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Did Fermilab just discover a new particle? · Daniel and Kelly’s Extraordinary Universe

0:08
Speaker 1: Hey all, Hey, do you know what today is? Wednesday?
0:12
Speaker 1: It's Wednesday, April seventh. Today is like Christmas for particle physicists. Really,
0:18
Speaker 1: but what if you don't celebrate Christmas, Well, then it's
0:20
Speaker 1: like Christmas and Hanukkah and Valentine's Day and your birthday
0:25
Speaker 1: all rolled into one. Nice. Does that mean all particle
0:27
Speaker 1: physicists get a special box of chocolates today? Kind of?
0:31
Speaker 1: Today's a day we find out the answer to a
0:34
Speaker 1: question we've been waiting twenty years for. Does that mean
0:38
Speaker 1: the chocolate's are twenty years old? To let's just holl
0:40
Speaker 1: him that particles and chocolates age like fine wine. Hi
0:59
Speaker 1: amor handmad cartoonists and the creator of PhD Comics. I
1:02
Speaker 1: am Daniel. I'm a particle physicist, and I like my
1:05
Speaker 1: chocolates nice and fresh, fresh out the cocoa tree. I've
1:10
Speaker 1: actually had cocoa beans themselves. They're pretty intense but tasty chocolate.
1:15
Speaker 1: The Universe and so welcome to our podcast, Daniel and
1:17
Speaker 1: Jorge Explain the Universe, a production of I Heart Radio
1:20
Speaker 1: in which we take a bite out of everything in
1:22
Speaker 1: the universe. We sample the flavors of corks, we talk
1:25
Speaker 1: about the size and the speed of black holes. We
1:28
Speaker 1: talk about how the universe got to be this way
1:30
Speaker 1: and the way it will look in a billion, or
1:33
Speaker 1: a trillion or a gazillion years. We have ambitions to
1:36
Speaker 1: take the entire universe and explain every little bit of
1:39
Speaker 1: it to you because there is a lot to understand
1:42
Speaker 1: and to learn about the universe, and the scientists are
1:45
Speaker 1: currently added trying to explore what things are made out
1:49
Speaker 1: of and what things can be made out of. That's right,
1:52
Speaker 1: when we're not taking a break to do a podcast,
1:54
Speaker 1: we are trying to unravel the nature of the universe
1:56
Speaker 1: by figuring out what are the smallest bits of it,
1:59
Speaker 1: how do those bits fit together, what are the patterns
2:02
Speaker 1: of those bits, and are there more bits we haven't
2:05
Speaker 1: found yet. Yeah, because there has been a lot of
2:08
Speaker 1: progress in physics and particle physics and understanding what matter
2:11
Speaker 1: and the forces are all made out of in this universe,
2:14
Speaker 1: but it's sort of an ongoing effort. There are still
2:17
Speaker 1: nooks and crannies and corners we haven't explored, and possibly
2:20
Speaker 1: big areas of physics that still remain totally unknown. Job
2:25
Speaker 1: security for a particle physicists. More nooks and crannies to explore.
2:30
Speaker 1: But no, you're absolutely right. We have found out a
2:32
Speaker 1: lot about the sub atomic nature of matter, but there
2:35
Speaker 1: are still lots of questions we don't know the answer to,
2:38
Speaker 1: and that tells us that there's probably a lot going
2:40
Speaker 1: on that we don't have any clue about. We don't
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Speaker 1: know if we figured out like most of the puzzle
2:45
Speaker 1: and we have a few details to wrap up, or
2:47
Speaker 1: if we're just looking at the tip of the particle iceberg.
2:50
Speaker 1: But then what is that iceberg made out of tanuel?
2:52
Speaker 1: And what does it float on? It's all questions embedded
2:55
Speaker 1: in questions. It floats on a sea of confusion. Yeah,
2:59
Speaker 1: and O cartoons are probably drowning in the scene there.
3:02
Speaker 1: But it is a pretty exciting time to be in physics.
3:05
Speaker 1: There are a lot of interesting results lately and coming
3:08
Speaker 1: out of the physics community, and so recently there was
3:11
Speaker 1: another big announcement. Yeah, that's right. We've had this mystery
3:14
Speaker 1: that's been sort of outstanding for twenty years, the result
3:18
Speaker 1: of an experiment that was quite surprising that didn't agree
3:21
Speaker 1: with our theoretical calculations. It suggested that maybe something new
3:25
Speaker 1: was going on, maybe it was being influenced by some
3:28
Speaker 1: other kind of particle or force and we hadn't yet discovered,
3:31
Speaker 1: but it wasn't really precise enough for us to know
3:33
Speaker 1: for sure, for us to hang our hats on. So
3:36
Speaker 1: people built a bigger, better, stronger, faster experiment to make
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Speaker 1: a more precise measurement, and those were the results that
3:42
Speaker 1: were just recently revealed. Yeah, and so to be on
3:45
Speaker 1: the podcast, we'll be talking about did Firmulab just discover
3:54
Speaker 1: a new particle whatever? Fermilab just discovered they definitely figured
3:58
Speaker 1: out how to trigger a lot of science headlines. Oh yeah,
4:01
Speaker 1: it was this pretty big in the pressed. This was everywhere.
4:04
Speaker 1: I don't think it's been a science event recently that
4:06
Speaker 1: triggered as many emails from listeners saying, what is this?
4:09
Speaker 1: Explained this to us, what's going on? I need to understand.
4:12
Speaker 1: It was everywhere I saw. It was on the front
4:14
Speaker 1: page in the New York Times, and people were tweeting
4:17
Speaker 1: about it. So it's kind of interesting and maybe significant
4:20
Speaker 1: result in physics. And for me, it was fascinating to
4:22
Speaker 1: see the sort of variety of headlines that people took,
4:26
Speaker 1: Like the New York Times was pretty stately and understated
4:29
Speaker 1: about it, but other places like Vice that had a
4:31
Speaker 1: headline that reads, government physics experiments suggests something unknown is
4:36
Speaker 1: influencing reality. Wow, that sounds like a pretty good plot
4:42
Speaker 1: for a movie. And I think it's technically true, isn't it.
4:45
Speaker 1: You know, it's an interesting choice of vocabulary, but it
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Speaker 1: is technically Every word in that headline is true. Government
4:52
Speaker 1: physics experiment suggests something unknown is influencing reality. There you go.
4:57
Speaker 1: You know, I can fact check it. It's definitely accurate.
4:59
Speaker 1: It was done by government physicists, and there is something
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Speaker 1: out there influencing that experiment. I don't know about all
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Speaker 1: of reality, but it's definitely true. With so kudos to
5:09
Speaker 1: that headline writer. They definitely took this sort of like
5:11
Speaker 1: movie trailer approach to writing that headline and how they
5:14
Speaker 1: added government physics experiment, Like, first of all, are there
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Speaker 1: non government physics experiment? Not many? Second of all, it
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Speaker 1: just makes it more sinister, doesn't it. No, I don't
5:22
Speaker 1: know they're going for sinister or like authoritative. You know,
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Speaker 1: this is not your friend Joe's physics experiment. This is
5:28
Speaker 1: like people in lab coats getting salaries. You know, you
5:31
Speaker 1: should believe this does still really have any friends. Let's
5:34
Speaker 1: be honest, I think they were going for sinister, you know,
5:36
Speaker 1: like the government is trying to do something crazy. Oh man,
5:39
Speaker 1: I just totally misread this one. I thought it was like,
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Speaker 1: trust us, we discovered something crazy, but instead you're suggesting
5:45
Speaker 1: it's like government about to build doomsday device that will
5:48
Speaker 1: ruin your weekend. I think that reveals your attitude towards government.
5:52
Speaker 1: An you're like trusting of the government more government. Hey,
5:56
Speaker 1: I'm a government physicist, so you know, I see you're
6:00
Speaker 1: one of them. Do you wear like, you know, sunglasses
6:04
Speaker 1: with your white lap coats and everything? Only when I'm
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Speaker 1: trying to influence reality, which is basically all the time.
6:08
Speaker 1: Since I'm part of reality, this podcast is influencing reality,
6:12
Speaker 1: is it though? We're just sound ways in the air, Daniel,
6:16
Speaker 1: Unless you think our listeners aren't part of reality, you know,
6:19
Speaker 1: hopefully they're real, but we don't have to be real.
6:21
Speaker 1: You know. This podcast is generated by an algorithm, a
6:24
Speaker 1: government physics algorithm. It's it's unreal. Anyways. It was a
6:28
Speaker 1: pretty big result, a lot of impressive out there about it,
6:31
Speaker 1: and I have to admit, Daniel, I didn't know about
6:33
Speaker 1: this weeks before the actual announcement. Oh wow, is that
6:36
Speaker 1: because you have a link into like the secret science
6:39
Speaker 1: results kinda I was commissioned to to make a comic
6:43
Speaker 1: about it by a journal, and so they sent me
6:46
Speaker 1: the secret paper weeks ago, saying you can't share it
6:48
Speaker 1: with anybody. Are you telling me you knew this answers
6:50
Speaker 1: one of the biggest questions in particle physics for weeks
6:53
Speaker 1: and didn't tell me a sworn of secrecy, Daniel. They
6:55
Speaker 1: would have revoked my cartoon is license if I've had
6:59
Speaker 1: told anyone. Plus also that they're like, they gave me
7:01
Speaker 1: the paper and they're like, you can't tell anyone what
7:03
Speaker 1: it says. And I'm like, I can't even read this paper.
7:06
Speaker 1: I wouldn't be able to tell you tell anyone, but
7:08
Speaker 1: my friend Daniel could read this paper. All right, Well,
7:14
Speaker 1: I admire your integrity. Yeah, thank you. At least you
7:17
Speaker 1: admire something about me. But it was a pretty exciting
7:20
Speaker 1: thing in the physics community. And let's talk about whether
7:23
Speaker 1: or not it lives up to the hype business, really
7:26
Speaker 1: something that might influence our view of reality or is
7:29
Speaker 1: it sort of another incremental result in the physics endeavor
7:33
Speaker 1: of humans? Yeah, well, you know, it's an important moment
7:36
Speaker 1: in particle physics because we have been desperate for a
7:39
Speaker 1: discovery for quite a long time, you know, I would
7:42
Speaker 1: say decades. We have known for a long time that
7:45
Speaker 1: our theory isn't correct, that isn't complete, at least it
7:49
Speaker 1: can't be the final answer, because there's so many unanswered
7:52
Speaker 1: questions in it, so many parts of our theory which
7:54
Speaker 1: just seems sort of like ad hawk or put in
7:57
Speaker 1: by hand, or unexplained. So we've been cast thing about
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Speaker 1: for a new discovery to give us a clue as
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Speaker 1: to how to change our theory or what the new
8:04
Speaker 1: vision of physics should be. And the main strategy for
8:08
Speaker 1: doing that has been things like building big particle accelerators,
8:11
Speaker 1: to trying to make new particles that we can add
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Speaker 1: to our table and give us a sense of the
8:15
Speaker 1: larger patterns. But that's been coming up kind of dry.
8:19
Speaker 1: We haven't found anything at the large age on collider
8:22
Speaker 1: other than the Higgs boson, which we already believed existed.
8:25
Speaker 1: So now we're sort of like looking under every rock.
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Speaker 1: Is there any experiment out there that can find something new?
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Speaker 1: Is there any measurement government physicists can do to find
8:34
Speaker 1: some discrepancy between our theory and nature because we need
8:39
Speaker 1: that kind of discrepancy in order to find something new.
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Speaker 1: So that's why this experiment is sort of like one
8:44
Speaker 1: of the last best hopes for particle physics, that we
8:47
Speaker 1: can figure out something new, find a clue that reveals
8:50
Speaker 1: a new idea about the nature of reality. I guess
8:54
Speaker 1: for some of our listeners who maybe we did not
8:56
Speaker 1: see the headlines, let's just talk about the announcement. So
8:58
Speaker 1: this was an announcement coming at a Fermi Lab, which
9:01
Speaker 1: is a particle physics laboratory outside of Chicago, and they've
9:05
Speaker 1: been around for forever, but and recently they announced that
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Speaker 1: some new results regarding the muan, which is a particle. Right,
9:12
Speaker 1: that's right, So you're familiar with the electron. It's part
9:14
Speaker 1: of you. It orbits all your atoms. The electron has
9:17
Speaker 1: a heavy cousin. It's much heavier than the electron, but
9:20
Speaker 1: it's otherwise totally identical. And the very existence of the
9:24
Speaker 1: muan is sort of a mystery, like why do we
9:26
Speaker 1: even have a muan. We don't know, but it's like
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Speaker 1: this copy of the electron, and it's a good place
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Speaker 1: to do precision measurements to try to like see if
9:34
Speaker 1: there's anything weird going on, because the muan has this
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Speaker 1: little magnetic field, and that magnetic field is very sensitive
9:40
Speaker 1: to the stuff going on all around the muan. Yeah,
9:43
Speaker 1: so they've been studying this particle for a long time
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Speaker 1: and they just did a new measurement of its magnetic
9:49
Speaker 1: moment and the results are what's kind of interesting with
9:53
Speaker 1: regards to what it means for our view of the universe.
9:56
Speaker 1: That's right, and you might be wondering, like, why does
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Speaker 1: the muan have a magnetic field? How does that even work?
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Speaker 1: We'll remember, a muan is this tiny fundamental particle. We
10:04
Speaker 1: don't really know if it's made of anything smaller. We
10:06
Speaker 1: sort of imagine it to be a tiny little dot.
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Speaker 1: But even though it's a tiny little dot, we also
10:11
Speaker 1: think it has this thing called quantum spin, which means
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Speaker 1: that in theory, it has some angular momentum because it
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Speaker 1: has electric charge and angle momentum. That means it has
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Speaker 1: a little magnetic field. And that magnetic field is a
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Speaker 1: really nice way to probe what the particle is doing
10:27
Speaker 1: as it flies through space. Is it just flying through
10:30
Speaker 1: space or does it also shoot off other particles briefly?
10:33
Speaker 1: And if it does shoot off other particles. Then, even
10:36
Speaker 1: though these are virtual particles that only exist for a
10:39
Speaker 1: fraction of a second, they can change the way the
10:42
Speaker 1: muan's magnetic field works. And it's sort of a great
10:45
Speaker 1: way to figure out what kinds of particles can exist,
10:49
Speaker 1: what's out there on nature's menu. Because it's quantum mechanical,
10:53
Speaker 1: every kind of particle that can be shot off the
10:55
Speaker 1: muan will be created and influence the muan's magnetic field.
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Speaker 1: So don't thing of the particles out there waiting for
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Speaker 1: the muan. They are like possible particles that the muan
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Speaker 1: briefly creates as it flies. If you like fields instead
11:08
Speaker 1: of particles, then another equivalent way to think about it
11:11
Speaker 1: is that the muan is flying through a bunch of
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Speaker 1: quantum fields and its energy can slide briefly into those
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Speaker 1: fields and then come back. Since that influences the muan's
11:20
Speaker 1: magnetic direction, you can tell when it happens, which gives
11:24
Speaker 1: you a clue if there are fields and particles you
11:27
Speaker 1: don't know about. And so what they do is they
11:29
Speaker 1: take this muan and they spin it in a certain direction,
11:32
Speaker 1: so they know the way it's going, sort of like
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Speaker 1: a gyroscope and then they stend it around in a
11:36
Speaker 1: circle a bunch of times until it decays into an
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Speaker 1: electron because muans don't actually last very long. They're unstable particles,
11:43
Speaker 1: and based on the direction the electron came out, they
11:45
Speaker 1: can tell how the muan was spinning. So now they
11:47
Speaker 1: know how the muan spin change from when they created
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Speaker 1: it to when it decayed, and that tells them basically
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Speaker 1: how all the other little particles out there were pushing
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Speaker 1: on the magnetic field of the muan, which tells you
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Speaker 1: something about what particles are out there. And they're measuring
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Speaker 1: this magnetic field of the muan, and I guess maybe
12:05
Speaker 1: a more basic question is like why do particles have
12:08
Speaker 1: magnetic fields? Isn't that weird? Like our particles little magnets. Yeah,
12:12
Speaker 1: it's kind of weird because you think of little particles
12:15
Speaker 1: as these little dots, and you know they have like
12:17
Speaker 1: spin and charge and mass and stuff. But anything that
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Speaker 1: has spin, quantum spin and has electric charge also has
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Speaker 1: a little magnetic field because remember that's where magnetic fields
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Speaker 1: come from, Like the magnetic field of your piece of
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Speaker 1: iron comes from electrons spinning inside of it, and so
12:36
Speaker 1: muans also spin, so they also have a small, little
12:39
Speaker 1: magnetic field. So then I guess the next question is
12:42
Speaker 1: why is this magnetic field of this little particle important
12:46
Speaker 1: and what could it tell us about other particles that
12:48
Speaker 1: could be out there. It's really important because the magnetic
12:51
Speaker 1: field tells us about the other particles that are out there,
12:53
Speaker 1: because the magnetic field allows the muan to sort of
12:56
Speaker 1: interact with those particles. As the muan is flying along,
13:00
Speaker 1: then the magnetic field gets sort of touched by all
13:02
Speaker 1: the other particles that are out there, you know. For example,
13:04
Speaker 1: like this magnetic field is carried by photons, so the
13:08
Speaker 1: way that magnetic field information is transmitted is through photons.
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Speaker 1: So muan can be flying along, it can like pop
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Speaker 1: off a little photon and then reabsorb it. And it
13:17
Speaker 1: can pop off a photon and that photon can interact
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Speaker 1: with other particles that can come out of the vacuum,
13:22
Speaker 1: you know, like pairs of electrons and positrons or any
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Speaker 1: other particle out there, and then get reabsorbed. So sort
13:28
Speaker 1: of what happens to that photon when it gets shot
13:30
Speaker 1: off the muan and then re absorbed can influence the
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Speaker 1: magnetic field of the muan and also can tell you
13:35
Speaker 1: about the other particles that are out there that can
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Speaker 1: talk to this magnetic field. And remember that by particles
13:41
Speaker 1: out there, we don't mean particles that are already existing
13:44
Speaker 1: and are hanging out waiting for the muan, but possible
13:48
Speaker 1: particles on nature's menu that can be created from the
13:51
Speaker 1: Muan's energy. That's what we're looking to explore. Well, I
13:54
Speaker 1: see you used sort of like the magnetic field of
13:56
Speaker 1: the muon is kind of an antenna almost, like do
13:58
Speaker 1: you use it to see how it gets influenced by
14:02
Speaker 1: other particles that are out there in the universe exactly,
14:06
Speaker 1: just like an antenna, because all those other particles also
14:09
Speaker 1: can sort of like talk magnetic language to the muon.
14:12
Speaker 1: And if you watch really carefully how the muan is
14:15
Speaker 1: spinning in the direction of its magnetic field, you can
14:17
Speaker 1: tell the signals that it's picking up from those other particles.
14:20
Speaker 1: And it's sort of like a gyroscope. You know, you
14:22
Speaker 1: start a gyroscope spinning, it should keep spinning the same
14:25
Speaker 1: way unless something applies forth to it. You know, give
14:28
Speaker 1: it a little push or a little twist or something.
14:30
Speaker 1: If you've got a muan spinning and you know the
14:32
Speaker 1: direction of its magnetic field, you can watch as that
14:34
Speaker 1: magnetic field changes and you can measure the influence of
14:37
Speaker 1: all the particles around it. Cool. So then that's what
14:40
Speaker 1: this experiment did, is that it's basically like a large
14:43
Speaker 1: tunnel or ring or like a tomb, and you have
14:46
Speaker 1: these muons flying around and you're sort of measuring how
14:49
Speaker 1: they get knocked around by the universe, basically how their
14:52
Speaker 1: little magnetic field gets tweaked by you know, what could
14:56
Speaker 1: possibly be out there in the universe. Yeah, it's a orcles.
15:00
Speaker 1: The muans go around in this ring and as they
15:02
Speaker 1: go around, they get tweaked by all these other particles,
15:05
Speaker 1: and it's a really cool way to try to find
15:07
Speaker 1: something new without knowing what's out there. Anything that interacts
15:11
Speaker 1: with the muan's magnetic field will give a little effect.
15:14
Speaker 1: So you add up all the different kinds of particles
15:17
Speaker 1: that can give an effect, and you get like an
15:18
Speaker 1: overall number, and you can compare that to what we
15:21
Speaker 1: calculate from our theory, where we add up the effects
15:23
Speaker 1: of all the particles we know about, and we can
15:26
Speaker 1: compare what nature is doing with all the real particles
15:29
Speaker 1: to what our calculations are doing. You know, with all
15:32
Speaker 1: the particles we know about, and that can give us
15:34
Speaker 1: a clue if there's any particles missing from our list. Cool. Yeah,
15:38
Speaker 1: you use this sort of like a metal detector, kind
15:40
Speaker 1: of like you're sensing what's out there. And if you
15:43
Speaker 1: think you know what's out there, then you should be
15:45
Speaker 1: able to predict what this little antenna will tell you.
15:48
Speaker 1: But if there are new things out there, the disintenna
15:51
Speaker 1: will not do what you expected to do. Yeah, and
15:53
Speaker 1: the differences are very very small. People have been calculating
15:56
Speaker 1: this stuff for decades and been measuring for decades, and
15:59
Speaker 1: most things agree. But if you measure it really, really precisely,
16:03
Speaker 1: then you can see the influence of like very rare,
16:06
Speaker 1: potentially new heavy particles. So we're talking about one of
16:09
Speaker 1: the most precisely known and most precisely measured quantities in
16:13
Speaker 1: all of physics. And the more precise we can make it,
16:17
Speaker 1: the better a test we can do to see if
16:18
Speaker 1: there are any particles out there that we might be missing.
16:21
Speaker 1: I guess you're looking super closely to see this little
16:24
Speaker 1: antenna you know, deviates from your theory, because if it
16:27
Speaker 1: deviates from your theory, that means your theory is not
16:30
Speaker 1: complete or there's new things out there. Yeah, and the
16:32
Speaker 1: experimental challenge is getting all the other sources of uncertainty
16:36
Speaker 1: out of the way, any other transient magnetic fields, or
16:39
Speaker 1: knowing exactly how you started this muan, or making sure
16:42
Speaker 1: nothing else is influencing it. It's a lot of work
16:45
Speaker 1: to set this experiment up and make it super duper precise.
16:48
Speaker 1: It's like lots of other experiments like the gravitational wave experiment,
16:51
Speaker 1: where they spent decades figuring out how to get those
16:54
Speaker 1: mirrors to balance and be really really quiet. There's a
16:56
Speaker 1: lot of just sort of like careful work in setting
16:59
Speaker 1: up the experiment like this, and there's also a lot
17:02
Speaker 1: of careful work in doing the calculation and making sure
17:04
Speaker 1: you're correctly accounting for all the particles that we do know.
17:08
Speaker 1: So it's like a huge project. It's not just like hey,
17:10
Speaker 1: I have this idea, let's go check this out tomorrow afternoon.
17:13
Speaker 1: You know, this takes decades to design and to organized
17:16
Speaker 1: and like really iron out all the wrinkles. Right. You
17:18
Speaker 1: get a wait for the chocolate to you know age,
17:21
Speaker 1: and you get to wait for everyone to sign the
17:23
Speaker 1: Valentine's Day card, and it just takes a long time,
17:27
Speaker 1: all right, Well, let's get into the theory of this
17:29
Speaker 1: experiment and also the experiment and how those two are
17:33
Speaker 1: not quite the same and what that means for our
17:36
Speaker 1: understanding of the universe. But first let's take a quick break.
17:52
Speaker 1: We're talking about Fermi labs recent announcement of a new
17:55
Speaker 1: interesting result regarding the men which is one of the
17:58
Speaker 1: fundamental particles, and they measured something about it and they
18:03
Speaker 1: predicted something about it, and it's not quite the same, Daniel,
18:06
Speaker 1: So maybe step us through what some of the theory
18:08
Speaker 1: calculations are and what they're actually calculating. So what they're
18:11
Speaker 1: trying to do is understand what happens when a muan
18:14
Speaker 1: is flying through space. And this is a quantum mechanical particle,
18:18
Speaker 1: and so you have to consider not just like the
18:20
Speaker 1: boring option that a muan just like flies through space
18:23
Speaker 1: and does nothing, but all the other possibilities. For example,
18:26
Speaker 1: a muan might also fly through space but emit a
18:29
Speaker 1: photon and then reabsorbed that photon. That's one possibility, it's
18:33
Speaker 1: not very unlikely. In fact, we think the particles are
18:36
Speaker 1: doing that all the time. And like we talked about
18:39
Speaker 1: in the episode about renormalization and like what's the electrons
18:42
Speaker 1: actual charge. What we measure is sort of like the
18:44
Speaker 1: combination of all the possibilities that the muan can do
18:47
Speaker 1: all at once. We don't just ever measure like a
18:50
Speaker 1: single particle doing one thing. So this kind of stuff
18:52
Speaker 1: is happening all the time. There's lots of different things
18:54
Speaker 1: that muan can be doing when it goes from A
18:56
Speaker 1: to B, and we try to consider like all those possibilities.
19:00
Speaker 1: So possibility one is just going a straight line. Possibility
19:03
Speaker 1: to is emit just a single particle and then reabsorb it.
19:06
Speaker 1: Possibility three is emit two particles and reabsorbed them. Possibility
19:10
Speaker 1: four is admit a photon and then that photon turns
19:13
Speaker 1: into two other particles which then collapse back into a photon,
19:17
Speaker 1: and then we can get reabsorbed by the muan. And
19:19
Speaker 1: you can imagine how it's easy to imagine lots and
19:21
Speaker 1: lots of different scenarios for what can happen for a
19:24
Speaker 1: muon when it goes from A to B, and all
19:26
Speaker 1: those scenarios affect the muan's magnetic moment just the same
19:30
Speaker 1: way all these kind of quantum interactions with the vacuum
19:33
Speaker 1: affect the electrons charge or its mass This is all
19:36
Speaker 1: part of like what makes the muan. So when you're
19:39
Speaker 1: calculating the overall magnetic moment of the muan, you need
19:42
Speaker 1: to account for all the things that it could be doing,
19:45
Speaker 1: including these little brief interactions it has where it interacts
19:48
Speaker 1: with magnetic fields and creates other particles. Right, So it's
19:52
Speaker 1: I guess it's kind of this idea that a particle
19:54
Speaker 1: isn't just like a particle like alone in the universe.
19:56
Speaker 1: It's like it's constantly doing stuff, doing quant the mechanical stuff.
20:00
Speaker 1: It's constantly you know, maybe popping off other particles and
20:04
Speaker 1: then reabsorming them, and it's not just like sitting there
20:07
Speaker 1: and doing nothing. Yeah, there's this difference between like the
20:09
Speaker 1: bare particle, which is sort of the simplest concept you
20:12
Speaker 1: can have in theory, than the actual particle in reality,
20:15
Speaker 1: which is part of the universe and interacting with all
20:17
Speaker 1: these quantum fields around it. And that's sort of like
20:20
Speaker 1: the thing we measured, the thing we observed. So the
20:22
Speaker 1: bare particle really only sort of exists in our minds
20:25
Speaker 1: like a single isolated particle doing nothing. In reality, the
20:28
Speaker 1: particles are constantly buzzing with all sorts of other virtual particles.
20:32
Speaker 1: And that's really what the muan is. Don't think of
20:34
Speaker 1: it like a muan surrounded by a cloud of other particles.
20:37
Speaker 1: The muan is that whole cloud. It's got like a
20:40
Speaker 1: bare particle at its core, but the whole thing together
20:43
Speaker 1: is the muan. And so it's sort of part of
20:46
Speaker 1: what the muan is is to have this cloud of
20:48
Speaker 1: other particles all part of it. Yeah, and it's kind
20:51
Speaker 1: of like a quantum mechanical cloud of other particles. It's
20:54
Speaker 1: constantly making right, Like, it's not just the bare particle,
20:57
Speaker 1: it's also at the same time simultaneously existing as all
21:01
Speaker 1: these other sort of with all of these other particles
21:04
Speaker 1: that are created and virtually exists for tiny moments of time. Yeah,
21:08
Speaker 1: And I think the quibble on the quantum mechanics of it,
21:10
Speaker 1: it's not really true that they all simultaneously exist, but
21:13
Speaker 1: that the possibilities of them all exist. And so there's
21:15
Speaker 1: a superposition of all those wave functions for the particle
21:18
Speaker 1: to be doing this or for the particle to be
21:20
Speaker 1: doing that, and if you're not measuring it, then all
21:23
Speaker 1: those options can exist at the same time. Doesn't really
21:26
Speaker 1: have a philosophical meaning to say, like they all actually
21:29
Speaker 1: do exist. But you know, that's a whole other digression.
21:31
Speaker 1: We can talk about quantum wave functions another time. So
21:34
Speaker 1: it's kind of like the cat, Like the cat is
21:36
Speaker 1: both live and dead, and that's so that's usually put,
21:38
Speaker 1: and so that me on is both alone and also
21:42
Speaker 1: has all these other friends around it. Yeah, well you
21:45
Speaker 1: might not be surprised to hear that I have an
21:47
Speaker 1: objection to how it's usually put. I would say the
21:49
Speaker 1: cat as a possibility of being alive and a possibility
21:51
Speaker 1: being dead. I don't know what it means for it
21:53
Speaker 1: to be alive and dead at the same time. That's
21:55
Speaker 1: the whole idea of classical physics that somehow these wave
21:57
Speaker 1: functions do collapse before we measure them. But in this case,
22:01
Speaker 1: there's an infinite number of things that meant can do.
22:03
Speaker 1: And the more particles you add, the more options, the
22:05
Speaker 1: more times like a particle emits another photon or turns
22:08
Speaker 1: into something else, the less likely those things are. So
22:11
Speaker 1: the most likely thing to happen is that the muon
22:14
Speaker 1: just sort of like goes from A to B. And
22:15
Speaker 1: then you can like add a correction to that by
22:17
Speaker 1: adding one particle, and you can add another correction to
22:20
Speaker 1: that by adding two particles. If you want to get
22:22
Speaker 1: like a rough idea, you just need to do a
22:24
Speaker 1: few of these calculations. If you want to get it
22:25
Speaker 1: like really really accurately, then you need to sum over
22:28
Speaker 1: like thousands and thousands of these different possibilities. It's kind
22:31
Speaker 1: of like, these are all different possibilities of what it
22:33
Speaker 1: can do, but somehow they all affect its magnetic field.
22:37
Speaker 1: And so like if you know, like it could do
22:40
Speaker 1: a B, C and D, you can add up a B,
22:42
Speaker 1: C and D and to get sort of like what
22:44
Speaker 1: the theory predicts what the magnetic field of me on
22:47
Speaker 1: is going to be? Right, that's right, And we use
22:49
Speaker 1: something called perturbation theory, which tells us that, like we
22:52
Speaker 1: do the biggest contributions first, and then the more ones
22:55
Speaker 1: that we add sort of we're just refining the smaller
22:57
Speaker 1: and smaller decimal places. So it's not like when we
23:00
Speaker 1: get to diagram number forty seven thousand, we're going to
23:03
Speaker 1: find something that totally changes the answer in the first
23:05
Speaker 1: decimal place. As we add diagrams that are more and
23:08
Speaker 1: more complex, we're getting smaller and smaller corrections, and so
23:11
Speaker 1: we're sort of like asthem tonically approaching what we think
23:14
Speaker 1: is the true value. But these calculations get harder and
23:16
Speaker 1: harder because the later diagrams have more particles, and they
23:20
Speaker 1: have loops and they have crazy stuff, and most importantly,
23:23
Speaker 1: some of these create particles that have the strong nuclear
23:25
Speaker 1: force in them, and those calculations are particularly tricky to do.
23:29
Speaker 1: And that's really at the heart of why this is
23:31
Speaker 1: so hard, right, And I guess the problem is that
23:34
Speaker 1: the neon it's not just doing a B, C and D.
23:36
Speaker 1: It's doing like abc d dot dot dot to like
23:39
Speaker 1: you know, infinite number of possibilities, right Like it it's
23:42
Speaker 1: almost like a fractal I think it's like it can
23:44
Speaker 1: be turned into a photon and then but then the
23:46
Speaker 1: photon can turn into two food things, and then those
23:49
Speaker 1: two things could turn into other things, and you know,
23:51
Speaker 1: the effects get smaller, but like the possibilities are endless,
23:54
Speaker 1: right Yeah. And there's a really interesting question. They're like,
23:57
Speaker 1: does it really have an infinite number of possibilities or
24:00
Speaker 1: is it just the way that we are organizing in
24:02
Speaker 1: our minds requires an infinite number of ideas because in reality,
24:06
Speaker 1: there's just a number. Like nature doesn't do an infinite
24:09
Speaker 1: number of calculations. Every time a muan goes from A
24:11
Speaker 1: to B, it just does its thing. So it could
24:13
Speaker 1: be like that our mathematics isn't expressed in a way
24:16
Speaker 1: that makes this kind of idea simple and compac Or
24:19
Speaker 1: it could be that there really are an infinite number
24:21
Speaker 1: of things possibly going on there, we just don't know.
24:23
Speaker 1: It's a really fun philosophical question. Philosophy. Yeah, we need
24:28
Speaker 1: a longer podcast for that, all right. So you can
24:30
Speaker 1: sort of predict what the meos magnetic field is supposed
24:33
Speaker 1: to be from all these other like virtual particles, and
24:35
Speaker 1: then you can also go out and measure the magnetic
24:38
Speaker 1: field using an experiment exactly. And that's what they did,
24:41
Speaker 1: like twenty years ago at Brookhaven. They did this experiment
24:45
Speaker 1: where they line up a bunch of muans, they get
24:47
Speaker 1: them all spinning in the right direction, and then they
24:50
Speaker 1: shoot them into their machine which zips them around in
24:52
Speaker 1: a circle using a big magnetic field. So they build
24:55
Speaker 1: this really big, very precise, very expensive magnet and they
24:58
Speaker 1: did this measurement this is twenty years ago at Brookhaven,
25:01
Speaker 1: and they found that the answer didn't really agree with
25:03
Speaker 1: their theoretical calculations and that's sort of what's set up
25:06
Speaker 1: what we're doing today. Because people were wondering about, like
25:09
Speaker 1: why doesn't this agree? So they decided they needed to
25:12
Speaker 1: do another experiment. They need to get more data, they
25:15
Speaker 1: need to like, you know, refine this answer. So they
25:17
Speaker 1: actually took that same magnet from Bookhaven and they shipped
25:20
Speaker 1: it over to Fermi Lab where they set up a
25:22
Speaker 1: whole new experiment using the same magnet, and they have
25:25
Speaker 1: like much much more data and they've been analyzing that
25:29
Speaker 1: and that's what the announcement was all about. Do you
25:30
Speaker 1: think they used the regular like U S Mail or
25:32
Speaker 1: did they fetexit or how does it want ship a
25:34
Speaker 1: giant physics magnet? You just put a lot of stamps
25:38
Speaker 1: on it and you hope that they pick it up.
25:40
Speaker 1: You no, this have great pictures. They had to take
25:42
Speaker 1: it on a boat for a while. They have it
25:44
Speaker 1: on this like double wide trailer crawling across the Fermi Lab.
25:47
Speaker 1: It was pretty cool. It's not an easy thing. The
25:50
Speaker 1: ship is definitely some additional charges. And I think the
25:53
Speaker 1: idea is that twenty years ago, like they found that
25:55
Speaker 1: the theory and the experiment are not the same. But
25:58
Speaker 1: it's sort of like borderline right, like it was three
26:00
Speaker 1: point five sigma difference, meaning it's like it's different, but
26:04
Speaker 1: it could be still kind of a statistical fluke. Right. Well,
26:07
Speaker 1: it's funny because we do all these things really quantitatively.
26:10
Speaker 1: We're very careful about the number when we're calculating it,
26:13
Speaker 1: and that we're very careful about theoretical value that we
26:15
Speaker 1: do really quantitative statistics to understand, like what's the probability
26:19
Speaker 1: that these two numbers are actually different versus that we
26:22
Speaker 1: just have like a random fluctuation in our experiment that
26:24
Speaker 1: makes them look different, because we don't want to get
26:26
Speaker 1: fooled by just like having a random fluctuation. So we
26:29
Speaker 1: do all these really careful calculations and then in the
26:32
Speaker 1: end it's still subjective because three point five sigma tells you,
26:35
Speaker 1: like the probability for this to not have been just
26:38
Speaker 1: a fluctuation, and it says it's pretty small, but it's
26:41
Speaker 1: not convincing, Like particle physicists don't find that level of
26:45
Speaker 1: discovery enough to believe the result. So three point five
26:48
Speaker 1: sigma is kind of impressive but sort of not enough.
26:51
Speaker 1: So I guess you could call it borderline. Yeah, it's
26:54
Speaker 1: kind of like flipping a coin and trying to see
26:55
Speaker 1: if it's like a loaded coin. And you get seven
26:58
Speaker 1: or seventy five heads in a row or out of
27:00
Speaker 1: a hundred, and you're like, does that mean that it's
27:03
Speaker 1: a loaded coin or does that mean that I just
27:05
Speaker 1: got lucky and got seventy five heads out of a hundred.
27:09
Speaker 1: And that's where the subjective element comes in. At what
27:11
Speaker 1: point do you declare this coin is fair? At what
27:13
Speaker 1: point do you declare the coin is not fair? And
27:15
Speaker 1: so in our field, we have this standard of five stigma,
27:18
Speaker 1: which is like one in three and a half million
27:21
Speaker 1: chants of it being a random fluctuation, And so three
27:24
Speaker 1: and a half stigma sounds like it's close to five stigma,
27:27
Speaker 1: but it's a whole gaussy entail kind of a thing,
27:29
Speaker 1: and so it's actually not that close. All right, So
27:31
Speaker 1: they put these muance inside of a magnetic ring and
27:34
Speaker 1: they're growing around and they're spinning, and you're sort of
27:36
Speaker 1: measuring also what happens to those muans, right, and kind
27:40
Speaker 1: of what happens to them tells you the value of
27:43
Speaker 1: the muance magnetic field. Yeah, so they get these muans
27:46
Speaker 1: spinning a certain way, they shoot them around in this
27:49
Speaker 1: ring this big magnet and the magnetic forces the spin
27:52
Speaker 1: just change a little bit, because the spin will change
27:54
Speaker 1: in the presence of a magnetic field, and they zoom
27:56
Speaker 1: around a few hundred times, and only a few hundred times.
27:59
Speaker 1: Be the muan doesn't live forever. Eventually mulan will decay
28:02
Speaker 1: into an electron and a couple of neutrinos. But that's
28:06
Speaker 1: good because that lets you measure the direction of the
28:09
Speaker 1: magnetic field at the end, because the direction of the
28:11
Speaker 1: electron tells you the direction of the muan spin and
28:15
Speaker 1: its magnetic field. So when the muan sort of dies,
28:17
Speaker 1: you can measure how much was it's been affected by
28:20
Speaker 1: this magnetic field, and that tells you what the muans
28:23
Speaker 1: magnetic field was by itself. They've spent twenty years sort
28:26
Speaker 1: of refining this experiment just to get more and more precise,
28:30
Speaker 1: and finally we got a numbers. So now we have
28:32
Speaker 1: two numbers. We have the number that the theorists predict
28:35
Speaker 1: based on all of the things that the muan can
28:37
Speaker 1: do of what this magnetic field should be, and we
28:40
Speaker 1: have a number that experimentally spent twenty years measuring. And
28:44
Speaker 1: they're not the same. And you know, they did this
28:46
Speaker 1: in a really cool way. They did it in a
28:48
Speaker 1: blind search way because this is a very important number
28:52
Speaker 1: and a lot of sort of careers rely on this.
28:54
Speaker 1: Folks want the number to be interesting. They're hoping it's
28:57
Speaker 1: going to deviate from the theory, but they definitely want
28:59
Speaker 1: to get it right, and so they do this in
29:01
Speaker 1: a blind way by sort of scrambling the data a
29:04
Speaker 1: little bit. They add like a random offset to all
29:07
Speaker 1: of the numbers that's sort of hidden. It's like a
29:09
Speaker 1: hidden key to the data. So they don't buyas the
29:11
Speaker 1: way they do the analysis to try to like push
29:13
Speaker 1: it in the direction that they may be subconsciously want.
29:16
Speaker 1: And so they held the key like in a secret
29:18
Speaker 1: office until just six weeks ago. So even the people
29:21
Speaker 1: working on this experiment for the last decade or so,
29:23
Speaker 1: I didn't know the answer until six weeks ago when
29:26
Speaker 1: they cracked open this key and they typed it in
29:28
Speaker 1: and then they finally saw the answer. Wow, it sounds
29:31
Speaker 1: like a spy novel, you know, like that there's a
29:34
Speaker 1: hidden key and nobody knew the secret until the very end. Well,
29:38
Speaker 1: I think it's actually really exciting because it makes it climactic.
29:41
Speaker 1: There's a moment when you're asking Nature a question and
29:44
Speaker 1: you're getting the answer right. Otherwise it sort of creeps
29:47
Speaker 1: up on you and like when you actually learn or
29:49
Speaker 1: here's a correction, oili's change this and the answer is
29:51
Speaker 1: sort of like evolving as you're improving your techniques. It's
29:54
Speaker 1: nice to have a definitive moment, a crisp time, when
29:57
Speaker 1: you say, Nature, what is the answer to this question?
30:00
Speaker 1: And then you get an answer back from the universe.
30:02
Speaker 1: All right, Well, they announced this result which everyone got
30:05
Speaker 1: very excited about recently, and so let's talk about what
30:09
Speaker 1: the result was and what it could mean about the universe.
30:12
Speaker 1: But first let's take another quick break. All right, so
30:28
Speaker 1: did a government physics experiment? So just something unknown is
30:31
Speaker 1: influencing reality, Daniel, The shady government physicists distrowed our understanding
30:37
Speaker 1: of the universe and reality. I'm trying to influence reality
30:40
Speaker 1: by eating boxes of chocolates. It seems to affect the
30:43
Speaker 1: reality of the size of my Trying to increase your
30:45
Speaker 1: magnetic field or decrease your magnetism just influenced my effect
30:49
Speaker 1: on the universe, my personal gravity. It might be shrinking
30:52
Speaker 1: your magnetism. Will have to ask your family. Yeah, so
30:55
Speaker 1: they found that the theoretical and the experimental results do
31:00
Speaker 1: are either different as it was sort of suggested twenty
31:02
Speaker 1: years ago, but now we know kind of more for certain. Yeah,
31:05
Speaker 1: these numbers have improved. Both theoretical numbers have been improved
31:10
Speaker 1: and the experimental numbers have been improved. So the uncertainties
31:12
Speaker 1: on these two numbers have shrunk, but the gap between
31:15
Speaker 1: them has not. So there's still like this opening between
31:18
Speaker 1: these two numbers. And you know, i'd read you this number,
31:21
Speaker 1: but it's sort of crazy. It's just like a very
31:23
Speaker 1: specific number, and the differences are in the last couple
31:25
Speaker 1: of digits of the like this twelve digit number, but
31:28
Speaker 1: you know, the scale of it is, like the theoretical
31:30
Speaker 1: value is to ten thousands of one percent smaller than
31:35
Speaker 1: the experimental value. That's like how precisely we've calculated and
31:38
Speaker 1: measured these quantities. Wait wait, wait, so then you're saying
31:41
Speaker 1: that the difference between the theoretical and the experimental is
31:45
Speaker 1: to ten thousands of one percent. That's the difference. Yeah,
31:49
Speaker 1: it's a really tiny difference. So you need really precise
31:52
Speaker 1: experiment and really careful calculations to even be sensitive to this.
31:56
Speaker 1: That's why it's so impressive that they can even ask
31:59
Speaker 1: this question. It's almost like you flip the coin and
32:02
Speaker 1: you've got heads, you know, fifty point oh oh one
32:07
Speaker 1: times more than you've got tails, And normally that would
32:10
Speaker 1: be like you know, in the noise, but maybe you
32:12
Speaker 1: flip the coin like a gazillion times to know that
32:15
Speaker 1: it's like, yeah, there's something a little bit biased about
32:17
Speaker 1: this coin, that's right, And if you're gonna do that measurement,
32:20
Speaker 1: you have to ask, well, do I expect I mean,
32:23
Speaker 1: the shape of the heads is not exactly the shape
32:25
Speaker 1: of the tails, and maybe that influences it with the
32:27
Speaker 1: air currents. And you've got to be like really precise
32:30
Speaker 1: about all of those calculations if you want to claim
32:33
Speaker 1: that it's unfair or that it's fair. And so you know,
32:36
Speaker 1: that's what they've done. They've done like a tour the
32:38
Speaker 1: force of these theoretical calculations and the experimental calculations, and
32:42
Speaker 1: so both of these results have changed, Like the experimental
32:45
Speaker 1: result we now have a new number from Fermi Lab
32:47
Speaker 1: as of yesterday, but also the theoretical results have changed.
32:51
Speaker 1: For example, they found like a mistake at one point
32:54
Speaker 1: where they made up the wrong sign, like they changed
32:56
Speaker 1: a plus to a minus accidentally, and that changed the result.
33:00
Speaker 1: And so they're constantly like improving and doing these things
33:02
Speaker 1: better because neither of these things are easy. It's a
33:05
Speaker 1: pretty tough thing. Like even the theory that it takes
33:07
Speaker 1: like supercomputers to compute these numbers. Yeah, well, there's actually
33:10
Speaker 1: a big controversy about how to do that theoretical calculation.
33:13
Speaker 1: And some folks are using supercomputers to try to calculate
33:16
Speaker 1: this thing from scratch out of all of these diagrams
33:19
Speaker 1: and include what happens when the hedraumic particles that feel
33:22
Speaker 1: the strong force are created out of the vacuum and
33:25
Speaker 1: all this kind of stuff. And there's another group that
33:27
Speaker 1: are trying to just like not do those calculations explicitly,
33:31
Speaker 1: but take them from other measurements, like other experimental results,
33:35
Speaker 1: and extrapolate from there to figure out like what are
33:38
Speaker 1: the bits and pieces and then use theory to sort
33:40
Speaker 1: of glue them together into a measurement. So the sort
33:43
Speaker 1: of two different approaches to doing this calculation, and there's
33:46
Speaker 1: some controversy there because the sort of traditional approach where
33:49
Speaker 1: we extrapolate from other experimental measurements and use theoretical glue.
33:53
Speaker 1: That's the one that has the discrepancy with the observed value.
33:57
Speaker 1: But there's a new result that uses like pure computation
34:00
Speaker 1: san and these crazy supercomputers in Europe, and it actually
34:03
Speaker 1: agrees with the experimental result pretty closely. All right, But
34:06
Speaker 1: we're talking about this result from Fermulab and they sort
34:09
Speaker 1: of confirmed that it's the theory and the experiment are different.
34:12
Speaker 1: And so, you know, assuming that they're right, or that
34:15
Speaker 1: it gets further confirmed and all the theory checks out,
34:18
Speaker 1: what could it mean about our model of the universe. Well,
34:21
Speaker 1: you're right that the Fermulab experimental result is the new
34:24
Speaker 1: shiny thing, and nobody is suggesting that it's wrong. But
34:27
Speaker 1: it's only interesting and it's only suggestive of new physics
34:31
Speaker 1: if it's different from the prediction. And we have two predictions,
34:35
Speaker 1: one that agrees with the Fermulab result and one that doesn't.
34:39
Speaker 1: And that's what the four point two sigma is. So
34:41
Speaker 1: the picture is a big cloudy on the theoretical side.
34:44
Speaker 1: As usual, there's a spectrum of possibilities, you know, from
34:47
Speaker 1: like the most boring to the more interesting to the
34:49
Speaker 1: totally crazy and potentially bonkers. Idea. As you said, the
34:52
Speaker 1: most boring possibility is that it's just a mistake somewhere.
34:55
Speaker 1: You know, maybe one of these theoretical groups has made
34:57
Speaker 1: an error or they've forgotten to include something as the
35:00
Speaker 1: minus signed wrong. You know, this is really really hard.
35:03
Speaker 1: So I personally I like this calculation done by the
35:05
Speaker 1: European supercomputers because it was done by the collaboration called
35:08
Speaker 1: BMW because they're in Budapest, Marseille and whipper Toll, and
35:12
Speaker 1: it's sort of like independent. They like start from scratch
35:14
Speaker 1: and they're just doing the calculation, so we'll just have
35:17
Speaker 1: to see what progress has made there in the future.
35:19
Speaker 1: But they're comparing to the same experimental results. So it
35:21
Speaker 1: really is sort of like a blow to this discrepancy
35:24
Speaker 1: to have a new theoretical calculation that doesn't show the discrepancy. Interesting, so,
35:28
Speaker 1: like they used some supercomputers and they found that there
35:31
Speaker 1: is no discrepancy with the experimental result. Yeah, the prediction
35:34
Speaker 1: they made, which came out well before the experimental result,
35:38
Speaker 1: is bang on to the new experimental result. So we
35:41
Speaker 1: don't know which of these two theoretical calculations is correct.
35:44
Speaker 1: But sort of muddies the water it's harder to claim
35:46
Speaker 1: that this discrepancy is the side of new physics new
35:49
Speaker 1: particles influencing reality when we don't exactly know if it's correct,
35:53
Speaker 1: all right, So that's the vanilla possibility. What's the chocolate
35:57
Speaker 1: chip possibility chocolate chips is that they're are some new
36:00
Speaker 1: particles out there influencing reality. You know, we strongly believe
36:04
Speaker 1: that there must be more particles out there. The story
36:06
Speaker 1: can't be complete. We look at the particles that we've
36:09
Speaker 1: discovered so of our in nature, and they just don't
36:11
Speaker 1: answer all of our questions, and we suspect that there
36:14
Speaker 1: are lots more really heavy particles out there. The problem
36:17
Speaker 1: with really heavy particles is that it takes a lot
36:19
Speaker 1: of energy to make them. You've got to smash particles
36:22
Speaker 1: together at the Large Hadron Collider with enough energy to
36:25
Speaker 1: actually create these things so you can study them and
36:27
Speaker 1: explore them. But if we don't have enough energy in
36:29
Speaker 1: our machines, that doesn't mean those particles don't exist. It
36:32
Speaker 1: just means we can't make them at the Large Hadron Collider,
36:35
Speaker 1: and the only way to study them is to see
36:37
Speaker 1: these little hints. So it's possible that this is a
36:40
Speaker 1: hint of those new particles that are out there that
36:42
Speaker 1: are influencing the Muance magnetic field because they appear in
36:45
Speaker 1: some of these diagrams, some of these calculations that change
36:49
Speaker 1: the Muans magnetic field. But that doesn't mean we know
36:51
Speaker 1: what they are, right, It's sort of like unspecific. It's
36:54
Speaker 1: like saying we know there's something out there, we just
36:56
Speaker 1: don't know what it is. It's a more indirect way
36:58
Speaker 1: of looking for a new part of right, because you're
37:01
Speaker 1: sort of like seeing how they influence other particles, which
37:04
Speaker 1: is not a direct measurement. All right, So then that's
37:07
Speaker 1: the chuckle chip possibility. Maybe there are new particles or
37:11
Speaker 1: heavier versions of our particles out there, and maybe the
37:14
Speaker 1: Mean is going through space and it sometimes creates these
37:17
Speaker 1: heavy particles which kind of tweak its magnetic field. Right,
37:20
Speaker 1: that's the idea, And then there's some even crazier ideas.
37:23
Speaker 1: People have specific theories for what might be influencing the
37:26
Speaker 1: Muan's magnetic field, and these other theories we can test
37:30
Speaker 1: because they're very specific. For example, my friend Dan Hooper
37:33
Speaker 1: at Fermulab, he has this idea for a new particle.
37:35
Speaker 1: It's called a z prime prime because it's sort of
37:38
Speaker 1: like the existing Z particle, but it's different. So it's
37:41
Speaker 1: a little bit of a twist on the Z particles,
37:43
Speaker 1: like the Z particles. Evil twin like Z would flare
37:47
Speaker 1: like the Z particles with little tail or something. It's
37:50
Speaker 1: a spicy version of the Z particle, and it's sort
37:53
Speaker 1: of like the Z but he would influence the muan's
37:55
Speaker 1: magnetic moment in just this way, because when the muan
37:58
Speaker 1: is flying along, it doesn't just create photon sometimes it
38:00
Speaker 1: creates z s and ws and all sorts of other particles.
38:03
Speaker 1: So it would also create the Z prime. It would
38:05
Speaker 1: explain this discrepancy. But the cool thing about it is
38:08
Speaker 1: that if this Z prime is real, it also would
38:10
Speaker 1: have been created in the early universe. It would have
38:13
Speaker 1: changed how the universe expanded, specifically because this Z prime,
38:17
Speaker 1: if you create it would probably decay mostly into these
38:20
Speaker 1: neutrino particles, which would boost the energy density of the
38:23
Speaker 1: radiation portion of the universe. And right now, there's a
38:26
Speaker 1: lot of questions about how the universe expanded in the
38:28
Speaker 1: early days. You can check out our podcast about the
38:31
Speaker 1: Hubble tension. This question of like how fast was the
38:34
Speaker 1: universe expanding we have all these measurements that again don't agree.
38:38
Speaker 1: So this z prime theory would explain not only the
38:41
Speaker 1: Muan's magnetic moment, but also this weird question about the
38:45
Speaker 1: expansion of the universe in its early days. So it's
38:47
Speaker 1: sort of like really nice because it would solve both
38:50
Speaker 1: of these problems at the same time. That's a new
38:52
Speaker 1: proposed particle. But would it also explained the difference between
38:56
Speaker 1: the theoretical and experimental measurements of the muan. Absolutely would, Yeah,
38:59
Speaker 1: it would solve both of those problems simultaneously. That doesn't
39:02
Speaker 1: mean that it's real, you know, but it's nice if
39:04
Speaker 1: there's another handle you can have on it. Because remember
39:08
Speaker 1: the Muans matagnetic field is very indirect. It sounds like
39:11
Speaker 1: a clear way to know what's responsible. So what you
39:14
Speaker 1: want to do is have like another way to test
39:16
Speaker 1: these things. Say, if it really is a Z prime,
39:18
Speaker 1: can I see it somewhere else to get confidence that
39:21
Speaker 1: it's a Z prime and not like a G prime
39:23
Speaker 1: or a D prime or some other weird particle. So
39:26
Speaker 1: he has a more specific prediction for another way we
39:28
Speaker 1: can test this particle. But that doesn't mean that it's right.
39:31
Speaker 1: Could it also be? Because I've heard it in the
39:33
Speaker 1: news and from some of the scientists that you know.
39:35
Speaker 1: This could maybe also point to maybe explain things like
39:39
Speaker 1: dark matter or why the Higgs boson has them as
39:42
Speaker 1: it has, like it could maybe even open it up
39:44
Speaker 1: further to like crazy new kinds of other particles. Yeah,
39:48
Speaker 1: it's harder to know whether it can tell us something
39:50
Speaker 1: about dark matter because we don't know whether dark matter
39:53
Speaker 1: interacts at all with the muan. It's true that this
39:55
Speaker 1: method can tell us about any particle that will interact
39:58
Speaker 1: with the muan, but it might be that dark matter
40:01
Speaker 1: only feels gravity. Now, the dominant theory of dark matter
40:04
Speaker 1: has a sort of interaction between dark matter and muans
40:08
Speaker 1: and other particles at a very very low level. So
40:10
Speaker 1: for some theories of dark matter, yes, this could explain it,
40:14
Speaker 1: but again, we don't really know what would be doing this.
40:16
Speaker 1: It just tells us there's some new particle out there
40:19
Speaker 1: that does interact with the muan. It doesn't tell us
40:22
Speaker 1: what that is. So dark matter is a favorite idea
40:25
Speaker 1: because it's another big unexplained mystery. Well, I think maybe
40:28
Speaker 1: the overall big headline is that maybe what we think
40:32
Speaker 1: can happen in the universe is not what is actually
40:36
Speaker 1: happening in the universe, like maybe there are things that
40:38
Speaker 1: we have an accounted for, or that maybe it makes
40:41
Speaker 1: our theory incomplete that we are seeing in this muon
40:45
Speaker 1: magnetic field that is not in our theory. That's I
40:47
Speaker 1: think that's sort of the general exciting part, right, Yeah,
40:50
Speaker 1: it's always exciting to find a place where our theory
40:53
Speaker 1: does not predict our experiments because it means it's a
40:56
Speaker 1: place to learn, it's a place to improve our theory,
40:58
Speaker 1: it's a place to add some thing new to our
41:01
Speaker 1: understanding of the universe. For a long time, all the
41:03
Speaker 1: experiments we do, like all the ones that the large
41:05
Speaker 1: Hadron collider, are very very well predicted by our theory,
41:09
Speaker 1: which means that it's working, which is exciting, but also
41:12
Speaker 1: means that there doesn't provide any clues for how to
41:14
Speaker 1: improve it, or expand it, or go to the next
41:17
Speaker 1: level of the theory. So any discrepancy like this is
41:20
Speaker 1: a wonderful clue that points us to maybe figuring out
41:23
Speaker 1: a deeper idea by the nature of the universe. But
41:25
Speaker 1: now let me maybe toss a bit of cold water
41:27
Speaker 1: on that. Remember that this is only exciting if the
41:30
Speaker 1: theory is right, and that's a bit of a fuzzy
41:33
Speaker 1: picture still. I actually think the other discrepancy in the
41:37
Speaker 1: B particles with Penguin diagrams at the Large Hadron Collider
41:40
Speaker 1: is much more promising and exciting because the theoretical issues
41:44
Speaker 1: are better controlled and there are several other experimental results
41:48
Speaker 1: that suggest the same thing. So if I had to
41:50
Speaker 1: put my money on something, I guess that this discrepancy
41:53
Speaker 1: in the formula nuance will turn out to be a
41:55
Speaker 1: problem in how the theory calculations were done, not actually
41:59
Speaker 1: a new particle. And I'm more excited that the LHC
42:02
Speaker 1: Penguin diagrams could be showing us new particles. So it
42:05
Speaker 1: was good to double check, you know, Like if you
42:07
Speaker 1: think this twenty year old chocolate it's gonna taste good,
42:10
Speaker 1: maybe you should try it for us, right, Yeah, and
42:12
Speaker 1: you should keep trying it. And that's what they're gonna
42:14
Speaker 1: be doing. This is just the first batch of results
42:16
Speaker 1: from this formulab experiment. They actually have a lot more
42:19
Speaker 1: data that they've already taken. It's like on a computer somewhere.
42:23
Speaker 1: They just haven't finished analyzing it, and they have ideas
42:26
Speaker 1: for how to improve the quality of their measurement to
42:29
Speaker 1: make it more precise, to shrink these errors even on
42:32
Speaker 1: the data they already have analyzed. So we should expect
42:35
Speaker 1: to see sometime in three more announcements about even more
42:40
Speaker 1: precise measurements of these quantities, and also progress on the
42:43
Speaker 1: theoretical side, as these two different groups try to figure
42:46
Speaker 1: out like why they're getting different answers and who is
42:48
Speaker 1: correct and maybe they can learn from each other. So
42:51
Speaker 1: this is a story we should keep following. Yeah, because
42:53
Speaker 1: this big announcement, as big as it was, it's really
42:56
Speaker 1: just like the first bun out of the oven, right,
42:58
Speaker 1: Like this is like their first batch of data. Uh,
43:00
Speaker 1: and they're expecting to get like, you know, twenties sixteen
43:03
Speaker 1: times more you know, me on spins detections, and that
43:08
Speaker 1: their estimates are just going to get better. Yes, absolutely,
43:11
Speaker 1: As they get more data, these statistical uncertainty will fall.
43:14
Speaker 1: And in this case, the statistical uncertainty just from like
43:17
Speaker 1: not having an infinite number of measurements is still the
43:20
Speaker 1: dominant source of uncertainty. As they get more data, they're
43:23
Speaker 1: gonna have to worry about other sources of uncertainty, systematic
43:26
Speaker 1: uncertainties and things about like how they're calibrating their experiment.
43:29
Speaker 1: But again, these are clever experimentalists and they have ways
43:32
Speaker 1: of reducing those things. So as time goes on, all
43:35
Speaker 1: the uncertainties will shrink and our knowledge of this quantity
43:38
Speaker 1: will improve, and maybe it will reveal something new in
43:41
Speaker 1: the universe influencing reality awesome, like maybe a new flavor
43:44
Speaker 1: of ice cream or that chocolate. Al Right, well, I
43:48
Speaker 1: guess as always, the answer is stay tuned. If you're
43:51
Speaker 1: still a little bit confused about this whole topic, you
43:53
Speaker 1: can read the comic that I drew for Physics the
43:56
Speaker 1: APS Journal at PhD comics dot com, slash me on
44:01
Speaker 1: m U O N and checked it out. But we
44:04
Speaker 1: hope you enjoyed that. Thanks for joining us, see you
44:06
Speaker 1: next time. Thanks for listening, and remember that Daniel and
44:17
Speaker 1: Jorge explain the Universe is a production of I Heart Radio.
44:20
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