Speaker 1: Hey, Daniel, when they operate a big complicated machine like
Speaker 1: the large Hadron Collider, Like, what's the worst that can happen?
Speaker 2: Ooh, other than pressing the wrong button and destroying a
Speaker 2: ten billion dollars science experiment?
Speaker 1: Can it get worse than that?
Speaker 2: I guess you could make a black hole that destroys
Speaker 2: the world.
Speaker 1: And now is that the absolute worst?
Speaker 2: Actually? No, the absolute worst is if the whole thing
Speaker 2: runs perfectly and nothing interesting happens.
Speaker 1: What's wrong with that?
Speaker 2: Well, then we'll have spent like ten billion dollars and
Speaker 2: learn nothing.
Speaker 1: And that's worse than destroying the whole planet.
Speaker 2: Yes, learning nothing is worse. Destroying the planet would be
Speaker 2: a great outcome. We'd learned so much.
Speaker 1: Yeah, we learned not to get physicists ten billion dollars.
Speaker 2: You can make that decision from inside the black hole.
Speaker 1: No, it'd already have been too late. We would learn
Speaker 1: our lesson for a brief second before we all die.
Speaker 3: Hi.
Speaker 1: I'm jorheam a cartoonists and the author of Oliver's Great
Speaker 1: Big Universe.
Speaker 2: Hi, I'm Daniel. I'm a particle physicist at professor at
Speaker 2: UC Irvine, and I'm desperate to discover something before I retire.
Speaker 1: Before you retire, or before you destroy the world.
Speaker 2: One and the same.
Speaker 1: Wait, I thought it would destroy the world. You would
Speaker 1: learn a lot, but then you would be retired.
Speaker 2: Exactly. I want to go out with a bang, learn something,
Speaker 2: and retire all on the same day.
Speaker 1: You know you can do that on your own. You
Speaker 1: don't have to involve the rest of us.
Speaker 2: I'm not so selfish. I want to include everybody.
Speaker 1: It would be preferable if you don't destroy the world
Speaker 1: in your little personal curiosity quest.
Speaker 2: Some people just don't know what they want until they
Speaker 2: get it. Isn't that what Steve Jobs said?
Speaker 1: Well, I definitely know I don't want to die in
Speaker 1: a black hole.
Speaker 2: Waituntil Apple releases a souit per slickt black hole that
Speaker 2: nobody can resist.
Speaker 1: Oh I see is that the new I Die two
Speaker 1: point zero?
Speaker 2: Yes? Better than the Eyehole. I don't know what that's for.
Speaker 1: Yeah, I want neither of those, please, but anyways, Welcome
Speaker 1: to our podcast Daniel and Jorge Explain the Universe, a
Speaker 1: production of iHeartRadio.
Speaker 2: In which we try to widen the gap between the
Speaker 2: moment we understand the universe and the moment we all perish.
Speaker 2: We want everybody out there to understand the nature of
Speaker 2: this crazy, beautiful, bizarre reality, and we want to enjoy
Speaker 2: that understanding as long as possible before our eventual demise.
Speaker 2: We hope that this podcast helps you bridge that gap,
Speaker 2: and until we do gain that final understanding of nature,
Speaker 2: we can fill you in on everything we do and
Speaker 2: do not understand along the way.
Speaker 1: That's right, because it is a mysterious and confounding universe
Speaker 1: full of interesting phenomena that we are still discovering and
Speaker 1: learning about every day. Everyday, scientists are making new discoveries
Speaker 1: about how things work, how they don't work, and what
Speaker 1: is and isn't they.
Speaker 2: And remember that research is exploration. When you think back
Speaker 2: to the story of scientific discovery, it seems like a
Speaker 2: very linear path. We discovered A then B THN, c THN, D, so,
Speaker 2: E and F were obvious right well back in the day,
Speaker 2: they weren't so obvious. There were lots of hints in
Speaker 2: various directions, and the path forward was not clear. Here
Speaker 2: we are on the forefront of human understanding or ignorance,
Speaker 2: and we don't know which direction science will take us.
Speaker 2: We don't know which hint will turn out to unravel
Speaker 2: our entire understanding of the universe, and which will turn
Speaker 2: out to just have been a loose cable.
Speaker 1: And which one will hopefully not destroy the world. I
Speaker 1: mean that's always a good thing, right.
Speaker 2: I mean that's the secondary consideration. But yes, I.
Speaker 1: Think Daniel, each episode you sound more and more like
Speaker 1: a superhero villain.
Speaker 2: I'm working on my mad scientist cackle. I haven't had
Speaker 2: a protect it yet.
Speaker 1: Are they going to make the large hydron collider now
Speaker 1: be activated by like a snap of your fingers. You
Speaker 1: have to put on like a glove and you have
Speaker 1: to snap your fingers to be activated.
Speaker 2: Yeah, is that the plan? Yeah? We hired a whole
Speaker 2: team from Marvel to help us design the interface.
Speaker 1: Oh there you go. So that mean you wear capes
Speaker 1: as well.
Speaker 2: It's a reverse the usual. Often marvels hiring scientists to
Speaker 2: be advisors on their films, but we're actually hiring the
Speaker 2: Marvel folks to tell us how to make our installations
Speaker 2: look super slick.
Speaker 1: I have to make it more exciting for people. What
Speaker 1: would be nice if this podcast made some of that
Speaker 1: Marvel money, You know what I'm saying.
Speaker 2: Yes, that's exactly the plan. This is step one.
Speaker 1: Right now, we're just making DC money, which is not
Speaker 1: a lot.
Speaker 2: But particle physics isn't all about the Benjamins. It's about
Speaker 2: the discoveries. It's about those moments when you force the
Speaker 2: universe to reveal the way it actually works. And the
Speaker 2: most delicious moments are the ones when we understand the
Speaker 2: universe is quite different from how we expected it.
Speaker 1: Yes, you said, science is all about exploration and following
Speaker 1: ideas and maybe promising directions, and sometimes you discover that
Speaker 1: things don't quite work the way you thought.
Speaker 2: Sometimes those discoveries are clear and dramatic, like when we
Speaker 2: found the Higgs boson, and everybody can see the very,
Speaker 2: very persuasive peak in our data. Sometimes, though, the discoveries
Speaker 2: begin with little hints, little things in our data that
Speaker 2: don't quite make sense, little clues that maybe some big
Speaker 2: discovery is just over the horizon.
Speaker 1: Yeah, although sometimes it seems like the horizon is getting
Speaker 1: farther and farther away. I mean, when was the Higgs
Speaker 1: boson discovered? It was a while though, right over ten years?
Speaker 2: Yeah, twenty twelve.
Speaker 1: Wow, time flies. That was a huge discovery. The whole
Speaker 1: world got very excited about that. But since then, there
Speaker 1: haven't been any new, big discoveries from the big collider there, right.
Speaker 2: Yeah, that's right, because research is exploration. We didn't know
Speaker 2: if there were tons and tons of new particles waiting
Speaker 2: for us around the corner, or if it was mostly
Speaker 2: just dust and rubble to be discovered. And the new
Speaker 2: particles are around more and more corners, if they even exist.
Speaker 2: That's the joy and disappointment of exploration.
Speaker 1: So how's all that dust and rubble looking dusty and rubbing?
Speaker 2: It gets hard to choke it down after a while,
Speaker 2: I'll be honest.
Speaker 1: Yeah, it's hard to swallow dust and rubble.
Speaker 2: I mean, you always prefer to make exciting discoveries. When
Speaker 2: they landed the rovers on Mars, I'm sure they were
Speaker 2: hoping to find little squishy creatures under some of those rocks.
Speaker 2: But you know, they've also just found dust and rubble.
Speaker 2: Doesn't mean we're not going to keep looking.
Speaker 1: But as you mentioned, science is about exploration, and so
Speaker 1: right now, even though you've only found dust and rubble
Speaker 1: for the last twelve years, there are maybe interesting things
Speaker 1: that you've discovered or noticed about the universe that maybe
Speaker 1: give you some excitement about continuing to explore.
Speaker 2: That's right, because before we make a big discovery, we
Speaker 2: often have hints that point us in that direction. Before
Speaker 2: we've discovered how neutrinos can change from one kind into another,
Speaker 2: we saw weird things in our measurements of neutrinos in
Speaker 2: the sky. So particle physicists are always on the lookout
Speaker 2: for the next anomaly, the next discrepancy, the next thing
Speaker 2: we don't understand, because it might be a hint for
Speaker 2: the next big discovery.
Speaker 1: So to be on the program, we'll be tagling the
Speaker 1: question what are the most promising particle physics anomalies?
Speaker 4: Now?
Speaker 1: These are anomalies, right, not anemonies anominees.
Speaker 2: These are not our enemies either.
Speaker 1: Yeah, and we're not going to do this anonymously.
Speaker 2: That's right, or according to memory?
Speaker 1: Okay, you push the grammar there too far. I'm not
Speaker 1: sure what the connection there.
Speaker 2: Is anomalies and memories homomonies. My momides, I don't know.
Speaker 1: Yeah, yeah, I think I think we've finished this upun
Speaker 1: thread here.
Speaker 2: The thing about anomalies is that they're indirect. They're just
Speaker 2: something we don't understand about our data. So explanations could
Speaker 2: be wow, something super exciting we're about to discover, or
Speaker 2: it could be. Oops, turns out we didn't calibrate things correctly.
Speaker 1: So what's the picture here? You're assorting third data, you're
Speaker 1: finding mostly dust and rubble, but sometimes in the dust
Speaker 1: and rubble you're like, maybe there's a little bit of
Speaker 1: rubble here. Looks a little bit different than it should look.
Speaker 2: Like, Yeah, exactly. It's a promising sign that maybe there's
Speaker 2: something exciting there, but you need more data. It's sort
Speaker 2: of like pictures of UFOs, like, oh, that would be
Speaker 2: exciting if it really is a UFO, but the pictures
Speaker 2: too fuzzy to really know. What you got to do
Speaker 2: is get more data, crisper photos, more sensor information, something
Speaker 2: like that.
Speaker 1: Oh boy, did you just compare particle physics to UFO spotting?
Speaker 2: Yes, absolutely, enthusiastically.
Speaker 1: An area fifty two is cern area fifty two for
Speaker 1: the big Large Hadron collider conspiracy.
Speaker 2: I may or may not have signed an NDA prohibiting
Speaker 2: me from answering that.
Speaker 1: Question, prohibiting you from having a podcast where you talk about.
Speaker 2: It for hours and hours, maybe or maybe not. I
Speaker 2: think theas it's probably no. It sounds like no, no comment.
Speaker 2: The other thing about anomalies is that sometimes they go away.
Speaker 2: You know, all of our data is statistical. We can
Speaker 2: never tell from one collision to the next whether there
Speaker 2: was a new particle or a Higgs boson or just
Speaker 2: something boring like protons glancing off of each other, and
Speaker 2: so all of our data is statistical, which means there
Speaker 2: are always little random wobbles. Sometimes those random wobbles can
Speaker 2: look like a new particle or a UFO, and then
Speaker 2: we gather more data and they just go away.
Speaker 1: Well, as usually, we were wondering how many people out
Speaker 1: there had thought about particle physics anomalies and what they
Speaker 1: might mean, or which ones are the most promising.
Speaker 2: Thanks very much to everybody who answers questions for the
Speaker 2: audience participation segment of the podcast. We'd love to hear
Speaker 2: your voice on the pod. Write me to Questions at
Speaker 2: Danielandhorgney dot com to sign up. So think about it
Speaker 2: for a second. What do you think are the most
Speaker 2: promising particle physics anomalies? Not aneminees, here's what people have
Speaker 2: to say.
Speaker 5: I don't think it's possible to have an unexplained result
Speaker 5: in a particle physics experiment because the theoretical physicists set
Speaker 5: it all up and tell the experimental physicists where to
Speaker 5: find it. So don't think it's going to be a particle.
Speaker 5: I'm just wondering if maybe that bit where general relativity
Speaker 5: does and quite fit quantum theory. What if, say Isaac
Speaker 5: Newton was right all along and it is all about gravity,
Speaker 5: and you've just left gravity out of the formulae and
Speaker 5: the calculations because you don't think it's big enough. But
Speaker 5: what if that proves Albert Einstein was wrong when he
Speaker 5: said that Newton was not wrong but limited. He rewrote Newton.
Speaker 5: What if Newton gets his revenge and Einstein's wrong? That
Speaker 5: might make the nine o'clock news.
Speaker 6: The only thing that comes to mind is the very
Speaker 6: high energy cosmic rays that strike the upper atmosphere and
Speaker 6: result in a shower of particles, some of which reach
Speaker 6: the ground, and that baseball energy particle is coming from
Speaker 6: a blazer.
Speaker 3: I'm not aware of any specific unexplained particle experiment results,
Speaker 3: but I guess in general terms the issue for particle
Speaker 3: physicists to work through there would be is this unexpected
Speaker 3: result something that can be explained by things that physicists
Speaker 3: are generally already aware of, or is it something new
Speaker 3: that they've discovered.
Speaker 5: Well, I don't know that many experiments, but maybe the
Speaker 5: penguin diagram and then has a cool name too.
Speaker 7: I don't know much about particles experiment results and what
Speaker 7: might be a real discovery, But if you could find
Speaker 7: a way to entangle my son's socks in the laundry
Speaker 7: so that when I find one, I always know where
Speaker 7: the other one is, that would be really helpful.
Speaker 1: Thanks byy.
Speaker 4: I'm only aware of one unexplained particle result. It was
Speaker 4: something to do with muons, either missing muons or many muons,
Speaker 4: and either way, I'm hopeful that it spurs a discovery
Speaker 4: of something smaller or some behavior that we're not expecting,
Speaker 4: because that always opens up new questions and new avenues
Speaker 4: for learning.
Speaker 8: Guessing something like doc motel particle or a graviton something
Speaker 8: of that nature. Other than not no idea.
Speaker 1: Well, like asked that before answering that I would need
Speaker 1: to learn what are the unexplained particle experiment results that
Speaker 1: have been generated?
Speaker 2: Please walk me through.
Speaker 1: That, all right? Mostly clear, I've known you what you're
Speaker 1: talking about.
Speaker 2: That surprised me a little bit because particle physics anomalies
Speaker 2: are often in the news and they're often like way overhyped.
Speaker 2: I get emails from listeners asking me about some news
Speaker 2: story that says that we're on the brink of a
Speaker 2: complete revolution in particle physics because of some weird lips
Speaker 2: somebody saw on their computer screen.
Speaker 1: I guess it depends where you're getting your news. Is
Speaker 1: it from the UFO newsletter? There?
Speaker 2: No, you see this stuff covered in pretty mainstream press.
Speaker 2: Sometimes the scientists are excited about their little anomaly and
Speaker 2: they tell the PR people, and then by the time
Speaker 2: it gets to science dot org they've transformed it into clear.
Speaker 1: Well, didn't sound like any of our listeners here that
Speaker 1: recorded their answer new of any physics anomaly, So maybe
Speaker 1: the question should have been, do you know of any
Speaker 1: particle physics anomalies?
Speaker 2: We have covered a few on the podcast because there
Speaker 2: are a few out there, a few areas where we
Speaker 2: might be on the verge of discovering something new or
Speaker 2: it could just go away when we gather more data.
Speaker 1: M All right, well, let's jump into the subject. Daniel,
Speaker 1: what do you describe as an anomaly? How do you
Speaker 1: know if something is anomalous?
Speaker 2: Something is an anomaly if it's a deviation from what
Speaker 2: we expect, and what we expect usually is disappointment. So
Speaker 2: we have a theory of particles, the standard model, that
Speaker 2: has a bunch of particles in it and a bunch
Speaker 2: of forces in it, and we can use that to
Speaker 2: predict what we would see in experiments. So, for example,
Speaker 2: if we smash protons together, the standard model tells us
Speaker 2: how often they'll bounce off at this angle, how often
Speaker 2: they'll bounce off at that angle, how often they'll make
Speaker 2: a Z boson or a W boson or a top quark.
Speaker 2: And we do a bunch of measurements and then we
Speaker 2: compare them to the predictions from our theory. And when
Speaker 2: things are bang on that's not anomalousts. And when there's
Speaker 2: any difference there, when what we see in our experiments
Speaker 2: collisions or cosmic rays or other kinds of experiments is
Speaker 2: different from what the theory predicted, that tells us that
Speaker 2: maybe there's something new going on, there's something happening in
Speaker 2: the universe that's not captured by our theory.
Speaker 1: Well, I guess it's a sort of an interesting dance
Speaker 1: between theory and experiment. Like, for example, if something is
Speaker 1: a theory and you expect it to be why did
Speaker 1: you expect it to be if you didn't prove it
Speaker 1: already before, or is this about extending the theory to
Speaker 1: new phenomenon or to new situations.
Speaker 2: Yeah, exactly, it's about extending the theory. Like the theory
Speaker 2: may have worked well for all previous experiments, but now
Speaker 2: we're in new territory. That's what we mean by exploration.
Speaker 2: When you turn a collider on it new energies, for example,
Speaker 2: you're creating conditions you haven't seen before. So maybe your
Speaker 2: theory is going to break down. Maybe there's a new
Speaker 2: particle that's going to be revealed that you need to
Speaker 2: then incorporate into your theory. Maybe there's a new force
Speaker 2: that's so weak you haven't seen it before, but at
Speaker 2: very high energies it reveals itself. That's why we do
Speaker 2: these experiments, hoping to force the universe to tell us
Speaker 2: how things work.
Speaker 1: I guess that's why in science you just call everything
Speaker 1: a theory, right, because you always leave yourself open to
Speaker 1: the possibility that your theory is wrong. The more you
Speaker 1: explore the universe or the more different situations you go
Speaker 1: out during test.
Speaker 2: Yeah, exactly. The point of the standard model is not
Speaker 2: to say this is definitive. This is how the universe works.
Speaker 2: It's a working project. It describes everything we know so far.
Speaker 2: It's like our current hypothesis. But we're always hoping to
Speaker 2: update it.
Speaker 1: Right, right, And that's why you called it the standard model,
Speaker 1: unequivocally the way things are. That's why you called it that, right, That's.
Speaker 2: Why I called it that. Yeah, it was named in
Speaker 2: a paper that came out a few years before I
Speaker 2: was born. But I'll totally take the blame for it
Speaker 2: being called the standard model.
Speaker 1: Well, you're continuing to use it that you're complicit.
Speaker 2: I think I heard you say it. Also, are you complicit?
Speaker 1: How I said it?
Speaker 2: You just called it the standard model, although derisively of course.
Speaker 1: I said, that's why you call it this standard model.
Speaker 2: Anyway, it's a standard model, but it's also changed over time.
Speaker 7: Right.
Speaker 2: We added neutrino masses to the standard model. So there's
Speaker 2: actually a big argument about what exactly is the standard model,
Speaker 2: which means it's not exactly standard. But the point is
Speaker 2: that we have a theory, we're developing it, we're testing
Speaker 2: it by doing these experiments, either by pushing to new
Speaker 2: energies or by looking out in space or creating conditions
Speaker 2: we've never explored before. We're hoping that one of those
Speaker 2: has an anomaly, a discrepancy from our prediction that shows
Speaker 2: us that there's something new in the universe that we
Speaker 2: need to describe with our theory.
Speaker 1: And this generally falls into sort of the different ways
Speaker 1: that you discover something, not just in signs, but in
Speaker 1: particular in particle physics. You can either look for things
Speaker 1: directly or indirectly, right.
Speaker 2: Yeah, the direct way is the most convincing and the
Speaker 2: most exciting. Like if you can actually create this new
Speaker 2: particle so it exists in the universe in your experiment,
Speaker 2: then you can sort of see it. I mean, we
Speaker 2: never actually see these things very directly, but we can
Speaker 2: see evidence of it. It was there, It left traces
Speaker 2: of the particles that decayed into That's how we discover
Speaker 2: the Higgs boson. That's how we discovered the top quark.
Speaker 2: We have a bunch of episodes about the discovery of
Speaker 2: each of these particles that tells you the story about
Speaker 2: how it was seeing, how it became convinced that it
Speaker 2: was there.
Speaker 1: Meaning like you think that it's there in a particular spot,
Speaker 1: you go look for it there in that spot and
Speaker 1: then you find it yeah, or.
Speaker 2: We're not sure exactly. We say it's somewhere in this
Speaker 2: territory and then we look around and we find it
Speaker 2: within that range. Like the Higgs boson, we didn't know
Speaker 2: in advance how heavy it would be, how much mass
Speaker 2: it had. There was a huge range of ideas, so
Speaker 2: we had to go out and scan that whole range.
Speaker 2: But we found it in that range and we were
Speaker 2: able to measure it, and that's what we call it
Speaker 2: direct measurement, even though some parts of those measurements, of
Speaker 2: course are indirect.
Speaker 1: So then what is indirect discovery?
Speaker 2: So the distinction between a direct discovery and indirect is
Speaker 2: a little bit fuzzy because you know everything is in
Speaker 2: the end indirect, but some measurements are more indirect than others. Like,
Speaker 2: for example, if you don't have enough energy to actually
Speaker 2: create the particle to exist in your experiment, but you
Speaker 2: can still interact with the fields that are out there
Speaker 2: that could make that particle, then that's more indirect because
Speaker 2: you're never actually creating the particle, but the fields themselves
Speaker 2: can still influence your experiment, Like if your protons interact
Speaker 2: with those fields and it changes how they behave. Then
Speaker 2: you don't see those fields directly, but you see the
Speaker 2: influence of the fields on the particles that you are studying.
Speaker 1: That's not indirect man, Like you're not looking for it,
Speaker 1: but you see some anomaly, which is sort of the
Speaker 1: topic of our discussion here.
Speaker 2: Yeah, that's exactly right. But we use these indirect measurements
Speaker 2: as a way to like catch some new thing, something
Speaker 2: we're not looking for. Like, very very precise measurements of
Speaker 2: the particles we do know can sometimes reveal anomalies, which
Speaker 2: are clues that there's something out there influencing those particles.
Speaker 2: So that's why we sometimes make very very precise measurements
Speaker 2: of the particles we already know about, so we can
Speaker 2: look for little deviations that would tell us there's something
Speaker 2: there we weren't looking for directly.
Speaker 1: So for example, like we've discovered the Higgs boson and
Speaker 1: we sort of know where to find and what looks
Speaker 1: like and how it comes out. But maybe if you
Speaker 1: generate a whole bunch of Higgs bosons at one after
Speaker 1: the other, maybe in doing that you can discover something
Speaker 1: weird that happens that you didn't think about before, that
Speaker 1: happens related to the Higgs boson.
Speaker 2: And that's exactly what we're doing right now. We discovered
Speaker 2: the Higgs boson ten years ago, and since then we've
Speaker 2: made huge numbers of them, piles and piles of Higgs bosons.
Speaker 2: We've been studying them, looking for anomalies, looking to see
Speaker 2: if the Higgs boson behaves in any weird new ways,
Speaker 2: because if it does, we'll need some other element of
Speaker 2: our theory to explain that. It will be a hint
Speaker 2: that there's something else beyond the Higgs boson for us
Speaker 2: to discover.
Speaker 1: Like instead of digging a hole in the field looking
Speaker 1: for something, you're maybe looking closer at the rock until
Speaker 1: you discover something that maybe you didn't.
Speaker 2: Expect, yeah, exactly. Or if you're looking for like weird
Speaker 2: new animals in the forest, like you suspect maybe Bigfoot
Speaker 2: is out there, you don't know how to look for
Speaker 2: big Foot directly, then you can look for other signs,
Speaker 2: you know, you like, look to see if there's any
Speaker 2: weird scratches on all the tra or if any neighborhood
Speaker 2: pets are missing, you like, make measurements of the things
Speaker 2: that you can to look for weirdness, any deviation from
Speaker 2: the ways trees and pets normally behave would give you
Speaker 2: a clue that there's something out there in the forest
Speaker 2: to discover.
Speaker 1: Like you would study maybe cats and pay attention to cats,
Speaker 1: and you think, well, if there's no bigfoot, then cats
Speaker 1: should behave this way. And if you find that cats,
Speaker 1: you know, avoid a certain area of forest for example,
Speaker 1: or get really skittish if you put on a gorilla
Speaker 1: suit or something, then you know, oh, maybe there's some
Speaker 1: evidence here or an anomaly that tells you maybe there's
Speaker 1: a bigfoot exactly.
Speaker 2: And the tricky thing there is that there could be
Speaker 2: multiple explanations. Your cats could be scared of you in
Speaker 2: a goerrilla costume because there's a big foot in the forest,
Speaker 2: or just because you look scary in a gorilla costume.
Speaker 2: So the thing about indirect measurements is that they can
Speaker 2: give you a hint of for lots of new things,
Speaker 2: but also they're frustratingly indirect.
Speaker 1: Yeah, if only you could just ask the cats, right,
Speaker 1: All right, Well, let's get into what are some famous
Speaker 1: anomalies that have led to this discoveries in science, and
Speaker 1: then let's get to the most exciting and promising ones
Speaker 1: in physics today. We'll dig into that, but first let's
Speaker 1: take a quick break.
Speaker 2: All right.
Speaker 1: We're talking about the most promising particle physics anomalies, the
Speaker 1: weirdest things out there that might point to the most
Speaker 1: exciting new discoveries in the future. And we've talked about
Speaker 1: what an anomaly is, Daniel. What are some examples of
Speaker 1: anomalies and physics that have led to very interesting discoveries.
Speaker 2: Well, one of the most famous, of course, is the
Speaker 2: measurement of how galaxies rotate. People thought they understood how
Speaker 2: galaxy spun and how much mass there was in a galaxy,
Speaker 2: and they went out there to check to say, hey,
Speaker 2: are stars rotating at the speeds we expect around the
Speaker 2: center of galaxies? And it turns out they weren't. They
Speaker 2: were rotating much much faster than people expected, and that
Speaker 2: was an anomaly. It was a discrepancy from what people
Speaker 2: predicted and expected. And to explain that, of course, is
Speaker 2: the whole idea of dark matter still to be resolved
Speaker 2: and understood in detail at the particle level. But maybe
Speaker 2: one of the biggest anomalies we've ever seen in physics.
Speaker 1: Mmm. And wasn't that done by a grad student or
Speaker 1: something like it's some lowly gratudent and good assign the
Speaker 1: task of like, yeah, I just check the galaxy rotations
Speaker 1: and then that gratsuand was like, wait a minute.
Speaker 2: There's some hints early on in the century from France
Speaker 2: Swiki and then Vera Rubin really did the most detailed
Speaker 2: analysis of galactic rotation curves, so she gets most of
Speaker 2: the credit, although she was overlooked for the Nobel Prize.
Speaker 2: Of course, what not a great track record on the
Speaker 2: Nobel Prize for assigning credit to women.
Speaker 1: M And that trying to be a huge discovery, right,
Speaker 1: I mean we found that there's five times more dark
Speaker 1: matter then there's regular matter in the universe. I mean
Speaker 1: it's like five times everything that we know about that exists.
Speaker 2: Yeah, exactly. And this is why we go out and
Speaker 2: make really precise measurements of things we think we already understand,
Speaker 2: because they can reveal things hiding under the surface, things
Speaker 2: waiting to be discovered.
Speaker 1: Mmmm. What's another famous anomaly.
Speaker 2: Well, people tried to understand how many neutrinos are coming
Speaker 2: to Earth. So they built a big detector underground to
Speaker 2: measure the rate of neutrinos, and they compared that to
Speaker 2: their prediction for how many neutrinos are being made by
Speaker 2: the Sun and how many should arrive on Earth. And
Speaker 2: they discovered they were seeing way fewer neutrinos than they expected,
Speaker 2: and for decades people didn't understand this. Then it turns
Speaker 2: out that's because neutrinos can change their type as they
Speaker 2: fly between the Sun and here if electron neutrinos can
Speaker 2: turn into mew on neutrinos and town neutrinos, which those
Speaker 2: detectors were not spotting. That was a huge discovery which
Speaker 2: started from an anomaly. Mmm.
Speaker 1: And did that person get credit?
Speaker 2: Those guys won the Nobel Prize? Yes, old white dudes
Speaker 2: always get credit.
Speaker 1: Emphasis und the word guys.
Speaker 7: Yes.
Speaker 1: Funny how that worried? All right, Well, let's pivot now
Speaker 1: to maybe some of them was current exciting anomalies. What
Speaker 1: are some of the things that scientists have found and
Speaker 1: make them go huh.
Speaker 2: There's a bunch of stuff going on that we don't understand.
Speaker 2: There are weird particles we see in cosmic rays from space.
Speaker 2: There are bizarre things going on with muons and their
Speaker 2: magnetic moments. There's all sorts of confusion about how the
Speaker 2: universe is expanding, there's always like five or ten of
Speaker 2: these things going on. Sometimes they fade away as we
Speaker 2: get more data, but some of these have persisted for
Speaker 2: a few years.
Speaker 1: Well, to take a deeper dive into this topic of
Speaker 1: anomalies and audities out there in space, Daniel, you talked
Speaker 1: to another particle physicists.
Speaker 2: That's right. I had a lot of fun talking with
Speaker 2: Harry Cliff. He's a particle physicist who works on a
Speaker 2: different experiment at the Large Hadron Collider. It's called LHCb
Speaker 2: B for studying bottom quarks, though he prefers to call
Speaker 2: them beauty quarks. And he just came out with a
Speaker 2: new book called Space Oddities, which is a really accessible
Speaker 2: and fun tour through some of these anomalies in particle physics.
Speaker 1: Isn't that the title is like a David Bowie song
Speaker 1: or something.
Speaker 2: Not an expert, but I hope he's publishing. How it's
Speaker 2: cleared the rights?
Speaker 1: Yeah, otherwise you're going to have an anomal lawsuit there.
Speaker 1: All right, Well, here is Daniel's conversation with particle physicist
Speaker 1: Harry Cliff.
Speaker 2: Okay, so then it's my great pleasure to welcome to
Speaker 2: the podcast, doctor Harry Cliff, He's a colleague of mine
Speaker 2: and also the author of the new book Space Oddities,
Speaker 2: an excellent and fun exploration of a bunch of really
Speaker 2: weird stuff we see in particle physics right now, Harry,
Speaker 2: thanks very much for joining us today.
Speaker 9: Well, thanks for having on the podcast.
Speaker 2: Yeah, well, I really enjoyed reading your book. I love
Speaker 2: thinking about all the weird stuff that we're seeing and
Speaker 2: all the funky stuff on the horizons of the frontiers
Speaker 2: of physics, in the things that might lead to the
Speaker 2: next big breakthrough. Tell me what exactly inspired you to
Speaker 2: write this book right now?
Speaker 9: The idea really came out of my own research.
Speaker 10: So I work, like you on the Large Hadron Collider,
Speaker 10: this big particle accelerator outside Geneva. So I work on
Speaker 10: an experiment called LHCb, which is one of the four
Speaker 10: main detectors spased around the ring. And the B in
Speaker 10: LHCb stands for Beauty, which is the name of one
Speaker 10: of the quarks. So these six fundamental particles, two of
Speaker 10: which make up nuclear material in ordinary atoms, and the
Speaker 10: Bee quark is the heaviest negatively charged quark. It is
Speaker 10: the fifth heaviest overall, so it's quite an exotic thing.
Speaker 2: Let me just interrupt you to orient our listeners because
Speaker 2: on the podcast we often refer to this as the
Speaker 2: bottom quirk, but you're calling it the beauty quirk. Is
Speaker 2: that just because you don't like saying the word bottom
Speaker 2: in your research?
Speaker 10: I think so that the history of this is that
Speaker 10: when the B and the T quarks were proposed, there
Speaker 10: were some people that tried to call them beauty and truth,
Speaker 10: and I think this was sort of to mirror charm and.
Speaker 9: Strange, which are the two second generation quarks.
Speaker 10: But physicists, I think Broady decided that was a bit
Speaker 10: too poetic, so they plumped for the more prosaic top
Speaker 10: and bottom.
Speaker 9: So most physicists call them top and bottom. But there's
Speaker 9: this weird.
Speaker 10: Thing in what we call flavor physics that we prefer
Speaker 10: to be known as beauty physicists and bottom physicists. So
Speaker 10: for us it's beauty, but yeah, most other physicists call
Speaker 10: it the bottom cork.
Speaker 9: But they are the same.
Speaker 2: Thing, right, because I did my PhD on the top quirk,
Speaker 2: and we had no issues calling ourselves top quark physicists
Speaker 2: or top physicists. But I can see how bottom physicis.
Speaker 9: Les positive yeah.
Speaker 2: Anyway, so you were working on the beauty quarks and
Speaker 2: you saw some weird stuff tell us.
Speaker 10: Yeah, So these quarks are really interesting to study because
Speaker 10: they're very heavy. They can decay to a very wide
Speaker 10: range of different standard model particles. So when they're created,
Speaker 10: they live for a really tiny fraction of a second,
Speaker 10: about one and a half trillions of a second. That's
Speaker 10: long enough them to fly a little distance in your
Speaker 10: detector because they're going at the speed of light, and
Speaker 10: then they decay, and there are certain very rare decay
Speaker 10: modes of these quarks. So basically that means that let's
Speaker 10: say you had a million of these beauty quarks created
Speaker 10: in your experiment, only around one of them would decay.
Speaker 9: In one of these very rare ways.
Speaker 10: And these rare decays are very interesting because basically, in
Speaker 10: our current theory of particle physics, the way these decays
Speaker 10: happen involves lots of complicated interactions of heavy particles, which
Speaker 10: makes them very suppressed. But if there is say a
Speaker 10: new force of nature that exists, which may be very weak,
Speaker 10: it can actually contribute to this decay process, and it
Speaker 10: can alter the measured properties of these decay so it
Speaker 10: might change, for example, how often the decays happen. It
Speaker 10: might change the angles the particles that come out of
Speaker 10: these beauty cork decays emerge at. So the basic game
Speaker 10: we play is you make very very precise measurements of
Speaker 10: these beautyquark decays. You compare them to hopefully a precise
Speaker 10: theoretical prediction using the standard model of particle physics, and
Speaker 10: if you see a difference, that can be an indirect
Speaker 10: clue that something new, something beyond our current understanding, is
Speaker 10: altering these decays, and that kind of gives you an
Speaker 10: inkling to the existence of, say a new force or
Speaker 10: some new heavy particle that we haven't seen before. So
Speaker 10: that's the sort of general the game we play lh
Speaker 10: to be broadly speaking, And for the last ten years,
Speaker 10: starting in about twenty fourteen, we've been seeing these anomalies
Speaker 10: in these very rare decays, so basically measurements that weren't
Speaker 10: lining up with the prediction of the standard model, and
Speaker 10: in some cases these were how often these decays was
Speaker 10: happening was different from what was predicted. Sometimes it was
Speaker 10: the angles. And what was intriguing about this is over time,
Speaker 10: more and more of these anomalies emerged, and they seem
Speaker 10: to paint a coherent picture. So it looked like these
Speaker 10: were all coming from some new fundamental interactions. So the
Speaker 10: most common explanations involved, broadly speaking, some kind of new force,
Speaker 10: and that got theorists very, very excited, and there was
Speaker 10: a lot of theoretical work pursuing this, and then a
Speaker 10: lot of experimental work. So I kind of came into
Speaker 10: this area, I suppose about a year after this picture
Speaker 10: started to emerge in twenty fifteen, and spent several years
Speaker 10: of my career making other measurements that might give us
Speaker 10: some more clues as to what was going on. So
Speaker 10: that was really how I got interested in the whole
Speaker 10: subject of anomalies and the way that anomalies can sometimes
Speaker 10: lead us to a big breakthrough in our understanding of
Speaker 10: the universe.
Speaker 9: And that's what the book Space obviously is about.
Speaker 10: It's essentially about, you know, how anomalies shape physics and
Speaker 10: cosmology through history, and focusing on five particularly big anomalies
Speaker 10: that have been doing the rounds in physics and cosmology
Speaker 10: in the last decade or so.
Speaker 2: And when you're working on an anomaly at that when
Speaker 2: you see something you don't understand tell us about what
Speaker 2: that's like. I mean, you're on the forefront of knowledge.
Speaker 2: You're like potentially standing, you know, one step away from
Speaker 2: some big revolution in our understanding. When you were working
Speaker 2: on that, you have that sense of like this could
Speaker 2: be historic. You know that we could be writing books
Speaker 2: about these discoveries in twenty years. We could be telling
Speaker 2: people about them, you know the way. I think like
Speaker 2: we pour over Einstein's notebooks now and you know, sort
Speaker 2: of stand over his shoulder. I wonder for the people
Speaker 2: making discoveries if they sort of like feel like the
Speaker 2: ghosts of the future paying attention to the sandwich they
Speaker 2: had that day in this Smithsonian. You know, like, was
Speaker 2: there that moment of excitement for you when you're working
Speaker 2: on this and you didn't yet know how it came out?
Speaker 2: Because across the ring we were all very excited. We
Speaker 2: were like waiting with bated breath to see if this
Speaker 2: was real.
Speaker 1: Yeah.
Speaker 10: I mean, there were several moments that are really exciting.
Speaker 10: There was one in Mark twenty twenty one when some
Speaker 10: of my colleagues who are working on one of these
Speaker 10: anomalies updated their measurement with using all the data that
Speaker 10: we'd recorded at LHCb up to that point, and I
Speaker 10: wasn't directly involved in the analysis, but I was a
Speaker 10: sort of inside observer, I suppose watching this whole process,
Speaker 10: and there was this really exciting moment where they what
Speaker 10: you call unblinded their data. So this is common practice
Speaker 10: in physics nowadays, which is that you perform your analysis
Speaker 10: blind in the sense that you can't look at the
Speaker 10: result until you've completely fixed your analysis procedure, you've done
Speaker 10: all your systematic studies, basically all the remains in the paper.
Speaker 10: Is essentially to put in the answer at the end,
Speaker 10: and the idea of doing this is you prevent yourself
Speaker 10: from biasing yourself or massaging the results one way or another,
Speaker 10: subconsciously or consciously. As a result of this, you have
Speaker 10: this moment where the result gets unscrambled and you see
Speaker 10: for the first time, you know what is actually happening here.
Speaker 10: And when that result was revealed in March twenty one,
Speaker 10: this anomaly had grown beyond this slightly arbitrary threshold known
Speaker 10: as three sigma, which is essentially where the experimental measurement
Speaker 10: is more than three standard deviations or three uncertainties away
Speaker 10: from your theory prediction and that is for some reason,
Speaker 10: conventionally in physics regarded as evidence. So at this point
Speaker 10: there's a sort of one in a few hundred chance
Speaker 10: that this would be a sort of random statistical fluke.
Speaker 10: It starts to look more convince more compelling as a
Speaker 10: real sign of new physics. So that was a really
Speaker 10: exciting moment, and you had this sense particularly that period
Speaker 10: in early twenty one. You had this result from LHCb,
Speaker 10: and then about a month later, another anomaly was confirmed
Speaker 10: by an experiment at Fermilab who were looking at the
Speaker 10: magnetism of a party called a muon, and that again
Speaker 10: sort of perhaps was interpreted as being evidence of some
Speaker 10: new force. So you had these kind of compiling results
Speaker 10: that were sort of suggesting that we were on the
Speaker 10: brink or something really exciting. And personally, I mean, my
Speaker 10: moment came a little bit later, and you know, all
Speaker 10: these measurements are sort of small contributions to an overall pitchure.
Speaker 10: There isn't like one moment where you go, you know,
Speaker 10: we've discovered something. And while I was working on a
Speaker 10: set of measurements with a student, they were less sensitive
Speaker 10: than the big one that came out in March, but Nonetheless,
Speaker 10: it was sort of we had this moment where we're
Speaker 10: on This was during sort of COVID time, so we
Speaker 10: weren't together, we were on zoom. We unblinded our measurements,
Speaker 10: and again our measurements lined up with the anomalies that
Speaker 10: everyone else had been seeing. So there was a real
Speaker 10: sense then of like, wow, you know, maybe there's something
Speaker 10: really going on here. So yeah, it was a very
Speaker 10: very exciting time, and you did feel like you were
Speaker 10: in amongst a.
Speaker 9: Process that could turn into something really big.
Speaker 2: Yeah, and this is sort of like the joy and
Speaker 2: the frustration of some of these precision measurements. Right, you're
Speaker 2: looking for something weird, something different, something that's not predicted
Speaker 2: by your theory, and you're sensitive to a whole broad
Speaker 2: range of stuff. But because you're sensitive to a whole
Speaker 2: broad range of stuff, it could be anything, right. It
Speaker 2: could be new particles, it could be new forces. It
Speaker 2: could also be like, wow, your cable wasn't plugged in correctly,
Speaker 2: And so that's you know, as you say in your book,
Speaker 2: the unglamorous work of measuring some quantity or another to
Speaker 2: increasing number of decimal places can seem like a nerdy obsession.
Speaker 2: But this is also the kind of work that can
Speaker 2: really lead to exciting discoveries.
Speaker 9: Yeah, it can, but you always have to be really careful.
Speaker 10: And I think more often than not, when you get
Speaker 10: an anomaly like this, I mean, there's usually sort of
Speaker 10: boring explanations for an anomaly. It's usually that it's a
Speaker 10: statistical wobble, you know, just basically bad luck in the data.
Speaker 10: And we saw that the LHC about ten years ago
Speaker 10: when there was this famous bump that was seen about
Speaker 10: both ATLAS and CMS, so people interpreted as evidence for
Speaker 10: some new particle outside the standard model.
Speaker 9: And it was this crazy period.
Speaker 10: I think it was announced just before Christmas twenty fifteen,
Speaker 10: and by Christmas there were already something like two hundred
Speaker 10: papers that had been published by theorists trying to explain
Speaker 10: what this little bump in a graph was. And lo
Speaker 10: and behold, you know, six months later, when more data
Speaker 10: was added, this bump just had melted away and it
Speaker 10: was just basically neither experiment done anything wrong. It was
Speaker 10: just a statistical wobble. And these things come and go,
Speaker 10: So that's one explanation. Sometimes it's as you say, it's
Speaker 10: a cable that's not plugged in properly, so some kind
Speaker 10: of experimental mistake that you just didn't realize was there.
Speaker 10: And sometimes actually it's also the theoretical prediction may not
Speaker 10: be totally solid, and this is maybe a sort of
Speaker 10: idea that's hard to get your head around because you
Speaker 10: kind of think, well, if you have a theory, surely
Speaker 10: you can just work out what the consequences of it are.
Speaker 9: But that's not necessarily the case. Sometimes it's particularly.
Speaker 10: In particle physics when you're dealing with the theory of
Speaker 10: quarks and gluons, particularly, which are very important at the
Speaker 10: life Chadron collider. Those kinds of effects are very hard
Speaker 10: to calculate, so you might have a prediction for what
Speaker 10: you expect to see, but that prediction comes with its
Speaker 10: own set of uncertainties and assumptions that could bias it.
Speaker 10: So you kind of have to eliminate all three of
Speaker 10: those possibilities before you can say, well, this is really
Speaker 10: the sign of something genuinely new.
Speaker 2: All right, So finding oddities in our data is a
Speaker 2: good way to make discoveries and also maybe just to
Speaker 2: find our own mistakes. And in the book you highlight
Speaker 2: a few of them. Let's dig into the first one.
Speaker 2: Which has to do with one of my favorite and
Speaker 2: craziest experiments, a balloon experiment looking for stuff from space.
Speaker 2: Tell us about the ANITA experiment in what it's are.
Speaker 10: So ANITA is a really cool experiment. Essentially, what it is,
Speaker 10: it's this giant radio antenna. So it looks a bit
Speaker 10: like a huge tannoid system with all these white, gleaming
Speaker 10: horns that stick off it, and it's launched into the
Speaker 10: Antarctic stratosphere on a huge NASA balloon. So this is
Speaker 10: this incredible thing which is made of gossamer thin polyethylene
Speaker 10: filled with helium, and when it gets up to its
Speaker 10: full altitude up in the stratosphere, it's the size of
Speaker 10: a football stadium. So this vast kind of you know,
Speaker 10: translucent orb underneath which hangs on a little cable this
Speaker 10: radio antenna, And what ANITA is looking for is radio signals.
Speaker 9: Coming out from the Antarctic ice sheet.
Speaker 10: And essentially the reason they're doing this is they're using
Speaker 10: Antarctica effectively as a giant detector. They're looking for. Particularly,
Speaker 10: ANITA is looking for high energy neutrinos. So these are
Speaker 10: neutrinos that are produced by really violent, extreme objects out
Speaker 10: there in the distant parts of the cosmos, they come in,
Speaker 10: they hit the Antarctic ice, and when they hit the
Speaker 10: ice they convert into electric charged particles. That creates a
Speaker 10: wave of radio signal that comes up out of the ice.
Speaker 10: And then by detecting these radio blasts, you can then
Speaker 10: essentially infer how energetic this neutrino was and sometimes also
Speaker 10: what direction it came from. So essentially as a wave
Speaker 10: of looking for these really really high engeneutrinos using Antarctica
Speaker 10: as a giant detector.
Speaker 2: I love the ingenuity of these experiments. So like we
Speaker 2: need a mile cube of ice. You can't build that,
Speaker 2: but let's just go like find it out there and
Speaker 2: take advantage of it. To me, this is like part
Speaker 2: of the real, you know, experimental cleverness of this field. People.
Speaker 2: Sometimes I think imagine that the theorists are the only
Speaker 2: ones being creative, but you know, it takes real creativity
Speaker 2: and ingenuity to come up with these ways to force
Speaker 2: the universe to reveal something to you. I love these experiments,
Speaker 2: and I'm also terrified and in awe of people who
Speaker 2: build their detector and then send it up on a
Speaker 2: balloon hoping that it works. And it comes back and
Speaker 2: they get data from it, like, oh my gosh, how terrifying.
Speaker 10: Yeah, I mean I spoke to the scientists who work
Speaker 10: on ANITA, and you know, the environment they're working out
Speaker 10: there in Antarctica is also really strange. There at this
Speaker 10: place called McMurdo, which is a US research based on
Speaker 10: the edge of the Antarctic constant, just on the edge
Speaker 10: of the ice sheet, and they're.
Speaker 9: Working in these pretty difficult conditions.
Speaker 10: You're out there at the balloon station in very low temperatures,
Speaker 10: working in this hangar, and then there's this moment where
Speaker 10: you take your instrument out onto the ice and it's
Speaker 10: attached the balloon and you're kind of watching with bated breath.
Speaker 9: Is it all going to go off? Is it going
Speaker 9: to switch on?
Speaker 10: In these very low temperatures, Like there's always a danger
Speaker 10: that your computer just doesn't boot up.
Speaker 9: And then this thing's launched into the air.
Speaker 10: And then they describe watching this sort of radio antenna
Speaker 10: getting small and small and disappearing, and they're sort of
Speaker 10: vanishing into the distance and communicating with it while it
Speaker 10: was still within line of sight to check it it's
Speaker 10: all working. So you're out there in this environment for
Speaker 10: a whole month, so you're readeddicating. It's not a job
Speaker 10: where you just go to the office and come home.
Speaker 10: You're really like immersed in this place for a long
Speaker 10: period of time, and you're away from your friends and family.
Speaker 10: So it's also I think the length that people go
Speaker 10: to to find out about the universe is really impressive.
Speaker 2: Yeah, every tiny little piece of knowledge you read about
Speaker 2: on your phone for like four seconds, it's like somebody
Speaker 2: dedicating their life to figuring out like why spiders, you know,
Speaker 2: live in these little nests in the ringforest, or how
Speaker 2: high energy neutrinos make it through the ice. So in
Speaker 2: this case, Anita is looking, you're saying, for super high
Speaker 2: energy neutrinos hitting the ice and then the radio waves
Speaker 2: bouncing back up into the atmosphere for us to record.
Speaker 2: And so what did they see that was weird?
Speaker 10: So they didn't see the neutrinos they were hoping to see,
Speaker 10: but what they did see were high energy cosmic rays.
Speaker 10: So these are essentially electrically charged particles like protons or
Speaker 10: heavy nuclei that come in and hit the ice and
Speaker 10: they will also produce these sort of radio signals. But
Speaker 10: what was weird was that in amongst all the cosmic
Speaker 10: rays signals that they saw, they saw too that appeared
Speaker 10: to have come from below.
Speaker 9: In other words, these looked.
Speaker 10: Like particles that had come from underneath the Antarctic ice
Speaker 10: sheet and burst up into the atmosphere. And such a
Speaker 10: thing should not be possible because when you have very
Speaker 10: high energy particles, they would only be able to travel
Speaker 10: a very short distance through the Earth before being absorbed
Speaker 10: by the rock at the solid interior of the Earth.
Speaker 10: So essentially, they had these two events where you had
Speaker 10: these upward going very high energy particles, and there was
Speaker 10: no particle that we know about that could produce such
Speaker 10: an effect.
Speaker 2: Why couldn't it be a neutrino. We're always hearing that
Speaker 2: neutrinos can pass through a light year of lead without issue.
Speaker 2: Why can't they pass through the Earth and then interact
Speaker 2: in the.
Speaker 10: Ice Basically because neutrinios are very weak interacting and the
Speaker 10: reason for that is they only interact with ordinary matter
Speaker 10: through the weak force. Now, the reason the weak force
Speaker 10: is weak is because the particle that communicates the weak force,
Speaker 10: which is the well the w and the z bosons,
Speaker 10: they're very heavy, so they have a mass of between
Speaker 10: eighty and ninety gv, so that's sort of about one
Speaker 10: hundred times the mass of the proton. So they're very
Speaker 10: heavy particles, and as a result, essentially the heaviness of
Speaker 10: those particles is what makes the weak force weak, because
Speaker 10: it's impossible for a low engineutray to actually create a
Speaker 10: real what we call a real Worz boson. Instead, it
Speaker 10: has to sort of basically send a little bit of
Speaker 10: energy through the W and z fields, but it's off
Speaker 10: resonance and it's all a bit of a mess, and
Speaker 10: so as a result, that force is very short ranged
Speaker 10: and very weak. But when you have a really high
Speaker 10: energy nutrino of the type that Anita is looking for,
Speaker 10: these are so energetic. When they collide with stuff in
Speaker 10: the physical material of the Earth, they can create a
Speaker 10: real w and Z boson. They have enough energy to
Speaker 10: make a real particle. So the weak force stops being
Speaker 10: weak and it becomes strong. For a low energinetry in
Speaker 10: the Earth is like transparent thing which they just go
Speaker 10: straight through. For heinagineutrino, though, it's a solid object and
Speaker 10: they can't get through it. So not even a neutrino
Speaker 10: could explain this kind of weird signal that Anita had
Speaker 10: been seeing.
Speaker 2: So we saw these weird signals that look like they're
Speaker 2: coming through the earth. What could these things be?
Speaker 10: You get an anomally like this, and then theorists go
Speaker 10: to town and they come up with all kinds of explanations.
Speaker 10: There were various ideas that went around. One was that
Speaker 10: this was an exotic type of neutrinos, something called a
Speaker 10: sterile neutrino. So steril neutrinos appear in quite a lot
Speaker 10: of extensions of the standard model. They're essentially even more
Speaker 10: antisocial neutrinos, So the neutrinos that don't even interact through
Speaker 10: the weak fource, so they're essentially totally decoupled from ordinary matter.
Speaker 10: The only way they can interact is gravitationally. But in
Speaker 10: some theories, these steril neutrinos can mix with the ordinary neutrinos.
Speaker 10: So essentially what happens is you imagine one of these
Speaker 10: steril neutrinos that goes through the Earth with lots of energy,
Speaker 10: but because it's a sterilic can just go straight through
Speaker 10: the Earth. That's fine, and then just by chance, when
Speaker 10: it gets close to the surface, it oscillates and converts
Speaker 10: into a normal neutrino, and then suddenly it sees the
Speaker 10: ice and it crashes into it creates this radio burst.
Speaker 10: So it sort of gets through the Earth kind of
Speaker 10: disguised in this invisible form and then turns into something
Speaker 10: visible just as by luck when it gets to the surface.
Speaker 10: So that was one possibility. Another possibility is that was
Speaker 10: some sort of supersymmetric particle traveling through the Earth. Other
Speaker 10: ideas that there was dark matter that was accumulating inside
Speaker 10: the Earth and annihilating and producing various exotic particles. One
Speaker 10: of the most crazy ideas, well crazy sounding, was this
Speaker 10: there was actually evidence of a universe made of antimatter
Speaker 10: where time goes backwards, which comes from a theory there
Speaker 10: was an attempt to sort of solve various cosmological problems,
Speaker 10: essentially to do with the Big Bang, where at the
Speaker 10: Big Bang there's two universes produced, one made of matter
Speaker 10: which goes forward in time, and one made of antimatter
Speaker 10: that goes backward in time. So I mean, all kinds
Speaker 10: of explanations for these things. There's also the mundane explanation.
Speaker 10: So one group of theorists suggested that actually, maybe what
Speaker 10: you're seeing here is not new physics, but effectively ice
Speaker 10: formations that are interfering with your measurements.
Speaker 9: So the way you.
Speaker 10: Tell the direction the particles come in is essentially you
Speaker 10: get this radio burst that it's like a kind of
Speaker 10: wiggly line on a celloscope. It looks a bit like that,
Speaker 10: and from the phase of that signal, so whether it
Speaker 10: kind of goes up then down or it goes down
Speaker 10: then up, you can tell whether it came directly from
Speaker 10: the ice or whether it was reflected. So the particles
Speaker 10: that come from above, their radio signals are reflected back up.
Speaker 10: The ones from below they have this unreflected profile. But
Speaker 10: people suggested, well, maybe there are these subsurface features in
Speaker 10: the ice, so like subglacial lakes or layers of compacted
Speaker 10: snow that could create multiple reflections that would make something
Speaker 10: look like it came from below, when actually it had
Speaker 10: some kind of complicated bouncing around in.
Speaker 9: The ice before it came back up again.
Speaker 10: So they proposed, well, what we actually need to do
Speaker 10: is a survey of Antarctica and look for new sub
Speaker 10: ice features that could explain this signal.
Speaker 9: Now, the experiment said, well.
Speaker 10: Actually, where we saw these two events, there's no evident
Speaker 10: for interesting features underneath the ice, So we don't think
Speaker 10: that's an explanation. So we don't know whether it's exciting
Speaker 10: new physics or whether it is just something to do
Speaker 10: with ice.
Speaker 2: And so help us understand why it's so hard to
Speaker 2: tell these various explanations apart. I mean they sound like
Speaker 2: totally different stories about what's happening. Is it just because
Speaker 2: we have such limited information. We don't have like the
Speaker 2: ice completely instrumented, We don't have like a picture of
Speaker 2: this interaction. I think people are probably used to imagining
Speaker 2: their minds particle experiments leading to these spectacular traces where
Speaker 2: you have all these particles you can sort of see
Speaker 2: what happened. Or do we have just less information about this?
Speaker 2: Why can't we look at this and say, oh, here's
Speaker 2: what it is and here's what it isn't.
Speaker 10: Well, I mean essentially, all that Anita sees is this
Speaker 10: radio signal. It's essentially hearing this radio chairup with a
Speaker 10: particular profile, and you have to then work out what
Speaker 10: you've seen based on that, and there are various bits
Speaker 10: of information. You know the shape of the profile, whether
Speaker 10: it's inverted or not inverted, that tells you whether it's
Speaker 10: reflected or not reflected. But you don't have any other information,
Speaker 10: so you don't have a track, you don't have you know,
Speaker 10: images of part article interactions. You're really just going off
Speaker 10: a relatively small amount of information, and there's many ways
Speaker 10: that you can produce that signal that you know. In
Speaker 10: terms of all the new physics explanations, ultimately what they
Speaker 10: boil down to is, at some point in charge particle
Speaker 10: gets produced that interacts with the ice. So actually, whether
Speaker 10: it's a steril neutrino, whether it's dark matter, whether it's
Speaker 10: an anti matter universe, they would all basically look the same.
Speaker 9: You wouldn't be able to turn the part.
Speaker 10: You would then need other experiments to go out and
Speaker 10: look for Well, okay, if it's the sterei on neutrino,
Speaker 10: we would expect to see this in other places, so
Speaker 10: let's go and look for it there.
Speaker 9: So this would only be one clue.
Speaker 10: It's like you've seen, you know, one footprint in the
Speaker 10: mud in the jungle when you're hunting for an animal.
Speaker 10: You don't necessarily know what animal it came from just
Speaker 10: from this one depression in the soul. You've got to
Speaker 10: get more evidence. So it would be a clue, but
Speaker 10: not convincing or not. It wouldn't tell you ultimately what
Speaker 10: caused it.
Speaker 2: Necessarily, personally, I find it kind of frustrating that we're
Speaker 2: doing particle physics in an era where a single observation
Speaker 2: can't make a discoveries. You say, it's like seeing a
Speaker 2: footprint or a tuft of hair or something you haven't
Speaker 2: like identified the actual animal. And I think back on
Speaker 2: in the days, you know, like when the positron was discovered,
Speaker 2: or you know, a cosmic rays or you know, the
Speaker 2: neutral current or whatever, where they saw something weird in
Speaker 2: their data and it was obvious that it was something new,
Speaker 2: that there was no other explanation other than a new particle.
Speaker 2: Why can't we do that anymore? Are we just passed
Speaker 2: the days of single event discovery because our experiments are
Speaker 2: so complex and our data are so indirect or do
Speaker 2: you think that's still something we could do?
Speaker 10: I mean, if you go back to the positron discovery,
Speaker 10: that's a great story because you know, you have Carl
Speaker 10: Anderson with his cloud chamber and he sees this one
Speaker 10: track going through his cloud chamber which is.
Speaker 9: Bending the wrong ways.
Speaker 10: You know, it looks like a positively charged electron. And
Speaker 10: on the basis of this one photograph that he's taken
Speaker 10: of one track he discovers antimatter.
Speaker 2: One day's experiment, one photograph, one Nobel price. It's a
Speaker 2: great ratio.
Speaker 10: I suspect he probably did a few more days experimenting
Speaker 10: than just the one photo.
Speaker 9: But yeah, I mean relatively speaking.
Speaker 10: But I think the reason that was accepted quite quickly
Speaker 10: is because it was expected. Durrak had predicted the existence
Speaker 10: of the positron based on theory, so people were primed
Speaker 10: to see this thing. So I think that's partly why
Speaker 10: it was accepted. But also, you know, with this one image,
Speaker 10: there was no other way of explaining this. How do
Speaker 10: you get a positively charged track that looks like an electron, Well,
Speaker 10: there's nothing that can do that, and he had ways
Speaker 10: of knowing that it wasn't electron going the opposite direction,
Speaker 10: for example, are tricking you. So when there are no
Speaker 10: other explanations, I think you can make a discovery based
Speaker 10: on a single measurement. So often though, I think nowadays
Speaker 10: in particle physics we're looking for really subtle effects, and
Speaker 10: you're often talking about if we go back to the
Speaker 10: LHC and the beauty quark anomalies. You're measuring some quantity
Speaker 10: to end decimal places and trying to compare it with
Speaker 10: your theory, and that measurement is kind of fraught with
Speaker 10: all kinds of potential systematic effects that you have to
Speaker 10: take into account. It's so rare that you just have
Speaker 10: this kind of thing that appears and it's, oh my god,
Speaker 10: you know that must be a new particle.
Speaker 9: I suppose you know.
Speaker 10: The closest became recently was the discovery of the Higgs boson,
Speaker 10: but that's still required two years of data taking and
Speaker 10: then you see a bump. But at that point when
Speaker 10: you saw the bump again, because the Higgs was expected,
Speaker 10: people are pretty ready to say, okay, even at the
Speaker 10: time they didn't say, this is a Higgs boson, but
Speaker 10: you know it's a Higgs like particle, and you know,
Speaker 10: gradually build more evidence.
Speaker 2: But even in that case, there's no event you can
Speaker 2: look at and say, okay, this proves to me there's
Speaker 2: the Higgs. Each one like could be Higgs or could
Speaker 2: be background. They're all sitting on top of a huge
Speaker 2: background spectrum, and so in the end it's all statistical
Speaker 2: and indirect, right, there's no like, hey, look we found it,
Speaker 2: let's buy our ticket to Sweden, which is frustrating, but
Speaker 2: you know, it also gives us power to discover all
Speaker 2: sorts of other stuff. I suppose.
Speaker 10: Actually the counterexample thinking about it is gravitational wave discovery
Speaker 10: in twenty fifteen.
Speaker 9: So that was one event.
Speaker 10: Albeit they had to extract it from you know, their data,
Speaker 10: using these the template techniques and all the rest of it,
Speaker 10: but that was one signal, and they were prepared to
Speaker 10: say we've discovered gravitational waves on the basis of one interaction.
Speaker 10: That wasn't sort of you know, having to sample vast
Speaker 10: numbers of you know things.
Speaker 9: It does still happen, all right, But again I guess that.
Speaker 10: That's helped by the fact that, again, you expected to
Speaker 10: see that, so you kind of knew what you should see,
Speaker 10: and you then you see the thing you.
Speaker 9: Expect and you oh, yes, okay, that's what that is.
Speaker 9: That's gravitational waves.
Speaker 2: All right. Well, that's really exciting, and I hope that
Speaker 2: what they have found in the ice in Antarctica is
Speaker 2: something new and weird and not just new layers of
Speaker 2: ice down there in Antarctica. I want to dig into
Speaker 2: some more of these anomalies. But first we have to
Speaker 2: take a quick break. Okay, we're back and I'm talking
Speaker 2: to doctor Harry Cliff about his fun new books Space Oddities,
Speaker 2: which tells us all about weird things that we are
Speaker 2: seeing in particle physics experiments that could be the hint
Speaker 2: of something new. Tell us about the muon G minus
Speaker 2: two experiment and what they are seeing.
Speaker 9: So yeah, muon G minus two is a very impressive experiment.
Speaker 10: So essentially what they're trying to measure is how magnetic
Speaker 10: an exotic particle called a muon is.
Speaker 9: So muon is essentially a heavy version of the electron.
Speaker 10: It's got a negative charge, it's about two hundred times
Speaker 10: more mass than an electron, and they're quite unstable. They
Speaker 10: only live for a millionth of a second or so
Speaker 10: before they decay into neutrinos and an electron usually. Now,
Speaker 10: the reason that measuring the magnetism of the mue is
Speaker 10: interesting is that it's sensitive to the existence of new
Speaker 10: quantum fields in the vacuum that we haven't seen before.
Speaker 10: So to sort of introduce that ode of a quantum
Speaker 10: field for people who aren't familiar in particle physics, actually
Speaker 10: we don't think of particles as being the fundamental ingredients
Speaker 10: of the universe. We actually think of particles as being
Speaker 10: manifestations of something more fundamental, which are these quantum fields
Speaker 10: that permeate all of space. So, for example, like an electron,
Speaker 10: we actually think of an electron as a little vibration
Speaker 10: in something called the electron field that fills the whole universe.
Speaker 10: And that means that if you take a little bit
Speaker 10: of empty space and you know, you look at it
Speaker 10: really hard, what you see.
Speaker 9: Is actually is not empty. Even when you get rid
Speaker 9: of all the particles.
Speaker 10: There are these fields that are still there, and we
Speaker 10: know about seventeen of.
Speaker 9: Them at the moment.
Speaker 10: There's you know, the quarks, the electons, the Higgs boson,
Speaker 10: and the force particles, glue on photons and so on.
Speaker 10: So these fields are always there, and there are certain
Speaker 10: properties of particles that are particularly sensitive to what is
Speaker 10: sitting around them in the vacuum. So essentially, you think
Speaker 10: about a muon, you have your muon, it's sitting in
Speaker 10: the vacuum. It actually interacts with all these quantum fields
Speaker 10: that are sitting there all the time, and what you
Speaker 10: actually measure is not the magnetism of the muon. It's
Speaker 10: on its own, but the magnetism of the muon plus
Speaker 10: all its interactions with these seventeen quantum fields, and they
Speaker 10: can be really quite complicated, these sort of interactions back
Speaker 10: and forth between each other.
Speaker 2: I think that's really helpful the way you're putting it.
Speaker 2: We're measuring these properties of the particles, but really they're
Speaker 2: showing us the interactions of the fields. Like even the
Speaker 2: mass of the muon is that way right. The muon
Speaker 2: itself doesn't have a mass. It's the interaction of the
Speaker 2: muon and the Higgs field that changes how the muon
Speaker 2: field oscillates and the sort of standing waves of its vibrations,
Speaker 2: and we measure that as the mass of the muon, But
Speaker 2: it tells us about the Higgs field, And so you're saying,
Speaker 2: measuring the magnetic moment of the muon also tells us
Speaker 2: about the other fields that could be out there. So
Speaker 2: it's a great example of this like indirect probe of
Speaker 2: all the stuff we might not know about.
Speaker 9: Yeah, yeah, yeah, exactly.
Speaker 10: And so the mun's magnetism was sort of measured back
Speaker 10: in the nineties, but then in two thousand there was
Speaker 10: an experiment at brook Haven near New York, where they
Speaker 10: measured the muon's magnetism and it came out three sigma
Speaker 10: away from the predictions of the Standard Model. So you
Speaker 10: had this tantalizing anomaly that was seemed to be evidence
Speaker 10: that there was something else in the vacuum, something beyond
Speaker 10: the Standard Model that was altering its magnetism. So this
Speaker 10: could be the clue to something really new and exciting.
Speaker 10: The problem was that the experiment shut down wasn't taking
Speaker 10: any more data. So how do you kind of resolve
Speaker 10: this mystery? Is it really new physics or is it
Speaker 10: something else or statistical effect, what have you. So some
Speaker 10: of the people who worked on that original Brookhaven experiment
Speaker 10: decided they were going to build a new and improved
Speaker 10: version of this muon G minus two experiment, and this
Speaker 10: involved essentially rebuilding the entire thing from scratch at Fermilab
Speaker 10: near Chicago.
Speaker 9: But I mean in terms of the lengths they go to.
Speaker 10: The only bit of the old experiment they recycled it
Speaker 10: was this superconducting magnetic ring. So essentially the way the
Speaker 10: experiment works is you fire muons into this magnetic ring.
Speaker 10: They go around the ring and as they go through
Speaker 10: this magnetic field, their magnetic moment processes, so it kind
Speaker 10: of wobbles about in the magnetic field. When the muons decay,
Speaker 10: you can essentially measure the speed of the wobble depending
Speaker 10: on how much energy the particles that are produced come
Speaker 10: out at You get this kind of wiggle plot essentially.
Speaker 10: But this big ring, it's like, you know, thirty meters across,
Speaker 10: very expensive. They couldn't afford to get a new one
Speaker 10: from scratch. They had this whole thing shipped from Long
Speaker 10: Island down the Atlantic Coastline, round Florida, through Hurrican Alley,
Speaker 10: up the Mississippi River and then over then closed lags
Speaker 10: of freeways to get this huge thing to Fermilab. So
Speaker 10: it's insane kind of like length that people go to. Again,
Speaker 10: so this whole process took a decade. They bring the
Speaker 10: new ring to Fermi Lab, they install it, they rebuild
Speaker 10: the entire experiment from scratch, taking real incredible care to
Speaker 10: measure every effect down to the sort of decimal place,
Speaker 10: characterize the magnetic feel beautifully. And then in twenty twenty
Speaker 10: one they announced their first measurement of the new magnetism
Speaker 10: there and again there's this dramatic moment where they unblind
Speaker 10: their results, and the big question is is this thing
Speaker 10: going to land on top of the old measurement and
Speaker 10: confirmed anomally or is it going to land on top
Speaker 10: of the theoretical prediction. And what happens is it lands
Speaker 10: bang on top of the Brookhaven results. So this confirms
Speaker 10: the anomaly. It grows to over four sigma, and it's
Speaker 10: potentially really really exciting. It looks like this is evidence
Speaker 10: for new physics. But so often with these anomaly stories,
Speaker 10: there's a sting in the tale, which is that this case,
Speaker 10: the very same day that the new experiment published their result,
Speaker 10: a group of theorists produced a new prediction of the
Speaker 10: magnetism of the new one, and this prediction came out
Speaker 10: much closer to the experimental measurement. So essentially you had
Speaker 10: these two predictions. One that was performed by this big
Speaker 10: consortium of over one hundred theorists working together, and then
Speaker 10: this new technique using something technically called lattice QCD, using
Speaker 10: big supercomputers. And so you have these two rival ways
Speaker 10: of addicting theoretically the same thing that we're giving different answers.
Speaker 10: And in one case there's a whacking great anomaly in
Speaker 10: new physics. In the other case, there's not much to see.
Speaker 2: Essentially, this is another example of what you were talking
Speaker 2: about earlier how it can be actually hard to know
Speaker 2: what our theory predicts. Just because we have a theory
Speaker 2: doesn't mean we know exactly how it predicts and experiments
Speaker 2: result will turn out. Right. So here we have two
Speaker 2: different groups using the same theory but getting different predictions,
Speaker 2: right because the calculations themselves are so hard to do.
Speaker 9: Yeah, that's right.
Speaker 10: And in this case it all comes down to again
Speaker 10: quarks and gluons, which.
Speaker 9: Are they are a real pain in the art basically.
Speaker 10: Because the theory that describes them is very, very difficult
Speaker 10: to make calculations with the theory of what called quantum
Speaker 10: chromo dynamics, so we said that the nuance magnetism is
Speaker 10: affected by everything that's in the vacuum. Where there are
Speaker 10: quarks and gluon fields in the vacuum, they affect the magnetism,
Speaker 10: and it's been very difficult historically to calculate this term.
Speaker 9: So the way it was done earlier.
Speaker 10: Previously was essentially to use experimental data where you have
Speaker 10: colliders that find electrons and anti electrons, electrons and positrons
Speaker 10: at each other and then they produce particles made of
Speaker 10: quarks and gluons. And you can take this collider data
Speaker 10: and you can essentially say, well, an electronic positron annihilating
Speaker 10: to make quarks and gluons is basically the same as
Speaker 10: a muon interacting with clarks and gluons. You just kind
Speaker 10: of flip the process on its side effectively, So you
Speaker 10: can take this data and then you can use a
Speaker 10: recipe to translate it into a prediction for the effect
Speaker 10: of quarks.
Speaker 9: And gluons on the muon.
Speaker 10: And that was how it was done, and this gave
Speaker 10: you this four sigma anomaly.
Speaker 2: That's very clever. That's like saying, we don't know how
Speaker 2: to do this calculation, but we can make the universe
Speaker 2: do this calculation and then extract that information and insert
Speaker 2: it into our calculation, sort of like using the universe
Speaker 2: as a computer. And that's pretty awesome.
Speaker 9: Yeah, exactly, Yeah, just take it from nature.
Speaker 10: That was sort of an accepted, you know, very authority
Speaker 10: tested method. But this new approach was using this technique
Speaker 10: called lattice QCD, which I'm not going to pretend to understand,
Speaker 10: but it's basically a way of calculating these sorts of
Speaker 10: effects from first principles using the equations of the strong interaction,
Speaker 10: where you break space and time up into this lattice
Speaker 10: of points and you solve the equations on these lattice
Speaker 10: points and you get your prediction.
Speaker 9: And they'd sort of made a.
Speaker 10: Breakthrough in this method and how to sort of apply
Speaker 10: it to the case of the muon and came up
Speaker 10: with a new calculation of this extra term in the calculation,
Speaker 10: and this shifted the result basically towards the experimental measurement.
Speaker 10: And so the big debate now is which of these
Speaker 10: two methods is right, you know, is it the experimentally
Speaker 10: driven one or is it the theoretically driven one, to
Speaker 10: put it in broad terms, And that is still unresolved.
Speaker 10: We don't know yet which is right. The big sort
Speaker 10: of drama in this story now is basically theorists having
Speaker 10: to sort of juke it out and figure out what's
Speaker 10: the right way of doing this and hopefully eventually get
Speaker 10: to a point where both of these methods converge on
Speaker 10: the same answer and we can kind of agree how
Speaker 10: magnetic mworanes really ought to be.
Speaker 2: This is very frustrating for an experimentalist because I feel
Speaker 2: like we've done our job. We forced the universe to
Speaker 2: reveal the answer here, and we just need to know
Speaker 2: what it's supposed to be right, and the things like
Speaker 2: can't get their house in order and figure out like
Speaker 2: what we were supposed to have measured. It's like, you know,
Speaker 2: get it together, folks. But in this scenario, is there
Speaker 2: something we expect? You were saying, this is a great
Speaker 2: way to probe other fields. What other kind of fields
Speaker 2: might be out there that could be giving this effect?
Speaker 2: Is this the kind of thing that's predicted by various
Speaker 2: theories with.
Speaker 10: Only nominally there are quite a lot of potential explanations
Speaker 10: on the market. So some involve supersymmetry, which is something
Speaker 10: that we've been looking for at the LHC for the
Speaker 10: last decade and have so far found no evidence for.
Speaker 10: But you know, it's so supersymmetry. Supersymmetric particles interacting essentially
Speaker 10: with the muon in the vacuum could produce an effect
Speaker 10: like this. Another possible A popular set of explanations involves
Speaker 10: what are known as dark forces, which sounds rather sinister,
Speaker 10: but these are essentially the idea that dark matter may
Speaker 10: not just be one particle like you know, it's often
Speaker 10: assumed it's like it's a whimp or it's an axion,
Speaker 10: But perhaps dark matter as a sector is quite rich
Speaker 10: and there are more than just as in the atomic sector,
Speaker 10: there are multiple particles interacting with forces. Maybe the dark
Speaker 10: sector involves multiple particles with its own set of forces.
Speaker 10: So there is one idea is this is actually evidence
Speaker 10: of some kind of dark force field that allows dark
Speaker 10: matter particles to interact with each other. That's subtly again
Speaker 10: altering the way that the muon behaves. So the honest
Speaker 10: answer is we don't know which of these is right yet.
Speaker 10: But again this would be a clue. So if this
Speaker 10: anomaly was confirmed and the theorists agree on some calculation
Speaker 10: that gives this anomaly some high significance, you would then
Speaker 10: know for pretty well certain there is something new out
Speaker 10: there to find, and you can make various arguments to say, well,
Speaker 10: the MW one has this certain mass, so we kind
Speaker 10: of know the energy scale that the new physics ought
Speaker 10: to show up at.
Speaker 9: So it kind of gives experiments.
Speaker 10: Like the LHC a target where we might expect, you know, say,
Speaker 10: is find a new particle in the GeV range, for example,
Speaker 10: and then you go and search for particular signatures. So
Speaker 10: it wouldn't be the discovery of a particular new particle,
Speaker 10: but it would tell you there is a new particle
Speaker 10: there to be found in that would drive an experimental
Speaker 10: effort to actually figure out what this thing is.
Speaker 2: Do you think it's important that we have a theoretical
Speaker 2: idea for what we're looking for before we discover it.
Speaker 2: You said something in your book which struck me. You said, quote,
Speaker 2: finding ourselves an unknown territory without a theoretical map to
Speaker 2: guide us has bewildered and disheartened many personally. I feel like, personally,
Speaker 2: I don't feel disheartened by not having a theoretical map.
Speaker 2: I feel excited. I'm like, Ooh, let's go out and
Speaker 2: explore this territory. Because my personal scientific fantasy is to
Speaker 2: find something unexpected, something that makes people go, what that's impossible,
Speaker 2: you know, because those are the moments that unravel everything
Speaker 2: we thought we understand about the universe, you know, the
Speaker 2: photoelectric effect, the black body spectrum, this kind of stuff.
Speaker 2: Why do you feel like people are bewildered or disheartened
Speaker 2: by not having theoretical guidance, not having like tips for
Speaker 2: where to go look and what we might see.
Speaker 10: I mean, personally, I agree with you. So I think,
Speaker 10: actually this moment is really exciting. The idea that we're
Speaker 10: exploring the universe as we find it empirically observationally.
Speaker 9: That's a great place to be.
Speaker 10: And I would love like you to see something new
Speaker 10: and unexpected that no one had.
Speaker 9: Predicted, because that's where you make the biggest progress.
Speaker 10: But I think it's fair to say that if you
Speaker 10: went back fifteen years before the Large Hadron Collider, there
Speaker 10: was this great sense of anticipation in terms of what
Speaker 10: we were going to find, and there were these very
Speaker 10: clearly defined targets for what people were going to look for,
Speaker 10: and great optimism that some of them would show up.
Speaker 10: So the Higgs was one of them, and that did
Speaker 10: obligingly show up for us, But there was good reasons
Speaker 10: to think it would because of all the success of
Speaker 10: the Standard Model decades beforehand. But then things like supersymmetry
Speaker 10: or extramensions of space there was a lot of work
Speaker 10: going into and lots of predictions and lots of experimental searches,
Speaker 10: and none of them turned up. So I think that
Speaker 10: did leave people who had invested a lot of time
Speaker 10: and effort into exploring those ideas feeling pretty dispirited. But
Speaker 10: it sort of depends which angle you're coming at it from,
Speaker 10: I think, and it is a sort of change that
Speaker 10: I think looking at the history of particle physics particularly,
Speaker 10: there has been a change in the last ten years.
Speaker 10: I think it's probably the biggest impact in a way
Speaker 10: of the LHC is sort of a shift from this
Speaker 10: theoretically led era back into one that is experimentally driven.
Speaker 10: If you went back to the middle of the twentieth century,
Speaker 10: that was a period where particle physics was really experimentally driven.
Speaker 10: You had all these particles appearing in cloud chambers and
Speaker 10: bubble chambers and collider experiments that no one really knew
Speaker 10: what was going on or understood, and that forced a
Speaker 10: theoretical effort to sort of make sense of this crazy
Speaker 10: zoo of particles, and out of that comes the quark
Speaker 10: model and then later the Standard Model. But since the
Speaker 10: Standard Model was established in the seventies, I think it's
Speaker 10: fair to say, broadly speaking, most of the story of
Speaker 10: particle physics has been a series of confirmations.
Speaker 9: Of predictions of the standard model. It's the great triumph
Speaker 9: of what Winberg.
Speaker 10: And Glashow and others did, which they predicted the existence
Speaker 10: of the Wnz bosons. They were found in the eighties.
Speaker 10: The Higgs boson was found in twenty twelve. The other
Speaker 10: quarks that were sort of predicted were discovered. So it
Speaker 10: was really a series of like, yep, tick, and now
Speaker 10: in twenty twelve we ticked the lark's box, and now
Speaker 10: we're like, Okay, there isn't a guide anymore. We filled
Speaker 10: in all the boxes, but we know there's more out there,
Speaker 10: but we don't necessarily know where to go next. There's
Speaker 10: been an adjustment have gone through and shifting from that
Speaker 10: era where you sort of knew what you were looking
Speaker 10: for and you expected to find it, to one where
Speaker 10: you don't really know any more what you're looking for
Speaker 10: and you're just going out and exploring and trying to
Speaker 10: design experiments and searches that are broad enough that they
Speaker 10: can capture even the things that you didn't necessarily predict
Speaker 10: ahead of time.
Speaker 2: Yeah, I feel like there's sort of a pendulum that
Speaker 2: swings between you know, philosophy and botany, and in the
Speaker 2: philosophical eras it's like, you know, we know how this
Speaker 2: all works, and we can predict it, and we know
Speaker 2: what you should do and how to look for it.
Speaker 2: And then we swing into the botany ERAa, where we're like, well,
Speaker 2: we have no idea what's going on. We're just taking
Speaker 2: data and describing all the weird stuff that we're seeing
Speaker 2: out there in the universe. And I feel like mostly
Speaker 2: we've been in the philosophy era, and it's exciting to
Speaker 2: me to swing into the botany area where you know,
Speaker 2: as you say, experimentalists are on the forefront and we
Speaker 2: can go out and discover weird new stuff that nobody understands.
Speaker 2: To me, that's really exciting.
Speaker 9: So we talking about botany, I mean just this historical aside.
Speaker 10: The same reaction came in the thirties when things like
Speaker 10: the mewon and the padrons were being discovered, where people
Speaker 10: like Fermi said all these new parts articles of period.
Speaker 10: People were quite dismayed by it because they were like,
Speaker 10: it didn't fit into this neat theoreist or picture.
Speaker 9: And I think it was firm who.
Speaker 10: Said, you know, if I could remember the name of
Speaker 10: all these particles, I would have been a botanist.
Speaker 9: So it's not the first time.
Speaker 2: He says they're dismissively. But to me, that's very exciting.
Speaker 9: Yeah.
Speaker 2: Yeah, So tell me how excited are people on the ground.
Speaker 2: I mean, you've done a great job of laying out
Speaker 2: these anomalies in your book and also giving us the
Speaker 2: caveats not over selling it. But you know, the people
Speaker 2: working on this stuff who are really seeing the details,
Speaker 2: are they excited? Are they betting that this is new physics?
Speaker 2: Or are they skeptical and jaded from all the anomalies
Speaker 2: that have come and gone.
Speaker 9: I think it depends on who you speak to.
Speaker 10: I mean, I think broadly speaking, I think it's fair
Speaker 10: to say that experimentalists tend to be more cautious.
Speaker 9: I don't know if jaded is the right word, but certainly
Speaker 9: more cautious.
Speaker 10: And theorists are are a bit more enthusiastic, and you know,
Speaker 10: and new and lomly turns up and they're like, amazing, great,
Speaker 10: and they kind of write loads of papers about what
Speaker 10: could explain this thing, and there's nothing wrong with that.
Speaker 10: I think that's sort of two different approaches to the
Speaker 10: same thing. And I think, you know, as experiment because
Speaker 10: you do have to be more cautious because you're claiming to,
Speaker 10: you know, measure what nature is actually doing, and you
Speaker 10: don't want to be biasing your results based on some
Speaker 10: presupposition of what you're expecting to see, whereas in theory,
Speaker 10: you know, you come up with an explanation, there's no
Speaker 10: harm done. Really, I mean, if it doesn't turn out
Speaker 10: to be true, that's that's sort of fine. But it
Speaker 10: depends on the anomaly. It depends on who you talk to.
Speaker 10: But like with me on G minus two, I think
Speaker 10: if you speak to Lattice QCD theorists, they will say, well,
Speaker 10: there's nothing to see here because it's you know, the
Speaker 10: Lattice says that there's no anomaly. If you speak to
Speaker 10: other theorists who worked on the other method, they'll tell you, oh, no,
Speaker 10: this method solid and there's new physics. So I think
Speaker 10: it really depends where you're coming from. I think the
Speaker 10: one anomaly in the book that I found the most
Speaker 10: compelling and where I think a lot of the field
Speaker 10: also believes this is something is actually not a particle
Speaker 10: physics anomaly, but one in cosmology which is anomally called
Speaker 10: the Hubble tension, which is essentially there's disagreement over how
Speaker 10: fast the universe is expanding or ought to be expanding.
Speaker 10: So you have these two methods of measuring this, one
Speaker 10: which involves looking at stuff we can see in the sky,
Speaker 10: so galaxies, measuring their distances and their speeds, and then
Speaker 10: you measure the expansion rate of the universe from that data.
Speaker 10: Another way that evolves looking at the light from the
Speaker 10: Big Bang, determining the properties of the early universe, and
Speaker 10: then using the standard cosmological model to run the clock
Speaker 10: forward and predict from that early data what the expansion
Speaker 10: rate should be.
Speaker 7: Now.
Speaker 10: And these two numbers do not agree with each other
Speaker 10: by over five sigma. Now, so this is a pretty
Speaker 10: gold plated anomaly, and at least it would be in
Speaker 10: particle physics terms. But in that case, you know, there's
Speaker 10: been this long argument for a decade now about what
Speaker 10: is going on, and lots of people trying to find
Speaker 10: mistakes in how we measure distances, for example in the
Speaker 10: local universe or drilling into the cosmic microwave background data
Speaker 10: that's used for this prediction. And after a decade of
Speaker 10: scouring the data and multiple different ways of measuring the
Speaker 10: same things, no one's found a problem, really, not nothing
Speaker 10: that can explain the size of the anomaly that you're seeing.
Speaker 9: So I think more and.
Speaker 10: More of the field is now coalescing around the belief
Speaker 10: that this is actually genuinely something profound that we don't understand.
Speaker 10: The difficulty there, I think, and this comes back to
Speaker 10: the point we were talking about earlier, is there isn't
Speaker 10: any ready made theoretical explanation for what's causing this. There
Speaker 10: is sort of various things that can help relieve the
Speaker 10: tension a bit, but none of them solve it. So
Speaker 10: it's not like there's one sort of new thing where
Speaker 10: you say, oh, it's dark energy like you had with
Speaker 10: the accelerated universe in the nineties.
Speaker 9: It looks like to explain this thing you need new.
Speaker 10: Physics, multiple different periods in the universe's history, of different types.
Speaker 10: And I think that makes people uncomfortable because this principle
Speaker 10: of Ocham's raiser, if you see something new, there should
Speaker 10: be some really simple explanation that just ah, right, yeah,
Speaker 10: you know, that's the answer, Whereas in this case it
Speaker 10: seems very difficult to do that. And I think it's
Speaker 10: meant that it has taken time for this anomaly to
Speaker 10: really kind of be accepted as a genuine effect, because
Speaker 10: it is hard to explain.
Speaker 2: Well, tell me a little bit about how you thought
Speaker 2: about presenting anomalies to the public, because your audience are
Speaker 2: people who can't really go through the details and question
Speaker 2: your arguments necessarily, and so there's a responsibility when you're
Speaker 2: presenting this stuff to the public. You want to make
Speaker 2: it sound exciting. You're selling a book, after all, but
Speaker 2: you also want to be responsible and you don't want
Speaker 2: to overhype stuff. And you tell in your book a
Speaker 2: story of sort of a disastrous example of this, you know,
Speaker 2: the BICEP two result. You said, quote, I can't think
Speaker 2: of a more disastrous example of scientific hubris than the
Speaker 2: sorry story of Bicep two, which I thought was, you know,
Speaker 2: harsh but fair. How did you strike a balance in
Speaker 2: your book?
Speaker 10: Yeah, And I think the way I try to put
Speaker 10: this across is that anomalies potentially can be revolutionary. They
Speaker 10: can give you this amazing new insight to something you
Speaker 10: never understood before, but they can also lead you astray.
Speaker 10: And so at the beginning of the book, I actually
Speaker 10: kind of have a whole chapter basically on how anomalies
Speaker 10: can trick you and how you can all go horribly wrong.
Speaker 10: I mean, so with the BICEP two example, that was
Speaker 10: this discovery in twenty fourteen where a telescope at the
Speaker 10: South Pole found evidence for gravitational way from inflation. So
Speaker 10: this period of exponential expansion that cosmologists believed happened in
Speaker 10: the very first instant of the Big Bang, and this
Speaker 10: was presented to the world before it was peer reviewed,
Speaker 10: this big press conference, and you know, this announcement that
Speaker 10: you know, essentially we'd heard the bee of the Big Bang,
Speaker 10: that we'd proven cosmic inflation, that we probe quantum gravity,
Speaker 10: you know, all this talk about Nobel prizes.
Speaker 9: And then within about.
Speaker 10: A month or two, the whole thing was undiscovered as
Speaker 10: it was realized that they'd taken a key bit of
Speaker 10: data from a PowerPoint presentation by the Plank Spacecraft collaboration,
Speaker 10: which was used to basically take into account the effect
Speaker 10: of dust contaminating their observations of the cosmic microwave background,
Speaker 10: and they misinterpreted this slide effectively, and when this was
Speaker 10: taken into account, the whole signal literally turned to.
Speaker 9: Dust, so it disappeared.
Speaker 10: So I think that the problem with what byStep two
Speaker 10: did was not necessarily that they made a mistake, because
Speaker 10: mistakes happened.
Speaker 9: That can happen, but it's the way it was communicated.
Speaker 10: I think that it was they called a press conference,
Speaker 10: they made a big deal out of it, and before
Speaker 10: it had been really thoroughly checked by external peer reviewers.
Speaker 10: I think that was what weren't wrong there. So in
Speaker 10: the book, you know, all of the anomalies, I talk
Speaker 10: about the reason their anomalies and not discoveries is because
Speaker 10: none of them are confirmed. And I go through each
Speaker 10: of them and say, well, you know, here's the exciting explanation,
Speaker 10: here's the boring explanation, and I think it hopefully gives
Speaker 10: readers a balanced view of, you know, what the story
Speaker 10: is with each of them. But the other way, I
Speaker 10: think that whether or not any of them actually turn
Speaker 10: into a new physics discovery, I think there's huge excitement
Speaker 10: just in the process of drilling into these things, and
Speaker 10: you know, learning about the experiments that people do, the
Speaker 10: lengths they go to to measure these quantities, the emotional
Speaker 10: rollercoaster people go through, you know, when they think they're
Speaker 10: seeing something and then they realize they haven't. One of
Speaker 10: the stories I tell in the book is my own
Speaker 10: research so we talked about this at the beginning of
Speaker 10: the podcast, where we thought collectively in our area of
Speaker 10: particle physics that we were seeing signs of something genuinely exciting.
Speaker 10: And what happened as I was writing the book, in fact,
Speaker 10: was that we discovered in some of our measurements there
Speaker 10: was a hidden or a missed background that we had
Speaker 10: not properly understood. And this was a real moment of
Speaker 10: you know, horror, essentially, when you realize that you put
Speaker 10: measurements out into the world that have an error in them,
Speaker 10: and when this was corrected, a set of the anomalies disappeared,
Speaker 10: and essentially that you know, once you're corrected for this effect,
Speaker 10: it agree with the standard model. So what I look
Speaker 10: like you're on the brink of discovering something really big.
Speaker 10: You realize, oh, actually it's the opposite. You've made a
Speaker 10: pretty spectacular Cocker.
Speaker 2: Said, trombone sound here.
Speaker 10: Yeah, yeah, So I think it's important to see that
Speaker 10: that's how science works. You know, when you're working at
Speaker 10: the edge of your understanding, you're in real danger of
Speaker 10: making mistakes because you're in territory that you don't know
Speaker 10: where you're stepping. You know, your foothold is not secure,
Speaker 10: and you may take as much care as you can
Speaker 10: where there's always a chance that you put a foot wrong,
Speaker 10: but gradually you know sciences self correcting. These mistakes are eventually,
Speaker 10: sometimes quite quickly found out, and even when the anomalies
Speaker 10: go away, you learn something new. So you may learn
Speaker 10: about how to make calculations with a standard model, for example,
Speaker 10: or you may learn about particular types of background processes
Speaker 10: that you didn't understand, and that allows you when you
Speaker 10: do another experiment or you make another prediction in the future,
Speaker 10: you're on much more solid grounds. So these anomalies are
Speaker 10: kind of a grindstone where you're sharpening your scientific tools.
Speaker 10: Even when they don't lead to a big breakthrough, they
Speaker 10: are kind of equipping you for the next steps.
Speaker 2: Yeah, well, let's hope that they lead to new anomalies
Speaker 2: that actually do turn out to be new particles. That's
Speaker 2: a lot more fun.
Speaker 9: Yeah, wonderful.
Speaker 2: Well, thanks very much for coming to talk to us
Speaker 2: about all the exciting hints on the edge of the
Speaker 2: particle physics frontier that might be the revolution in our
Speaker 2: understanding about the universe. And I encourage everyone to check
Speaker 2: out Harry's new book space oddities everywhere books are sold. Harry,
Speaker 2: thanks very much for joining us today on the podcast.
Speaker 9: Thanks for having me. Great talking to you.
Speaker 1: All right, an interesting conversation. What's your takeaway from all
Speaker 1: of those oddities out there?
Speaker 2: I think they're all exciting, but I'm not one hundred
Speaker 2: percent convinced that any of them really mean a new discovery,
Speaker 2: a new deep understanding of the universe.
Speaker 1: Wait, what you're skeptical of a scientist saying, hey, let's
Speaker 1: go explore the.
Speaker 2: No I think it's great to explore the unknown. One
Speaker 2: thing I really like about Harry's book is that he
Speaker 2: tells you why they're potentially exciting, but he also gives
Speaker 2: you a realistic sense for why they might have prosaic explanations.
Speaker 2: It might just be that the ice in Antarctica is
Speaker 2: not as simple as we thought, or that the calculations
Speaker 2: of the Standard Model are harder to do than we
Speaker 2: expect it, so we're not sure exactly what to compare
Speaker 2: it to. So stay tuned, is the final answer.
Speaker 1: So these oddities are maybe not so odd.
Speaker 2: We might mean that we learned something deeper about the universe,
Speaker 2: or we might just learn about the ice in Antarctica.
Speaker 2: Either way, we're going to learn something.
Speaker 1: Yeah, and hopefully not destroy the planet, right right, hopefully
Speaker 1: hopefully question mark dot dot dot great and this is
Speaker 1: the part where you cackle with Danny Great. Hey, Niseth,
Speaker 1: can we cut off his funding now? Please? Thank you?
Speaker 1: All right, Well, another interesting reminder. There are still lots
Speaker 1: of discover out there, at least a lot of data
Speaker 1: and a lot of sciences stiff through to look for
Speaker 1: things that we maybe didn't expect because the history of
Speaker 1: science is that it's always surprising us.
Speaker 2: It's always surprising, and it's always fantastic.
Speaker 1: It's stay tuned, and that's what we shouldn't destroyed. No comment,
Speaker 1: All right, Well, we hope you enjoyed that. Thanks for
Speaker 1: joining us. See you next time.
Speaker 2: For more science and curiosity, come find us on social
Speaker 2: media where we answer questions and post videos. We're on Twitter,
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