Harry Cliff: Particle Physics and the Large Hadron Collider | AI Podcast #92 with Lex Fridman

The following is a conversation with Harry Cliff, a

particle

physicist at the University of Cambridge who works on the Large Hadron Collider beauty experiment and who specializes in investigating the slight differences between matter and antimatter by studying a type of Particle called beauty quark or B quark is part of the group of physicists who are looking for evidence of new

particle

s that can answer some of the most important questions of modern

physics

. He is also an exceptional science communicator with some of the clearest and most engaging explanations of basic concepts in particle

physics

. Anyone who has ever heard that when I visited London I knew I had to talk to him and we had this conversation in the conference room of the Royal Institute, which has hosted lectures for more than two centuries by some of the world's greatest scientists and science communicators. story for Michael.

Faraday to Carl Sagan this conversation was recorded before the outbreak of the pandemic for all who feel the medical, psychological and financial burden of this crisis. Sending you love your way, stay strong or in this together we will overcome this, this is artificial. intelligence

podcast

if you enjoy it, subscribe. I need to review it with five stars on a patreon supported

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or just connect on Twitter at lex Friedman spelled Friday DM and as usual I'll do a few minutes of announcements now and never any. ads in the middle that may interrupt the flow of conversation I hope it works for you and doesn't hurt the listening experience quick summary of ads for sponsors expressvpn and cash app please consider supporting the podcast by getting expressvpn and expressvpn calm / Lex Pod and download the Cash App and use collected podcasts.

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I imagine I use it on Linux. Shout out to a bunch of Windows Android, but it's available everywhere else to get it once again and expressvpn comm/flex pod to get a discount and support this podcast. And now here's my conversation with Harry Cliff, let's get started. with probably one of the coolest things humans have ever created, the Large Hadron Collider, ohc what is it, how does it work? Well, it's essentially this gigantic particle accelerator 27 kilometers in circumference, this big ring, it's buried 100,100 meters below the surface in the field. right outside of Geneva in Switzerland, and really what it's ultimately about is trying to understand what the building blocks of the universe are so you can think of it like a gigantic microscope and the analogy is actually pretty accurate. effectively, except it's a microscope that looks at the structure of the vacuum for this kind of thing to study particles that are microscopic entities, it has to be huge, yeah, gigantic Waxhaw, so what do you mean by studying the vacuum?

Well, I mean particle physics. As a field, it's sort of misnamed because particles are not the fundamental ingredients of the universe, they're not fundamental at all, so the things that we think are the true building blocks of the universe are invisible, fluid like objects called quantum. fields, so these are fields like the magnetic field around a magnet that exists everywhere in space, they are always there, in fact it is curious that they were in the wrong institution because this is where Michael Faraday effectively invented the idea of ​​the field . experiments with magnets and coils of wire, so he realized that, you know, it was a very famous experiment that he did where he got a magnet and put a piece of paper on top of it and then sprinkled iron filings on it and he found that the filings of iron were ready. themselves in these kind of loops that were actually charting the invisible influence of this magnetic field, which is something that you know we've all experienced, we all felt like we were holding a magnet or two poles of the magnet and we were pushing together and we felt this.

What this force pushes back is that these are real physical objects and the way we think about particles in modern physics is that they are essentially little vibrations, little waves in these otherwise invisible fields that are everywhere. parts, they fill the whole universe, you know, I don't know. apologist perhaps for the ridiculous question, are you comfortable with the idea that the fundamental nature of our reality is fields because to me, particles, you know, a bunch of different building blocks make more sense intellectually and visually as if were they? being able to visualize that kind of idea more easily yes, are you psychologically comfortable with the idea that the basic building block is not a block but a field?

I think it's um. I think it's a pretty magical idea. I find her quite attractive and she is fine. because of a misunderstanding of what particles are like when we do science in school and we draw a picture of an atom, you draw a nucleus like, you know, with some protons or neutrons, these little spheres in the middle and then you have some electrons. like little flies flying around the atom and that is a completely misleading picture of what an atom is like, it's nothing like that, the electron is not like a little planet orbiting the atom, it's a thing that stretches out and wobbles in wave form and we know that I've known this since the beginning of the 20th century thanks to quantum mechanics, so when we keep using this word particle, because sometimes when we do experiments, particles behave as if they were little marbles or little bullets , you know in the LHC when particles collide with each other, you will know that you will get like hundreds of particles fly through the detector and they all take a trajectory and you will be able to see from the detector where they have gone and they look like little bullets. so they behave that way, you know, most of the time, but when you study them carefully you'll see that they're not little spheres, they're viral perturbations in these underlying fields, that's how we really think about nature.

This is amazing, but I also think it's kind of magical, so here we are, our bodies are basically made up of little knots of energy in these invisible objects around us and what's the story of the vacuum when it comes to the LHC. So why did you mention the word void? Okay, so if we go back and tell ourselves the physics that we know, atoms are made of electrons that were discovered about 100 years ago and then the nucleus of the atom, you have another two. types of particles there is something called an up quark and a down quark and those three particles make up every atom in the universe so we think of this as waves in fields so there is something called an electron field and every electron in the universe is a wave that is moves in this electron field, the electron field is everywhere, we can't see it, but every electron in our body is a little wave in this thing that is there all the time and the quark feels the same, so there is a quark field above. and an up quark is not a wave in the up quark field and the down quark is a small wave in something else called a down quark field, so these fields are always there now that we potentially know a certain number of fields in what We call it the standard model of particle physics and the most recent one we discovered was the Higgs field and the way we discovered the Higgs field was to create a little wave in it, so what the LHC did was shoot two protons between yes with much, much force. with enough energy to create a perturbation in this Higgs field and that is what appears as what we call the Higgs boson, so this particle that everyone was using about eight years ago is proof that actually the particle in itself is, I mean, it's interesting but what's really interesting is the field because it's the Higgs field that we think is the reason why electrons and quarks have mass and it's that invisible field that's always there. which gives mass to the particles.

The Higgs boson is just our way of testing it. it's there basically so the Large Hadron Collider to get that wave in the Higgs field requires a huge amount of energy yeah it opposes that's why you need this huge that's why size matters here so maybe There are a million questions here, but back up, why does size matter in the context of a particle

collider

? So why does a

large

r size allow you higher energy collisions? So the reason is pretty simple, and that is that there are two types of particle accelerators that you can build, one is circular. which is like the LHC, the other one is a very long line, so the advantage of a circular machine is that you can send particles around a ring and you can kick them every time they spin, so imagine you have an es in actually a little bit about the LHC, which is about only 30 meters long, where you have a bunch of metal boxes that have oscillating electric fields of millions of volts inside them, which are timed so that when a proton passes through one of these boxes, the field you see as you approach is attractive. when it comes out of the box it flips over and it gets icky and the proton is attracted and then ejected out the other side so it gets a little bit faster so you send it out but then you send it back again and it's amazing the moment of that synchronization. wait, yeah, yeah, yeah, yeah, I think there's going to be a multiplicative effect on the questions that I have, okay, let me pay attention for a second to how the orchestration of that is fundamentally a hardware problem or a software problem, a problem like How is that understood?

I mean, maybe, first of all I should say that I'm not an engineer, so the guys that I didn't build the LHC for, they're much better people at these things than me, for sure, but maybe, but. from your kind of intuition from the echoes of what you understand that you heard about house design what is your feeling like what are the engineering aspects that the acceleration part is not a challenge okay, there are always challenges for everything, but basically you have these beams that Go around you like you see the particle rays are divided into little clusters, so they call their part like swarms of bees, if you want, and there are around, I think it's something on the order of 2000 clusters spaced around the ring and them, if you were.

If you are a certain point on the ring counting clusters, you will get 40 million clusters passing you every second, so they come in like you know, like they are cars passing on a very fast highway, so you should have it if you are an electric field. which you're using to accelerate particles that need to be timed so that when a bunch of protons arrive it has the right signal to attract them and then spins at the right time, but I think the voltage in those boxes ranges to hundreds of megahertz so you make them at about 40 megahertz, but they oscillate much faster than the beam, so I think you know it's difficult engineering, but in principle it's not, you know, a really serious challenge.

The biggest problem is that the engineers probably like to yell at Ureña, they probably do, what? Well, in terms of coming back to this, why is it so big? Well, the reason is that you want the particles to go through that accelerator element over and over again, so you want to spin them again, that's why it's round. The question is why it couldn't be done. you make it smaller, well the basic answer is that these particles goelements a little like that and people try it. to start trying to impose some order, then Murray Gelman, an American theoretical physicist from New York, realizes that there are these symmetries in these particles that, if you organize them in a certain way, they relate to each other and he uses these principles of symmetry to predict the existence of undiscovered particles that are then discovered in accelerators, so this begins to suggest that there are not just random collections of junk, but that there is actually an order to this a little bit more later, in 1960, again, it's around the 1960s. he proposes along with another physicist named George Zweig that these symmetries arise because just like the patterns on the periodic table arise because atoms are made of electrons and protons, these patterns They are due to the fact that these particles are made of smaller things and they are called quarks, so these are the particles that are predicted from theory for a long time, no one really believes that they are real.

Many people think that there is some kind of theoretical convenience that fits the data, but there is no evidence that anyone has done that. I've seen a quark in any experiment and many experiments are done to try to find quarks, just try to remove a quark from it, so the idea is that if protons and neutrons say they are made of quarks, you should work to remove a quark and see the quark that never happens and we've still never managed to do it really isn't, but the way it's done in the end is this machine built in California in the Stanford lab, the Stanford Linear Accelerator, which is essentially a gigantic three-kilometer-long electron cannon that fires.

The electrons almost at the speed of light in the protons and when you do these experiments what you find is a very high energy, the electrons bounce off small hard objects inside the proton. So it's a bit like taking an x-ray of the proton: you're shooting these very light high energy particles and they ping little things inside the proton that are like ball bearings, if you will, so that's actually how they get solved. that there are three things inside the proton that are quarks the quarks that govern why I was able to predict so that's really the evidence that convinces people that these things are real the fact that we've never seen one in an experiment directly they're always trapped inside other particles and the reason for this essentially has to do with the strong force, the strong forces, the force holds the quarks together and it is so strong that it is impossible to release a quark, so if you try to remove a quark from a proton , what really ends What happens is that you create this, that this spring-like bond in the strong force that we have imagined is two quarks that are held together by a very powerful spring, you pull it, and you pull it, you pull it, and each time it is stored more energy in that bond. stretch a spring and eventually the tension becomes so great that the spring breaks and the energy in that bond becomes two new quarks that go on the broken ends, so you started with two quarks to end up with four quarks, so you never get to take a quark you just end up producing many more quarks in the process, so how do we forgive the dumb question again?

How do we know quarks are real? So, well, from these experiments where we can scatter electrons into protons that can dig. in the proton and they break off and they can bounce off these quarks so you can see from the angles that the electrons are coming from Alice, you can infer, you can infer that these things are there, the quark model can also be used, it has a lot of successes , you can use it to predict the existence of new particles that have not been seen and basically, there is a lot of data that basically shows that when we shoot protons at each other at the LHC, a lot of quarks are thrown everywhere and every time.

They try to escape from, say, one of their protons, they create a whole jet of quarks that flies out and has joined up with other types of particles made of quarks, so they are all the kind of theoretical predictions of the basic theory of La strong force and the quarks match what we're seeing in experiments, we've just never seen a real quark on its own because unfortunately it's impossible to get them out on their own, so quarks are crazy little things that are hard to find. imagine. So what else is part of the story here? So the other thing that's happening at that time around the sixties is an attempt to understand the forces that cause these particles to interact with each other to have the electromagnetic force, which is the force that was discovered to some extent in this room. or at least in this building, so the first, what we call quantum field theory of the electromagnetic force, was developed in the 1940s and 1950s by Fineman Richard Feynman, among other people, Julian Schwinger Tominaga, who came up with the first what we call a quantum field theory of the electromagnetic force and this is where this description that I gave you at the beginning that particles are waves and fields well in this theory the photon the light particle is described as people in this quantum field called electromagnetic field and then we try to prove what we can arrive at a quantum field theory of the other forces of the strong force and the weak force the other third the third force that we have not discussed which is the weak force which is a nuclear force that really We don't experience it in our daily lives but it is responsible for radioactive decay.

It is the force that lets you know that a radioactive atom becomes a different element, for example, and there are some that we have mentioned explicitly, but technically there are four forces, yes. , I guess three of them were in the standard model, like weak, strong and electromagnetic, and then there's gravity in this gravity, which we don't worry about because maybe we bring that in at the end, yeah, gravity, so far we don't have a quantum theory and if you can solve that problem you'll win a Nobel Prize, well we'll have to bring up the graviton at some point.

I'll ask you. but let's leave that aside for now so those three are good, good man, an electromagnetic force, the quantum field, yeah, where does the weak force come in? So, yeah, well, first I want to say that the strong force is a little bit easier, the strong force is a bit like the electromagnetic force, it's a force that holds things together, so that's the force that keeps things together. quarks inside the proton, for example, so a quantum field theory of that force was discovered, I think it was in the sixties, and it predicts the existence of new force particles called gluons, so gluons are a bit like the photon, the photon is the particle of electromagnetism, the gluons are the particles of the strong force, so it exists as if there is an electromagnetic field, there is something called a gluon field that is also around us. but in this part there are some of these particles, I guess force carriers or whatever they carry, it depends on how you want to think about it.

I really mean the field, the strong force field, the gluon field, it's what binds the quarks, the gluons. They are the little waves in that field, in the same way that the photon is a wave in the electromagnetic field, but what really makes the connection is the field. I mean, you may have heard people talk about things like edge like You've heard the phrase virtual particle, so sometimes if you listen to people describing how forces are exchanged between particles, they often talk about the idea that You know if you have an electron and another electron, and they repel each other. the electromagnetic force of the electro bratok, you can think of it as if they are exchanging photons, so they are shooting photons back and forth at each other and that causes them to repel each other, therefore time is a virtual particle, yes, that's what we call a virtual particle in other words, it's not a real thing, it doesn't actually exist, so it's an artifact of the way that theorists do calculations, so when they do calculations in quantum field theory , no one has figured out a way to treat the entire field you have. break down the field into simpler things so you can basically treat the field as if it were made up of a lot of these virtual photons, but there's no experiment you can do that can't detect the exchange of these particles.

What is really happening in reality is the electromagnetic field is deformed by the charge of the electron and that causes the force, but the way we do the calculations involves parts, let's say it's a little confusing, but it's actually a technique Mathematics, it's not something that corresponds to reality, I mean, that's part of it, I guess. the fireman's diagrams yes, it's this virtual product, okay, it's true, yes, some of these have mass, some don't mm-hmm, that's what it means to have no mass and maybe you can tell right which one of them is. have mass or which ones are not and why mass is important or relevant in this cabinet in this field view of the universe well, there are only two particles in the standard model that have no mass, which are the photon and the gluons, so they are massless particles, but the electron, quarks and are a bunch of other particles that I haven't talked about.

There's something called a muon and Tau, which are basically heavy versions of the electron that are unstable and can be made in accelerators. but they don't form atoms or anything, they don't exist long enough, but all particles of matter are twelve, six quarks and six what we call leptons, which include the electron and its too heavy versions, and three neutrinos, all of them. They have mass and also this is the critical point, so the weak force, which is the third of these quantum forces, which is one of the most difficult forces to understand, the particles of that force have very

large

masses and there are three of them.

They are called the W plus the W minus and the Z boson and have masses between 80 and 90 times that of protons, they are very heavy, learn wow, they are very heavy things, they are the heaviest, I suppose they are not the heaviest particle. heavy is the top quark, which has a mass of about 175 protons, so it is really massive, we don't know why it is so massive, but they are coming back to the weak force, so the problem in the 60s and 70 was that the reason the electromagnetic force is a force that we can experience in our daily lives, so if we have a magnet and a piece of metal, you can hold it, you know, a meter away, if it's powerful, you laugh and you will feel a strength. whereas the weak force only becomes evident when you basically have two particles in contact at the scale of a nucleus, so if you get two very short distances before this force manifests itself, it doesn't, we don't have weak forces in this . room, they don't notice them and the reason for this is that the particle, the field that transmits the weak force, the particle associated with that field has a very large mass, which means that the field dies very quickly, he says, while a electric charge if you were to look at the shape of the electric field, it would fall off with this, you know, this is called the inverse square law, which is the idea that the force is halved every time you double the distance, I'm not sorry, It doesn't have it splits into quarters every time you see every time you double the distance between, say, the two particles, while the weak force moves a little bit away from the nucleus and just disappears.

The reason for this is that these fields are the particles that go with them. They have a very large mass, but the problem that theorists faced in the sixties was that if you tried to introduce massive force fields, the theory gave you meaningless answers, so you would end up with infinite results for many of the calculations you attempted. To do that, it basically turned out that it seemed like quantum field theory being incompatible with having massive items, not just the force particles actually, but even the electron, was a problem, so this is where the Higgs that we alluded to comes in and the solution was to say well, actually all the particles in the standard model of mass have no mass, so the quarks, the electron, have no mass, nor do these weak particles, they have no mass either, what happens is that they actually acquire mass through another process they get it from somewhere else they don't actually have it intrinsically so this idea that was introduced by Peter Higgs is the most famous one but it's actually about six people who come up with it the idea more or less at the same time.

The moment is that you introduce a new quantum field which is another one of these invisible things like everywhere and it is through the interaction with this field that the particles gain mass, so you can think of, say, an electron in the field Higgs, a kind of Higgs field. it clumps around the electron, it's attracted to the electron and that energy that's stored in that field around the electron is what we see as the mass of the electron, but if you could somehow turn off the Higgs field, then all the particles in nature would do it. they become massless and fly at the speed of light, so this idea of ​​the Higgs fieldIt was a bound state of these objects and the Higgs.

It wouldn't be a start, if that were correct, it would be the first in a series of Technicolor particles. Technicolor. I think I'm not a theorist, but it's not a business, basically, it wasn't done very well, particularly since the LHC found the Higgs, that kind of rules out, you know. a lot of these theories are Technicolor, but there are other things that look a little bit like Technicolor, so there's a theory called partial composite nursing, which is an idea that some of my colleagues at Cambridge have been working on, which is kind of similar idea that the Higgs is a united state of some strongly interacting particles and that the Standard Model particles themselves (the more exotic ones like the top quark) are also sort of mixtures of these composite particles, so it is a kind of extension of the standard model that explains this problem with the Higgs.

The bosons have a Goldilocks value, but it also helps us understand that now we are in a situation a little bit like the periodic table where we have six quarks, six leptons in these kinds of ranges in this nice table and there you can see these columns where the patterns repeat and you're okay, maybe there's something deeper here is that you know and so this could be something that this partial composite NOS theory could. Lane enlarged this image allowing us to see the full symmetrical pattern and understand what it is. the ingredients why we have wind, one of the big questions in particle physics is why there are three copies of the particles of matter, in what we call the first generation, of which we are made, there is the electron, the electron neutrino, the up. quark and down quark are the most common particles of matter in the universe, but then there are copies of these four particles in the second and third generation, so things like muons and top quarks and other things that we don't know why we see them These patterns we have no idea where they come from, so that's another big question.

Know? Can we discover the deeper order that explains this particular ribbon particle period table we see? Is it possible that the deepest order includes almost a single entity? so I guess something that string theory dreams of is this is this part is essentially this the dream is to discover something simple and beautiful and unifying yeah I mean that's the dream and I think for some people for a lot of people still It is the dream, so there is a great book by Steven Weinberg, who is one of the theoretical physicists who was instrumental in building the Standard Model, so he came up with others with the electroweak theory, the theory that unifies electromagnetism and the weak force, and here in this book, I think it was in the late '80s and early '90s, called Dreams of a Final Theory, which is a very nice book, quite short, about this idea of ​​a final unifying theory that brings everything together and I think you can get an idea by reading his written book. in the late 80s and early 90s there was a feeling that such a theory was coming and that was the time when string theory had been very exciting, so in string theory there was something called the superstring revolution and very excited theoretical physicists discovered these theoretical objects these little vibrating loops of string that in principle was not only a quantum theory of gravity but could explain all the particles in the standard model and put them all together and you, as you say, have an object. the string and you can pluck it and the way it vibrates gives you these different notes, each of which is a different part, so it's a very beautiful idea, but the problem is that, well, there are some people who find that their math is very difficult, so people I've spent three decades or more trying to understand string theory and I think if you talked to most string theorists they would probably freely admit that no one really knows what string theory is yet.

I mean, there's been a lot of work, but it really isn't. understood and the other problem is that string theory mainly makes predictions about physics that occurs at energies far beyond what we will ever be able to test in the laboratory, yes probably ever, by the way, sorry, they take a million of tangents, but is there room for complete innovation? how to build a particle

collider

that could give us an order of magnitude increase in any kind of energy or whether we need to keep increasing the size of the thing. I mean, maybe yes, I mean there are ideas, but to give you an idea of ​​the Gulf that has to be bypassed for the LHC to collide particles with an energy of what we call fourteen terrorist electron volts, which is basically equivalent to accelerating a proton through 14 trillion volts, which brings us to the energies where the Higgs and these weak particles live.

They are very massive, the scale where the strings manifest themselves is something called the Planck scale, which I think is on the order of 10 to hang, that's right, it's 10 to 18 gigaelectron volts, so about 10 to 15 electron volts of terror, then. you're talking, you know, billions of times more energy, more than 10 to 15, 10 to 14, bigger, it's a very large number, so you know we're not just talking about an order of magnitude increase in energy, We are talking about 14 orders. of magnitude of energy increase, to give you an idea of ​​what it would look like if you built a particle accelerator with current technology larger or smaller and then our solar system started with the size of the galaxy, so you need to put a particle . accelerator that circled the Milky Way to reach the energies where strings would be seen if they existed, so there is a fundamental problem which is that most of the predictions of the unified theories of quantum theories of gravity only make statements that are testable . energies that we will not be able to fathom, unless there is some incredible technological or scientific advance, you know, completely unexpected, that is almost impossible to imagine, never, you never say never, but it seems very unlikely, yes, I can only see the news.

Elon Musk decides to build a particle collider the size of ours it would have to be we would have to get together with all our galactic neighbors to pay for everything what are the exciting possibilities of the Large Hadron Collider what is there to discover in it in this order of magnitude of scale , are there any other bigger efforts on the horizon, big in this space, what are the open problems, the exciting possibilities that you mentioned, supersymmetry, yes, very good, there are many new ideas, well, there are many problems that we face, so there is a problem?

With the Higgs field that supersymmetry was supposed to solve, there is the fact that 95% of the universe we know from cosmology and astrophysics is invisible and that it is made of dark matter and energy, which are really just words for things that we don't know what they are. it's what Donald Rumsfeld called a known unknown we know we don't know what they are good that's better than an unknown unknown yes well there may be some unknown unknowns but I don't know what those are yes but the hope is the particle accelerator could help us understand dark energy dark matter there is still some hope for that there is hope for that yes, so one of the hopes is that the LHC can produce a Dark Matter particle in its collisions and you know that could be that the LHC will still discover new particles which could still have supersymmetry, but maybe it's harder to find than we originally thought and, you know, it's possible that dark matter particles are being produced, but we're just not looking in the right place. part of the data for them that that is possible, it could be that we need more data, that these processes are very rare and we need to collect a lot of data before we see them, but I think a lot of people would now say that the possibilities The possibility of the LHC discovering directly new particles in the near future is quite scarce, we may need a decade more of data before we can see anything or we may not see anything, that's what we are, so I mean physics, the experiments that I work on a detector called LHC B, which is one of these four big detectors that are spaced around the ring and we do slightly different things than the big ones.

There are two big experiments called exits and CMS, three thousand physicists and scientists and computer scientists in each of them are the ones who discovered the Higgs, then they look for supersymmetry and dark matter, etc., which we look at in our standard model of particles called B quarks, which depending on your preference is background or beauty, we tend to say beauty because it sounds sexier, yes, but these particles are interesting because you can make a lot of them, we make billions or Billy hundreds of billions of these things. So they can measure their properties very precisely to be able to make these really beautiful precision measurements and what.

What we're doing really is kind of a complementary thing to the other big experiments, which are, if you think the self-analogy that I often use is if you imagine that you're looking inward, you're in a jungle and you're looking for a The same thing happens. with the elephant and you are a hunter and you are like they say relevance is very rare, you don't know where in the jungle the jungles are big, so there are two ways to do it, or you can go out and wander in the jungle. and try to find the elephant, the problem is that if the elephant there is only one elephant, the jungles are big, the chances of running into it are very small or you can look on the ground and see if you see footprints left by the elephant and if the elephant is moving. you have a chance that you have a better chance of maybe seeing the elephant's footprints if you see the footprints you're okay there's an elephant maybe I don't know what kind of elephant it is but I have a feeling there's something out there so that's it.

It is more or less what we do we are the trace the people we are we are looking for the trace the impressions that the quantum fields that we have not managed to directly create the particle of the effects that these quantum fields have on the fields of the ordinary standard model that we already know that these are particles, the way they behave can be influenced by the presence of, say, superfields or dark matter fields or whatever you want, and it's the way they decay and can be altered slightly from what our La Theory tells us that they should behave safely and that it is easier to collect large amounts of data and B and B quarks.

We know that billions and billions of these things can be made very precise measurements and the only place really is at the LHC or actually in high energy physics right now where there's pretty compelling evidence that there might be something beyond the standard model is in these beautiful quarks that decay just to clarify what the difference is between the different four experiments, e.g. the emission is from the type of particles that collide are the energies that collided what is the fundamental difference different experiments the collisions are the same what is different is the design of the detectors that is why they are called Atlas and CMS, they are called general purpose detectors and they are basically barrel shaped machines and the collisions happen in the middle of the barrel and the barrel captures all the particles that come flying in all directions, so in a sphere they can effectively fly and it can record all those particles and what is . the interruption site, but what is the recording mechanism?

Oh, these detectors, if you've seen pictures of them, they're huge like Atlas, they're 25 meters high, 45 meters long and huge machines, instruments. I guess you'll actually call them. They're like onions, so they have concentric layers, layers of sensing detectors, different types of detectors, so close to the beam tube you have what a disk is usually made of silicon, their tracking detectors, so they're made small pieces of silicon strips or silicon pixels. and when a particle passes through the silicon, it gives a little electrical signal and you get these points, you know, electrical points through your detector, which allows you to reconstruct the trajectory of the particle, so that's the medium and then the outside of these detectors, you have things.

They are called calorimeters that measure the energies of the particles and at the edges there are things called muon chambers that basically meet these muon particles, which are the heavy version of the electron, they are there like high speed bullets and they can go directly to the edge of the detectors, if you see something on the edge it's a muon, that's how they work generally speaking and everything that is recorded there, everything is transmitted to you, you know computers must be amazing, so the LHCb is different , so we are looking for these B quarks. Yes, B quarks tend to be produced along the beam lines, so in a collision the B quark tends to fly close to the beam tube, so we build the detector with a kind of pyramidal cone shape that basically looks in a direction that we ignore.

If you have collision things going everywhere, we ignore all the things here and weWe veer sideways, we're just looking at this little region near the beam tube where most of these B quarks are made, so is there anything different about the sensors? involved in the B quark collection, yes, Jack Thérèse, there are some differences, so one of the differences is that one of the ways you know you've seen a B quark is that B quarks actually have quite a lifetime. long by particle standards, so to live for 1.5 trillion seconds, which is if you're a fundamental particle, is a very long time because you know the Higgs boson, I think it lives about a trillionth of a trillionth of a second. or maybe even less than that. so these are pretty long-lived things and they'll actually fly a small distance before breaking down, so they'll fly, you know, a few centimeters, maybe if you're lucky they'll break down into other things, so what we have to do in the In the middle of the detector that you want to be able to see, you have your place where the protons collide with each other and that produces a lot of particles that fly away, so you have a lot of lines, a lot of clues that point to that collision of protons and then you are looking for a couple more footprints, maybe two or three that point to a different place, this may be a few centimeters from the proton collision and that is the sign that the little B particle has flown a few centimeters and has decayed somewhere else, so we need to be able to resolve very precisely the proton collision from the decay of particle B, so the center of our detector is very sensitive and gets very close to the collisions, so you have this detector of delicate and really beautiful silicon that is found, I think it is seven thousand millimeters of the beam and the LHC beam has as much energy as the takeoff of a jumbo jet, so it is enough to melt a ton of copper and how does this thing have furiously powerful next door, it's very delicate, you know, the sense of consent, sir, so that in those aspects of our detector that are specialized in discovering these particular B quarks that we were interested in and, I mean, I remember seeing somewhere that there is any mention of matter and antimatter connected to these beautiful quarks who is that what what the connection, yeah, what's the connection?

Yes, there is a connection which is that when these B particles are produced, it will be these particles that are considered the B quark. You see that the B quark is inside, so they are bound together inside what we call beauty particles where the B quark binds with another quark or two, maybe two other clocks, depending on what it is, there is a particular set of these B particles that exhibit this property called oscillation, so if you convert it, for the sake of argument, into matter version of one of these B particles as it travels because of the magic of quantum mechanics, it oscillates back and forth between its matter and antimatter versions, so this strange flipping back and forth and what We can use this is a laboratory to carry out tests. the symmetry between matter and antimatter, then if the symmetry but transparency is precise, then we should see these B particles decay as often as matter as they do as antimatter because this oscillation should be uniform, it should spend a long time in each state, but what we actually see is that one of the states spends more time and is more likely to decay into one state than the other, so this gives us a way to test this fundamental symmetry between matter and antimatter.

So what can be returned? question or before about this fundamental symmetry, it seems that if this perfect symmetry between matter and antimatter if the equal amount of each in our universe would simply destroy itself mm-hm and just as you mentioned, it seems that we live in a very unlikely universe where No destroys itself, yes, do you have any intuition on why that is? Well, I'm not a theory, I don't have any particular idea. I mean, I make measurements to test and prove these things, but I mean, in terms of the basic problem, is that at the Big Bang, if you use the Standard Model to figure out what should have happened, you should have gotten equal amounts of matter and antimatter because every time you create a particle in our collisions for the exam, but when we collide things together, you create a particle, you create an antiparticle, they always come together.

They always annihilate together, so there is no way to produce more matter than antimatter as we have discovered so far, which means that in the Big Bang you get equal amounts of matter and antimatter as the universe expands and cools during the Big Bang, not long after. the Big Bang I think a few seconds after the Big Bang you have this event called the great annihilation, which is where all the particles, the antiparticles collide with each other, annihilate and become mostly light and you end up with a later universe, if that's what happened. then the universe we live in today would be black and empty, apart from a few photons, that would be like that, there are things in this, there are things in the universe, it seems to be made simply of matter, so there is a great mystery as to Where it appeared.

This happens and there are several ideas that involve some sort of physics that happens in the first trillionth of a second or so of the Big Bang, so it could be that one possibility is that the Higgs field is somehow involved in this thing that there was this event. that took place in the early universe, where the Higgs field basically turned on, it took on its modern value and when that happened, this caused all the particles to gain mass and the universe basically went through a phase transition where there was a plasma hot massless particles and then in that plasma it's almost like a gas that turns into water droplets.

Small bubbles form in the universe, where the Higgs field has acquired its modern value, the particles have mass and this phase transition in some models can cause more matter. that antimatter is produced depending on how matter bounces around in these bubbles in the early universe, so that's one idea, there are other ideas that have to do with neutrinos, that there are exotic types of neutrinos that can decay in a biased way to become only matter and not antimatter. and people are trying to test these ideas, that's what we're trying to do at LHC B, there are neutrino experiments planned, they're trying to do this kind of thing too, so yes, there are ideas, but at the moment there is no clear evidence of which.

Some of these ideas may be right, so we are talking about some amazing ideas, by the way, never hurt anyone, be so eloquent when describing even just a standard model, so I am amazed, I only listen if you are interesting, just have fun enjoying it . So, yes, theoretical particle physics is fascinating to me. One of the most fascinating things about the Large Hadron Collider is the human side of it, where a group of brilliant people who probably have egos got together and collaborated together and countries. I guess collaborating together, you know, for the funds and that it's all just collaboration everywhere because maybe I don't know what the right question is here, but almost what is your intuition about how this was able to happen and what the lessons are?

What should we do. learn for the future of human civilization in terms of our scientific progress because it seems like this is a great illustration of how we work together to do something great. Yes, I think it's possibly the best example I can think of of international collaboration. Basically, for some unpleasant purpose, you know, I mean, so when I started in this field in 2008, as a new PhD student, the LHC was basically finished, so I didn't have to go around asking for money for it or trying to expose the case, so I have great admiration for the people who accomplished this because this was a project that was first imagined in the 1970s and the late 1970s was when the first talks about the LHC were discussed and it took two decades and a half. of campaigning and fundraising and persuasion until they started breaking ground and building it in the early 2000s, so I think the reason just from the standpoint of this type of science, the scientists there, I think the reason In Ultimately what works is that everywhere everyone is there for the same reason, which is good in principle, at least they are there because they are interested in the world and want to know what the basic ingredients of our universe are. . the laws of nature, so everyone is going in the same direction, of course, everyone has their own things they are interested in, everyone has their own careers to consider and you know and pretend there aren't many competitions, this is funny .

What in these experiments are your collaborators, your eight hundred collaborators at the LHC, but you are also competitors because you are academics at your various universities and you want to be the one who publishes the article with the most citations, you already know new measurements. So there's a funny thing where you're trying to stake out your territory and at the same time you're collaborating and you have to work together to make the experiments work and it actually works incredibly well considering all of that and I think there was actually, I think, McKinsey. or one of these big management consulting firms came into CERN about a decade ago to try to understand how these organizations work.

They discover it. I don't think they can. I mean, I think one of the things that interests one about the other. The interesting thing about these experiments is that in their large operations, such as the media, there are 3,000 people. Now there is one person nominally who is the boss of Atlas. They are called spokesperson and the spokesperson is usually elected by the collaboration, but they have no real power. I really mean they can't fire anyone, they're not anyone's boss, so you know, my boss prefers the professor, a Cambridge professor, not the boss of my experiments, the boss of my experiment can't tell me what to do. really and I mean, all you have are independent academics who are their own bosses, who you know, so somehow, though, through a kind of consensus and discussion and a lot of meetings, you know that things happen and they get done , but it's like the Queen hears you. in the UK she's the spokesperson again so no don't pick her you know whatever everyone seems to love her.

I don't know from my outside perspective, yes, but yes, giant egos, brilliant people and in the future, do you think I would choose anyone? Bring up one thing you said, just that thing about brilliant people because no, I'm not saying that people aren't great, yes, but I think there is this kind of impression that physicists will have to be brilliant or genius, which is not true. is. It's actually true and you know you have to be relatively bright for sure, but you know a lot of people, a lot of the most successful experimental physicists and not necessarily the people with the biggest brains, are the people you know particularly one of the skills.

The most important thing in particle physics is the ability to work with others and collaborate and exchange ideas and also work hard and often it's more of a determination or some kind of other skill set that's not just being, you know, a big brain. , very true, so I mean there are parallels to that in the world of machine learning, if you wanted to, if you want to solve any real world problem, what I see is that particle accelerators are essentially an instantiation of theoretical physics in the real world and, for example, that you don't necessarily have to be brilliant, but rather obsessed, systematic, rigorous, not very stubborn, all those kinds of qualities that make a great engineer, so this scientific scientist, purely speaking, is the practitioner of the scientific method, so you're right, but anyway Timmy.

That's Timmy, he's been my father as a physicist. I argue with him all the time. To me, engineering is the highest form of science and he thinks it's nonsense that the real work is done by theoretical editing, so we actually have arguments about things like that. people like Elon Musk, for example, because I think his work is pretty brilliant, but fundamentally he's not making any serious progress, he's just creating in this world by implementing. I would like ideas to happen and have a big impact for me. That's the Edison. that Timmy is a brilliant piece of work, but to him it's complicated details that someone will discover anyway that's all.

I mean, I don't know if you think there's a real difference in temperament between, say, a physicist and an engineer, if it's just What interested you, I don't know, I mean because you know a lot of what experimental physicists do is , to some extent, engineering and it's not what I do. I mainly do data stuff, but you know a lot of people would be called electrical engineers. but they trained as physicists but they learned electrical engineering, for example, because they were building detectors, so there is not such a clear division. I think so, it's interesting, I mean, but it seems like if you work with data, there seems to be a certain like if Ifor those kinds of things how do you think about communication process of communicating these ideas in a way that is inspiring, what I would say, his talks are inspiring to please the general audience.

Actually, you don't have to be a scientist. You can still get inspired without really knowing much about yourself. Start from the beginning. very basic, so what is the preparation process and then the romantic question is how does it feel to perform here? I mean the profession, yes, I mean the process, I mean the talk. My favorite talk I gave here was a call beyond the Higgs, which you can find on every institution's YouTube channel, which you should go watch. I mean, their channels have a lot of great talks and a lot of great people too. I mean, I gave one a version many times, so part of it is just practice, right?

And I don't really have a great theory about how to communicate with people. It's more that I'm really interested and excited about those idiots and I like talking about them and during the process of doing it. I guess I discovered stories that work and explanations that well, you see a practice, you legitimately mean just giving talks, I said I started, you know, when I was a PhD student giving talks in schools and I still do that too. of time and doing things, I haven't done a bit of comedy, which went reasonably well, even if it was scary and that's unusual, there's also a new one that I wouldn't necessarily recommend. look at that, I'm going to post the links in various places to make sure people click on them, yeah, it's basically like I have a story in my head and, you know, I have an idea about what I want to say.

I usually have some images to back up what I'm saying and I get up and do it and I don't really wish there was some kind of process. You should probably have some proper process. This sounds like I'm just making it up. Move on and I think the bottom line they said is I don't know if you know who a guy named Joe Rogan is, yeah he's fine, so he also sounds like you in the sense that he's not. He's very introspective about his process, but he's an incredibly engaging conversationalist and I think one of the things that you and he share that I could see is a genuine curiosity and passion for the subject.

I think that could be captured systematically. You know, I'm cultured. Sure there is a process, but somehow you come to it naturally. I think maybe there's also something else that is understanding something. There's this firefighter quote, you name it, which is what I can't create. I don't understand, so I don't do it. I'm not particularly super bright, so to understand something I have to break it down to its simplest element, yeah, and you know, if I can tell people about it, that helps me understand it too, so. In fact, I've learned to understand physics a lot more from the communication process because it forces you to really examine the ideas you're communicating in a coffin and makes you realize that you don't really understand the ideas.

I'm speaking and I'm writing a book right now. I had this experience yesterday where I realized I didn't really understand a pretty fundamental theoretical aspect of my own topic and I had to hide away for a couple of hours. of days reading textbooks and thinking about it to make sure that the explanation I gave captured as close as possible to what is actually happening in the theory and to do that you have to really understand it correctly and yes, and there are layers to understanding it, Yeah. It seems like the more there has to be some kind of Fineman's law, I mean, the more you understand the services, you're just able to convey, you know the essence of the idea, so it's like that the other way around.

The effect is that the more you understand, the simpler what you actually convey and therefore the more accessible in some ways it becomes, that's why Weak Fineman's lectures are really accessible, it was just contradictory, yes, although there are some ideas that are very difficult to explain, it doesn't matter. how well or poorly you understand, I still can't adequately explain the Higgs mechanism, yes, because some of these ideas only exist in mathematics and the only way to really develop an understanding is to unfortunately get a graduate degree in physics, but I think you can get an idea of ​​what is happening and I am trying to do it in a way that is not misleading but also intelligible, so let me ask you the romantic question of what is for you the most unfair question.

It's the most beautiful idea in physics One that fills you It's the most surprising The strangest The strangest There are many different definitions of beauty mmm-hmm and I'm sure there are several for you, but does anything come to mind? that you think is especially, I mean, well, beautiful, there's something specific about something more general, so maybe the specific, a first widget is a cone. I first came across this when I was a student, I found it incredible, so this idea that the forces of nature electromagnetism strong force the weak force that arise in our theories has a consequence dissymmetries so symmetry is in the laws of nature in essentially the equations that are used to describe these ideas the process by which theories create these types of models as they say imagining that the universe obeys this particular type of symmetry is a symmetry that is not so far removed from a geometric symmetry as the rotations of a cube, it's not that you can't think about it that way, but it's a similar idea and you say okay, if the universe respects the symmetry that you find that you have to introduce. a force that has the properties of electromagnetism or a different symmetry you get the strong force or a different symmetry you get the weak force then these interactions seem to come from something deeper, it suggests that they come from some deeper symmetry principle, I mean it depends a little bit about how you look at it because it could be that we were actually just recognizing symmetries, you see, but there's something quite charming about that, but I guess one more important thing that makes me wonder is, actually, if you look at the laws of nature , as? particles interact when you get very close, they're basically pretty simple things, they bounce off each other exchanging, you know, through force fields and they move in very simple ways and somehow these basic ingredients, these few particles that we know and the forces. creates this universe that is incredibly complicated and has things like you and me in it and you know, the Earth and the stars that produce matter there caused by this from the gravitational energy of their own mass that is then sprayed into the universe and forms other things.

I mean the fact that there's an incredibly long history that goes back to, you know, as far back as we can, we can take history back to, you know, a billionth of a second after the Big Bang, we can trace the origins of things. that we are made and altum Utley comes from these simple ingredients with these simple rules and the fact that you can generate such complexity from that is really mysterious and strange, I think, and it's not even a question that physicists can really address because we are kind of trying to find these really elementary laws, but it turns out that going from elementary laws and a few particles to something even as complicated as a molecule becomes very difficult and therefore going from a molecule to a human being is a problem that, as you know, can be solved.

It can't be addressed, at least not right now, so yes, the emergence of complexity from simple rules is so beautiful and so mysterious, and we also don't have good mathematics to even try to address that emerging phenomenon, which is why we have chemistry. and biology and other subjects too, yeah, I don't think, I don't think there's a better way to finish it, Harry, I can't, I mean, I think I speak for a lot of people who can't wait to do it. Look at what will happen in the next 5, 10 or 20 years with you. I think you're one of the great communicators of our time, so I hope you continue that and I hope it grows.

I'm definitely a big fan, so it was an honor to talk to you. today, thanks to someone, thank you so much for listening to this conversation with Harry Cliff and thanks to our sponsors, expressvpn app and cash. Consider supporting the podcasts by getting expressvpn and expressvpn comm slash flexpod and downloading the cash app and using compilation podcasts if you enjoy this podcast please subscribe on youtube review it with five stars a patreon supported apple podcast just connect with me on twitter at lex Friedman and now let me leave you with some words from Harry Cliff, you and I are remnants of every particle of our bodies. is a survivor of an almighty matter-antimatter shootout that occurred shortly after the Big Bang; in fact, only one in a billion particles created at the beginning of time has survived to this day.

Thanks for listening and I hope to see you next time. you