three sigma tension again. But they couldn't really get any more meaningful data out of the experiment. So this anomaly just sat there at three sigma for years and years. And Chris and his colleagues then went on to redesign in your own.

new version of the experiment, basically taking some of the original equipment, this big superconducting ring that was used at Brookhaven, shipping it to Fermilab, rebuilding the whole experiment. In the meantime, the theoretical technology is evolving. So this calculation of this magnetism is incredibly difficult. There are all these different terms in the calculation that have to be done. And the really hard bit is basically the way that the muon interacts with quarks and gluons in the vacuum. So you have this sort of like, you can think of it as this virtual haze of quarks and gluons that follows the muon around. And the theory of quarks and gluons, QCD, quantum chromodynamics is famously impossible, very difficult to calculate. And so there was this

kind of clever method where rather than trying to work out how quarks and gluons influence the muon, they take experimental data where you collide electrons and positrons to make quarks and gluons, which is basically the same process turned on its side, and you translate that data and plug it into your theory prediction, and you get a very precise prediction for the muons magnetism by doing this. So the first time that the new experiment unblinded, the real question was, is the new measurement with a new machine going to line up with the old experimental measurement, or is it going to line up with a theory, the new theory prediction, which is even more precise now? And it lands bang on top of the old Brookhaven measurement. And everyone's really happy. You combine the results. You get over four

sigma tension. This is starting to live really serious. And people think, okay, well, in a year, when we've got more data, this will be 5 Sigma and we can declare the discovery of something new. Because what that's really saying, this an nominally is saying that there's something else in the vacuum that is not in our prediction, that is altering the muon's properties. And one, you mentioned the fifth force. So one possibility is there is a new gauge field or some new kind of vector field, like the photon or the Z boson in the vacuum. And that is altering the properties of muon. So, I mean, but you can basically come up with lots of explanations. It could be super symmetry, extra forces, dark forces that are related to dark energy.

But basically what is telling you is, if this is real, there is something new. And the standard model is missing something, which is very exciting. But then the big twist is just after actually the same day that the Fermilab experiment released their first result from the first year of data taking, after a decade of laboriously building this high precision piece of kit, this other theory group called the BMW collaboration in Germany, come up with a new calculation of the mons magnetism based not on this kind of experimental data, but this technique called lattice QCD, which is basically a way of solving the equations of quantum chromodynamics using supercomputers in effect. And when they do this, they get

a result, there's much better agreement with the experimental measurement. So if you believe the standard theory prediction, you maybe discover new physics, if you believe this new approach, then there's nothing to see, basically. And what has happened, subsubstably, subsequently, me on G minus two experiments taking more data, their result is now well over 5 sigma with the old prediction, but it now looks like this new lattice QCD technique is actually the correct one. And people are more confident it's the right approach. So the anomaly has gone from 5 sigma or more to one sigma, i.e. no anomaly, basically, anymore. And I think the thing people are still trying to unpick is what went wrong with the original theory calculation. So this

is an unusual example in some ways. It's like it's anomaly driven by a theoretical miscalculation, not by an experiment. So you have to feel a little bit sorry for the experimentalist, I think, because they've devoted a decade or more of their lives to building this incredible piece of kit. And it really is like a giant Swiss watch, this thing, really high precision. They make this beautiful, pristine measurement. And then it turns out the whole motivation for the experiment was actually, the theory was off. But I suppose what I would say, just to sum it all up, although that's maybe disappointing from Newfix's point of view, what it does do, actually, we've learned a huge amount about how to calculate with quantum chromodynamics.

as a result. So that's one of the points I make in the book. Even when an anomaly doesn't lead to some big breakthrough and fundamental breakthrough, it often really sharpens your scientific tools. So we now have a much better understanding of how to do these sorts of calculations and how to build these precision experiments, which sort of lays the foundation for future discoveries. So it may be, maybe this time, no new physics, but this may be a key ingredient to the next discovery as and when it comes. So it's not all doom and glue. I ask my audience, as I often do, on Twitter, X, on YouTube, on my YouTube community or post tab. For some questions for you, I got a bunch, and some of them will lead into a segue into more

questions from my favorite guest, which is me, to ask you for your opinion about the more sociology of physics and science in general, but we'll get to that in a second. So Cameron Banick asks, how likely are neutrinos to lead to new physics? Well, I think it's really hard to say. I mean, when you say like before you've done the measurement, is it going to lead to new physics? I wouldn't want to place a bet, but there's a lot about neutrinos we don't understand. So they're definitely worth investigating. And the more places we look, the more likely we are to see something. So, I mean, one of the things that's, I think, really interesting in the future experiments, neutrinos that are coming up.

So you have in the States, June, which is being built at the moment, this huge new neutrino experiment between Fermilab and a deep mine out west. And one of the things that June is going to try and do is measure whether neutrinos violate matter-antimatter asymmetry. So what we technically call charge parity symmetry. And there's some weak evidence from a Japanese experiment called T2K that they do. And if they do, that could be the explanation or it could be part of the explanation as to why the physical universe exists. You've alluded to it at the beginning of the conversation,

that the fact that there isn't this perfect symmetry between matter and antimatter allowed the universe as we know it to come into existence, because without it, it would all be annihilated in the Big Bang and there'd be nothing. That's what I'm really interested to see when June reports its results. Does it see the neutrino's respect matter, antimatter asymmetry or not? And if they don't, that may be the clue to solving one of the biggest mysteries actually in fundamental physics, which is how we got here. And my question is a follow-up to Cameron's is we, as you point out at the end of the book

with a discussion about Simon's Observatory, you mentioned in the context of your encounters with your friend and my friend Joe Dunkley, is now the spokesperson of the Simon's Observatory, that instruments like Act and Simon's Observatory in particular are gearing up to measure and help to resolve, perhaps to resolve the tension known as the Hubble Tension, although I say it's much cheaper than the $200 million Simon's Observatory, just hire a team of therapists to counsel us cosmologists. Let's say we are successful, not in that endeavor, but we have another significant science goal with Simon's Observatory in addition to looking for inflationary gravitational waves, so called B mode polarization,

which you discuss, but also measure the mass and relative. relativistic energy density budget of neutrinos or, you know, relativistic particles. I want to ask you a question to do a hypothetical. We are successful, quote unquote, or our competitors, it doesn't matter. And a cosmology experiment, like the CMB experiment, measures the mass of the sum of neutrino masses. That would, if I'm not mistaken, mark the first time that a mass of an elementary particle is measured not on the Earth. It would be measured cosmologically. It would be measured astrophysically.

It would be the first measurement of the 17 elementary particles having to do with their three fungible characteristics mass been in charge that was not measured in a lab like you operated. Would your colleagues believe it? Let's say we come up, it's 3-4 sigma. We measure the hierarchy, whether it's inverted or standard. What would be the reaction, sociologically speaking? Would you guys believe it or does it really need to do what's called a direct detection before an honest-to-goodness practicing master of particle physics like you and your colleagues? would believe it. That's a very good question. I mean, I should say I'm not a neutrino physicist. You probably have to ask a real neutrino expert to get their view. I mean, I don't really know

the details of how these measurements are done. So I guess the question would be to what assumptions is it based on? Which cosmological models you have to assume? What are you assuming about dark energy or dark matter? So I guess that's where the uncertainty may come in. If it's built on some model that is not regarded as being totally solid, then I suspect people probably would want to see a laboratory experiment confirm the result in one way or another. And I suppose it also depends a bit. In particle physics,

if it had just been one detector that had discovered the Higgs boson, I don't think people would necessarily have been totally convinced. You always want it with anything, some confirmation externally. So whether that comes from another astronomical experiment observation or if it has to come from particle physics, I don't know.

But yeah, I think on the other hand, particle physics do take a lot of what, you know, you guys say to us very seriously. There are all these dark matter experiments and a lot of my colleagues at the LHC spend their lives looking for dark matter. And that is based not on any evidence from laboratories here on Earth. It's purely astronomical in nature. And that drives a lot of what we do.

So I think for sure people take what cosmologists and astrophysicists take seriously. I guess the question is what are the details of the measurement? Getting back to some of the anomalies that you speak about in the book, the notion that physics may be hiding in plain sight, so to speak, and it will take new and better. or microscopes, if you will, to really unravel the detective, the mystery story. I think there's no better example than your field of research, which is LHCB. So talk about what is LHCB, what has been the history of the last over a decade. I mean, I'm only familiar with the previous interview that you did on the podcast.

But talk about this and these different measurements and the level of conflict or tension, as we said before, where these anomalies went back and forth whipsonging between new physics and just consistency with the standard model. So talk about that effort as one of the key players in this endeavor. Yeah. So, well, LHCB, it's one of the four experiments on the Large Hadron Collider. So you have this big 27-kilometer ring, four places where the particles collide four big detectors.

And LHCB is one of them. And LHCB is a specialized detector. So what the B stands for is beauty, which is a name for one of the six quarks, also called the bottom quark, more usually called the bottom quark. I think I'd probably made this joke last time as well. but the reason it's beauty for us is we'd rather be beauty physicist than bottom physicists. So we call it the beauty quark.

And the experiment, really what it does is it produces, you know, the large Hadron Collider produces billions of these beauty quarks every year and the experiment is designed specifically to capture as many as possible record their properties. And the reason these things, broadly speaking, are interesting, is that these bottom quarks, beauty quarks are unstable. So you make one of these things, it decays in about one and a half trillions of a second. And because it's the fifth heavy. of the quarks, it can decay into a lot of different particles in the standard model.

So there's a very rich phenomenology associated with these things. And the way they decay, generally how a particle decays, a fundamental particle decays in the standard model, is it involves the weak force. So the bottom quark will radiate something called a W boson, and it will turn into a charm quark, and then that charm quark will decay into a down quark, and you basically end up with ordinary matter at the end, which is the stuff that hits your detector, broadly speaking. And what we saw at LHCB, we've been looking at a series of different, what we call rare decays. So there are lots of different ways these bottom quarts can decay.

And there are some of these processes that are very suppressed in the standard model. So they are predicted to happen less often than one in a million. So one in a million or less. And some of them parts in a billion or fewer. And the reason these rare decays are interesting, because they're so, basically the reason they're suppressed is for them to happen, you need a complicated combination of the weak force and the electromagnetic force and top quarks and all kinds of stuff to get together in the right way to mediate the decay. And that's what makes them rare. The analogy is a bit like you're trying to

get between two subway stations on a subway network that don't have a direct connection. You have to change at multiple stations and it just becomes very complicated and no one can be bothered to make the journey. But if there's new physics, so let's say there's some new quantum field in nature, some fifth force or something else, that is a bit like a new metro line, a new subway line connecting those two stations directly. And so that can provide a new route for the decay to happen and it can change the rate the decay happens. It can change some of the properties of the decay, like what directions do the particles go in what the energies, the energy spectrum, that kind of stuff. So broadly speaking, you try and get a load of these rare decays,

you try and observe them, you measure their properties and then you compare to your standard model prediction. And if you see a deviation, that could be new physics. So that's the kind of game, really. It's a very similar thing to the Mu-1G-minus-2 experiment, but just at higher energy in a collider, really, in many ways. What we started to see back in 2014, actually, was that first of all, if you look at the angles that the particles were coming out from these decays at, they didn't match the predictions of the standard model. And as the story has evolved, this is now over three sigma tension. And the latest measurements seem to confirm this as well. So that these angular anomalies, they are still there. The thing that got everyone really excited is there was a series of measurements

testing this principle of the standard model called lepton universality, which is basically the idea that the forces in the standard model interact with the charged leptons with the same strength. So the leptons are the electron, the muon and the tau, these three charged particles that we find in nature. So what we've been doing is comparing how often one of these rare decays produces electrons and how often it produces muons and comparing the two. And you basically get a ratio and then the standard model that ratio is one.

They happen at the same rate. And what we've been seeing was this ratio, muons over electrons, was actually smaller than one. It was 0.7, 0.8 or so. And the reason this was so exciting is because the devil, again, with these measurements, is often in the theory. And these particles, these quarks, they're quarks, they interact with gluons and QCD is involved. And it's very hard to calculate QCD. So any measurement you make, the theoretical prediction has quite a big uncertainty because it's difficult to calculate. calculate stuff in QCD. But if you take two processes that are basically the same and all you're

doing is flipping an electron for a muon, the QCD bit is the same in both of them and it cancels out. So your theory uncertainty disappears, basically. So your theory is really well known. The theory says this ratio is one, no ifs, no buts. There's no possible effects in the standard model that we could miss. We know this thing must be one. So if it's not one in your experiment, you know damn well that you are seeing new physics or the experiment is wrong. So what we see. saw a series of these measurements of lepton testing lepton universality. My colleagues made several. I made one myself with a student, which came out in 2000, what was it, 2020, 2021 now. And they were all down. They were all below one, all of them. And combined with these

angrier anomalies and also anomalies in the rates of these decay, so basically how often they happened, the theory community got really pretty excited because what they found was all of these different anomalies in different areas of particle physics, there were some other ones as well that actually came from other experiments, Bell and Babar, these B experiments in Japan and the US, you bring all these together and you can introduce a fairly modest extension of the standard model and explain all of them at once without breaking anything else, anywhere else. And what got people really excited is often these theories hinted at some deeper structure beneath the standard model. In other words, there's this mystery, which we still don't have

an answer to, which is in the standard model, the matter particles come in three generations or families they're often called. The first generation is the stuff we're made from, electrons and up and down quarks. Then there are heavier versions, which include the muon and the tau and the top quark and all this kind of stuff. And we don't know why they exist. It's a bit like zoology. We found these things in nature. We arranged them in a table. Or maybe it's more like the periodic table of the elements. Like you see these repeating patterns, but we don't understand where the patterns come from. The way that the patterns in the periodic table are explained by atomic structure. The hope was that these new theories would explain the structure of the standard model in terms of some deeper theory.

And so that's what everyone got very excited about. But then what happened basically was in sort of 2022, my colleagues made another of these lepton universality measurements, reanalyzing some of the same data and got a different answer. And this was basically a clue that once it unraveled that turned out there was a mistake in these lepton universality tests. And so once that was corrected, those sets of anomalies disappeared. and they've basically now gone. But we still are left with these other anomalies,

the other bits of the picture, and they are still there. So we are in this very ambiguous state now where we've really got egg on our faces in some ways. These anomalies that were the ones that were the most promising have disappeared, but these other anomalies that are much more affected by these QCD effects,

but look experimentally much more solid, are still there? And again, it's a bit like the Mue and G-1G-2 situation. It's like, are these remaining anomalies just QCD and we need to understand QCD better? Yeah, it could be an experimental measurement problem we don't think so this time or is it actually still new physics that's the journey we're still on trying to disentangle these things so it's been a it's been a bit of a roller coaster it's a great height of excitement i have to say you're talking about the sort of the way these things are publicized

the actual messaging from the experiment was very cautious we had it was actually made fun of on social media at the time that we had this phrase that we put out which was we're cautiously excited and so we were always like very cognizant of the fact that this could turn out to be nothing but nonetheless when you're in the middle of it and you feel like this could be something really big, you can't help but get a little bit excited. And having been through the disappointment and the embarrassment and I think a lot of people found it very difficult, actually, the unraveling of this. And now being it to pick yourself up and say, okay, we're going to carry on. We've still got these other things to investigate. It's been an interesting lesson in science,

I think for me and my colleagues for sure. And so going back to your previous book, how to make an apple pie from scratch. Shout out to the great Carl Sagan. I got a finger puppet of him was a discussion in that book, which one of my, viewers is asking his name is LV GamerCats, which I recommend to you as a choice for an upcoming child's name, perhaps. A GamerCats makes a great name for a baby. He says, you described how a hypothetical Svaloron might explain the matter-antameter asymmetry that we started off the podcast talking about. Is that still your preferred explanation? Svalorons are, they're not particles, but they are features of the standard model.

And they are basically a kind of like in the standard model, we have these forces, the weak force in particular, which is generated by this thing called the Higgs mechanism. So we have this thing called the Higgs field and we have the W and the Zed fields, which are the force fields of the weak interaction. And a spalloron is kind of a coherent motion of all of these fields moving together in unison in some way. But unlike a particle is like a vibration in one of these fields. You can think of a particle like a ripple on a pond. It's a ripple in one of these fields. So like a photon is a ripple in the electromagnetic field. A sphaleron isn't a vibration in that way.

It's this kind of coherent motion. They come out of the standard model. They're just part of the equations of the standard model essentially. So they're very weird objects. They haven't existed in the universe since the very earliest moments of the Big Bang. You need energy densities and temperatures that existed about a trillionth of a second after the Big Bang to make these Svalorons. But in the very early universe, according to the standard model, they would have been abundant. They would have been a lot of them around.

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turn your big business idea into... Sign up for your $1 per month trial at Shopify.com slash special offer. And they have this very weird ability, unlike anything in the standard model, they can make more particles than antiparticles. So they're kind of these weird machines that you feed particles in and antiparticles come out or vice versa. So in principle, the standard model has this ability to break antimatter asymmetry in the early universe through these sphalerons and through other processes as well. They're almost certainly involved in some way in how matter was made. during the Big Bang. But there are different versions of this story. So the two I talk about in the book, there's one called, this is a terrible terminology, but it's called Electro-Week Barriosgenesis.

So this is basically the production of barons, i.e. protons and neutrons during what's called the Electro-week phase transition. So this is a transition around a trillionth of a second after the Big Bang when the Higgs field switched on for the first time and the forces, as we know them took their current form. And it's a sort of phase transition in much the same way as like water in a kettle boiling is a phase transition. And at this phase transition, in certain models with these phalarons involved, you can make matter over antimatter. The problem is for that to work, you need new physics at the same scales that we're probing at the large Hadron Collider. And we're not seeing it at the moment anyway. So that looks kind of disfavored. Another option, which is probably

more popular, is something called leptogenesis, which is associated with, neutrinos and connected to what we were talking about before with June, this idea that basically the neutrinos have these very heavy partners, sterile neutrinos with very large masses, that you have to go back even further in the history of the universe to find these things. They would have existed at what's called like the grand unified scale. So this is an energy scale just below the plank scale in like, you know, the first tiny fraction of a second. And there are processes there where these leptons, these very heavy leptons decay preferentially to matter

versus antimatter. And then the spallorons can mix everything up. and at the end of it all, you get matter left over. So there are these two rival processes, and there's others as well. The problem is that with bariogenesis, we can test it because the energy scales are what we can probe at the LHC, but we don't find any evidence for it. With leptogenesis, the energy scales are the gut scale, which we can't access experimentally. So it's tricky to say one way or another.

But as to the question about Svalorans, they probably played a role. But what we haven't yet done actually has seen these things in nature, or maybe we can do that in the coming years. That would be cool. As for the new book, I do hope you'll be narrating the audio version yourself. So check plus, you did that. Without giving away any spoilers, what is your gut feel on dark matter? Is it a particle, primordial black hole, or see something like Mond, which he says is cringe-worthy.

I'm a particle physicist, so maybe it's a bit like when you have a hammer, everything looks like a nail. But, I mean, I imagine it's probably a particle because everything we know about is a particle. So it would be surprising if it was something other than that. And we have dark matter particles. They're called neutrinos. Yeah, we do. Exactly. Exactly.

As to what kind of particles, whether they're wimps or axions or something else, I would remain agnostic about that until we have any evidence. I mean, the Wimp paradigm is coming under a lot of pressure from collider experiments, but also from direct detection where, you know, we're pushing really close now to this limit of observation of this neutrino fog where basically you can't tell dark matter apart from neutrinos. they're not very easily. So, I mean, I suspect it's a particle. I'm not, again, I'm not a cosmologist or a gravitation expert, so I'd probably not qualified. But I mean, from what I

understand from people who are experts in these things, the broad view is that Mond is not the right approach. I mean, I found the kind of primordial black holes thing quite intriguing, because it's a neat way of doing it without actually invoking any new physics. You just need, well, you need something in the early universe that can make these primordial black holes. And you need them to survive long enough in the universe to still be dark matter and not have evaporated by Hawking radiation. And I think there is, I don't know, it seems to, when I hear different people, they say different things.

Some people say, oh, there's still a narrow window where these things can have the mass of an asteroid or something and they could be around. We wouldn't have seen them through microlensing or whatever. Other people say, nah, it's not really viable. So, I mean, I'll leave that to the experts, probably. A topic that comes up quite frequently is a notion of what's called blinding, which is not what I think happened to your King Lear many centuries ago. What is blinding? Why is it so important? Not every experiment does this, but it seems to be

quite powerful. So should every experiment be mandated to do a blind analysis? First of all, explain what is a blind analysis? And then how can it help to prevent experimentalists from going blind with their own in love, with their own results? Maybe I'll start with the quotes. I think it's chapter three in the book. I begin with a Feynman quote, which is really close to my heart, which is the first rule is you must not fool yourself and you are the easiest person to fool. So blinding is basically, a way of protecting ourselves from kidding ourselves or fooling ourselves. So the common thing we do in particle physics is you're looking for a new particle. And new particle, like the Higgs boson,

the way it appeared in the experiment was as a bump in a graph. So you plot a graph as a function of energy, you get some little excess, and that little excess is your hint that there's a new particle there. But what you're doing with your data, for example, you're cleaning it, you're purifying it, you're reducing noise. So let's imagine you're looking at that graph continuously, as you're fiddling around with the different things you can do. And by doing certain things, you can move the background down. And you find, oh, a certain setting, I can make that bump a little bit bigger. And what you might actually be doing there is just massaging the data so that some statistical

fluctuation gets enhanced. And then you actually see a mirage that isn't really there. So that's why we blind ourselves. So the idea, basically, it applies in both cosmology and in particle physics and in other areas of science. You prepare all your methods. You decide how you're going to analyze your data. You write your fits, your data selection, all this kind of.

of stuff. That's all frozen. That's all done. You agree everything with some kind of internal review committee usually in a big experiment. And then you freeze everything. And you say, okay, we've tested this to the end of degree. We really believe what we're doing. And then there is this moment where you open the box and you're allowed to look at the result. And you, up until this point, you are blind. You can't look at the result. The result was often scrambled by some cipher. So in muon g minus two, they literally had this number that was written out in an envelope, stored in a safe. And then I won at Fermilab, one sense, so I think the University of Washington in case Fermilap caught fire and burned down and they lost the envelope. And this envelope was

basically the frequency of the experiments clock because you need that to be able to figure out basically how quickly the muon wobbles and therefore how magnetic it is. So they lift with this moment where they plug this cipher in and they see the result appear. And that is good scientific because it stops you biasing yourself unintentionally. But it's also nice from a storytelling point of view because it gives you this moment of reveal where there's this kind of very dramatic opening of the box. But it's very, very common. It's very rare, actually, in the experiment I work on now for us not to blind ourselves. You have to really argue the case why you're not going to blind your analysis if you think that's what you need to do. And then we look through all these experiments from DOM, G-minus 2, even LHCB, bicep, you know, me close to my heart, but disappointing, obviously, reason. Nevertheless, we learn from it. To first approximation, if you were to form a prior, somebody claims some, the prior should be that they're probably wrong, even if the experimental evidence.

seems to be mini-sigma. Dama is what, 20 sigma or something like that by now? How should we approach this as a scientist? We can't be experts in every single field. You know, at what level do we outsource our credulity in something to the sigma, to the confidence levels, or at what level do we really have to dig into, maybe not the data, but into the methodology, the framework that maybe the pedigree of the experimentalist, for example, so that we don't, you know, fall victim to, you know, believing the bicep, the opera, the dama, these anomalies that turn out to be, and for those of you who may be thinking, I'm being too harsh on myself and Harry and our colleagues, I mean, it's much worse in

other fields, legitimate fraud. I mean, big farmer's not going to make much money if there turns out to be G-minus-2 turns out to be significantly deviant from the standard model. So how should, you know, a scientifically-minded, most of my audience is PhDs, masters, bachelor, So how should we look at anomalies when they're announced? Because they're always announced to great fanfare. The Anita announcement was made at one time in the New York Post, which is like the Daily Mail or the mirror in the UK. So how do we react to these things? There's a story in the book when I interviewed Adam Reese, and he talked about this professor that he had when he was a student.

Young students would burst into his office quite often with this. They'd have read about some new experimental result that was showing some anomaly. And the professor would just go, it's wrong. Straight away, it's wrong. go, you know, basically because he was an old wizened guy, he'd been through the works, he's seen how these things come and go. But if you take that attitude, it's really no fun, I think, right? So there's two things in science.

There's the actual acquisition of knowledge. But science is also, it's a spectator sport to an extent. It's fun to follow what's happening. You should be skeptical, for sure. But if you become so skeptical, you just don't listen to anything and you don't engage in the process, then I think that's a bit sad. I think you're missing out on something. But what I would say, I think, in terms of anomalies, I mean, one of the problems that I think

scientists have is often they're not in control of how their results are communicated. So you mentioned Anita. I mean, so Anita saw these weird upward going particles coming out of the Antarctic ice. They were very cautious. They made no claims to what they were. They simply said, we've seen a couple of these events. We can't explain them. We've done what we can to figure out whether there's stuff in the ice that could be causing this. We don't have an explanation. But then that gets taken by some journalists and mangled and turned into this story. As much as they may try and dampen it down, that's kind of out of your control. So I think I would look at who's reporting it. If it's in the New York Post of the Daily Mail, they wouldn't necessarily

be my first port of call for kind of reliable scientific reporting. Maybe go to nature or somewhere like that first and see what they're saying. But sometimes people, I mean, it does happen that scientists overblow their own results. And I think she's reading your book, the story of this big press conference around the Bicep 2 results. And they were pretty upfront about the claims they were making. And they weren't shy about it. And I think that is the sort of difference. That's where you can legitimately criticize scientists, because everyone makes mistakes. I think it's totally, you know, if it's an honest mistake, we made a mistake. And I think what I'm quite proud of at LHCB is we were the ones that discovered

the mistake as well. We found the mistake ourselves and then we put it out there. We didn't try and hide it. We were as upfront as we could be said Mayor Culper. And I think that's hopefully reassuring, if you remember the public, to say, okay, these scientists are harsh on themselves. They're going to fix their own mistakes if they can. Equally, we didn't make any great claims about this. We said it's interesting. It's exciting. Maybe this is something. Maybe it's not. But that's how science works. And I think with the history of science, often the way it's told, it's almost this linear story from ignorance to progress and knowledge. And that's not how it works. There are all these wrong turns, false dawns, but eventually you get there. So there's lots of

bumps in the road. And I think you don't want to miss out on the bumps. That's part of the fun of the journey. Yeah, I would say we teach our students, at least in labs, we teach them. Science proceeds from Nobel Prize to Nobel Prize without loss of enthusiasm. I have one more question for my audience. And then one I'll wrap up with a big picture sweeping question for myself. So this comes from somebody can't tell gender, Katerim, Dow, 43. Anyway, does anything need to change in quantum mechanics to resolve the black hole information paradox? And what do you think is the cause of that problem, that this another anomaly, not really discuss much of the book, but still important to you nonetheless?

God, you're saving the easy ones for last, right? I mean, I mean, I am spectacularly unqualified to talk about the black. whole information paradox. I am an experimental particle physicist. We do not make black holes. I do not know. I'm not going to try and pretend I have an answer to that. And that's what a good scientist should say. So how dare you ask a question? No, that is that's exactly right. So I love it when I get a question. I'm finished talking about Bicep or Simon's Observatory, Inflation, Cosmic Borefringence and Sub. Well, global warming. And what do you think about that? I'm like, look, I hope when you have someone a climatologist talking about her work and you ask them,

about cosmology, they don't answer the question. I hope that they actually punt it to me or one of my colleagues. Okay, last question. You open in the beginning of the book with a wonderful quote from Isaac Asimov about the phrase, that's funny. So talk about what does that phrase, what does it mean to you, that the way that a good scientist should react to anomalies is not to be scared of them at all, right? So how do you interpret Isaac Asimov's favorite statement?

The quote is, the most exciting phrase to hear in science is not Eureka. But that's funny. Science doesn't work by these moments of revelation. You jump out of the bath and you've figured it all out. It's usually you're sitting in the lab or you're staring at some bit of data on a screen and you go, that's not quite right. What's going on there? I remember as a student noticing this with some of the more senior physicist in the experiment where you'd show a graph, some plot of some data. And you think it looked basically fine and boring.

And they go, what's happening over there in the corner? What's that? And you go, I just thought it was nothing. It's probably nothing, right? I don't know, I think you should have a look at that. And then you look into it and you discover, oh, actually there's some effect that we completely missed and we need to take account of.

And that's the kind of the instinct, I think, more experienced or more able scientists have. And we talked about this at the very beginning of the podcast, right? It's the people that have the kind of the instinct to follow those little clues that often make the biggest discoveries, whether that's Penzias and Wilson in their microwave buzz or it's Rutherford and his blurry alpha particles. It's those little strange things that you really need to pay attention to.

It's very rare that discovery reveals itself. in a big flash in the way that maybe we've imagined through the kind of popular tellings of the history of science. Harry, thank you so much for sharing another brilliant book. What's next? Another book in the works? I've got an idea. I'm thinking about a book about nothing, but we'll see how that goes.

I might even try and write a bit of fiction. We'll see. It worked for Seinfeld. And Lawrence Krauss. Harry Cleft, Dr. Harry Cliff. Thank you for joining us. I love talking to you. I'm always so excited when I see a new book.

Everyone should go out and get the new paperback edition or the audio book you actually hear Harry's voice, which adds 10 IQ points. So he's up to 199 at this point by my reckoning. Harry Cliff, good luck with all your endeavors, including a very important one coming up for you and your partner. Love talking to you. And everyone, please check him out. Put links to all of his works, his books, his social media, his LinkedIn, where I follow him as well on here. And Harry, have a great day. Great night.

Thank you for staying up late, by the way. Thanks, Brian. It was a real pleasure talking to you. Great fun. Thank you. As always, thank you so much, my friend. Cheers. Bye then.