Latest / Daniel and Kelly’s Extraordinary Universe / How do we measure the Higgs boson mass?

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How do we measure the Higgs boson mass? · Daniel and Kelly’s Extraordinary Universe

• 0:08
  Speaker 1: Hey, Daniel, I have a rude physics question.
• 0:11
  Speaker 2: Oh no, not another dark matter poop.
• 0:13
  Speaker 1: Jokeer, I hope, I think we did that one already.
• 0:16
  Speaker 2: All right then, shoot, all right?
• 0:18
  Speaker 1: Is the Higgs boson heavier than expected?
• 0:21
  Speaker 2: Are you asking if physicists think the Higgs is like
• 0:24
  Speaker 2: too round? That is a bit rude.
• 0:27
  Speaker 1: I'm talking about it's mass, not its volume.
• 0:31
  Speaker 2: Maybe the Higgs doesn't just give mass to other particles,
• 0:34
  Speaker 2: it gives them muscles.
• 0:36
  Speaker 1: What like the Higgs is the steroids of the universe?
• 0:40
  Speaker 1: Is that legal?
• 0:41
  Speaker 2: Lots of physics say yes.
• 0:58
  Speaker 1: I am more hamm and cartoonist, the author of Oliver's
• 1:01
  Speaker 1: Great Big Universe.
• 1:02
  Speaker 2: Hi, I'm Daniel. I'm a particle physicist and a professor
• 1:05
  Speaker 2: at UC Irvine, and I feel like my density increases every.
• 1:08
  Speaker 1: Year, density of knowledge or density of chocolate eaten, like
• 1:13
  Speaker 1: your chocolate cores is getting bigger.
• 1:15
  Speaker 2: Well, those two things are tightly correlated, so I'd say
• 1:18
  Speaker 2: yes to.
• 1:18
  Speaker 1: Be What do you need like chocolate gives you knowledge?
• 1:25
  Speaker 2: Well, there's definitely a correlation between Nobel Prizes one and
• 1:28
  Speaker 2: chocolate consumed per capita.
• 1:30
  Speaker 1: Oh interesting, but which one comes first?
• 1:34
  Speaker 2: We don't have to get into correlation versus causation when
• 1:37
  Speaker 2: it comes to chocolate.
• 1:38
  Speaker 1: I think we do. I mean makes a big difference.
• 1:40
  Speaker 1: Like if you have to eat a lot of chocolate
• 1:42
  Speaker 1: after you win the Noble Price, and you kind of
• 1:44
  Speaker 1: have a lot of work to do.
• 1:45
  Speaker 2: All right, let me go get some chocolate and then
• 1:47
  Speaker 2: we'll figure this out.
• 1:47
  Speaker 1: No, no, no, that's the whole point. You should maybe
• 1:50
  Speaker 1: figure out what's the causation here.
• 1:53
  Speaker 2: I can't figure anything out without chocolate. It's my superpower.
• 1:56
  Speaker 1: Then you're in a paradox. What did you need chocolate
• 1:59
  Speaker 1: after you win the Nobel Prize? But you can win
• 2:01
  Speaker 1: the Nobel Prize until unless you eat a lot of chocolate.
• 2:03
  Speaker 2: What if I opt for a Nobel Price that's not gold,
• 2:05
  Speaker 2: it's just gold foil around bad chocolate.
• 2:08
  Speaker 1: That doesn't af fix your paradox, though maybe it may
• 2:12
  Speaker 1: just means it's impossible. But anyways, Welcome to our podcast,
• 2:15
  Speaker 1: Daniel and Jorge Explain the Universe, a production of iHeartRadio.
• 2:18
  Speaker 2: In which we dig into the apparent paradox of our universe.
• 2:22
  Speaker 2: It is both mysterious and bizarre, and yet somehow also understandable.
• 2:27
  Speaker 2: Working carefully at the cold face of knowledge, we can
• 2:30
  Speaker 2: hammer away at it and slowly build up an understanding
• 2:33
  Speaker 2: of how this universe works from its tiny little quantum
• 2:37
  Speaker 2: particles that weave themselves together to give us this reality
• 2:40
  Speaker 2: we know and love.
• 2:41
  Speaker 1: That's right, the universe is deliciously perplexing. It's dark, and
• 2:45
  Speaker 1: it's velvedly smooth, just like chocolate, which means we can't
• 2:48
  Speaker 1: get enough of it.
• 2:49
  Speaker 2: And it is massive. Not only is it very, very large,
• 2:53
  Speaker 2: but it's also filled with a lot of stuff black
• 2:57
  Speaker 2: holes and neutron stars and just normal stars and rocky
• 3:01
  Speaker 2: planets and maybe squishy little beings crawling on their surface.
• 3:04
  Speaker 1: And thank goodness it has squishy little beings like us,
• 3:07
  Speaker 1: because we're here to ask questions about it, and we
• 3:09
  Speaker 1: do that here on the podcast, where we tackle the
• 3:11
  Speaker 1: big unknowns about how this universe works and why it
• 3:14
  Speaker 1: is the way it is.
• 3:15
  Speaker 2: And often on the podcast we're telling you about the
• 3:17
  Speaker 2: things that we have learned in science. But one of
• 3:19
  Speaker 2: my favorite kinds of episodes are the ones that dig
• 3:22
  Speaker 2: into how we figure it out how we know what
• 3:25
  Speaker 2: we know. Rather than just swallowing the numbers as scientists
• 3:27
  Speaker 2: give us, we want to unwrap them and figure out
• 3:30
  Speaker 2: how exactly they measured this or that to be whatever
• 3:33
  Speaker 2: number it is.
• 3:34
  Speaker 1: Yeah, because there is a lot to know about the
• 3:35
  Speaker 1: universe and a lot that science has figured out, and
• 3:37
  Speaker 1: it's interesting to dig into how it is that we
• 3:39
  Speaker 1: know these things. Just sometimes the story is maybe even
• 3:43
  Speaker 1: better than the facts that you've learned.
• 3:45
  Speaker 2: Experimental science is not just go out there and check
• 3:48
  Speaker 2: the theoretical predictions. Sometimes the theory doesn't make any predictions,
• 3:52
  Speaker 2: and it just says, we don't know how heavy this
• 3:54
  Speaker 2: thing is. Go measure it, and measuring it requires inventing
• 3:57
  Speaker 2: all sorts of cool and clever tre That's what experimental
• 4:01
  Speaker 2: science is all about, and we like to celebrate that
• 4:04
  Speaker 2: here in the podcast. We've had fun episodes about all
• 4:06
  Speaker 2: of the inventiveness necessary to measure the speed of light,
• 4:10
  Speaker 2: or to measure the gravitational constant.
• 4:12
  Speaker 1: Or to measure how much chocolate. Physicists can eat safely.
• 4:16
  Speaker 2: Data says there is no upper bound.
• 4:20
  Speaker 1: Really, that doesn't sound like a scientific statement. I think
• 4:23
  Speaker 1: science is pretty clear there is a limit to how
• 4:25
  Speaker 1: much chocolate you can eat.
• 4:27
  Speaker 2: I don't know. I haven't yet collapsed into a black hole,
• 4:29
  Speaker 2: but that may be in my future.
• 4:31
  Speaker 1: I guess it's hard to prove a negative or a
• 4:33
  Speaker 1: maximum m hm.
• 4:34
  Speaker 2: Really the question is if you eat a lot of
• 4:36
  Speaker 2: white chocolate, do you turn into a white hole or
• 4:38
  Speaker 2: a black hole?
• 4:39
  Speaker 1: So to be on the podcast, we'll be asking the
• 4:41
  Speaker 1: question how do we measure the Higgs Bosons mass?
• 4:50
  Speaker 2: Did you say mass or math?
• 4:52
  Speaker 1: I think I said mass, right, So we do.
• 4:55
  Speaker 2: Have to use a lot of math to figure out
• 4:57
  Speaker 2: the Higgs Boson mass.
• 4:58
  Speaker 1: Of course, exposed on have its own math.
• 5:01
  Speaker 2: As far as we know, there is just one math.
• 5:03
  Speaker 2: There is the math. But everything has its own mass,
• 5:07
  Speaker 2: and it's an interesting puzzle to figure out why some
• 5:09
  Speaker 2: particles have a lot of it, why some particles don't
• 5:12
  Speaker 2: seem to have a lot of it, and to learn
• 5:13
  Speaker 2: about exactly how we measure the mass of these tiny
• 5:17
  Speaker 2: little particles. You can even just barely see.
• 5:19
  Speaker 1: Well, some particles don't have any mass, right.
• 5:21
  Speaker 2: Yeah, that's right. Photons have no mass, Gluons have no mass. Gravitons,
• 5:26
  Speaker 2: if they exist, probably have no mass as well. Mass
• 5:29
  Speaker 2: isn't even a necessary attribute, like you can be a
• 5:31
  Speaker 2: thing without having any stuff to you.
• 5:34
  Speaker 1: Right, Although, as we've talked about many times on the podcast,
• 5:37
  Speaker 1: the question or the idea of mass is kind of
• 5:39
  Speaker 1: a tricky one, right, Like there are different kinds of masses,
• 5:42
  Speaker 1: and also like what you might call mass is not
• 5:45
  Speaker 1: necessarily the stuff that you have about you.
• 5:47
  Speaker 2: Yeah, our intuitive understanding of mass is different from the
• 5:51
  Speaker 2: sort of mathematical physical description of matter at its most microscopic.
• 5:55
  Speaker 1: Well, this is an interesting question because the Higgs boson
• 5:58
  Speaker 1: is a pretty big deal in the right. I mean,
• 6:00
  Speaker 1: it was discovered a few years ago and people were
• 6:03
  Speaker 1: very excited because apparently it is a very important particle
• 6:06
  Speaker 1: in the pathion of particles in that it gives mass
• 6:09
  Speaker 1: to other particles.
• 6:10
  Speaker 2: Yeah, the Higgs boson is a feature of the Higgs field,
• 6:13
  Speaker 2: which fills the whole universe. Like other quantum fields, it
• 6:15
  Speaker 2: can be excited into making a particle, or it can
• 6:18
  Speaker 2: be chill and relaxed down to its lowest state. But
• 6:21
  Speaker 2: the Higgs boson, the Higgs particle, the excitation of the
• 6:24
  Speaker 2: Higgs field, has all sorts of particle like properties. It moves,
• 6:28
  Speaker 2: it has mass, and the value of its mass is
• 6:31
  Speaker 2: really important. It's important theoretically and it's important experimentally.
• 6:35
  Speaker 1: As the big question is how do you measure the
• 6:37
  Speaker 1: mass of something so important, so crucial to the concept
• 6:40
  Speaker 1: of mass itself like the Higgs boson, and so, as
• 6:43
  Speaker 1: usually you were wondering how many people out there had
• 6:45
  Speaker 1: thought about this question and wondered if they can just
• 6:47
  Speaker 1: ask the Higgs boson it's mass.
• 6:49
  Speaker 2: How rude, But thank you very much everybody who volunteers
• 6:52
  Speaker 2: for this segment of the podcast. If you would like
• 6:54
  Speaker 2: to participate, please don't be shy and write to me
• 6:57
  Speaker 2: to questions at Danielanjorge dot com. I am waiting for
• 7:00
  Speaker 2: your email.
• 7:01
  Speaker 1: So think about it for a second. How do you
• 7:03
  Speaker 1: think physicists measure the Higgs bosons mass? Here's what people
• 7:07
  Speaker 1: had to say.
• 7:08
  Speaker 3: I know from the episode on where does the Higgs
• 7:11
  Speaker 3: get its mass that you can look at how it
• 7:16
  Speaker 3: interacts with the other fields like the top cork and
• 7:20
  Speaker 3: the strange cork, and maybe with its interacting with its
• 7:24
  Speaker 3: own field. But I have no idea how you measure it.
• 7:28
  Speaker 4: I now believe that we can view a boson, and
• 7:35
  Speaker 4: so therefore I would imagine you could put it in
• 7:40
  Speaker 4: a particle accelerator and throw something at it, and by
• 7:47
  Speaker 4: that makes the calculations to measure its mass.
• 7:51
  Speaker 5: Measuring the mass of the Higgs is going to be
• 7:54
  Speaker 5: exceedingly difficult. Even an optical system would probably be much
• 8:00
  Speaker 5: too large to get the mass of the system. I
• 8:04
  Speaker 5: one could assume that some interplanetary system telescope might actually
• 8:12
  Speaker 5: be a way to go, if we were able to
• 8:16
  Speaker 5: figure that out.
• 8:17
  Speaker 6: If I remember it right, the Higgs boson was discovered
• 8:23
  Speaker 6: when they could detect a pair of photons that were
• 8:29
  Speaker 6: emitted in the collider. So maybe its mass would be
• 8:33
  Speaker 6: equivalent to the energy of those two photoms.
• 8:37
  Speaker 2: I have no idea.
• 8:38
  Speaker 5: It could have something to do with its track after
• 8:42
  Speaker 5: collision analysis it.
• 8:43
  Speaker 1: Turned all right. I am with the last person here
• 8:46
  Speaker 1: who said, I have no idea. Sounds like a great title.
• 8:49
  Speaker 2: For a book. We should write a book like that.
• 8:53
  Speaker 1: Maybe with Tilight we have No Idea and make it
• 8:55
  Speaker 1: available for purchase at bookstores and kind of book website.
• 9:01
  Speaker 1: That would be a good idea.
• 9:03
  Speaker 2: That would be a very good idea. In fact, if
• 9:05
  Speaker 2: you went to we have no idea dot com, you
• 9:08
  Speaker 2: might even be able to find such a book.
• 9:09
  Speaker 1: That's an amazing idea. But yeah, this is an interesting question.
• 9:12
  Speaker 1: How do you measure the Higgs bosons mass? If the
• 9:14
  Speaker 1: Higgs feel is what gives things mass, it's a bit
• 9:17
  Speaker 1: of a conundrum there, So when don't we start at
• 9:19
  Speaker 1: the beginning at Daniel? What is the Higgs boson for
• 9:22
  Speaker 1: people who don't.
• 9:23
  Speaker 2: Know, So, the Higgs boson is an idea that came
• 9:25
  Speaker 2: out of the nineteen sixties when people were looking at
• 9:28
  Speaker 2: the electromagnetic interaction, which is mediated by the photon, and
• 9:33
  Speaker 2: the weak force, which is mediated by the Z and
• 9:36
  Speaker 2: the W bosons. So you have these two forces which
• 9:39
  Speaker 2: seemed pretty different. The weak force is very weak and
• 9:42
  Speaker 2: it has these three weird bosons that mediate it, and
• 9:45
  Speaker 2: the electromagnetic force is very strong. It's the one that
• 9:47
  Speaker 2: we know, you know, makes lightning and magnets and all
• 9:50
  Speaker 2: sorts of stuff and binds together protons electrons into atoms
• 9:52
  Speaker 2: and weaves those atoms together into molecules and basically makes
• 9:56
  Speaker 2: the structure of everything around us. So it's felt like
• 9:59
  Speaker 2: very different forces, but people had an idea that they
• 10:01
  Speaker 2: might just click together into one larger idea, which they
• 10:05
  Speaker 2: call the electroweak force.
• 10:07
  Speaker 1: Now, what do people know about the weak force or
• 10:09
  Speaker 1: how do we discover it and what do we think
• 10:12
  Speaker 1: it was for?
• 10:12
  Speaker 2: Well, the weak force was discovered several decades ago, and
• 10:15
  Speaker 2: it was known to be involved in radioactive decay. So,
• 10:18
  Speaker 2: for example, when a nucleus decays down to a lighter element,
• 10:22
  Speaker 2: it does so using a process called beta decay. Then
• 10:25
  Speaker 2: that involves the weak force. So we knew that the
• 10:28
  Speaker 2: weak force was a thing, and we knew that it
• 10:30
  Speaker 2: did some stuff and it was different from electromagnetism. We
• 10:33
  Speaker 2: had postulated the idea that there might be a particle
• 10:36
  Speaker 2: out there that only feels the weak force, the neutrino,
• 10:39
  Speaker 2: but it hadn't yet been observed.
• 10:42
  Speaker 1: Like we knew about radioactive decay, like uranium decays into
• 10:46
  Speaker 1: a lower mass uranium. But I guess you needed some
• 10:48
  Speaker 1: kind of mechanism for it to do that, and you
• 10:50
  Speaker 1: had to sort of invent the force to do that,
• 10:52
  Speaker 1: or like it only made sense if you had this
• 10:54
  Speaker 1: new kind of force.
• 10:56
  Speaker 2: Yeah, you can't explain radioactive decay using just electromagnetism or
• 11:00
  Speaker 2: just a strong force. You need a new kind of phenomenon.
• 11:03
  Speaker 2: And that's sort of the history of forces, right. We
• 11:05
  Speaker 2: see all this stuff out there in the world, and
• 11:08
  Speaker 2: we tried to describe it using sort of like the
• 11:10
  Speaker 2: shortest possible list of explanations. But sometimes you have to
• 11:13
  Speaker 2: add one, you know, like when first time people ever
• 11:15
  Speaker 2: saw lightning. They're like, hmm, well, you can't explain that
• 11:18
  Speaker 2: with everything we know, So let's add some into the lists.
• 11:20
  Speaker 2: Let's say there's a new kind of force electricity, and
• 11:24
  Speaker 2: people saw magnets and they're like, ooh wow, this is
• 11:26
  Speaker 2: a cool new thing. So then magnets were added to
• 11:28
  Speaker 2: the list. Later, we try to shrink that list by
• 11:31
  Speaker 2: seeing if we can combine those forces. So electricity and
• 11:33
  Speaker 2: magnetism actually two sides of the same force, now just
• 11:37
  Speaker 2: one idea electromagnetism. So the weak force was responsible for
• 11:41
  Speaker 2: a distinct kind of phenomena that we couldn't explain using
• 11:43
  Speaker 2: other forces. But then people were eager to see if
• 11:46
  Speaker 2: they could squeeze it together with the other forces.
• 11:48
  Speaker 1: What made them think that you could squeeze them together, Like,
• 11:51
  Speaker 1: for example, they didn't try to squish together electromagnetism and gravity,
• 11:55
  Speaker 1: did they?
• 11:55
  Speaker 2: Oh? Yes they did. Einstein spent most of his life
• 11:57
  Speaker 2: trying to accomplish that actually and failing, And so theorists
• 12:01
  Speaker 2: basically trying to squeeze everything possible together. You know, it's
• 12:03
  Speaker 2: like we're looking at a bunch of puzzle pieces on
• 12:05
  Speaker 2: the table and we're like, hm, does this fit with that? Nope?
• 12:07
  Speaker 2: Does this fit with that? Nope? And electricity and magnetism
• 12:11
  Speaker 2: almost fit together just perfectly together with the weak force,
• 12:15
  Speaker 2: like they clicked into place, almost perfectly. There was just
• 12:18
  Speaker 2: like a little gap missing, and that gap was the
• 12:20
  Speaker 2: Higgs boson. Oh.
• 12:21
  Speaker 1: Interesting, So the Higgs field and the Higgs boson was
• 12:25
  Speaker 1: that missing piece exactly.
• 12:26
  Speaker 2: That's why they suspected that it existed, because it seemed
• 12:30
  Speaker 2: very likely that these two forces could click together, but
• 12:32
  Speaker 2: it didn't quite work. The problem was that photons have
• 12:36
  Speaker 2: no mass. Their mass lists right, but the W and
• 12:38
  Speaker 2: Z bosons were very, very massive, and that made it
• 12:41
  Speaker 2: very very hard to click these two together unless you
• 12:44
  Speaker 2: had some special thing out there which could give mass
• 12:47
  Speaker 2: to the W and the Z and not give it
• 12:49
  Speaker 2: to the photon. And that's what the Higgs does. It
• 12:52
  Speaker 2: solves this problem of electroweak symmetry. It's called and noo.
• 12:55
  Speaker 2: They tried to bring in the strong force. They just
• 12:59
  Speaker 2: decide to the strong force. People basically work on every combination.
• 13:04
  Speaker 2: If you could bring the strong force together with the
• 13:06
  Speaker 2: electroweak force, then you've achieved a grand unified theory, something
• 13:10
  Speaker 2: nobody has been able to make work.
• 13:11
  Speaker 1: So far mathematically, would you have to call it like
• 13:13
  Speaker 1: the electro met force. It's not weak, it's not strong.
• 13:17
  Speaker 1: It's just kind of meant.
• 13:19
  Speaker 2: Well, you know, there'd be an interesting argument there about
• 13:21
  Speaker 2: like which names get kept and which names get dropped.
• 13:23
  Speaker 2: I don't know if you noticed, but when electromagnetism got
• 13:26
  Speaker 2: merged with the weak force, magnetism got dropped, like the
• 13:29
  Speaker 2: least influential partner in a law firm that merged with
• 13:32
  Speaker 2: a bigger firm. Right, it's just gone.
• 13:35
  Speaker 1: They couldn't just keep phyphonating. I guess I don't know.
• 13:38
  Speaker 2: I think they could have. It's a bummer to lose magnetism.
• 13:41
  Speaker 2: I like magnets. I don't know what they would call it.
• 13:43
  Speaker 2: But the official name right now is the Grand Unified Theory.
• 13:46
  Speaker 2: You can bring those together, then you have a grand
• 13:48
  Speaker 2: unified theory. And people have been trying all sorts of ways,
• 13:51
  Speaker 2: but nobody's been able to make it click.
• 13:52
  Speaker 1: All right, So then the Higgs boson and the Higgs
• 13:54
  Speaker 1: field made the electromagnetic force and the weak force click together.
• 13:58
  Speaker 1: So that's kind of where it came from the idea
• 13:59
  Speaker 1: for it.
• 14:00
  Speaker 2: That's right, That's why we thought it had to be
• 14:02
  Speaker 2: there it or something else which did that job, which
• 14:05
  Speaker 2: gave mass to the w Z bosons. And also they
• 14:07
  Speaker 2: were able to add a little piece to the Higgs
• 14:09
  Speaker 2: force and say, oh, also it interacts with all the
• 14:11
  Speaker 2: matter particles and gives them mass as well. So it
• 14:14
  Speaker 2: was a very cute little idea, and then we found
• 14:17
  Speaker 2: it in twenty twelve, this fantastic triumph of theoretical physics,
• 14:20
  Speaker 2: to say, you know, there's a pattern out there that's
• 14:23
  Speaker 2: missing a piece. It would make much more sense if
• 14:25
  Speaker 2: it existed in the universe, and boom, there it does.
• 14:27
  Speaker 2: It makes you feel like, wow, math is not just
• 14:30
  Speaker 2: like describing the universe. Maybe it's dictating how the universe works.
• 14:34
  Speaker 1: You know, wait, which math? The math are one of
• 14:36
  Speaker 1: the math?
• 14:38
  Speaker 2: The math, and in this case it's group theory. This
• 14:40
  Speaker 2: really weird, abstract kind of math that was invented by
• 14:43
  Speaker 2: a bunch of French guys in the eighteen hundreds, not
• 14:45
  Speaker 2: because they were interested in particle physics or really physics
• 14:48
  Speaker 2: at all. They were just like, huh, look at these
• 14:50
  Speaker 2: cool symmetries and patterns. Maybe we can describe them mathematically.
• 14:54
  Speaker 2: And then decades later particle physicists were like Ooh, that
• 14:57
  Speaker 2: math perfectly described the patterns we're among these particles. Thank
• 15:01
  Speaker 2: you very much mathematicians for inventing this tool.
• 15:03
  Speaker 1: All right, So, then the Higgs field and the Higgs
• 15:06
  Speaker 1: boson is what gives other particles their mass, right, Like,
• 15:09
  Speaker 1: if the electron has a certain mass with meaning that
• 15:11
  Speaker 1: it's hard to get it moving and it's hard to
• 15:14
  Speaker 1: get it to stop, that's inertial mass. That's all due
• 15:17
  Speaker 1: to the Higgs field.
• 15:18
  Speaker 2: That's right. As the electron moves through the universe, it
• 15:20
  Speaker 2: interacts with the Higgs field. That changes how the electron
• 15:24
  Speaker 2: moves in a way that to us looks like the
• 15:26
  Speaker 2: electron itself has mass. And there's an argument to me
• 15:29
  Speaker 2: made to say that the true, the real, the pure
• 15:32
  Speaker 2: electron has no mass. But what we see isn't the
• 15:35
  Speaker 2: pure electron. We see this like cloud of an electron
• 15:38
  Speaker 2: interacting with Higgs bosons, and that's what we call an
• 15:41
  Speaker 2: electron because that's what we interact with. We see, we
• 15:44
  Speaker 2: measure in our laboratory, and that object, the sort of
• 15:47
  Speaker 2: electron interwoven with the Higgs field, that thing has the
• 15:50
  Speaker 2: mass of an electron.
• 15:52
  Speaker 1: And that's also how you explain how some particles like
• 15:54
  Speaker 1: the photon don't have mass. Right, You just figure out
• 15:57
  Speaker 1: that in the universe some particles interact with the Higgs
• 15:59
  Speaker 1: fields and then some don't, right, Like the photon doesn't
• 16:02
  Speaker 1: interact with the Higg fields, and so it doesn't have
• 16:03
  Speaker 1: this inertial mass.
• 16:05
  Speaker 2: Right exactly. And on one hand, it answers a deep
• 16:07
  Speaker 2: question why does the electron have mass? The answer is, oh,
• 16:10
  Speaker 2: it interacts with the Higgs field, but it doesn't answer
• 16:12
  Speaker 2: a much deeper question, which is like, well, why does
• 16:14
  Speaker 2: the muon have more mass? The answer is just, well,
• 16:17
  Speaker 2: it interacts more with the Higgs boson, sort of like
• 16:19
  Speaker 2: kicks the question down the road to like, well, why
• 16:22
  Speaker 2: does the mwon interact with the Higgs boson more than
• 16:24
  Speaker 2: the electron? We don't know. That's just like a number
• 16:26
  Speaker 2: out there.
• 16:27
  Speaker 1: We have to measures, Like, you didn't really answer the question,
• 16:30
  Speaker 1: you just changed the name of the thing.
• 16:33
  Speaker 2: Well, we answered the question, but it revealed another deeper question.
• 16:36
  Speaker 2: It's like we ran the ball down the field another
• 16:38
  Speaker 2: ten yards somid some progress, we know a little bit
• 16:41
  Speaker 2: more how to focus, But no, we definitely didn't finally
• 16:43
  Speaker 2: answer the question.
• 16:45
  Speaker 1: And so the Higgs field gives mass to other particles, right,
• 16:48
  Speaker 1: like quarks and electrons and its cousins. Even the neutrina
• 16:52
  Speaker 1: has a little bit of mass, they think, right, The.
• 16:54
  Speaker 2: Neutrinos definitely do have a little bit of mass. We
• 16:56
  Speaker 2: don't know exactly how much they have, but we know
• 16:58
  Speaker 2: it's very very small. We don't actually know that neutrinos
• 17:02
  Speaker 2: get their mass from the Higgs. That's one idea that
• 17:05
  Speaker 2: there are neutrinos and anti neutrinos and they do the
• 17:07
  Speaker 2: same thing the other particles do and get mass. It's
• 17:10
  Speaker 2: also possible the neutrino is even weirder. It might be
• 17:13
  Speaker 2: its own anti particle, and so it might get its
• 17:15
  Speaker 2: mass in another way. Remember, the Higgs boson is not
• 17:18
  Speaker 2: the only way to get mass. You can get mass
• 17:20
  Speaker 2: anytime you have any kind of internal stored energy. For example,
• 17:24
  Speaker 2: we think dark matter probably doesn't get its mass from
• 17:26
  Speaker 2: the Higgs field. So neutrinos might do the same things electrons,
• 17:30
  Speaker 2: or they might do something totally different. Mm.
• 17:33
  Speaker 1: Interesting. All right, Well, that's the Higgs boson and we
• 17:36
  Speaker 1: know that it gives other particles mass. But the question
• 17:39
  Speaker 1: now is who gives the Higgs boison its mass? And
• 17:42
  Speaker 1: more importantly, for this episode, how do we measure it?
• 17:45
  Speaker 1: And so let's dig into those questions. But first let's
• 17:48
  Speaker 1: take a quick break. All right, we're talking about the
• 18:02
  Speaker 1: Higgs boson. Would you say it's the world's third most
• 18:05
  Speaker 1: famous particle.
• 18:06
  Speaker 2: Third most famous? It might be the most famous. I
• 18:09
  Speaker 2: think it's Michael Jordan of particles.
• 18:10
  Speaker 1: Really, you think it's more famous than the electron quarks
• 18:14
  Speaker 1: maybe or photons. Photons are really probably up there. So
• 18:17
  Speaker 1: I would say it's like photons, electrons, and then maybe
• 18:19
  Speaker 1: the Higgs boson.
• 18:20
  Speaker 2: I guess I probably have a skewed view of it,
• 18:22
  Speaker 2: but I would guess Higgs boson first and then electron.
• 18:26
  Speaker 1: I guess it is the most popular particle among physicists
• 18:29
  Speaker 1: who study the Higgs boson. That makes sense.
• 18:33
  Speaker 2: I would say, I have a massive interest in the
• 18:34
  Speaker 2: Higgs boson.
• 18:35
  Speaker 1: Yes, you're heavily biased. All right, Well, we were talking
• 18:39
  Speaker 1: about how the Higgs field and the Higgs boson gives
• 18:41
  Speaker 1: mass to other particles. But then now the question is
• 18:44
  Speaker 1: what gives Higgs boson its mass and how do we
• 18:47
  Speaker 1: measure it?
• 18:47
  Speaker 2: Yeah, the Higgs boson is like the barber who shaves
• 18:50
  Speaker 2: himself for herself. The Higgs actually gives mass to itself. Right,
• 18:56
  Speaker 2: the Higgs is a really interesting particle because it interacts
• 18:59
  Speaker 2: with its That's not true for every particle, like the photon,
• 19:03
  Speaker 2: for example, only interacts with particles that have any electric
• 19:07
  Speaker 2: charge plus or minus a neutral particle. The photon will
• 19:10
  Speaker 2: just fly right by, and the photon is neutral electrically,
• 19:14
  Speaker 2: so it doesn't interact with itself. But the Higgs boson
• 19:17
  Speaker 2: does interact with itself. Two Higgs bosons coming near each
• 19:20
  Speaker 2: other will bounce off each other or attract each other sometimes.
• 19:24
  Speaker 1: WHOA Okay, So I guess that is kind of strange
• 19:27
  Speaker 1: and different. So the Higgs boson when it's out there
• 19:29
  Speaker 1: and it sees another Higgs boson, they can ignore each other.
• 19:32
  Speaker 2: They cannot ignore each other exactly. They're like x's that
• 19:35
  Speaker 2: are still angry at each other. They always end up entangled.
• 19:38
  Speaker 1: Are you saying the whole universe is one big, u
• 19:43
  Speaker 1: sad and dramatic story.
• 19:44
  Speaker 2: Yeah. And then they go home. They both eat chocolate
• 19:46
  Speaker 2: to feel better. Now, the Higgs boson flies through the universe,
• 19:49
  Speaker 2: and like other particles, it feels the Higgs field and
• 19:52
  Speaker 2: it interacts with the other Higgs bosons. The other manifestations
• 19:55
  Speaker 2: of the Higgs field and pigs up mass, and so
• 19:58
  Speaker 2: the interaction of the Higgs fiel with itself gives it mass.
• 20:02
  Speaker 1: Is that the order you would put it in, like
• 20:04
  Speaker 1: you have a Higgs boson which is like a little
• 20:06
  Speaker 1: blip in the field, and then that blip interacts with
• 20:09
  Speaker 1: the field it's made out of too.
• 20:11
  Speaker 2: Exactly in just the same way that an electron interacts
• 20:14
  Speaker 2: or the Higgs field. A Higgs boson also interacts or
• 20:16
  Speaker 2: the Higgs field, and it has a similar effect on
• 20:19
  Speaker 2: the Higgs boson as it does on the electron. What
• 20:22
  Speaker 2: we're measuring when we measure the Higgs boson is actually
• 20:24
  Speaker 2: this little cloud of a Higgs interacting with other higgses.
• 20:29
  Speaker 1: So then that means if the Higgs boson has inertial mass,
• 20:31
  Speaker 1: that means the Higgs boson is not dumb, doesn't go
• 20:36
  Speaker 1: at the speed of light.
• 20:37
  Speaker 2: The Higgs boson does not travel at the speed of
• 20:39
  Speaker 2: light exactly because nothing that has mass can go at
• 20:42
  Speaker 2: the speed of light. And the Higgs boson mass is
• 20:44
  Speaker 2: sort of interesting from like a philosophical perspective, like whoa
• 20:46
  Speaker 2: the thing that has mass gives mass itself. It's like
• 20:49
  Speaker 2: Santa Claus giving himself a present or something. But it's
• 20:52
  Speaker 2: also really fascinating theoretically for other reasons, because the Higgs
• 20:56
  Speaker 2: boson doesn't just get mass from its interactions with itself.
• 20:59
  Speaker 2: It also who gets mass from interactions with other particles.
• 21:02
  Speaker 2: Like we know that the Higgs interacts with electrons, and
• 21:05
  Speaker 2: we know that interacts with top quarks, and so those
• 21:08
  Speaker 2: interactions give mass to electrons and top quarks, but also
• 21:11
  Speaker 2: to the Higgs. So the Higgs gets its mass from
• 21:14
  Speaker 2: interacting with itself and from interacting with the other particles.
• 21:17
  Speaker 1: Wait, so the mass of the Higgs changes depending on
• 21:20
  Speaker 1: who's around it. Like, what if there's no electron or
• 21:23
  Speaker 1: meal on around it, would that mean the Eiggs boson
• 21:25
  Speaker 1: is lighter?
• 21:26
  Speaker 2: Question because I said fields, and those fields are everywhere,
• 21:29
  Speaker 2: or there's always an electron field and there's always a
• 21:31
  Speaker 2: top quark field. So the Higgs boson interacts with those fields,
• 21:34
  Speaker 2: whether or not they're actually electrons or top quarks around,
• 21:38
  Speaker 2: whether those fields are excited enough to make real particles,
• 21:41
  Speaker 2: it interacts with the fields themselves.
• 21:45
  Speaker 1: Well, I guess, just for the record, I think it's
• 21:46
  Speaker 1: okay Santa Claus wants to buy himself a gift. I mean,
• 21:50
  Speaker 1: the poor guy, I mean allwis only gets one birthday
• 21:54
  Speaker 1: present a year from missus Sanna. He can buy himself
• 21:57
  Speaker 1: a little some fum.
• 22:00
  Speaker 2: Yeah, go ahead, Santa Claus, get yourself some dark chocolate.
• 22:03
  Speaker 1: That's right, you do you? Although maybe he likes white chocolate.
• 22:07
  Speaker 2: Yeah, maybe he likes peppermint bark. Who knows. Somebody's got
• 22:09
  Speaker 2: to like that stuff they keep making it.
• 22:11
  Speaker 1: Maybe it's the Santa himself.
• 22:14
  Speaker 2: But there's something of a mystery about the Higgs boson mass,
• 22:16
  Speaker 2: which is why we're so interested in measuring it, and
• 22:19
  Speaker 2: that comes from its interactions with these other particles. It's
• 22:21
  Speaker 2: interactions with matter particles like electrons and top quarks that
• 22:25
  Speaker 2: makes its mass much much bigger, and when it interacts
• 22:28
  Speaker 2: with other bosons like w bosons or gluons or whatever,
• 22:31
  Speaker 2: that makes its mass smaller. And the fascinating thing is
• 22:35
  Speaker 2: that these two numbers are really really big. They're like
• 22:38
  Speaker 2: billions of times bigger than the eventual mass of the
• 22:41
  Speaker 2: Higgs boson, which means these two numbers sort of cancel
• 22:44
  Speaker 2: each other out almost exactly. It's kind of a mystery
• 22:47
  Speaker 2: of modern physics.
• 22:48
  Speaker 1: Mm weird. So the Higgs field is that the only
• 22:52
  Speaker 1: field that interacts with all the other fields, or do
• 22:54
  Speaker 1: all fields interact with each other, or is that unique
• 22:57
  Speaker 1: to the Higgs field. It seems like maybe the Higgs
• 22:59
  Speaker 1: field is. It's just an everyone's business.
• 23:03
  Speaker 2: Every particle we discovered so far feels the weak force,
• 23:06
  Speaker 2: So the Higgs feels the weak force, just like the
• 23:08
  Speaker 2: neutrinos do, and the W and the C and the quarks.
• 23:11
  Speaker 2: Everybody feels the weak force. But the Higgs is neutral,
• 23:14
  Speaker 2: so it doesn't interact with photons directly, for example. But
• 23:17
  Speaker 2: it's fascinating to me that you do this accounting, Like
• 23:19
  Speaker 2: the Higgs boson gets a little bit of mass from
• 23:21
  Speaker 2: interacting with itself, we don't know exactly how much. Then
• 23:24
  Speaker 2: it gets a huge amount of mass from interacting with
• 23:27
  Speaker 2: electrons and nuance and stuff. And then it loses a
• 23:29
  Speaker 2: huge amount of mass from interacting with w's and z's, etc.
• 23:33
  Speaker 2: And that comes back to almost zero. Like these two
• 23:36
  Speaker 2: big numbers, the huge addition and the huge subtraction, don't
• 23:39
  Speaker 2: have to be close to each other. They're two enormous numbers,
• 23:42
  Speaker 2: and yet they almost balance. Brings the Higgs boson mass
• 23:46
  Speaker 2: back down to a reasonable value. In another universe, the
• 23:49
  Speaker 2: Higgs boson could have been like a million times heavier
• 23:52
  Speaker 2: than it ended up being so heavy we could never
• 23:54
  Speaker 2: even discover it.
• 23:55
  Speaker 1: Oh, I guess that's a weird concept for a non
• 23:59
  Speaker 1: particle to understand, which is like, how do you lose
• 24:03
  Speaker 1: mass in an interaction?
• 24:04
  Speaker 2: Like?
• 24:05
  Speaker 1: What does it mean that, like the Higgs boson loses
• 24:07
  Speaker 1: mass when it interacts with certain particles, like it gets
• 24:10
  Speaker 1: lighter and moves faster, it's easier to move around. What
• 24:13
  Speaker 1: does that mean?
• 24:14
  Speaker 2: I think intuitively, the way to think about it is
• 24:15
  Speaker 2: that interacting with some of these fields adds to the
• 24:19
  Speaker 2: internal stored energy of the effective Higgs boson, and interacting
• 24:23
  Speaker 2: with other fields decreases the internal stored energy. Adding to
• 24:26
  Speaker 2: the internal stored energy means getting more mass. Losing internal
• 24:30
  Speaker 2: stored energy means decreasing your mass. So it's not like
• 24:33
  Speaker 2: it gets a kick. It actually like sucks away some
• 24:36
  Speaker 2: of the internal stored energy the interaction with some of
• 24:39
  Speaker 2: these fields.
• 24:41
  Speaker 1: But then that's a whole different mechanism for getting mass, right,
• 24:44
  Speaker 1: which is like having stored energy inside that doesn't come
• 24:48
  Speaker 1: from the Higgs field, does it?
• 24:49
  Speaker 2: In this case, it comes from the interaction between the
• 24:51
  Speaker 2: Higgs field and these other particles. So even the Higgs
• 24:54
  Speaker 2: field interaction you can think about as internal stored energy.
• 24:58
  Speaker 2: Like you think about the electron moving through the universe,
• 25:00
  Speaker 2: what is its mass? You could just say it comes
• 25:02
  Speaker 2: from the Higgs field, but really what's happening is you're
• 25:05
  Speaker 2: creating a new object, which is this electron that interacts
• 25:08
  Speaker 2: with the Higgs field, and that thing has energy which
• 25:10
  Speaker 2: in the end is coming from the Higgs field, and
• 25:13
  Speaker 2: it's storing that energy internally in this new thing. This
• 25:15
  Speaker 2: like cloud of electrons and Higgs is sort of interacting together.
• 25:19
  Speaker 2: So it's really all the same kind of mechanism. The
• 25:21
  Speaker 2: Higgs is like an example of how you can have
• 25:24
  Speaker 2: internal stored energy, but you're right, it's not the only one.
• 25:27
  Speaker 2: Like other forces can give you internal stored energy, like
• 25:30
  Speaker 2: the gluons inside the proton give you internal.
• 25:32
  Speaker 1: Stored energy, and then when those get a lot of
• 25:34
  Speaker 1: internal stored energy like in the proton, it feels heavier.
• 25:39
  Speaker 1: Is that also due to the Higgs field or is
• 25:40
  Speaker 1: that just due to some other unknown mechanism in the universe.
• 25:43
  Speaker 2: That's just the fundamental nature of mass that we don't
• 25:46
  Speaker 2: really understand. That internal stored energy has inertia, and you know,
• 25:49
  Speaker 2: you can change the relationship between those gluons, increasing or
• 25:53
  Speaker 2: decreasing mass. Right, so if those gluons interact with something
• 25:56
  Speaker 2: else outside and change their relative energy levels, that can
• 25:59
  Speaker 2: change the mass of the particle.
• 26:01
  Speaker 1: Well, I guess the other question I had was, you know,
• 26:03
  Speaker 1: you said that the Higgs boson doesn't move at the
• 26:05
  Speaker 1: speed of light, but at the same time it's a
• 26:07
  Speaker 1: particle that gives other particles mass. Does that mean that
• 26:10
  Speaker 1: mass is not instantaneous or that there's some kind of
• 26:14
  Speaker 1: delay in how the universe or how you feel mass
• 26:17
  Speaker 1: in some particles.
• 26:18
  Speaker 2: Like if you change the mass of a particle, would
• 26:21
  Speaker 2: that ripple out at less than the speed of light?
• 26:24
  Speaker 1: Or like if an electron moves, you know, the inertia
• 26:28
  Speaker 1: you would feel is somehow delayed because it has to
• 26:31
  Speaker 1: get it from the Higgs field, which doesn't move at
• 26:32
  Speaker 1: the speed of light.
• 26:33
  Speaker 2: Information about any motion is always delayed, even if it
• 26:36
  Speaker 2: travels at the speed of light. Right, Even like gravitational waves,
• 26:39
  Speaker 2: which travel at the speed of light are not instantaneous.
• 26:42
  Speaker 2: So whether or not you travel at the speed of
• 26:44
  Speaker 2: light or not, you're still not propagating information instantaneously.
• 26:48
  Speaker 1: M so I guess I mean more of a delay,
• 26:51
  Speaker 1: like you could see something happen before you feel its mass.
• 26:54
  Speaker 2: I think we had to pull apart a little bit
• 26:56
  Speaker 2: here the gravitational and the inertial situation, because this see
• 27:00
  Speaker 2: something's mass really means to observe it moving. Right. Mass
• 27:04
  Speaker 2: is all about like what is your inertia? How do
• 27:07
  Speaker 2: you move through the universe? How do you respond to forces?
• 27:09
  Speaker 2: And we're not talking about like how your existence changes,
• 27:13
  Speaker 2: like the curvature of space time and ripples from your acceleration. Right,
• 27:16
  Speaker 2: we're not talking about gravitational waves. We're just talking about
• 27:19
  Speaker 2: inertial mass.
• 27:20
  Speaker 1: Well, I guess that the question is the same. You know,
• 27:22
  Speaker 1: do you feel inertial mass at a later time that
• 27:24
  Speaker 1: you would like if a photon bounced off of an electron.
• 27:27
  Speaker 2: It's a great question. I haven't thought about it before,
• 27:29
  Speaker 2: but I think that probably what's going on is that
• 27:32
  Speaker 2: this is all internal to the object we call the electron,
• 27:35
  Speaker 2: and we don't have enough energy to like break the
• 27:37
  Speaker 2: electron open and see the Higgs is inside propagating. We
• 27:40
  Speaker 2: just like wrap that whole thing up into an object
• 27:43
  Speaker 2: we call the electron. And what we're talking about here
• 27:45
  Speaker 2: is something that's really going on inside the electron. You'd
• 27:48
  Speaker 2: be worried about, like how long it takes a Higgs
• 27:49
  Speaker 2: boson to move from one side of the electron to
• 27:52
  Speaker 2: the other. But from our point of view on the outside,
• 27:54
  Speaker 2: the electron is effectively a point particle, so it's not
• 27:57
  Speaker 2: really an issue like whether the Higgs can get from
• 27:59
  Speaker 2: one inside of the electron to the other to make
• 28:02
  Speaker 2: it like a consistent object with a single kind of mass.
• 28:05
  Speaker 1: It just seems like it's like a force that has
• 28:09
  Speaker 1: a certain delay to it, you know, like a slower
• 28:11
  Speaker 1: force than say the electro magnetic force, which communicates with photons,
• 28:15
  Speaker 1: which are going at the speed of light.
• 28:17
  Speaker 2: Yeah, that's right. Photons do travel at speed of light,
• 28:19
  Speaker 2: and ripples in the Higgs field travels slower. There are
• 28:23
  Speaker 2: some particles whose mass changes. Remember, neutrinos don't have a
• 28:27
  Speaker 2: definite mass when they are created. They are a mixture
• 28:30
  Speaker 2: of various mass states, so that kind of inertial mass
• 28:34
  Speaker 2: information might propagate it less than the speed of light.
• 28:37
  Speaker 1: All right, Well, let's get to the main question of
• 28:39
  Speaker 1: the episode, which is how do you measure the mass
• 28:41
  Speaker 1: of the Higgs boson. That was kind of a part
• 28:44
  Speaker 1: of what the big discovery was in twenty twelve, right,
• 28:46
  Speaker 1: Like you kind of had to guess what its mass
• 28:48
  Speaker 1: was to know where to look for it.
• 28:50
  Speaker 2: Yeah, it's a really interesting bit of scientific history because
• 28:53
  Speaker 2: when Higgs came up with this idea, his theory work
• 28:56
  Speaker 2: no matter what the mass to the Higgs was, Like
• 28:58
  Speaker 2: the Higgs could be very very or super duper honk
• 29:02
  Speaker 2: and heavy and his theory would still work. And that's cool.
• 29:05
  Speaker 2: It makes a very powerful theory, but it's also sort
• 29:08
  Speaker 2: of frustrating from an experimental point of view because he
• 29:10
  Speaker 2: didn't predict the Higgs mass. If his theory only worked
• 29:13
  Speaker 2: for one value of the Higgs mass, then he could
• 29:15
  Speaker 2: have said, go out there, look for it. It has
• 29:18
  Speaker 2: this value, I predict it, you know, like baby Ruth
• 29:20
  Speaker 2: calling his shot. But instead he said, well it might
• 29:22
  Speaker 2: exist and it might have any value. So you got
• 29:25
  Speaker 2: to look for in all sorts of different ways.
• 29:27
  Speaker 1: Meaning like the mass would work no matter what the
• 29:30
  Speaker 1: mass of the Higgs boson is, or would you have
• 29:32
  Speaker 1: like very different universes if it did have different masses, if.
• 29:36
  Speaker 2: You know all the particles that are out there in
• 29:38
  Speaker 2: the universe interacting with the Higgs boson, then you know
• 29:41
  Speaker 2: what its mass is because its mass comes from interacting
• 29:44
  Speaker 2: with itself and interacting with all those other particles. If
• 29:47
  Speaker 2: you don't know the other particles out there in the universe,
• 29:49
  Speaker 2: you don't know everything that's contributing to the Higgs mass.
• 29:52
  Speaker 2: And so we didn't know. We didn't know what all
• 29:54
  Speaker 2: the particles were. We still don't know what all the
• 29:55
  Speaker 2: particles are. If you measure all the other particles very
• 29:58
  Speaker 2: very precisely, then you can predict what the Higgs mass
• 30:01
  Speaker 2: could be. But that's only if you know all the
• 30:03
  Speaker 2: particles in the universe, and we're pretty sure we don't.
• 30:06
  Speaker 1: So I guess he just didn't know what the mass
• 30:08
  Speaker 1: of the Higgs boson was supposed to be, just because
• 30:11
  Speaker 1: you didn't have all the information about what else is
• 30:13
  Speaker 1: out there in the universe exactly.
• 30:14
  Speaker 2: And that's another reason why knowing the mass is exciting,
• 30:17
  Speaker 2: because it gives you a way to tell, like, is
• 30:19
  Speaker 2: there something out there we don't know about, something else
• 30:21
  Speaker 2: interacting with the Higgs field and making it heavier or
• 30:23
  Speaker 2: making it lighter. What we can do is predict the
• 30:25
  Speaker 2: value the Higgs field based on all the particles that
• 30:27
  Speaker 2: we do think are out there. Then we can go
• 30:29
  Speaker 2: out there and measure the Higgs and say does it
• 30:31
  Speaker 2: agree with our prediction?
• 30:33
  Speaker 1: All right, So then we discovered the Higgs boson, and
• 30:35
  Speaker 1: so what is its mass? And how do we know
• 30:37
  Speaker 1: what its mass was?
• 30:38
  Speaker 2: So we measure the mass of particles in a weird unit.
• 30:41
  Speaker 2: It's called the GeV giggle electron volts one billion electron bolts.
• 30:46
  Speaker 2: It's actually a pretty convenient unit because the proton weighs
• 30:49
  Speaker 2: about one GeV. Our electrons are much much lighter than that.
• 30:52
  Speaker 2: For example, they're like half of an MeV half of
• 30:55
  Speaker 2: a million electron bolts, and the Higgs boson is about
• 30:59
  Speaker 2: one hundred and twenty five of these things. It's one
• 31:01
  Speaker 2: hundred and twenty five point three five plus or minus
• 31:05
  Speaker 2: point one five GeV.
• 31:07
  Speaker 1: Wait, the mass of the Higgs boson is one hundred
• 31:10
  Speaker 1: and twenty five times greater than the mass of a proton.
• 31:13
  Speaker 2: Yeah, exactly, it's the second heaviest particle we know. It's
• 31:16
  Speaker 2: lighter only than the top quark, which is about one
• 31:19
  Speaker 2: hundred and seventy three GeV.
• 31:21
  Speaker 1: Well, it's kind of weird to think about, right, Like
• 31:23
  Speaker 1: the electron is thousands of times slighter and yet when
• 31:26
  Speaker 1: it interacts with the Higgs boson, the Higgs boson is heavier.
• 31:30
  Speaker 2: Yeah, exactly. The top quark interacts with the higgs boson
• 31:34
  Speaker 2: like crazy. Those two guys have a party every time
• 31:37
  Speaker 2: they meet. And that's why the top quark is super
• 31:39
  Speaker 2: duper heavy.
• 31:40
  Speaker 1: That's why it's the top because it's it's a fun particle.
• 31:44
  Speaker 1: It's thet I don't know it likes to party.
• 31:50
  Speaker 2: But we know the higgs Boson mass very very precisely.
• 31:53
  Speaker 2: We know it more precisely than the top quark. Even
• 31:55
  Speaker 2: the top quark we discovered in the nineties and we've
• 31:57
  Speaker 2: been working to measure it's mass ever since. Then. With
• 32:00
  Speaker 2: the Higgs boson, we know a precision of one part
• 32:02
  Speaker 2: in one.
• 32:03
  Speaker 1: Thousand, all right, So then how do we know the mass?
• 32:05
  Speaker 1: How do you measure the mass of any particle? You
• 32:07
  Speaker 1: can't just put it on a scale, right, and you
• 32:09
  Speaker 1: can't just like drop it from a building to see
• 32:11
  Speaker 1: how fast it accelerates, exactly.
• 32:14
  Speaker 2: We can't do any of those kinds of things that
• 32:16
  Speaker 2: you usually do because these particles last for only a
• 32:19
  Speaker 2: few moments. You know, we're talking like ten to the
• 32:21
  Speaker 2: negative twenty three seconds, which means it. Technically, we don't
• 32:24
  Speaker 2: even see these particles. Nobody's ever seen a Higgs boson.
• 32:28
  Speaker 2: They never even seen a track of a Higgs boson
• 32:31
  Speaker 2: left in one of our detectors, because they just don't
• 32:34
  Speaker 2: last for long enough already, and then it decays into
• 32:36
  Speaker 2: other stuff. We know the Higgs exists because of patterns
• 32:39
  Speaker 2: in those particle decays that are consistent with the Higgs
• 32:42
  Speaker 2: being there and inconsistent with the Higgs not being there.
• 32:45
  Speaker 2: So then to measure its mass, we have to look
• 32:47
  Speaker 2: at the patterns of those particles and try to extract
• 32:50
  Speaker 2: that information the streak that those particles left after the
• 32:53
  Speaker 2: Higgs boson turned into them. Mmm. Yeah.
• 32:56
  Speaker 1: We often use the analogy of like studying an accidency.
• 33:00
  Speaker 1: After the accident, you sort of study the debris and
• 33:02
  Speaker 1: you kind of figure out, like, oh, this car crash
• 33:06
  Speaker 1: into that car is here at this point, and they
• 33:07
  Speaker 1: crash in the corner back corner, and because the fenders
• 33:11
  Speaker 1: over here, we know how fast they were going. You're
• 33:13
  Speaker 1: saying like, somewhere between the crash and finding the debris,
• 33:17
  Speaker 1: like a Higgs boson popped up into the universe and
• 33:20
  Speaker 1: then it disappeared again.
• 33:21
  Speaker 2: Yeah, and the car crash analogy is helpful, but it's
• 33:23
  Speaker 2: also misleading an important way, because when you're looking at
• 33:26
  Speaker 2: a car crash, you're looking at pieces of the car, right,
• 33:29
  Speaker 2: the fender is here and the windshield wipers over there.
• 33:32
  Speaker 2: When you're looking at the results of a particle collision,
• 33:34
  Speaker 2: you're not looking at like pieces of the Higgs boson.
• 33:36
  Speaker 2: The Higgs boson doesn't like break in half and you
• 33:39
  Speaker 2: find bits of it here and bits of it there.
• 33:41
  Speaker 2: It converts from a Higgs boson into totally different kinds
• 33:44
  Speaker 2: of matter. So, for example, a Higgs boson can decay
• 33:47
  Speaker 2: into two bottom quarks, and that doesn't mean that there
• 33:50
  Speaker 2: are two bottom quarks inside a Higgs boson. It means
• 33:53
  Speaker 2: that the energy that used to be in the Higgs
• 33:55
  Speaker 2: field is now in the bottom quark field. The Higgs
• 33:57
  Speaker 2: is gone. It's not like it's bits are rearranged into
• 33:59
  Speaker 2: something else. It's gone and that energy is now in
• 34:02
  Speaker 2: a different field.
• 34:03
  Speaker 1: Right. Yeah, things trend into energy, but sort of the
• 34:06
  Speaker 1: analogy is still the same, right, Like all the parts
• 34:08
  Speaker 1: still have to fit together at the end, Like you
• 34:10
  Speaker 1: can't just invent energy out of nowhere, like you have
• 34:13
  Speaker 1: to do some accounting to make sure that all the
• 34:15
  Speaker 1: bits that you got at the end were part of
• 34:18
  Speaker 1: the same thing at the beginning, and that is actually
• 34:21
  Speaker 1: how you find the mass, right like you do the
• 34:23
  Speaker 1: through accounting.
• 34:24
  Speaker 2: Exactly through accounting basically a quantum information and energy. Quantum
• 34:28
  Speaker 2: information is sort of amazing. We talked about the podcast
• 34:30
  Speaker 2: a few times, and the idea is that quantum information
• 34:33
  Speaker 2: is not destroyed in the universe, which means that every
• 34:36
  Speaker 2: past moment in the universe creates a unique present because
• 34:40
  Speaker 2: as a unique connection, as where there was a one
• 34:42
  Speaker 2: to one mapping, you can reverse it. You can say,
• 34:44
  Speaker 2: I'm going to take the present, I'm going to rewind
• 34:46
  Speaker 2: it figure out what was going on in the past.
• 34:48
  Speaker 2: And so you can take the particles that the Higgs
• 34:50
  Speaker 2: boson decayed into, maybe like two bottom quarks that we
• 34:53
  Speaker 2: see in our detector. You can figure out what the
• 34:55
  Speaker 2: Higgs boson was doing. Most specifically, you can figure out
• 34:58
  Speaker 2: its momentum and you can figure out its energy, and
• 35:02
  Speaker 2: from those two pieces of information you can measure its mass.
• 35:05
  Speaker 1: I guess, so that means you sort of infer its mass,
• 35:08
  Speaker 1: right or you deduce its mass from what it's doing
• 35:11
  Speaker 1: or what do you see its progeny doing.
• 35:13
  Speaker 2: Yeah, and that makes it sound a little bit indirect,
• 35:15
  Speaker 2: and the end all measurements are indirect, are all inferences
• 35:18
  Speaker 2: based on observation. That's when we feel pretty confident in
• 35:21
  Speaker 2: But yeah, we're measuring the energy of the two particles.
• 35:24
  Speaker 2: And you know, one of the listeners actually came very
• 35:26
  Speaker 2: close to answering it. He said, the Higgs was discovered
• 35:29
  Speaker 2: when they saw a pair of photons, and maybe the
• 35:31
  Speaker 2: mass is equivalent to the energy of those photons. And
• 35:34
  Speaker 2: that's almost exactly right. The energy of those photons tells
• 35:38
  Speaker 2: you a lot, and also their direction and their momentum
• 35:41
  Speaker 2: tells you the momentum of the Higgs, and with that
• 35:43
  Speaker 2: information together you can get the mass. Because remember of
• 35:46
  Speaker 2: energy we're talking about like energy of motion, which is
• 35:48
  Speaker 2: the momentum, and then energy of mass. And so if
• 35:50
  Speaker 2: you have the total energy and you know the momentum,
• 35:53
  Speaker 2: the last little bit has to be the mass.
• 35:56
  Speaker 1: Sounds like that listener was very enlightened.
• 36:00
  Speaker 2: Brilliant, brilliant comment.
• 36:01
  Speaker 1: And so let's shed more light into this measurement of
• 36:04
  Speaker 1: the Higgs bosons mass. What's hard about that and what
• 36:08
  Speaker 1: does it mean about our picture of the universe? So
• 36:10
  Speaker 1: let's stick in to that. But first let's take another
• 36:13
  Speaker 1: quick break. All right, we're talking about the Higgs bosons.
• 36:28
  Speaker 1: Higgs boson researchers favorite particle.
• 36:31
  Speaker 2: Yeah, that's right, or maybe the most famous particle and
• 36:33
  Speaker 2: maybe our favorite particle because it's the last one we discovered.
• 36:36
  Speaker 2: And it's not very often that you discover a new
• 36:38
  Speaker 2: particle from the top quark in the nineties and the
• 36:41
  Speaker 2: Higgs boson in the early twenty tens and nothing ever since.
• 36:45
  Speaker 2: So you spent a lot of time studying each one
• 36:47
  Speaker 2: because they're precious.
• 36:49
  Speaker 1: So if you discover a new particle, that'll be your
• 36:51
  Speaker 1: new favorite. I see how fickly your a physicists are.
• 36:54
  Speaker 2: That's right, The young one is always the baby particle
• 36:57
  Speaker 2: of the family, and you know you gotta love the baby.
• 36:59
  Speaker 1: Just fall in the latest trend, the latest hit particle. Well,
• 37:03
  Speaker 1: we're asking the question of how you measure the mass
• 37:05
  Speaker 1: of the Higgs boson, and it seems like you do
• 37:07
  Speaker 1: it at the Large Hadron Collider and any collider can
• 37:10
  Speaker 1: any collider study the mass of the Higgs or right now,
• 37:13
  Speaker 1: is the Large Hadron Collider at the only collider that
• 37:15
  Speaker 1: can do that?
• 37:16
  Speaker 2: Well, the LAHC doesn't have a monopoly on a per se.
• 37:18
  Speaker 2: It's just that it's the only one that has enough
• 37:20
  Speaker 2: energy to make the Higgs boson, and so it's the
• 37:23
  Speaker 2: only place that it can be studied. So far, we're
• 37:25
  Speaker 2: working on plans for other colliders, including maybe even a
• 37:28
  Speaker 2: Muon collider that can make like huge numbers of Higgs bosons,
• 37:32
  Speaker 2: but you have to make it in order to study it.
• 37:34
  Speaker 1: And so we were talking about how you collide things
• 37:36
  Speaker 1: and then you look at the debris, and then you
• 37:39
  Speaker 1: figure out that in some crashes, like the evidence you
• 37:42
  Speaker 1: see can only be explained by the Higgs boson, and
• 37:46
  Speaker 1: from the debris can also sort of infer what its
• 37:49
  Speaker 1: mass is. And so we got that down pretty good.
• 37:52
  Speaker 2: We have that down pretty good. There's been a lot
• 37:53
  Speaker 2: of really really careful studies, and this is not an
• 37:56
  Speaker 2: easy thing to do. I mean, we're saying the Higgs
• 37:59
  Speaker 2: boson turns to two photons or two bottom quarks or
• 38:02
  Speaker 2: sometimes two w bosons, and we're just saying, oh, you
• 38:05
  Speaker 2: measure those particles, masses and energies. But that's not trivial.
• 38:08
  Speaker 2: You know, that involves building and calibrating complicated detectors in
• 38:12
  Speaker 2: order to measure those streaks and extract that information.
• 38:16
  Speaker 1: Yeah, and also like that it doesn't happen every time
• 38:18
  Speaker 1: you crash some particles, right, Like, you have to collide
• 38:21
  Speaker 1: trillions of particles to sort of get one where maybe
• 38:25
  Speaker 1: a Higgs boson can be seen.
• 38:26
  Speaker 2: Oh yeah, great point. The Higgs boson is really really rare.
• 38:29
  Speaker 2: That's why we collide particles so often, millions and millions
• 38:33
  Speaker 2: of times per second, hoping that maybe like one of
• 38:35
  Speaker 2: those collisions will give us a Higgs boson. So first
• 38:38
  Speaker 2: we have to smash in the particles together to get
• 38:40
  Speaker 2: a sample that's going to have a bunch of Higgs
• 38:42
  Speaker 2: bosons in them. Then we have to try to isolate
• 38:44
  Speaker 2: the collisions that we think probably come from the Higgs boson,
• 38:47
  Speaker 2: but that's not totally possible. Some of those collisions will
• 38:50
  Speaker 2: always be due to other stuff that just happens to Also,
• 38:53
  Speaker 2: give two photons that look kind of like a Higgs boson,
• 38:57
  Speaker 2: or give two w bosons that look kind of like
• 38:59
  Speaker 2: a Higgs photon. So you can never say this collision
• 39:02
  Speaker 2: has a Higgs in it or that collision has a
• 39:04
  Speaker 2: Higgs in it. It's always statistical. You have a set
• 39:06
  Speaker 2: of collisions you say, we think there's like ten percent
• 39:08
  Speaker 2: Higgs in here, or there's fourteen percent Higgs in here.
• 39:11
  Speaker 1: But I guess since the Higgs boson gives all particles
• 39:14
  Speaker 1: their mass, isn't technically the Higgs boson in all collisions too.
• 39:18
  Speaker 2: It is, but sort of in a virtual sense. Like
• 39:20
  Speaker 2: the Higgs field is everywhere, and the Higgs field is
• 39:22
  Speaker 2: involved in everything, even low energy collisions. But if you
• 39:26
  Speaker 2: want to study its mass, you have to make a
• 39:27
  Speaker 2: real Higgs boson. You have to excite the field enough
• 39:30
  Speaker 2: so that it pops out an actual Higgs boson, a
• 39:33
  Speaker 2: real one, not a virtual one.
• 39:35
  Speaker 1: What's the difference?
• 39:36
  Speaker 2: Virtual particles really just saying another ripple in the fields,
• 39:39
  Speaker 2: like information wiggling through the field. But that information can
• 39:42
  Speaker 2: propagate in all sorts of ways that particles don't propagate.
• 39:45
  Speaker 2: You know, particles, for example, have a specific mass, or
• 39:48
  Speaker 2: real Higgs boson moving through the Higgs field has a
• 39:51
  Speaker 2: very specific mass. Virtual particles don't have to follow those rules.
• 39:54
  Speaker 2: They can have all sorts of weird masses, including like
• 39:56
  Speaker 2: zero or negative masses. Virtual particles are not really particles,
• 40:01
  Speaker 2: they're just ripples in the Higgs field. You can sometimes
• 40:03
  Speaker 2: kind of describe using particle like words.
• 40:07
  Speaker 1: But I guess, if the Higgs boson is so rare,
• 40:09
  Speaker 1: is it really what's giving mass to the other particles then,
• 40:13
  Speaker 1: because I feel like you're saying it's rare and virtual
• 40:16
  Speaker 1: and you rarely ever see it, but at the same time,
• 40:18
  Speaker 1: it's affecting us all the time everywhere.
• 40:20
  Speaker 2: Yeah, because the Higgs field is everywhere. Even if there
• 40:22
  Speaker 2: are no real Higgs bosons around, the Higgs field fills
• 40:25
  Speaker 2: the whole universe, and it's constantly interacting with your electrons
• 40:29
  Speaker 2: and your top quarks. So maybe what you're getting at
• 40:31
  Speaker 2: is it is possible to detect the Higgs field and
• 40:34
  Speaker 2: to deduce things about it from its interactions with those particles, right, Like,
• 40:38
  Speaker 2: by measuring the top quark very precisely and measuring the
• 40:41
  Speaker 2: w boson very very precisely, we can learn a lot
• 40:43
  Speaker 2: about the Higgs field, and that's how they make those
• 40:45
  Speaker 2: predictions of what the Higgs mass sort of has to
• 40:48
  Speaker 2: be like. Before we found the Higgs boson mass, we
• 40:50
  Speaker 2: had ideas for what its mass might be based on
• 40:53
  Speaker 2: these sort of indirect measurements observations of how it's affecting
• 40:56
  Speaker 2: the other particles.
• 40:58
  Speaker 1: All right, Well, let's get to what we know about
• 41:00
  Speaker 1: the mass of the Higgs field. So you said, we
• 41:02
  Speaker 1: know that it's one hundred and twenty five zero point
• 41:04
  Speaker 1: thirty five GEVs plus or minus zero point one percent.
• 41:08
  Speaker 1: What does that mean? Is that more than what we expected?
• 41:11
  Speaker 1: It seems like it's a lot, because it's one hundred
• 41:13
  Speaker 1: times more than the mass of the proton. But is
• 41:16
  Speaker 1: that surprising or is that expected? Is it interesting that
• 41:19
  Speaker 1: it weighs that much or could it have been any
• 41:21
  Speaker 1: other mass?
• 41:21
  Speaker 2: Well, first of all, it's very impressive that it's measured
• 41:24
  Speaker 2: so precisely. Like, this is really hard. I guess it's
• 41:27
  Speaker 2: kind of my job so.
• 41:29
  Speaker 1: This horn, But like this is not hard, Yes, according
• 41:33
  Speaker 1: to people who had to do it.
• 41:36
  Speaker 2: It is really hard. You know, like a Higgs boson
• 41:38
  Speaker 2: decays the two photons. You got to measure those photons
• 41:41
  Speaker 2: really precisely. You got to come up with all sorts
• 41:42
  Speaker 2: of clever ways to know, like how can you tell
• 41:45
  Speaker 2: the difference between photon and dis energy and that energy
• 41:47
  Speaker 2: and how do you know for sure? Like people spend
• 41:50
  Speaker 2: weeks and weeks sweating over the details, the tiny little
• 41:54
  Speaker 2: problems it might crop up in your photon calibration which
• 41:57
  Speaker 2: gets propagated to your Higgs Boson calibration. And it's all
• 42:01
  Speaker 2: because this number means a lot, as you were saying earlier,
• 42:04
  Speaker 2: like the Higgs bison could have been heavier, it could
• 42:06
  Speaker 2: have been lighter. It was a little bit of a
• 42:08
  Speaker 2: surprise to some people that it was so light, because remember,
• 42:12
  Speaker 2: those two numbers have to somehow balance each other out,
• 42:15
  Speaker 2: like a huge, big random positive number and a huge,
• 42:18
  Speaker 2: big random negative number somehow almost cancel out to give
• 42:21
  Speaker 2: this slightly positive number. And there's some folks out there
• 42:24
  Speaker 2: who were thinking that those numbers are never going to
• 42:26
  Speaker 2: cancel out, that they were going to give us a
• 42:29
  Speaker 2: huge number, like something so big we would never see
• 42:31
  Speaker 2: it in the large Hadron colliner.
• 42:33
  Speaker 1: So it was lighter than people expected. They thought it
• 42:36
  Speaker 1: was going to be even more huge.
• 42:38
  Speaker 2: Yeah, some people thought it was going to be really huge.
• 42:40
  Speaker 2: Other people have ideas to explain that sort of apparent coincidence.
• 42:43
  Speaker 2: They say, well, maybe there is a connection between all
• 42:46
  Speaker 2: the particles that are making the Higgs heavier and all
• 42:48
  Speaker 2: the particles that are making the Higgs lighter. Maybe there's
• 42:50
  Speaker 2: like a balance in the universe, a symmetry that says
• 42:53
  Speaker 2: for every particle that's making the Higgs heavier, there has
• 42:55
  Speaker 2: to be one making the Higgs lighter, and that's why
• 42:58
  Speaker 2: these two things cancel each other out. Maybe there are
• 43:00
  Speaker 2: a whole bunch of other particles out there and then
• 43:03
  Speaker 2: just sort of like magically balancing everything that we have seen.
• 43:06
  Speaker 2: And that's a theory called supersymmetry. It says to make
• 43:09
  Speaker 2: those two different contributions balance and keep the Higgs field
• 43:12
  Speaker 2: very very light. So for some people when we saw
• 43:15
  Speaker 2: the Higgs boson mass, was you think it's kind of heavy.
• 43:17
  Speaker 2: Some people think it's kind of light. Actually, they thought
• 43:20
  Speaker 2: maybe this is a hint that there are these super
• 43:22
  Speaker 2: symmetric fields out there.
• 43:24
  Speaker 1: Could the Higgs boson have had zero mass? Was that
• 43:27
  Speaker 1: a possibility when you went into it, or did the
• 43:29
  Speaker 1: Peter Higgs theory say it had to have some mass.
• 43:32
  Speaker 2: It could have had zero mass. That is a possibility,
• 43:34
  Speaker 2: But you know, then it would have been pretty easy
• 43:36
  Speaker 2: to find because it would have been very easy to create,
• 43:40
  Speaker 2: and early searches for the Higgs bosons in the seventies,
• 43:42
  Speaker 2: for example, ruled that out pretty quickly. So by the
• 43:45
  Speaker 2: time we turned on the Large Hadron collider, we already
• 43:47
  Speaker 2: knew the Higgs Boson had to be heavier than like
• 43:49
  Speaker 2: one hundred and fifteen or so gv because remember, there
• 43:53
  Speaker 2: was another collider in the nineties which ran into the
• 43:55
  Speaker 2: early two thousands called the LP Large Electron possit Tron Collider,
• 44:01
  Speaker 2: and that one would have found the Higgs boson if
• 44:03
  Speaker 2: it was up to about one hundred and fourteen GeV.
• 44:06
  Speaker 1: All right, well, then what does it mean that it
• 44:08
  Speaker 1: has the mass that it has. What does it mean
• 44:10
  Speaker 1: for the future, I guess, or our understanding of the
• 44:13
  Speaker 1: models of the universe.
• 44:14
  Speaker 2: Right now, it means that there's no specific evidence for
• 44:16
  Speaker 2: other particles out there. Like if the Higgs boson had
• 44:19
  Speaker 2: had some very crazy heavy mass, it would mean, oh,
• 44:22
  Speaker 2: it's getting influenced by another particle out there that's making
• 44:25
  Speaker 2: it heavier, a particle we haven't seen yet. So in
• 44:27
  Speaker 2: that way, like making a very precise measurement at the
• 44:29
  Speaker 2: Higgs Boson mass is a great way to test our understanding,
• 44:32
  Speaker 2: you know, because these things are all connected. You might
• 44:35
  Speaker 2: remember that there was a very precise measurement at the
• 44:37
  Speaker 2: w Boson mass last year. They gave a very weird result,
• 44:40
  Speaker 2: a result that didn't agree with all of our calculations,
• 44:43
  Speaker 2: and these are all tightly coupled, the W the top
• 44:45
  Speaker 2: the Higgs. If you change one of them, it changes
• 44:47
  Speaker 2: all the other ones. So getting a weird value for
• 44:50
  Speaker 2: the W mass means maybe there's something else going on
• 44:52
  Speaker 2: out there. So that's why it's important to get a
• 44:55
  Speaker 2: very precise measurement. It's like without creating those new particles,
• 44:58
  Speaker 2: you can be sensitive to their existence, which is a
• 45:00
  Speaker 2: pretty cool way to explore the universe indirectly. It's also
• 45:04
  Speaker 2: relevant to the question of whether the Higgs field is stable.
• 45:08
  Speaker 2: How the Higgs interacts with itself changes how stable the
• 45:12
  Speaker 2: Higgs field is, and that's connected to the Higgs mass,
• 45:15
  Speaker 2: But the Higgs boson also, because it couples to itself,
• 45:18
  Speaker 2: its mass effects whether might collapse, and if Higgs field
• 45:21
  Speaker 2: collapses it changes the whole structure of the universe and
• 45:24
  Speaker 2: our whole experience. So measuring the Higgs boson mass tells
• 45:28
  Speaker 2: us whether or not the Higgs field is likely to
• 45:30
  Speaker 2: be stable or unstable.
• 45:32
  Speaker 1: M you say that, it also tells you whether there
• 45:35
  Speaker 1: are more particles out there. So if you have this
• 45:37
  Speaker 1: measurement down pretty good, does that mean that you don't
• 45:40
  Speaker 1: think there are other particles out there yet to discover.
• 45:43
  Speaker 1: You think we've maybe discovered them all.
• 45:45
  Speaker 2: Well, if you can where this recent measurement of the
• 45:47
  Speaker 2: W mass by CDF, the one that says that everything
• 45:49
  Speaker 2: is out of whack and the things don't agree, then
• 45:52
  Speaker 2: everything agrees pretty nicely. At the top, the W, and
• 45:54
  Speaker 2: the Higgs are all consistent with each other, and that
• 45:57
  Speaker 2: means that there isn't evidence for anything new out there yet.
• 46:00
  Speaker 2: Other hand, it leaves this question unanswered of why the
• 46:03
  Speaker 2: top and the W and all that stuff add up
• 46:05
  Speaker 2: to give a Higgs that's so light, Like I said,
• 46:07
  Speaker 2: just a coincidence. The masses of these particles are tuned
• 46:10
  Speaker 2: to one part in ten to the ten, so that
• 46:12
  Speaker 2: the Higgs boson just happens to come out to be
• 46:14
  Speaker 2: this very small number. It seems like too big a coincidence,
• 46:17
  Speaker 2: and so we're looking for another explanation. And another explanation
• 46:21
  Speaker 2: might be other particles out there that like help balance
• 46:24
  Speaker 2: the Higgs boson mass, but we just don't know so far.
• 46:27
  Speaker 1: All right, Well, I guess stay tuned. You have the
• 46:30
  Speaker 1: large Headron collider. You just upgraded it, right, you're running
• 46:32
  Speaker 1: that maybe faster than it had been before.
• 46:35
  Speaker 2: Yeah, that's right. We're getting more and more collisions every time,
• 46:38
  Speaker 2: and more protons in every collision, and we're going to
• 46:41
  Speaker 2: run it for another ten issue, and we're going to
• 46:43
  Speaker 2: run it for decades longer and collect huge piles of
• 46:46
  Speaker 2: events and sift through them for evidence to see if
• 46:48
  Speaker 2: the Higgs is doing something weird, because we can measure
• 46:51
  Speaker 2: the higgs boson mass in all sorts of different ways
• 46:53
  Speaker 2: when it decaysed to photons, or in it decays to
• 46:55
  Speaker 2: bottom quarks or in the case to w bosons, and
• 46:58
  Speaker 2: we can also compare those against each other. Does the
• 47:00
  Speaker 2: Higgs look heavier when it turns into a photon or
• 47:03
  Speaker 2: when it turns into quarks, or when it turns into w's.
• 47:05
  Speaker 2: If there's any disagreement there, that's another hint that something
• 47:08
  Speaker 2: new is going on.
• 47:09
  Speaker 1: Wait, the mask can change.
• 47:11
  Speaker 2: The mass should be the same no matter how you
• 47:13
  Speaker 2: measure it. It should be the same if it turns
• 47:15
  Speaker 2: into photons, or if it turns into b's orf it
• 47:17
  Speaker 2: turns into w's. But if there's something else going on,
• 47:20
  Speaker 2: if it's not the Higgs that we thought it was,
• 47:22
  Speaker 2: or if there's more than one higgs, or if there
• 47:24
  Speaker 2: are other particles getting involved. Then you might measure different
• 47:27
  Speaker 2: masses in those different decay modes, and that would be
• 47:29
  Speaker 2: a signed this something else going on you don't understand.
• 47:32
  Speaker 1: Could be that the Higgs boson is actually made out
• 47:34
  Speaker 1: of white chocolate, not dark travel.
• 47:37
  Speaker 2: It's been Santus present to himself all this time.
• 47:40
  Speaker 1: All this time. That's right, it's the clos hypothesis. Should
• 47:45
  Speaker 1: have been the clouds field. Yeah, the Clawson, there you go,
• 47:49
  Speaker 1: the Sandton. All right. Well, a lot of interesting questions
• 47:53
  Speaker 1: talking about and thinking about in this fundamental particle of
• 47:56
  Speaker 1: the universe. I guess the next time you step on
• 47:58
  Speaker 1: a scale, think about you're measuring what your mass is,
• 48:01
  Speaker 1: and think about how many virtual or real Higgs Bosons
• 48:05
  Speaker 1: are flying all around you and inside of you.
• 48:07
  Speaker 2: And how this is just one step in our understanding
• 48:10
  Speaker 2: of the universe. We have this crazy model we put
• 48:13
  Speaker 2: together on our heads and it makes predictions and it
• 48:15
  Speaker 2: has blank spaces in it. Then me go out and
• 48:17
  Speaker 2: confront the actual universe and see if we can get
• 48:20
  Speaker 2: this model to describe everything that we experience.
• 48:23
  Speaker 1: So thanks for joining us, see you next time.
• 48:34
  Speaker 2: Thanks for listening, and remember that Daniel and Jorge explain
• 48:37
  Speaker 2: the universe is a production of iHeartRadio. For more podcasts
• 48:41
  Speaker 2: from iHeartRadio, visit the iHeartRadio app, Apple Podcasts, or wherever
• 48:46
  Speaker 2: you listen to your favorite shows.