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Speaker 1: Hey, Daniel, I have a rude physics question.

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Speaker 2: Oh no, not another dark matter poop.

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Speaker 1: Jokeer, I hope, I think we did that one already.

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Speaker 2: All right then, shoot, all right?

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Speaker 1: Is the Higgs boson heavier than expected?

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Speaker 2: Are you asking if physicists think the Higgs is like

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Speaker 2: too round? That is a bit rude.

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Speaker 1: I'm talking about it's mass, not its volume.

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Speaker 2: Maybe the Higgs doesn't just give mass to other particles,

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Speaker 2: it gives them muscles.

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Speaker 1: What like the Higgs is the steroids of the universe?

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Speaker 1: Is that legal?

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Speaker 2: Lots of physics say yes.

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Speaker 1: I am more hamm and cartoonist, the author of Oliver's

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Speaker 1: Great Big Universe.

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Speaker 2: Hi, I'm Daniel. I'm a particle physicist and a professor

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Speaker 2: at UC Irvine, and I feel like my density increases every.

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Speaker 1: Year, density of knowledge or density of chocolate eaten, like

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Speaker 1: your chocolate cores is getting bigger.

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Speaker 2: Well, those two things are tightly correlated, so I'd say

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Speaker 2: yes to.

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Speaker 1: Be What do you need like chocolate gives you knowledge?

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Speaker 2: Well, there's definitely a correlation between Nobel Prizes one and

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Speaker 2: chocolate consumed per capita.

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Speaker 1: Oh interesting, but which one comes first?

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Speaker 2: We don't have to get into correlation versus causation when

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Speaker 2: it comes to chocolate.

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Speaker 1: I think we do. I mean makes a big difference.

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Speaker 1: Like if you have to eat a lot of chocolate

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Speaker 1: after you win the Noble Price, and you kind of

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Speaker 1: have a lot of work to do.

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Speaker 2: All right, let me go get some chocolate and then

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Speaker 2: we'll figure this out.

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Speaker 1: No, no, no, that's the whole point. You should maybe

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Speaker 1: figure out what's the causation here.

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Speaker 2: I can't figure anything out without chocolate. It's my superpower.

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Speaker 1: Then you're in a paradox. What did you need chocolate

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Speaker 1: after you win the Nobel Prize? But you can win

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Speaker 1: the Nobel Prize until unless you eat a lot of chocolate.

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Speaker 2: What if I opt for a Nobel Price that's not gold,

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Speaker 2: it's just gold foil around bad chocolate.

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Speaker 1: That doesn't af fix your paradox, though maybe it may

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Speaker 1: just means it's impossible. But anyways, Welcome to our podcast,

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Speaker 1: Daniel and Jorge Explain the Universe, a production of iHeartRadio.

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Speaker 2: In which we dig into the apparent paradox of our universe.

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Speaker 2: It is both mysterious and bizarre, and yet somehow also understandable.

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Speaker 2: Working carefully at the cold face of knowledge, we can

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Speaker 2: hammer away at it and slowly build up an understanding

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Speaker 2: of how this universe works from its tiny little quantum

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Speaker 2: particles that weave themselves together to give us this reality

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Speaker 2: we know and love.

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Speaker 1: That's right, the universe is deliciously perplexing. It's dark, and

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Speaker 1: it's velvedly smooth, just like chocolate, which means we can't

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Speaker 1: get enough of it.

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Speaker 2: And it is massive. Not only is it very, very large,

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Speaker 2: but it's also filled with a lot of stuff black

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Speaker 2: holes and neutron stars and just normal stars and rocky

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Speaker 2: planets and maybe squishy little beings crawling on their surface.

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Speaker 1: And thank goodness it has squishy little beings like us,

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Speaker 1: because we're here to ask questions about it, and we

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Speaker 1: do that here on the podcast, where we tackle the

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Speaker 1: big unknowns about how this universe works and why it

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Speaker 1: is the way it is.

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Speaker 2: And often on the podcast we're telling you about the

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Speaker 2: things that we have learned in science. But one of

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Speaker 2: my favorite kinds of episodes are the ones that dig

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Speaker 2: into how we figure it out how we know what

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Speaker 2: we know. Rather than just swallowing the numbers as scientists

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Speaker 2: give us, we want to unwrap them and figure out

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Speaker 2: how exactly they measured this or that to be whatever

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Speaker 2: number it is.

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Speaker 1: Yeah, because there is a lot to know about the

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Speaker 1: universe and a lot that science has figured out, and

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Speaker 1: it's interesting to dig into how it is that we

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Speaker 1: know these things. Just sometimes the story is maybe even

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Speaker 1: better than the facts that you've learned.

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Speaker 2: Experimental science is not just go out there and check

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Speaker 2: the theoretical predictions. Sometimes the theory doesn't make any predictions,

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Speaker 2: and it just says, we don't know how heavy this

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Speaker 2: thing is. Go measure it, and measuring it requires inventing

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Speaker 2: all sorts of cool and clever tre That's what experimental

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Speaker 2: science is all about, and we like to celebrate that

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Speaker 2: here in the podcast. We've had fun episodes about all

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Speaker 2: of the inventiveness necessary to measure the speed of light,

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Speaker 2: or to measure the gravitational constant.

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Speaker 1: Or to measure how much chocolate. Physicists can eat safely.

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Speaker 2: Data says there is no upper bound.

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Speaker 1: Really, that doesn't sound like a scientific statement. I think

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Speaker 1: science is pretty clear there is a limit to how

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Speaker 1: much chocolate you can eat.

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Speaker 2: I don't know. I haven't yet collapsed into a black hole,

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Speaker 2: but that may be in my future.

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Speaker 1: I guess it's hard to prove a negative or a

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Speaker 1: maximum m hm.

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Speaker 2: Really the question is if you eat a lot of

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Speaker 2: white chocolate, do you turn into a white hole or

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Speaker 2: a black hole?

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Speaker 1: So to be on the podcast, we'll be asking the

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Speaker 1: question how do we measure the Higgs Bosons mass?

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Speaker 2: Did you say mass or math?

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Speaker 1: I think I said mass, right, So we do.

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Speaker 2: Have to use a lot of math to figure out

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Speaker 2: the Higgs Boson mass.

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Speaker 1: Of course, exposed on have its own math.

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Speaker 2: As far as we know, there is just one math.

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Speaker 2: There is the math. But everything has its own mass,

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Speaker 2: and it's an interesting puzzle to figure out why some

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Speaker 2: particles have a lot of it, why some particles don't

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Speaker 2: seem to have a lot of it, and to learn

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Speaker 2: about exactly how we measure the mass of these tiny

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Speaker 2: little particles. You can even just barely see.

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Speaker 1: Well, some particles don't have any mass, right.

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Speaker 2: Yeah, that's right. Photons have no mass, Gluons have no mass. Gravitons,

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Speaker 2: if they exist, probably have no mass as well. Mass

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Speaker 2: isn't even a necessary attribute, like you can be a

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Speaker 2: thing without having any stuff to you.

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Speaker 1: Right, Although, as we've talked about many times on the podcast,

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Speaker 1: the question or the idea of mass is kind of

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Speaker 1: a tricky one, right, Like there are different kinds of masses,

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Speaker 1: and also like what you might call mass is not

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Speaker 1: necessarily the stuff that you have about you.

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Speaker 2: Yeah, our intuitive understanding of mass is different from the

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Speaker 2: sort of mathematical physical description of matter at its most microscopic.

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Speaker 1: Well, this is an interesting question because the Higgs boson

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Speaker 1: is a pretty big deal in the right. I mean,

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Speaker 1: it was discovered a few years ago and people were

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Speaker 1: very excited because apparently it is a very important particle

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Speaker 1: in the pathion of particles in that it gives mass

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Speaker 1: to other particles.

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Speaker 2: Yeah, the Higgs boson is a feature of the Higgs field,

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Speaker 2: which fills the whole universe. Like other quantum fields, it

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Speaker 2: can be excited into making a particle, or it can

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Speaker 2: be chill and relaxed down to its lowest state. But

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Speaker 2: the Higgs boson, the Higgs particle, the excitation of the

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Speaker 2: Higgs field, has all sorts of particle like properties. It moves,

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Speaker 2: it has mass, and the value of its mass is

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Speaker 2: really important. It's important theoretically and it's important experimentally.

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Speaker 1: As the big question is how do you measure the

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Speaker 1: mass of something so important, so crucial to the concept

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Speaker 1: of mass itself like the Higgs boson, and so, as

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Speaker 1: usually you were wondering how many people out there had

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Speaker 1: thought about this question and wondered if they can just

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Speaker 1: ask the Higgs boson it's mass.

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Speaker 2: How rude, But thank you very much everybody who volunteers

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Speaker 2: for this segment of the podcast. If you would like

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Speaker 2: to participate, please don't be shy and write to me

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Speaker 2: to questions at Danielanjorge dot com. I am waiting for

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Speaker 2: your email.

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Speaker 1: So think about it for a second. How do you

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Speaker 1: think physicists measure the Higgs bosons mass? Here's what people

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Speaker 1: had to say.

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Speaker 3: I know from the episode on where does the Higgs

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Speaker 3: get its mass that you can look at how it

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Speaker 3: interacts with the other fields like the top cork and

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Speaker 3: the strange cork, and maybe with its interacting with its

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Speaker 3: own field. But I have no idea how you measure it.

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Speaker 4: I now believe that we can view a boson, and

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Speaker 4: so therefore I would imagine you could put it in

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Speaker 4: a particle accelerator and throw something at it, and by

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Speaker 4: that makes the calculations to measure its mass.

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Speaker 5: Measuring the mass of the Higgs is going to be

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Speaker 5: exceedingly difficult. Even an optical system would probably be much

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Speaker 5: too large to get the mass of the system. I

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Speaker 5: one could assume that some interplanetary system telescope might actually

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Speaker 5: be a way to go, if we were able to

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Speaker 5: figure that out.

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Speaker 6: If I remember it right, the Higgs boson was discovered

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Speaker 6: when they could detect a pair of photons that were

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Speaker 6: emitted in the collider. So maybe its mass would be

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Speaker 6: equivalent to the energy of those two photoms.

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Speaker 2: I have no idea.

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Speaker 5: It could have something to do with its track after

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Speaker 5: collision analysis it.

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Speaker 1: Turned all right. I am with the last person here

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Speaker 1: who said, I have no idea. Sounds like a great title.

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Speaker 2: For a book. We should write a book like that.

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Speaker 1: Maybe with Tilight we have No Idea and make it

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Speaker 1: available for purchase at bookstores and kind of book website.

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Speaker 1: That would be a good idea.

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Speaker 2: That would be a very good idea. In fact, if

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Speaker 2: you went to we have no idea dot com, you

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Speaker 2: might even be able to find such a book.

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Speaker 1: That's an amazing idea. But yeah, this is an interesting question.

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Speaker 1: How do you measure the Higgs bosons mass? If the

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Speaker 1: Higgs feel is what gives things mass, it's a bit

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Speaker 1: of a conundrum there, So when don't we start at

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Speaker 1: the beginning at Daniel? What is the Higgs boson for

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Speaker 1: people who don't.

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Speaker 2: Know, So, the Higgs boson is an idea that came

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Speaker 2: out of the nineteen sixties when people were looking at

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Speaker 2: the electromagnetic interaction, which is mediated by the photon, and

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Speaker 2: the weak force, which is mediated by the Z and

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Speaker 2: the W bosons. So you have these two forces which

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Speaker 2: seemed pretty different. The weak force is very weak and

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Speaker 2: it has these three weird bosons that mediate it, and

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Speaker 2: the electromagnetic force is very strong. It's the one that

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Speaker 2: we know, you know, makes lightning and magnets and all

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Speaker 2: sorts of stuff and binds together protons electrons into atoms

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Speaker 2: and weaves those atoms together into molecules and basically makes

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Speaker 2: the structure of everything around us. So it's felt like

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Speaker 2: very different forces, but people had an idea that they

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Speaker 2: might just click together into one larger idea, which they

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Speaker 2: call the electroweak force.

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Speaker 1: Now, what do people know about the weak force or

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Speaker 1: how do we discover it and what do we think

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Speaker 1: it was for?

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Speaker 2: Well, the weak force was discovered several decades ago, and

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Speaker 2: it was known to be involved in radioactive decay. So,

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Speaker 2: for example, when a nucleus decays down to a lighter element,

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Speaker 2: it does so using a process called beta decay. Then

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Speaker 2: that involves the weak force. So we knew that the

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Speaker 2: weak force was a thing, and we knew that it

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Speaker 2: did some stuff and it was different from electromagnetism. We

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Speaker 2: had postulated the idea that there might be a particle

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Speaker 2: out there that only feels the weak force, the neutrino,

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Speaker 2: but it hadn't yet been observed.

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Speaker 1: Like we knew about radioactive decay, like uranium decays into

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Speaker 1: a lower mass uranium. But I guess you needed some

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Speaker 1: kind of mechanism for it to do that, and you

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Speaker 1: had to sort of invent the force to do that,

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Speaker 1: or like it only made sense if you had this

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Speaker 1: new kind of force.

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Speaker 2: Yeah, you can't explain radioactive decay using just electromagnetism or

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Speaker 2: just a strong force. You need a new kind of phenomenon.

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Speaker 2: And that's sort of the history of forces, right. We

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Speaker 2: see all this stuff out there in the world, and

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Speaker 2: we tried to describe it using sort of like the

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Speaker 2: shortest possible list of explanations. But sometimes you have to

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Speaker 2: add one, you know, like when first time people ever

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Speaker 2: saw lightning. They're like, hmm, well, you can't explain that

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Speaker 2: with everything we know, So let's add some into the lists.

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Speaker 2: Let's say there's a new kind of force electricity, and

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Speaker 2: people saw magnets and they're like, ooh wow, this is

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Speaker 2: a cool new thing. So then magnets were added to

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Speaker 2: the list. Later, we try to shrink that list by

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Speaker 2: seeing if we can combine those forces. So electricity and

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Speaker 2: magnetism actually two sides of the same force, now just

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Speaker 2: one idea electromagnetism. So the weak force was responsible for

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Speaker 2: a distinct kind of phenomena that we couldn't explain using

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Speaker 2: other forces. But then people were eager to see if

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Speaker 2: they could squeeze it together with the other forces.

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Speaker 1: What made them think that you could squeeze them together, Like,

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Speaker 1: for example, they didn't try to squish together electromagnetism and gravity,

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Speaker 1: did they?

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Speaker 2: Oh? Yes they did. Einstein spent most of his life

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Speaker 2: trying to accomplish that actually and failing, And so theorists

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Speaker 2: basically trying to squeeze everything possible together. You know, it's

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Speaker 2: like we're looking at a bunch of puzzle pieces on

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Speaker 2: the table and we're like, hm, does this fit with that? Nope?

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Speaker 2: Does this fit with that? Nope? And electricity and magnetism

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Speaker 2: almost fit together just perfectly together with the weak force,

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Speaker 2: like they clicked into place, almost perfectly. There was just

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Speaker 2: like a little gap missing, and that gap was the

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Speaker 2: Higgs boson. Oh.

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Speaker 1: Interesting, So the Higgs field and the Higgs boson was

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Speaker 1: that missing piece exactly.

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Speaker 2: That's why they suspected that it existed, because it seemed

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Speaker 2: very likely that these two forces could click together, but

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Speaker 2: it didn't quite work. The problem was that photons have

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Speaker 2: no mass. Their mass lists right, but the W and

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Speaker 2: Z bosons were very, very massive, and that made it

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Speaker 2: very very hard to click these two together unless you

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Speaker 2: had some special thing out there which could give mass

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Speaker 2: to the W and the Z and not give it

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Speaker 2: to the photon. And that's what the Higgs does. It

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Speaker 2: solves this problem of electroweak symmetry. It's called and noo.

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Speaker 2: They tried to bring in the strong force. They just

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Speaker 2: decide to the strong force. People basically work on every combination.

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Speaker 2: If you could bring the strong force together with the

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Speaker 2: electroweak force, then you've achieved a grand unified theory, something

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Speaker 2: nobody has been able to make work.

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Speaker 1: So far mathematically, would you have to call it like

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Speaker 1: the electro met force. It's not weak, it's not strong.

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Speaker 1: It's just kind of meant.

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Speaker 2: Well, you know, there'd be an interesting argument there about

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Speaker 2: like which names get kept and which names get dropped.

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Speaker 2: I don't know if you noticed, but when electromagnetism got

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Speaker 2: merged with the weak force, magnetism got dropped, like the

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Speaker 2: least influential partner in a law firm that merged with

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Speaker 2: a bigger firm. Right, it's just gone.

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Speaker 1: They couldn't just keep phyphonating. I guess I don't know.

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Speaker 2: I think they could have. It's a bummer to lose magnetism.

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Speaker 2: I like magnets. I don't know what they would call it.

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Speaker 2: But the official name right now is the Grand Unified Theory.

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Speaker 2: You can bring those together, then you have a grand

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Speaker 2: unified theory. And people have been trying all sorts of ways,

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Speaker 2: but nobody's been able to make it click.

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Speaker 1: All right, So then the Higgs boson and the Higgs

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Speaker 1: field made the electromagnetic force and the weak force click together.

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Speaker 1: So that's kind of where it came from the idea

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Speaker 1: for it.

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Speaker 2: That's right, That's why we thought it had to be

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Speaker 2: there it or something else which did that job, which

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Speaker 2: gave mass to the w Z bosons. And also they

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Speaker 2: were able to add a little piece to the Higgs

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Speaker 2: force and say, oh, also it interacts with all the

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Speaker 2: matter particles and gives them mass as well. So it

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Speaker 2: was a very cute little idea, and then we found

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Speaker 2: it in twenty twelve, this fantastic triumph of theoretical physics,

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Speaker 2: to say, you know, there's a pattern out there that's

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Speaker 2: missing a piece. It would make much more sense if

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Speaker 2: it existed in the universe, and boom, there it does.

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Speaker 2: It makes you feel like, wow, math is not just

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Speaker 2: like describing the universe. Maybe it's dictating how the universe works.

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Speaker 1: You know, wait, which math? The math are one of

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Speaker 1: the math?

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Speaker 2: The math, and in this case it's group theory. This

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Speaker 2: really weird, abstract kind of math that was invented by

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Speaker 2: a bunch of French guys in the eighteen hundreds, not

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Speaker 2: because they were interested in particle physics or really physics

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Speaker 2: at all. They were just like, huh, look at these

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Speaker 2: cool symmetries and patterns. Maybe we can describe them mathematically.

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Speaker 2: And then decades later particle physicists were like Ooh, that

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Speaker 2: math perfectly described the patterns we're among these particles. Thank

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Speaker 2: you very much mathematicians for inventing this tool.

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Speaker 1: All right, So, then the Higgs field and the Higgs

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Speaker 1: boson is what gives other particles their mass, right, Like,

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Speaker 1: if the electron has a certain mass with meaning that

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Speaker 1: it's hard to get it moving and it's hard to

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Speaker 1: get it to stop, that's inertial mass. That's all due

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Speaker 1: to the Higgs field.

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Speaker 2: That's right. As the electron moves through the universe, it

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Speaker 2: interacts with the Higgs field. That changes how the electron

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Speaker 2: moves in a way that to us looks like the

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Speaker 2: electron itself has mass. And there's an argument to me

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Speaker 2: made to say that the true, the real, the pure

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Speaker 2: electron has no mass. But what we see isn't the

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Speaker 2: pure electron. We see this like cloud of an electron

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Speaker 2: interacting with Higgs bosons, and that's what we call an

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Speaker 2: electron because that's what we interact with. We see, we

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Speaker 2: measure in our laboratory, and that object, the sort of

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Speaker 2: electron interwoven with the Higgs field, that thing has the

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Speaker 2: mass of an electron.

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Speaker 1: And that's also how you explain how some particles like

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Speaker 1: the photon don't have mass. Right, You just figure out

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Speaker 1: that in the universe some particles interact with the Higgs

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Speaker 1: fields and then some don't, right, Like the photon doesn't

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Speaker 1: interact with the Higg fields, and so it doesn't have

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Speaker 1: this inertial mass.

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Speaker 2: Right exactly. And on one hand, it answers a deep

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Speaker 2: question why does the electron have mass? The answer is, oh,

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Speaker 2: it interacts with the Higgs field, but it doesn't answer

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Speaker 2: a much deeper question, which is like, well, why does

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Speaker 2: the muon have more mass? The answer is just, well,

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Speaker 2: it interacts more with the Higgs boson, sort of like

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Speaker 2: kicks the question down the road to like, well, why

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Speaker 2: does the mwon interact with the Higgs boson more than

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Speaker 2: the electron? We don't know. That's just like a number

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Speaker 2: out there.

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Speaker 1: We have to measures, Like, you didn't really answer the question,

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Speaker 1: you just changed the name of the thing.

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Speaker 2: Well, we answered the question, but it revealed another deeper question.

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Speaker 2: It's like we ran the ball down the field another

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Speaker 2: ten yards somid some progress, we know a little bit

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Speaker 2: more how to focus, But no, we definitely didn't finally

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Speaker 2: answer the question.

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Speaker 1: And so the Higgs field gives mass to other particles, right,

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Speaker 1: like quarks and electrons and its cousins. Even the neutrina

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Speaker 1: has a little bit of mass, they think, right, The.

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Speaker 2: Neutrinos definitely do have a little bit of mass. We

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Speaker 2: don't know exactly how much they have, but we know

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Speaker 2: it's very very small. We don't actually know that neutrinos

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Speaker 2: get their mass from the Higgs. That's one idea that

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Speaker 2: there are neutrinos and anti neutrinos and they do the

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Speaker 2: same thing the other particles do and get mass. It's

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Speaker 2: also possible the neutrino is even weirder. It might be

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Speaker 2: its own anti particle, and so it might get its

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Speaker 2: mass in another way. Remember, the Higgs boson is not

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Speaker 2: the only way to get mass. You can get mass

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Speaker 2: anytime you have any kind of internal stored energy. For example,

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Speaker 2: we think dark matter probably doesn't get its mass from

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Speaker 2: the Higgs field. So neutrinos might do the same things electrons,

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Speaker 2: or they might do something totally different. Mm.

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Speaker 1: Interesting. All right, Well, that's the Higgs boson and we

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Speaker 1: know that it gives other particles mass. But the question

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Speaker 1: now is who gives the Higgs boison its mass? And

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Speaker 1: more importantly, for this episode, how do we measure it?

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Speaker 1: And so let's dig into those questions. But first let's

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Speaker 1: take a quick break. All right, we're talking about the

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Speaker 1: Higgs boson. Would you say it's the world's third most

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Speaker 1: famous particle.

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Speaker 2: Third most famous? It might be the most famous. I

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Speaker 2: think it's Michael Jordan of particles.

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Speaker 1: Really, you think it's more famous than the electron quarks

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Speaker 1: maybe or photons. Photons are really probably up there. So

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Speaker 1: I would say it's like photons, electrons, and then maybe

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Speaker 1: the Higgs boson.

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Speaker 2: I guess I probably have a skewed view of it,

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Speaker 2: but I would guess Higgs boson first and then electron.

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Speaker 1: I guess it is the most popular particle among physicists

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Speaker 1: who study the Higgs boson. That makes sense.

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Speaker 2: I would say, I have a massive interest in the

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Speaker 2: Higgs boson.

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Speaker 1: Yes, you're heavily biased. All right, Well, we were talking

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Speaker 1: about how the Higgs field and the Higgs boson gives

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Speaker 1: mass to other particles. But then now the question is

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Speaker 1: what gives Higgs boson its mass and how do we

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Speaker 1: measure it?

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Speaker 2: Yeah, the Higgs boson is like the barber who shaves

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Speaker 2: himself for herself. The Higgs actually gives mass to itself. Right,

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Speaker 2: the Higgs is a really interesting particle because it interacts

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Speaker 2: with its That's not true for every particle, like the photon,

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Speaker 2: for example, only interacts with particles that have any electric

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Speaker 2: charge plus or minus a neutral particle. The photon will

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Speaker 2: just fly right by, and the photon is neutral electrically,

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Speaker 2: so it doesn't interact with itself. But the Higgs boson

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Speaker 2: does interact with itself. Two Higgs bosons coming near each

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Speaker 2: other will bounce off each other or attract each other sometimes.

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Speaker 1: WHOA Okay, So I guess that is kind of strange

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Speaker 1: and different. So the Higgs boson when it's out there

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Speaker 1: and it sees another Higgs boson, they can ignore each other.

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Speaker 2: They cannot ignore each other exactly. They're like x's that

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Speaker 2: are still angry at each other. They always end up entangled.

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Speaker 1: Are you saying the whole universe is one big, u

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Speaker 1: sad and dramatic story.

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Speaker 2: Yeah. And then they go home. They both eat chocolate

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Speaker 2: to feel better. Now, the Higgs boson flies through the universe,

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Speaker 2: and like other particles, it feels the Higgs field and

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Speaker 2: it interacts with the other Higgs bosons. The other manifestations

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Speaker 2: of the Higgs field and pigs up mass, and so

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Speaker 2: the interaction of the Higgs fiel with itself gives it mass.

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Speaker 1: Is that the order you would put it in, like

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Speaker 1: you have a Higgs boson which is like a little

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Speaker 1: blip in the field, and then that blip interacts with

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Speaker 1: the field it's made out of too.

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Speaker 2: Exactly in just the same way that an electron interacts

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Speaker 2: or the Higgs field. A Higgs boson also interacts or

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Speaker 2: the Higgs field, and it has a similar effect on

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Speaker 2: the Higgs boson as it does on the electron. What

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Speaker 2: we're measuring when we measure the Higgs boson is actually

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Speaker 2: this little cloud of a Higgs interacting with other higgses.

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Speaker 1: So then that means if the Higgs boson has inertial mass,

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Speaker 1: that means the Higgs boson is not dumb, doesn't go

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Speaker 1: at the speed of light.

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Speaker 2: The Higgs boson does not travel at the speed of

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Speaker 2: light exactly because nothing that has mass can go at

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Speaker 2: the speed of light. And the Higgs boson mass is

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Speaker 2: sort of interesting from like a philosophical perspective, like whoa

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Speaker 2: the thing that has mass gives mass itself. It's like

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Speaker 2: Santa Claus giving himself a present or something. But it's

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Speaker 2: also really fascinating theoretically for other reasons, because the Higgs

442
00:20:56,280 --> 00:20:59,320
Speaker 2: boson doesn't just get mass from its interactions with itself.

443
00:20:59,560 --> 00:21:02,719
Speaker 2: It also who gets mass from interactions with other particles.

444
00:21:02,760 --> 00:21:05,560
Speaker 2: Like we know that the Higgs interacts with electrons, and

445
00:21:05,600 --> 00:21:08,120
Speaker 2: we know that interacts with top quarks, and so those

446
00:21:08,119 --> 00:21:11,080
Speaker 2: interactions give mass to electrons and top quarks, but also

447
00:21:11,240 --> 00:21:14,040
Speaker 2: to the Higgs. So the Higgs gets its mass from

448
00:21:14,040 --> 00:21:17,240
Speaker 2: interacting with itself and from interacting with the other particles.

449
00:21:17,400 --> 00:21:20,159
Speaker 1: Wait, so the mass of the Higgs changes depending on

450
00:21:20,200 --> 00:21:23,000
Speaker 1: who's around it. Like, what if there's no electron or

451
00:21:23,040 --> 00:21:25,840
Speaker 1: meal on around it, would that mean the Eiggs boson

452
00:21:25,960 --> 00:21:26,399
Speaker 1: is lighter?

453
00:21:26,640 --> 00:21:29,320
Speaker 2: Question because I said fields, and those fields are everywhere,

454
00:21:29,400 --> 00:21:31,520
Speaker 2: or there's always an electron field and there's always a

455
00:21:31,560 --> 00:21:34,800
Speaker 2: top quark field. So the Higgs boson interacts with those fields,

456
00:21:34,920 --> 00:21:38,840
Speaker 2: whether or not they're actually electrons or top quarks around,

457
00:21:38,960 --> 00:21:41,720
Speaker 2: whether those fields are excited enough to make real particles,

458
00:21:41,720 --> 00:21:43,520
Speaker 2: it interacts with the fields themselves.

459
00:21:45,080 --> 00:21:46,879
Speaker 1: Well, I guess, just for the record, I think it's

460
00:21:46,920 --> 00:21:50,120
Speaker 1: okay Santa Claus wants to buy himself a gift. I mean,

461
00:21:50,840 --> 00:21:54,159
Speaker 1: the poor guy, I mean allwis only gets one birthday

462
00:21:54,200 --> 00:21:57,600
Speaker 1: present a year from missus Sanna. He can buy himself

463
00:21:57,800 --> 00:21:59,480
Speaker 1: a little some fum.

464
00:22:00,280 --> 00:22:02,560
Speaker 2: Yeah, go ahead, Santa Claus, get yourself some dark chocolate.

465
00:22:03,440 --> 00:22:06,880
Speaker 1: That's right, you do you? Although maybe he likes white chocolate.

466
00:22:07,000 --> 00:22:09,600
Speaker 2: Yeah, maybe he likes peppermint bark. Who knows. Somebody's got

467
00:22:09,720 --> 00:22:11,119
Speaker 2: to like that stuff they keep making it.

468
00:22:11,440 --> 00:22:12,840
Speaker 1: Maybe it's the Santa himself.

469
00:22:14,119 --> 00:22:16,720
Speaker 2: But there's something of a mystery about the Higgs boson mass,

470
00:22:16,760 --> 00:22:19,000
Speaker 2: which is why we're so interested in measuring it, and

471
00:22:19,040 --> 00:22:21,800
Speaker 2: that comes from its interactions with these other particles. It's

472
00:22:21,840 --> 00:22:25,400
Speaker 2: interactions with matter particles like electrons and top quarks that

473
00:22:25,480 --> 00:22:28,160
Speaker 2: makes its mass much much bigger, and when it interacts

474
00:22:28,160 --> 00:22:31,680
Speaker 2: with other bosons like w bosons or gluons or whatever,

475
00:22:31,960 --> 00:22:35,720
Speaker 2: that makes its mass smaller. And the fascinating thing is

476
00:22:35,720 --> 00:22:38,159
Speaker 2: that these two numbers are really really big. They're like

477
00:22:38,240 --> 00:22:41,000
Speaker 2: billions of times bigger than the eventual mass of the

478
00:22:41,080 --> 00:22:44,200
Speaker 2: Higgs boson, which means these two numbers sort of cancel

479
00:22:44,280 --> 00:22:47,400
Speaker 2: each other out almost exactly. It's kind of a mystery

480
00:22:47,440 --> 00:22:48,480
Speaker 2: of modern physics.

481
00:22:48,880 --> 00:22:52,520
Speaker 1: Mm weird. So the Higgs field is that the only

482
00:22:52,560 --> 00:22:54,760
Speaker 1: field that interacts with all the other fields, or do

483
00:22:54,840 --> 00:22:57,480
Speaker 1: all fields interact with each other, or is that unique

484
00:22:57,520 --> 00:22:59,639
Speaker 1: to the Higgs field. It seems like maybe the Higgs

485
00:22:59,640 --> 00:23:01,560
Speaker 1: field is. It's just an everyone's business.

486
00:23:03,240 --> 00:23:06,200
Speaker 2: Every particle we discovered so far feels the weak force,

487
00:23:06,640 --> 00:23:08,760
Speaker 2: So the Higgs feels the weak force, just like the

488
00:23:08,840 --> 00:23:11,520
Speaker 2: neutrinos do, and the W and the C and the quarks.

489
00:23:11,560 --> 00:23:14,359
Speaker 2: Everybody feels the weak force. But the Higgs is neutral,

490
00:23:14,400 --> 00:23:17,600
Speaker 2: so it doesn't interact with photons directly, for example. But

491
00:23:17,640 --> 00:23:19,800
Speaker 2: it's fascinating to me that you do this accounting, Like

492
00:23:19,800 --> 00:23:21,680
Speaker 2: the Higgs boson gets a little bit of mass from

493
00:23:21,720 --> 00:23:24,560
Speaker 2: interacting with itself, we don't know exactly how much. Then

494
00:23:24,560 --> 00:23:27,000
Speaker 2: it gets a huge amount of mass from interacting with

495
00:23:27,040 --> 00:23:29,600
Speaker 2: electrons and nuance and stuff. And then it loses a

496
00:23:29,640 --> 00:23:33,120
Speaker 2: huge amount of mass from interacting with w's and z's, etc.

497
00:23:33,520 --> 00:23:36,400
Speaker 2: And that comes back to almost zero. Like these two

498
00:23:36,480 --> 00:23:39,880
Speaker 2: big numbers, the huge addition and the huge subtraction, don't

499
00:23:39,920 --> 00:23:42,720
Speaker 2: have to be close to each other. They're two enormous numbers,

500
00:23:42,920 --> 00:23:46,280
Speaker 2: and yet they almost balance. Brings the Higgs boson mass

501
00:23:46,359 --> 00:23:49,200
Speaker 2: back down to a reasonable value. In another universe, the

502
00:23:49,280 --> 00:23:52,480
Speaker 2: Higgs boson could have been like a million times heavier

503
00:23:52,520 --> 00:23:54,840
Speaker 2: than it ended up being so heavy we could never

504
00:23:54,920 --> 00:23:55,639
Speaker 2: even discover it.

505
00:23:55,840 --> 00:23:59,280
Speaker 1: Oh, I guess that's a weird concept for a non

506
00:23:59,280 --> 00:24:03,280
Speaker 1: particle to understand, which is like, how do you lose

507
00:24:03,320 --> 00:24:04,600
Speaker 1: mass in an interaction?

508
00:24:04,960 --> 00:24:05,040
Speaker 2: Like?

509
00:24:05,080 --> 00:24:07,800
Speaker 1: What does it mean that, like the Higgs boson loses

510
00:24:07,840 --> 00:24:10,800
Speaker 1: mass when it interacts with certain particles, like it gets

511
00:24:10,880 --> 00:24:13,480
Speaker 1: lighter and moves faster, it's easier to move around. What

512
00:24:13,520 --> 00:24:14,000
Speaker 1: does that mean?

513
00:24:14,080 --> 00:24:15,879
Speaker 2: I think intuitively, the way to think about it is

514
00:24:15,880 --> 00:24:19,159
Speaker 2: that interacting with some of these fields adds to the

515
00:24:19,200 --> 00:24:23,240
Speaker 2: internal stored energy of the effective Higgs boson, and interacting

516
00:24:23,280 --> 00:24:26,840
Speaker 2: with other fields decreases the internal stored energy. Adding to

517
00:24:26,880 --> 00:24:30,520
Speaker 2: the internal stored energy means getting more mass. Losing internal

518
00:24:30,560 --> 00:24:33,639
Speaker 2: stored energy means decreasing your mass. So it's not like

519
00:24:33,760 --> 00:24:36,280
Speaker 2: it gets a kick. It actually like sucks away some

520
00:24:36,320 --> 00:24:39,280
Speaker 2: of the internal stored energy the interaction with some of

521
00:24:39,280 --> 00:24:39,960
Speaker 2: these fields.

522
00:24:41,119 --> 00:24:44,520
Speaker 1: But then that's a whole different mechanism for getting mass, right,

523
00:24:44,600 --> 00:24:48,000
Speaker 1: which is like having stored energy inside that doesn't come

524
00:24:48,000 --> 00:24:49,159
Speaker 1: from the Higgs field, does it?

525
00:24:49,320 --> 00:24:51,560
Speaker 2: In this case, it comes from the interaction between the

526
00:24:51,600 --> 00:24:54,720
Speaker 2: Higgs field and these other particles. So even the Higgs

527
00:24:54,760 --> 00:24:58,199
Speaker 2: field interaction you can think about as internal stored energy.

528
00:24:58,400 --> 00:25:00,479
Speaker 2: Like you think about the electron moving through the universe,

529
00:25:00,520 --> 00:25:02,760
Speaker 2: what is its mass? You could just say it comes

530
00:25:02,760 --> 00:25:05,240
Speaker 2: from the Higgs field, but really what's happening is you're

531
00:25:05,240 --> 00:25:08,000
Speaker 2: creating a new object, which is this electron that interacts

532
00:25:08,000 --> 00:25:10,600
Speaker 2: with the Higgs field, and that thing has energy which

533
00:25:10,760 --> 00:25:13,080
Speaker 2: in the end is coming from the Higgs field, and

534
00:25:13,119 --> 00:25:15,639
Speaker 2: it's storing that energy internally in this new thing. This

535
00:25:15,800 --> 00:25:18,840
Speaker 2: like cloud of electrons and Higgs is sort of interacting together.

536
00:25:19,240 --> 00:25:21,760
Speaker 2: So it's really all the same kind of mechanism. The

537
00:25:21,840 --> 00:25:24,119
Speaker 2: Higgs is like an example of how you can have

538
00:25:24,240 --> 00:25:27,080
Speaker 2: internal stored energy, but you're right, it's not the only one.

539
00:25:27,200 --> 00:25:29,960
Speaker 2: Like other forces can give you internal stored energy, like

540
00:25:30,000 --> 00:25:32,840
Speaker 2: the gluons inside the proton give you internal.

541
00:25:32,440 --> 00:25:34,800
Speaker 1: Stored energy, and then when those get a lot of

542
00:25:34,840 --> 00:25:38,720
Speaker 1: internal stored energy like in the proton, it feels heavier.

543
00:25:39,000 --> 00:25:40,680
Speaker 1: Is that also due to the Higgs field or is

544
00:25:40,720 --> 00:25:43,760
Speaker 1: that just due to some other unknown mechanism in the universe.

545
00:25:43,800 --> 00:25:46,120
Speaker 2: That's just the fundamental nature of mass that we don't

546
00:25:46,119 --> 00:25:49,560
Speaker 2: really understand. That internal stored energy has inertia, and you know,

547
00:25:49,640 --> 00:25:53,199
Speaker 2: you can change the relationship between those gluons, increasing or

548
00:25:53,240 --> 00:25:56,240
Speaker 2: decreasing mass. Right, so if those gluons interact with something

549
00:25:56,280 --> 00:25:59,240
Speaker 2: else outside and change their relative energy levels, that can

550
00:25:59,359 --> 00:26:01,080
Speaker 2: change the mass of the particle.

551
00:26:01,119 --> 00:26:03,560
Speaker 1: Well, I guess the other question I had was, you know,

552
00:26:03,600 --> 00:26:05,960
Speaker 1: you said that the Higgs boson doesn't move at the

553
00:26:05,960 --> 00:26:07,879
Speaker 1: speed of light, but at the same time it's a

554
00:26:07,880 --> 00:26:10,679
Speaker 1: particle that gives other particles mass. Does that mean that

555
00:26:10,800 --> 00:26:13,960
Speaker 1: mass is not instantaneous or that there's some kind of

556
00:26:14,040 --> 00:26:17,240
Speaker 1: delay in how the universe or how you feel mass

557
00:26:17,280 --> 00:26:18,520
Speaker 1: in some particles.

558
00:26:18,320 --> 00:26:21,720
Speaker 2: Like if you change the mass of a particle, would

559
00:26:21,720 --> 00:26:24,160
Speaker 2: that ripple out at less than the speed of light?

560
00:26:24,520 --> 00:26:28,280
Speaker 1: Or like if an electron moves, you know, the inertia

561
00:26:28,320 --> 00:26:31,280
Speaker 1: you would feel is somehow delayed because it has to

562
00:26:31,280 --> 00:26:32,879
Speaker 1: get it from the Higgs field, which doesn't move at

563
00:26:32,920 --> 00:26:33,520
Speaker 1: the speed of light.

564
00:26:33,640 --> 00:26:36,520
Speaker 2: Information about any motion is always delayed, even if it

565
00:26:36,560 --> 00:26:39,879
Speaker 2: travels at the speed of light. Right, Even like gravitational waves,

566
00:26:39,880 --> 00:26:42,359
Speaker 2: which travel at the speed of light are not instantaneous.

567
00:26:42,880 --> 00:26:44,520
Speaker 2: So whether or not you travel at the speed of

568
00:26:44,560 --> 00:26:47,960
Speaker 2: light or not, you're still not propagating information instantaneously.

569
00:26:48,080 --> 00:26:50,919
Speaker 1: M so I guess I mean more of a delay,

570
00:26:51,920 --> 00:26:54,359
Speaker 1: like you could see something happen before you feel its mass.

571
00:26:54,520 --> 00:26:56,040
Speaker 2: I think we had to pull apart a little bit

572
00:26:56,040 --> 00:27:00,320
Speaker 2: here the gravitational and the inertial situation, because this see

573
00:27:00,320 --> 00:27:04,359
Speaker 2: something's mass really means to observe it moving. Right. Mass

574
00:27:04,400 --> 00:27:07,000
Speaker 2: is all about like what is your inertia? How do

575
00:27:07,000 --> 00:27:09,760
Speaker 2: you move through the universe? How do you respond to forces?

576
00:27:09,960 --> 00:27:13,000
Speaker 2: And we're not talking about like how your existence changes,

577
00:27:13,080 --> 00:27:16,719
Speaker 2: like the curvature of space time and ripples from your acceleration. Right,

578
00:27:16,720 --> 00:27:18,960
Speaker 2: we're not talking about gravitational waves. We're just talking about

579
00:27:19,000 --> 00:27:19,720
Speaker 2: inertial mass.

580
00:27:20,280 --> 00:27:22,239
Speaker 1: Well, I guess that the question is the same. You know,

581
00:27:22,280 --> 00:27:24,720
Speaker 1: do you feel inertial mass at a later time that

582
00:27:24,760 --> 00:27:27,440
Speaker 1: you would like if a photon bounced off of an electron.

583
00:27:27,520 --> 00:27:29,359
Speaker 2: It's a great question. I haven't thought about it before,

584
00:27:29,600 --> 00:27:31,919
Speaker 2: but I think that probably what's going on is that

585
00:27:32,000 --> 00:27:35,119
Speaker 2: this is all internal to the object we call the electron,

586
00:27:35,600 --> 00:27:37,359
Speaker 2: and we don't have enough energy to like break the

587
00:27:37,400 --> 00:27:40,720
Speaker 2: electron open and see the Higgs is inside propagating. We

588
00:27:40,880 --> 00:27:43,119
Speaker 2: just like wrap that whole thing up into an object

589
00:27:43,200 --> 00:27:45,399
Speaker 2: we call the electron. And what we're talking about here

590
00:27:45,400 --> 00:27:48,280
Speaker 2: is something that's really going on inside the electron. You'd

591
00:27:48,280 --> 00:27:49,960
Speaker 2: be worried about, like how long it takes a Higgs

592
00:27:49,960 --> 00:27:52,119
Speaker 2: boson to move from one side of the electron to

593
00:27:52,200 --> 00:27:54,280
Speaker 2: the other. But from our point of view on the outside,

594
00:27:54,280 --> 00:27:57,240
Speaker 2: the electron is effectively a point particle, so it's not

595
00:27:57,320 --> 00:27:59,840
Speaker 2: really an issue like whether the Higgs can get from

596
00:27:59,840 --> 00:28:02,080
Speaker 2: one inside of the electron to the other to make

597
00:28:02,080 --> 00:28:04,920
Speaker 2: it like a consistent object with a single kind of mass.

598
00:28:05,400 --> 00:28:09,040
Speaker 1: It just seems like it's like a force that has

599
00:28:09,080 --> 00:28:11,480
Speaker 1: a certain delay to it, you know, like a slower

600
00:28:11,520 --> 00:28:15,200
Speaker 1: force than say the electro magnetic force, which communicates with photons,

601
00:28:15,240 --> 00:28:17,040
Speaker 1: which are going at the speed of light.

602
00:28:17,160 --> 00:28:19,400
Speaker 2: Yeah, that's right. Photons do travel at speed of light,

603
00:28:19,440 --> 00:28:22,920
Speaker 2: and ripples in the Higgs field travels slower. There are

604
00:28:23,040 --> 00:28:27,159
Speaker 2: some particles whose mass changes. Remember, neutrinos don't have a

605
00:28:27,240 --> 00:28:30,600
Speaker 2: definite mass when they are created. They are a mixture

606
00:28:30,720 --> 00:28:34,560
Speaker 2: of various mass states, so that kind of inertial mass

607
00:28:34,600 --> 00:28:37,000
Speaker 2: information might propagate it less than the speed of light.

608
00:28:37,280 --> 00:28:39,080
Speaker 1: All right, Well, let's get to the main question of

609
00:28:39,080 --> 00:28:41,800
Speaker 1: the episode, which is how do you measure the mass

610
00:28:41,840 --> 00:28:44,080
Speaker 1: of the Higgs boson. That was kind of a part

611
00:28:44,080 --> 00:28:46,680
Speaker 1: of what the big discovery was in twenty twelve, right,

612
00:28:46,840 --> 00:28:48,720
Speaker 1: Like you kind of had to guess what its mass

613
00:28:48,840 --> 00:28:49,960
Speaker 1: was to know where to look for it.

614
00:28:50,040 --> 00:28:52,800
Speaker 2: Yeah, it's a really interesting bit of scientific history because

615
00:28:53,080 --> 00:28:56,320
Speaker 2: when Higgs came up with this idea, his theory work

616
00:28:56,480 --> 00:28:58,680
Speaker 2: no matter what the mass to the Higgs was, Like

617
00:28:58,720 --> 00:29:02,000
Speaker 2: the Higgs could be very very or super duper honk

618
00:29:02,040 --> 00:29:05,600
Speaker 2: and heavy and his theory would still work. And that's cool.

619
00:29:05,640 --> 00:29:08,120
Speaker 2: It makes a very powerful theory, but it's also sort

620
00:29:08,120 --> 00:29:10,440
Speaker 2: of frustrating from an experimental point of view because he

621
00:29:10,480 --> 00:29:13,800
Speaker 2: didn't predict the Higgs mass. If his theory only worked

622
00:29:13,840 --> 00:29:15,800
Speaker 2: for one value of the Higgs mass, then he could

623
00:29:15,800 --> 00:29:17,920
Speaker 2: have said, go out there, look for it. It has

624
00:29:18,000 --> 00:29:20,440
Speaker 2: this value, I predict it, you know, like baby Ruth

625
00:29:20,520 --> 00:29:22,920
Speaker 2: calling his shot. But instead he said, well it might

626
00:29:22,960 --> 00:29:25,360
Speaker 2: exist and it might have any value. So you got

627
00:29:25,360 --> 00:29:27,480
Speaker 2: to look for in all sorts of different ways.

628
00:29:27,440 --> 00:29:29,920
Speaker 1: Meaning like the mass would work no matter what the

629
00:29:30,280 --> 00:29:32,760
Speaker 1: mass of the Higgs boson is, or would you have

630
00:29:32,880 --> 00:29:36,600
Speaker 1: like very different universes if it did have different masses, if.

631
00:29:36,520 --> 00:29:37,960
Speaker 2: You know all the particles that are out there in

632
00:29:38,000 --> 00:29:41,000
Speaker 2: the universe interacting with the Higgs boson, then you know

633
00:29:41,040 --> 00:29:44,080
Speaker 2: what its mass is because its mass comes from interacting

634
00:29:44,080 --> 00:29:47,200
Speaker 2: with itself and interacting with all those other particles. If

635
00:29:47,200 --> 00:29:49,400
Speaker 2: you don't know the other particles out there in the universe,

636
00:29:49,440 --> 00:29:51,880
Speaker 2: you don't know everything that's contributing to the Higgs mass.

637
00:29:52,400 --> 00:29:54,000
Speaker 2: And so we didn't know. We didn't know what all

638
00:29:54,000 --> 00:29:55,760
Speaker 2: the particles were. We still don't know what all the

639
00:29:55,760 --> 00:29:58,480
Speaker 2: particles are. If you measure all the other particles very

640
00:29:58,560 --> 00:30:01,320
Speaker 2: very precisely, then you can predict what the Higgs mass

641
00:30:01,320 --> 00:30:03,480
Speaker 2: could be. But that's only if you know all the

642
00:30:03,520 --> 00:30:06,200
Speaker 2: particles in the universe, and we're pretty sure we don't.

643
00:30:06,360 --> 00:30:08,840
Speaker 1: So I guess he just didn't know what the mass

644
00:30:08,840 --> 00:30:11,040
Speaker 1: of the Higgs boson was supposed to be, just because

645
00:30:11,120 --> 00:30:13,280
Speaker 1: you didn't have all the information about what else is

646
00:30:13,280 --> 00:30:14,680
Speaker 1: out there in the universe exactly.

647
00:30:14,720 --> 00:30:17,200
Speaker 2: And that's another reason why knowing the mass is exciting,

648
00:30:17,560 --> 00:30:19,200
Speaker 2: because it gives you a way to tell, like, is

649
00:30:19,240 --> 00:30:21,240
Speaker 2: there something out there we don't know about, something else

650
00:30:21,520 --> 00:30:23,760
Speaker 2: interacting with the Higgs field and making it heavier or

651
00:30:23,840 --> 00:30:25,800
Speaker 2: making it lighter. What we can do is predict the

652
00:30:25,880 --> 00:30:27,640
Speaker 2: value the Higgs field based on all the particles that

653
00:30:27,680 --> 00:30:29,600
Speaker 2: we do think are out there. Then we can go

654
00:30:29,640 --> 00:30:31,480
Speaker 2: out there and measure the Higgs and say does it

655
00:30:31,560 --> 00:30:32,760
Speaker 2: agree with our prediction?

656
00:30:33,080 --> 00:30:35,480
Speaker 1: All right, So then we discovered the Higgs boson, and

657
00:30:35,560 --> 00:30:37,720
Speaker 1: so what is its mass? And how do we know

658
00:30:37,760 --> 00:30:38,600
Speaker 1: what its mass was?

659
00:30:38,840 --> 00:30:41,040
Speaker 2: So we measure the mass of particles in a weird unit.

660
00:30:41,040 --> 00:30:46,440
Speaker 2: It's called the GeV giggle electron volts one billion electron bolts.

661
00:30:46,720 --> 00:30:49,600
Speaker 2: It's actually a pretty convenient unit because the proton weighs

662
00:30:49,600 --> 00:30:52,640
Speaker 2: about one GeV. Our electrons are much much lighter than that.

663
00:30:52,680 --> 00:30:55,480
Speaker 2: For example, they're like half of an MeV half of

664
00:30:55,480 --> 00:30:59,120
Speaker 2: a million electron bolts, and the Higgs boson is about

665
00:30:59,120 --> 00:31:01,760
Speaker 2: one hundred and twenty five of these things. It's one

666
00:31:01,840 --> 00:31:05,000
Speaker 2: hundred and twenty five point three five plus or minus

667
00:31:05,200 --> 00:31:07,240
Speaker 2: point one five GeV.

668
00:31:07,760 --> 00:31:10,040
Speaker 1: Wait, the mass of the Higgs boson is one hundred

669
00:31:10,040 --> 00:31:13,080
Speaker 1: and twenty five times greater than the mass of a proton.

670
00:31:13,400 --> 00:31:16,760
Speaker 2: Yeah, exactly, it's the second heaviest particle we know. It's

671
00:31:16,840 --> 00:31:19,040
Speaker 2: lighter only than the top quark, which is about one

672
00:31:19,120 --> 00:31:21,160
Speaker 2: hundred and seventy three GeV.

673
00:31:21,520 --> 00:31:23,239
Speaker 1: Well, it's kind of weird to think about, right, Like

674
00:31:23,320 --> 00:31:26,600
Speaker 1: the electron is thousands of times slighter and yet when

675
00:31:26,600 --> 00:31:30,560
Speaker 1: it interacts with the Higgs boson, the Higgs boson is heavier.

676
00:31:30,840 --> 00:31:33,959
Speaker 2: Yeah, exactly. The top quark interacts with the higgs boson

677
00:31:34,160 --> 00:31:37,000
Speaker 2: like crazy. Those two guys have a party every time

678
00:31:37,080 --> 00:31:39,200
Speaker 2: they meet. And that's why the top quark is super

679
00:31:39,280 --> 00:31:39,920
Speaker 2: duper heavy.

680
00:31:40,160 --> 00:31:43,800
Speaker 1: That's why it's the top because it's it's a fun particle.

681
00:31:44,720 --> 00:31:48,760
Speaker 1: It's thet I don't know it likes to party.

682
00:31:50,200 --> 00:31:53,000
Speaker 2: But we know the higgs Boson mass very very precisely.

683
00:31:53,040 --> 00:31:55,360
Speaker 2: We know it more precisely than the top quark. Even

684
00:31:55,400 --> 00:31:57,720
Speaker 2: the top quark we discovered in the nineties and we've

685
00:31:57,720 --> 00:32:00,040
Speaker 2: been working to measure it's mass ever since. Then. With

686
00:32:00,040 --> 00:32:02,800
Speaker 2: the Higgs boson, we know a precision of one part

687
00:32:02,880 --> 00:32:03,240
Speaker 2: in one.

688
00:32:03,160 --> 00:32:05,600
Speaker 1: Thousand, all right, So then how do we know the mass?

689
00:32:05,640 --> 00:32:07,360
Speaker 1: How do you measure the mass of any particle? You

690
00:32:07,360 --> 00:32:09,320
Speaker 1: can't just put it on a scale, right, and you

691
00:32:09,360 --> 00:32:11,400
Speaker 1: can't just like drop it from a building to see

692
00:32:11,480 --> 00:32:14,480
Speaker 1: how fast it accelerates, exactly.

693
00:32:14,520 --> 00:32:16,160
Speaker 2: We can't do any of those kinds of things that

694
00:32:16,200 --> 00:32:19,400
Speaker 2: you usually do because these particles last for only a

695
00:32:19,440 --> 00:32:21,520
Speaker 2: few moments. You know, we're talking like ten to the

696
00:32:21,560 --> 00:32:24,720
Speaker 2: negative twenty three seconds, which means it. Technically, we don't

697
00:32:24,720 --> 00:32:28,560
Speaker 2: even see these particles. Nobody's ever seen a Higgs boson.

698
00:32:28,840 --> 00:32:31,320
Speaker 2: They never even seen a track of a Higgs boson

699
00:32:31,440 --> 00:32:33,960
Speaker 2: left in one of our detectors, because they just don't

700
00:32:34,000 --> 00:32:36,760
Speaker 2: last for long enough already, and then it decays into

701
00:32:36,760 --> 00:32:39,320
Speaker 2: other stuff. We know the Higgs exists because of patterns

702
00:32:39,360 --> 00:32:42,360
Speaker 2: in those particle decays that are consistent with the Higgs

703
00:32:42,440 --> 00:32:45,160
Speaker 2: being there and inconsistent with the Higgs not being there.

704
00:32:45,600 --> 00:32:47,520
Speaker 2: So then to measure its mass, we have to look

705
00:32:47,560 --> 00:32:49,920
Speaker 2: at the patterns of those particles and try to extract

706
00:32:50,000 --> 00:32:53,360
Speaker 2: that information the streak that those particles left after the

707
00:32:53,440 --> 00:32:56,240
Speaker 2: Higgs boson turned into them. Mmm. Yeah.

708
00:32:56,280 --> 00:32:59,920
Speaker 1: We often use the analogy of like studying an accidency.

709
00:33:00,240 --> 00:33:02,680
Speaker 1: After the accident, you sort of study the debris and

710
00:33:02,760 --> 00:33:05,960
Speaker 1: you kind of figure out, like, oh, this car crash

711
00:33:06,000 --> 00:33:07,600
Speaker 1: into that car is here at this point, and they

712
00:33:07,680 --> 00:33:10,840
Speaker 1: crash in the corner back corner, and because the fenders

713
00:33:11,480 --> 00:33:13,400
Speaker 1: over here, we know how fast they were going. You're

714
00:33:13,400 --> 00:33:17,000
Speaker 1: saying like, somewhere between the crash and finding the debris,

715
00:33:17,200 --> 00:33:20,040
Speaker 1: like a Higgs boson popped up into the universe and

716
00:33:20,080 --> 00:33:21,200
Speaker 1: then it disappeared again.

717
00:33:21,360 --> 00:33:23,400
Speaker 2: Yeah, and the car crash analogy is helpful, but it's

718
00:33:23,400 --> 00:33:26,360
Speaker 2: also misleading an important way, because when you're looking at

719
00:33:26,400 --> 00:33:29,440
Speaker 2: a car crash, you're looking at pieces of the car, right,

720
00:33:29,480 --> 00:33:31,920
Speaker 2: the fender is here and the windshield wipers over there.

721
00:33:32,080 --> 00:33:34,200
Speaker 2: When you're looking at the results of a particle collision,

722
00:33:34,240 --> 00:33:36,440
Speaker 2: you're not looking at like pieces of the Higgs boson.

723
00:33:36,640 --> 00:33:39,360
Speaker 2: The Higgs boson doesn't like break in half and you

724
00:33:39,400 --> 00:33:41,280
Speaker 2: find bits of it here and bits of it there.

725
00:33:41,480 --> 00:33:44,800
Speaker 2: It converts from a Higgs boson into totally different kinds

726
00:33:44,800 --> 00:33:47,440
Speaker 2: of matter. So, for example, a Higgs boson can decay

727
00:33:47,760 --> 00:33:50,479
Speaker 2: into two bottom quarks, and that doesn't mean that there

728
00:33:50,480 --> 00:33:53,160
Speaker 2: are two bottom quarks inside a Higgs boson. It means

729
00:33:53,160 --> 00:33:55,040
Speaker 2: that the energy that used to be in the Higgs

730
00:33:55,040 --> 00:33:57,640
Speaker 2: field is now in the bottom quark field. The Higgs

731
00:33:57,720 --> 00:33:59,840
Speaker 2: is gone. It's not like it's bits are rearranged into

732
00:33:59,840 --> 00:34:02,400
Speaker 2: something else. It's gone and that energy is now in

733
00:34:02,480 --> 00:34:03,400
Speaker 2: a different field.

734
00:34:03,760 --> 00:34:05,960
Speaker 1: Right. Yeah, things trend into energy, but sort of the

735
00:34:06,000 --> 00:34:08,120
Speaker 1: analogy is still the same, right, Like all the parts

736
00:34:08,120 --> 00:34:10,360
Speaker 1: still have to fit together at the end, Like you

737
00:34:10,400 --> 00:34:13,279
Speaker 1: can't just invent energy out of nowhere, like you have

738
00:34:13,320 --> 00:34:15,880
Speaker 1: to do some accounting to make sure that all the

739
00:34:15,880 --> 00:34:18,080
Speaker 1: bits that you got at the end were part of

740
00:34:18,080 --> 00:34:21,200
Speaker 1: the same thing at the beginning, and that is actually

741
00:34:21,280 --> 00:34:23,200
Speaker 1: how you find the mass, right like you do the

742
00:34:23,320 --> 00:34:24,480
Speaker 1: through accounting.

743
00:34:24,160 --> 00:34:28,200
Speaker 2: Exactly through accounting basically a quantum information and energy. Quantum

744
00:34:28,239 --> 00:34:30,960
Speaker 2: information is sort of amazing. We talked about the podcast

745
00:34:30,960 --> 00:34:33,040
Speaker 2: a few times, and the idea is that quantum information

746
00:34:33,320 --> 00:34:36,600
Speaker 2: is not destroyed in the universe, which means that every

747
00:34:36,760 --> 00:34:40,319
Speaker 2: past moment in the universe creates a unique present because

748
00:34:40,360 --> 00:34:42,120
Speaker 2: as a unique connection, as where there was a one

749
00:34:42,200 --> 00:34:44,200
Speaker 2: to one mapping, you can reverse it. You can say,

750
00:34:44,400 --> 00:34:46,680
Speaker 2: I'm going to take the present, I'm going to rewind

751
00:34:46,680 --> 00:34:48,400
Speaker 2: it figure out what was going on in the past.

752
00:34:48,960 --> 00:34:50,920
Speaker 2: And so you can take the particles that the Higgs

753
00:34:50,960 --> 00:34:53,880
Speaker 2: boson decayed into, maybe like two bottom quarks that we

754
00:34:53,920 --> 00:34:55,800
Speaker 2: see in our detector. You can figure out what the

755
00:34:55,880 --> 00:34:58,839
Speaker 2: Higgs boson was doing. Most specifically, you can figure out

756
00:34:58,880 --> 00:35:02,319
Speaker 2: its momentum and you can figure out its energy, and

757
00:35:02,400 --> 00:35:05,600
Speaker 2: from those two pieces of information you can measure its mass.

758
00:35:05,840 --> 00:35:08,080
Speaker 1: I guess, so that means you sort of infer its mass,

759
00:35:08,120 --> 00:35:10,879
Speaker 1: right or you deduce its mass from what it's doing

760
00:35:11,280 --> 00:35:13,120
Speaker 1: or what do you see its progeny doing.

761
00:35:13,239 --> 00:35:15,200
Speaker 2: Yeah, and that makes it sound a little bit indirect,

762
00:35:15,560 --> 00:35:18,080
Speaker 2: and the end all measurements are indirect, are all inferences

763
00:35:18,120 --> 00:35:20,960
Speaker 2: based on observation. That's when we feel pretty confident in

764
00:35:21,040 --> 00:35:24,000
Speaker 2: But yeah, we're measuring the energy of the two particles.

765
00:35:24,160 --> 00:35:26,120
Speaker 2: And you know, one of the listeners actually came very

766
00:35:26,120 --> 00:35:29,320
Speaker 2: close to answering it. He said, the Higgs was discovered

767
00:35:29,320 --> 00:35:31,719
Speaker 2: when they saw a pair of photons, and maybe the

768
00:35:31,760 --> 00:35:34,480
Speaker 2: mass is equivalent to the energy of those photons. And

769
00:35:34,480 --> 00:35:38,080
Speaker 2: that's almost exactly right. The energy of those photons tells

770
00:35:38,080 --> 00:35:41,000
Speaker 2: you a lot, and also their direction and their momentum

771
00:35:41,080 --> 00:35:43,360
Speaker 2: tells you the momentum of the Higgs, and with that

772
00:35:43,480 --> 00:35:46,200
Speaker 2: information together you can get the mass. Because remember of

773
00:35:46,320 --> 00:35:48,600
Speaker 2: energy we're talking about like energy of motion, which is

774
00:35:48,600 --> 00:35:50,680
Speaker 2: the momentum, and then energy of mass. And so if

775
00:35:50,719 --> 00:35:53,319
Speaker 2: you have the total energy and you know the momentum,

776
00:35:53,440 --> 00:35:55,640
Speaker 2: the last little bit has to be the mass.

777
00:35:56,880 --> 00:35:58,800
Speaker 1: Sounds like that listener was very enlightened.

778
00:36:00,200 --> 00:36:01,560
Speaker 2: Brilliant, brilliant comment.

779
00:36:01,960 --> 00:36:04,680
Speaker 1: And so let's shed more light into this measurement of

780
00:36:04,680 --> 00:36:08,000
Speaker 1: the Higgs bosons mass. What's hard about that and what

781
00:36:08,120 --> 00:36:10,680
Speaker 1: does it mean about our picture of the universe? So

782
00:36:10,760 --> 00:36:13,000
Speaker 1: let's stick in to that. But first let's take another

783
00:36:13,080 --> 00:36:28,080
Speaker 1: quick break. All right, we're talking about the Higgs bosons.

784
00:36:28,440 --> 00:36:30,600
Speaker 1: Higgs boson researchers favorite particle.

785
00:36:31,000 --> 00:36:33,360
Speaker 2: Yeah, that's right, or maybe the most famous particle and

786
00:36:33,400 --> 00:36:36,279
Speaker 2: maybe our favorite particle because it's the last one we discovered.

787
00:36:36,520 --> 00:36:38,879
Speaker 2: And it's not very often that you discover a new

788
00:36:38,880 --> 00:36:41,320
Speaker 2: particle from the top quark in the nineties and the

789
00:36:41,360 --> 00:36:45,200
Speaker 2: Higgs boson in the early twenty tens and nothing ever since.

790
00:36:45,400 --> 00:36:47,319
Speaker 2: So you spent a lot of time studying each one

791
00:36:47,360 --> 00:36:48,360
Speaker 2: because they're precious.

792
00:36:49,280 --> 00:36:51,000
Speaker 1: So if you discover a new particle, that'll be your

793
00:36:51,040 --> 00:36:54,719
Speaker 1: new favorite. I see how fickly your a physicists are.

794
00:36:54,920 --> 00:36:57,280
Speaker 2: That's right, The young one is always the baby particle

795
00:36:57,320 --> 00:36:59,680
Speaker 2: of the family, and you know you gotta love the baby.

796
00:36:59,480 --> 00:37:03,080
Speaker 1: Just fall in the latest trend, the latest hit particle. Well,

797
00:37:03,239 --> 00:37:05,680
Speaker 1: we're asking the question of how you measure the mass

798
00:37:05,680 --> 00:37:07,799
Speaker 1: of the Higgs boson, and it seems like you do

799
00:37:07,840 --> 00:37:10,399
Speaker 1: it at the Large Hadron Collider and any collider can

800
00:37:10,400 --> 00:37:12,839
Speaker 1: any collider study the mass of the Higgs or right now,

801
00:37:13,000 --> 00:37:15,520
Speaker 1: is the Large Hadron Collider at the only collider that

802
00:37:15,560 --> 00:37:15,920
Speaker 1: can do that?

803
00:37:16,200 --> 00:37:18,719
Speaker 2: Well, the LAHC doesn't have a monopoly on a per se.

804
00:37:18,840 --> 00:37:20,640
Speaker 2: It's just that it's the only one that has enough

805
00:37:20,719 --> 00:37:23,600
Speaker 2: energy to make the Higgs boson, and so it's the

806
00:37:23,600 --> 00:37:25,960
Speaker 2: only place that it can be studied. So far, we're

807
00:37:25,960 --> 00:37:28,840
Speaker 2: working on plans for other colliders, including maybe even a

808
00:37:28,920 --> 00:37:32,280
Speaker 2: Muon collider that can make like huge numbers of Higgs bosons,

809
00:37:32,480 --> 00:37:34,239
Speaker 2: but you have to make it in order to study it.

810
00:37:34,560 --> 00:37:36,800
Speaker 1: And so we were talking about how you collide things

811
00:37:36,840 --> 00:37:39,320
Speaker 1: and then you look at the debris, and then you

812
00:37:39,360 --> 00:37:42,440
Speaker 1: figure out that in some crashes, like the evidence you

813
00:37:42,440 --> 00:37:45,520
Speaker 1: see can only be explained by the Higgs boson, and

814
00:37:46,200 --> 00:37:49,520
Speaker 1: from the debris can also sort of infer what its

815
00:37:49,600 --> 00:37:51,959
Speaker 1: mass is. And so we got that down pretty good.

816
00:37:52,000 --> 00:37:53,680
Speaker 2: We have that down pretty good. There's been a lot

817
00:37:53,680 --> 00:37:56,640
Speaker 2: of really really careful studies, and this is not an

818
00:37:56,680 --> 00:37:59,160
Speaker 2: easy thing to do. I mean, we're saying the Higgs

819
00:37:59,200 --> 00:38:02,200
Speaker 2: boson turns to two photons or two bottom quarks or

820
00:38:02,239 --> 00:38:05,200
Speaker 2: sometimes two w bosons, and we're just saying, oh, you

821
00:38:05,239 --> 00:38:08,760
Speaker 2: measure those particles, masses and energies. But that's not trivial.

822
00:38:08,840 --> 00:38:12,799
Speaker 2: You know, that involves building and calibrating complicated detectors in

823
00:38:12,960 --> 00:38:15,800
Speaker 2: order to measure those streaks and extract that information.

824
00:38:16,040 --> 00:38:18,759
Speaker 1: Yeah, and also like that it doesn't happen every time

825
00:38:18,760 --> 00:38:21,560
Speaker 1: you crash some particles, right, Like, you have to collide

826
00:38:21,840 --> 00:38:25,040
Speaker 1: trillions of particles to sort of get one where maybe

827
00:38:25,080 --> 00:38:26,759
Speaker 1: a Higgs boson can be seen.

828
00:38:26,840 --> 00:38:29,560
Speaker 2: Oh yeah, great point. The Higgs boson is really really rare.

829
00:38:29,960 --> 00:38:33,320
Speaker 2: That's why we collide particles so often, millions and millions

830
00:38:33,360 --> 00:38:35,680
Speaker 2: of times per second, hoping that maybe like one of

831
00:38:35,719 --> 00:38:38,160
Speaker 2: those collisions will give us a Higgs boson. So first

832
00:38:38,200 --> 00:38:40,319
Speaker 2: we have to smash in the particles together to get

833
00:38:40,320 --> 00:38:42,040
Speaker 2: a sample that's going to have a bunch of Higgs

834
00:38:42,080 --> 00:38:44,400
Speaker 2: bosons in them. Then we have to try to isolate

835
00:38:44,440 --> 00:38:47,400
Speaker 2: the collisions that we think probably come from the Higgs boson,

836
00:38:47,719 --> 00:38:50,239
Speaker 2: but that's not totally possible. Some of those collisions will

837
00:38:50,280 --> 00:38:53,360
Speaker 2: always be due to other stuff that just happens to Also,

838
00:38:53,480 --> 00:38:56,600
Speaker 2: give two photons that look kind of like a Higgs boson,

839
00:38:57,040 --> 00:38:59,560
Speaker 2: or give two w bosons that look kind of like

840
00:38:59,560 --> 00:39:02,120
Speaker 2: a Higgs photon. So you can never say this collision

841
00:39:02,160 --> 00:39:03,960
Speaker 2: has a Higgs in it or that collision has a

842
00:39:04,000 --> 00:39:06,400
Speaker 2: Higgs in it. It's always statistical. You have a set

843
00:39:06,400 --> 00:39:08,800
Speaker 2: of collisions you say, we think there's like ten percent

844
00:39:08,840 --> 00:39:11,399
Speaker 2: Higgs in here, or there's fourteen percent Higgs in here.

845
00:39:11,520 --> 00:39:14,680
Speaker 1: But I guess since the Higgs boson gives all particles

846
00:39:14,760 --> 00:39:18,399
Speaker 1: their mass, isn't technically the Higgs boson in all collisions too.

847
00:39:18,640 --> 00:39:20,440
Speaker 2: It is, but sort of in a virtual sense. Like

848
00:39:20,480 --> 00:39:22,920
Speaker 2: the Higgs field is everywhere, and the Higgs field is

849
00:39:22,920 --> 00:39:26,040
Speaker 2: involved in everything, even low energy collisions. But if you

850
00:39:26,080 --> 00:39:27,680
Speaker 2: want to study its mass, you have to make a

851
00:39:27,719 --> 00:39:30,279
Speaker 2: real Higgs boson. You have to excite the field enough

852
00:39:30,560 --> 00:39:33,239
Speaker 2: so that it pops out an actual Higgs boson, a

853
00:39:33,280 --> 00:39:34,920
Speaker 2: real one, not a virtual one.

854
00:39:35,400 --> 00:39:36,240
Speaker 1: What's the difference?

855
00:39:36,520 --> 00:39:39,840
Speaker 2: Virtual particles really just saying another ripple in the fields,

856
00:39:39,880 --> 00:39:42,759
Speaker 2: like information wiggling through the field. But that information can

857
00:39:42,800 --> 00:39:45,600
Speaker 2: propagate in all sorts of ways that particles don't propagate.

858
00:39:45,880 --> 00:39:48,239
Speaker 2: You know, particles, for example, have a specific mass, or

859
00:39:48,280 --> 00:39:50,960
Speaker 2: real Higgs boson moving through the Higgs field has a

860
00:39:51,080 --> 00:39:54,040
Speaker 2: very specific mass. Virtual particles don't have to follow those rules.

861
00:39:54,080 --> 00:39:56,360
Speaker 2: They can have all sorts of weird masses, including like

862
00:39:56,480 --> 00:40:01,000
Speaker 2: zero or negative masses. Virtual particles are not really particles,

863
00:40:01,040 --> 00:40:03,799
Speaker 2: they're just ripples in the Higgs field. You can sometimes

864
00:40:03,960 --> 00:40:06,560
Speaker 2: kind of describe using particle like words.

865
00:40:07,560 --> 00:40:09,600
Speaker 1: But I guess, if the Higgs boson is so rare,

866
00:40:09,920 --> 00:40:12,960
Speaker 1: is it really what's giving mass to the other particles then,

867
00:40:13,120 --> 00:40:15,600
Speaker 1: because I feel like you're saying it's rare and virtual

868
00:40:16,040 --> 00:40:18,080
Speaker 1: and you rarely ever see it, but at the same time,

869
00:40:18,160 --> 00:40:20,240
Speaker 1: it's affecting us all the time everywhere.

870
00:40:20,440 --> 00:40:22,759
Speaker 2: Yeah, because the Higgs field is everywhere. Even if there

871
00:40:22,760 --> 00:40:25,960
Speaker 2: are no real Higgs bosons around, the Higgs field fills

872
00:40:25,960 --> 00:40:29,520
Speaker 2: the whole universe, and it's constantly interacting with your electrons

873
00:40:29,520 --> 00:40:31,920
Speaker 2: and your top quarks. So maybe what you're getting at

874
00:40:31,960 --> 00:40:34,400
Speaker 2: is it is possible to detect the Higgs field and

875
00:40:34,440 --> 00:40:38,799
Speaker 2: to deduce things about it from its interactions with those particles, right, Like,

876
00:40:38,840 --> 00:40:41,239
Speaker 2: by measuring the top quark very precisely and measuring the

877
00:40:41,400 --> 00:40:43,840
Speaker 2: w boson very very precisely, we can learn a lot

878
00:40:43,880 --> 00:40:45,719
Speaker 2: about the Higgs field, and that's how they make those

879
00:40:45,760 --> 00:40:48,040
Speaker 2: predictions of what the Higgs mass sort of has to

880
00:40:48,080 --> 00:40:50,719
Speaker 2: be like. Before we found the Higgs boson mass, we

881
00:40:50,800 --> 00:40:53,360
Speaker 2: had ideas for what its mass might be based on

882
00:40:53,400 --> 00:40:56,920
Speaker 2: these sort of indirect measurements observations of how it's affecting

883
00:40:56,960 --> 00:40:57,960
Speaker 2: the other particles.

884
00:40:58,239 --> 00:41:00,439
Speaker 1: All right, Well, let's get to what we know about

885
00:41:00,480 --> 00:41:02,440
Speaker 1: the mass of the Higgs field. So you said, we

886
00:41:02,520 --> 00:41:04,759
Speaker 1: know that it's one hundred and twenty five zero point

887
00:41:04,800 --> 00:41:08,560
Speaker 1: thirty five GEVs plus or minus zero point one percent.

888
00:41:08,760 --> 00:41:11,360
Speaker 1: What does that mean? Is that more than what we expected?

889
00:41:11,440 --> 00:41:13,760
Speaker 1: It seems like it's a lot, because it's one hundred

890
00:41:13,960 --> 00:41:16,120
Speaker 1: times more than the mass of the proton. But is

891
00:41:16,160 --> 00:41:19,279
Speaker 1: that surprising or is that expected? Is it interesting that

892
00:41:19,320 --> 00:41:21,319
Speaker 1: it weighs that much or could it have been any

893
00:41:21,320 --> 00:41:21,920
Speaker 1: other mass?

894
00:41:21,920 --> 00:41:24,640
Speaker 2: Well, first of all, it's very impressive that it's measured

895
00:41:24,800 --> 00:41:27,799
Speaker 2: so precisely. Like, this is really hard. I guess it's

896
00:41:27,840 --> 00:41:29,200
Speaker 2: kind of my job so.

897
00:41:29,360 --> 00:41:33,360
Speaker 1: This horn, But like this is not hard, Yes, according

898
00:41:33,360 --> 00:41:38,800
Speaker 1: to people who had to do it.

899
00:41:36,600 --> 00:41:38,600
Speaker 2: It is really hard. You know, like a Higgs boson

900
00:41:38,640 --> 00:41:41,120
Speaker 2: decays the two photons. You got to measure those photons

901
00:41:41,160 --> 00:41:42,839
Speaker 2: really precisely. You got to come up with all sorts

902
00:41:42,840 --> 00:41:45,239
Speaker 2: of clever ways to know, like how can you tell

903
00:41:45,239 --> 00:41:47,600
Speaker 2: the difference between photon and dis energy and that energy

904
00:41:47,640 --> 00:41:50,240
Speaker 2: and how do you know for sure? Like people spend

905
00:41:50,320 --> 00:41:54,440
Speaker 2: weeks and weeks sweating over the details, the tiny little

906
00:41:54,440 --> 00:41:57,759
Speaker 2: problems it might crop up in your photon calibration which

907
00:41:57,800 --> 00:42:01,160
Speaker 2: gets propagated to your Higgs Boson calibration. And it's all

908
00:42:01,239 --> 00:42:04,600
Speaker 2: because this number means a lot, as you were saying earlier,

909
00:42:04,600 --> 00:42:06,719
Speaker 2: like the Higgs bison could have been heavier, it could

910
00:42:06,719 --> 00:42:08,640
Speaker 2: have been lighter. It was a little bit of a

911
00:42:08,680 --> 00:42:12,160
Speaker 2: surprise to some people that it was so light, because remember,

912
00:42:12,360 --> 00:42:15,320
Speaker 2: those two numbers have to somehow balance each other out,

913
00:42:15,560 --> 00:42:18,080
Speaker 2: like a huge, big random positive number and a huge,

914
00:42:18,120 --> 00:42:21,759
Speaker 2: big random negative number somehow almost cancel out to give

915
00:42:21,800 --> 00:42:24,840
Speaker 2: this slightly positive number. And there's some folks out there

916
00:42:24,920 --> 00:42:26,840
Speaker 2: who were thinking that those numbers are never going to

917
00:42:26,920 --> 00:42:28,840
Speaker 2: cancel out, that they were going to give us a

918
00:42:29,000 --> 00:42:31,919
Speaker 2: huge number, like something so big we would never see

919
00:42:31,920 --> 00:42:33,240
Speaker 2: it in the large Hadron colliner.

920
00:42:33,600 --> 00:42:36,480
Speaker 1: So it was lighter than people expected. They thought it

921
00:42:36,520 --> 00:42:38,440
Speaker 1: was going to be even more huge.

922
00:42:38,640 --> 00:42:40,480
Speaker 2: Yeah, some people thought it was going to be really huge.

923
00:42:40,520 --> 00:42:43,560
Speaker 2: Other people have ideas to explain that sort of apparent coincidence.

924
00:42:43,600 --> 00:42:46,000
Speaker 2: They say, well, maybe there is a connection between all

925
00:42:46,000 --> 00:42:48,200
Speaker 2: the particles that are making the Higgs heavier and all

926
00:42:48,239 --> 00:42:50,560
Speaker 2: the particles that are making the Higgs lighter. Maybe there's

927
00:42:50,560 --> 00:42:53,080
Speaker 2: like a balance in the universe, a symmetry that says

928
00:42:53,320 --> 00:42:55,719
Speaker 2: for every particle that's making the Higgs heavier, there has

929
00:42:55,840 --> 00:42:58,359
Speaker 2: to be one making the Higgs lighter, and that's why

930
00:42:58,400 --> 00:43:00,719
Speaker 2: these two things cancel each other out. Maybe there are

931
00:43:00,760 --> 00:43:03,000
Speaker 2: a whole bunch of other particles out there and then

932
00:43:03,080 --> 00:43:06,080
Speaker 2: just sort of like magically balancing everything that we have seen.

933
00:43:06,560 --> 00:43:09,319
Speaker 2: And that's a theory called supersymmetry. It says to make

934
00:43:09,360 --> 00:43:12,160
Speaker 2: those two different contributions balance and keep the Higgs field

935
00:43:12,360 --> 00:43:14,960
Speaker 2: very very light. So for some people when we saw

936
00:43:15,000 --> 00:43:17,400
Speaker 2: the Higgs boson mass, was you think it's kind of heavy.

937
00:43:17,400 --> 00:43:19,960
Speaker 2: Some people think it's kind of light. Actually, they thought

938
00:43:20,000 --> 00:43:22,760
Speaker 2: maybe this is a hint that there are these super

939
00:43:22,760 --> 00:43:24,040
Speaker 2: symmetric fields out there.

940
00:43:24,200 --> 00:43:26,960
Speaker 1: Could the Higgs boson have had zero mass? Was that

941
00:43:27,000 --> 00:43:29,680
Speaker 1: a possibility when you went into it, or did the

942
00:43:29,719 --> 00:43:32,560
Speaker 1: Peter Higgs theory say it had to have some mass.

943
00:43:32,600 --> 00:43:34,520
Speaker 2: It could have had zero mass. That is a possibility,

944
00:43:34,880 --> 00:43:36,560
Speaker 2: But you know, then it would have been pretty easy

945
00:43:36,600 --> 00:43:39,640
Speaker 2: to find because it would have been very easy to create,

946
00:43:40,040 --> 00:43:42,640
Speaker 2: and early searches for the Higgs bosons in the seventies,

947
00:43:42,640 --> 00:43:45,239
Speaker 2: for example, ruled that out pretty quickly. So by the

948
00:43:45,320 --> 00:43:47,680
Speaker 2: time we turned on the Large Hadron collider, we already

949
00:43:47,719 --> 00:43:49,640
Speaker 2: knew the Higgs Boson had to be heavier than like

950
00:43:49,719 --> 00:43:53,440
Speaker 2: one hundred and fifteen or so gv because remember, there

951
00:43:53,480 --> 00:43:55,759
Speaker 2: was another collider in the nineties which ran into the

952
00:43:55,800 --> 00:44:00,920
Speaker 2: early two thousands called the LP Large Electron possit Tron Collider,

953
00:44:01,080 --> 00:44:03,440
Speaker 2: and that one would have found the Higgs boson if

954
00:44:03,440 --> 00:44:05,760
Speaker 2: it was up to about one hundred and fourteen GeV.

955
00:44:06,440 --> 00:44:08,080
Speaker 1: All right, well, then what does it mean that it

956
00:44:08,120 --> 00:44:10,120
Speaker 1: has the mass that it has. What does it mean

957
00:44:10,120 --> 00:44:12,279
Speaker 1: for the future, I guess, or our understanding of the

958
00:44:13,120 --> 00:44:14,480
Speaker 1: models of the universe.

959
00:44:14,320 --> 00:44:16,520
Speaker 2: Right now, it means that there's no specific evidence for

960
00:44:16,680 --> 00:44:19,200
Speaker 2: other particles out there. Like if the Higgs boson had

961
00:44:19,239 --> 00:44:22,040
Speaker 2: had some very crazy heavy mass, it would mean, oh,

962
00:44:22,040 --> 00:44:25,160
Speaker 2: it's getting influenced by another particle out there that's making

963
00:44:25,200 --> 00:44:27,680
Speaker 2: it heavier, a particle we haven't seen yet. So in

964
00:44:27,719 --> 00:44:29,719
Speaker 2: that way, like making a very precise measurement at the

965
00:44:29,760 --> 00:44:32,840
Speaker 2: Higgs Boson mass is a great way to test our understanding,

966
00:44:32,920 --> 00:44:35,160
Speaker 2: you know, because these things are all connected. You might

967
00:44:35,160 --> 00:44:37,120
Speaker 2: remember that there was a very precise measurement at the

968
00:44:37,280 --> 00:44:40,360
Speaker 2: w Boson mass last year. They gave a very weird result,

969
00:44:40,480 --> 00:44:42,959
Speaker 2: a result that didn't agree with all of our calculations,

970
00:44:43,239 --> 00:44:45,520
Speaker 2: and these are all tightly coupled, the W the top

971
00:44:45,600 --> 00:44:47,560
Speaker 2: the Higgs. If you change one of them, it changes

972
00:44:47,640 --> 00:44:50,040
Speaker 2: all the other ones. So getting a weird value for

973
00:44:50,080 --> 00:44:52,759
Speaker 2: the W mass means maybe there's something else going on

974
00:44:52,880 --> 00:44:55,200
Speaker 2: out there. So that's why it's important to get a

975
00:44:55,280 --> 00:44:58,320
Speaker 2: very precise measurement. It's like without creating those new particles,

976
00:44:58,320 --> 00:45:00,800
Speaker 2: you can be sensitive to their existence, which is a

977
00:45:00,800 --> 00:45:04,520
Speaker 2: pretty cool way to explore the universe indirectly. It's also

978
00:45:04,560 --> 00:45:07,920
Speaker 2: relevant to the question of whether the Higgs field is stable.

979
00:45:08,520 --> 00:45:12,200
Speaker 2: How the Higgs interacts with itself changes how stable the

980
00:45:12,239 --> 00:45:15,200
Speaker 2: Higgs field is, and that's connected to the Higgs mass,

981
00:45:15,239 --> 00:45:17,920
Speaker 2: But the Higgs boson also, because it couples to itself,

982
00:45:18,400 --> 00:45:21,640
Speaker 2: its mass effects whether might collapse, and if Higgs field

983
00:45:21,640 --> 00:45:24,840
Speaker 2: collapses it changes the whole structure of the universe and

984
00:45:24,880 --> 00:45:28,800
Speaker 2: our whole experience. So measuring the Higgs boson mass tells

985
00:45:28,920 --> 00:45:30,920
Speaker 2: us whether or not the Higgs field is likely to

986
00:45:30,960 --> 00:45:32,480
Speaker 2: be stable or unstable.

987
00:45:32,680 --> 00:45:35,600
Speaker 1: M you say that, it also tells you whether there

988
00:45:35,640 --> 00:45:37,840
Speaker 1: are more particles out there. So if you have this

989
00:45:37,960 --> 00:45:40,680
Speaker 1: measurement down pretty good, does that mean that you don't

990
00:45:40,680 --> 00:45:43,040
Speaker 1: think there are other particles out there yet to discover.

991
00:45:43,239 --> 00:45:44,839
Speaker 1: You think we've maybe discovered them all.

992
00:45:45,120 --> 00:45:47,120
Speaker 2: Well, if you can where this recent measurement of the

993
00:45:47,200 --> 00:45:49,640
Speaker 2: W mass by CDF, the one that says that everything

994
00:45:49,680 --> 00:45:52,359
Speaker 2: is out of whack and the things don't agree, then

995
00:45:52,440 --> 00:45:54,960
Speaker 2: everything agrees pretty nicely. At the top, the W, and

996
00:45:54,960 --> 00:45:57,120
Speaker 2: the Higgs are all consistent with each other, and that

997
00:45:57,160 --> 00:45:59,680
Speaker 2: means that there isn't evidence for anything new out there yet.

998
00:46:00,000 --> 00:46:03,400
Speaker 2: Other hand, it leaves this question unanswered of why the

999
00:46:03,440 --> 00:46:05,160
Speaker 2: top and the W and all that stuff add up

1000
00:46:05,160 --> 00:46:07,279
Speaker 2: to give a Higgs that's so light, Like I said,

1001
00:46:07,360 --> 00:46:09,920
Speaker 2: just a coincidence. The masses of these particles are tuned

1002
00:46:10,160 --> 00:46:12,600
Speaker 2: to one part in ten to the ten, so that

1003
00:46:12,640 --> 00:46:14,680
Speaker 2: the Higgs boson just happens to come out to be

1004
00:46:14,760 --> 00:46:17,480
Speaker 2: this very small number. It seems like too big a coincidence,

1005
00:46:17,880 --> 00:46:20,840
Speaker 2: and so we're looking for another explanation. And another explanation

1006
00:46:21,000 --> 00:46:24,200
Speaker 2: might be other particles out there that like help balance

1007
00:46:24,200 --> 00:46:26,600
Speaker 2: the Higgs boson mass, but we just don't know so far.

1008
00:46:27,400 --> 00:46:29,960
Speaker 1: All right, Well, I guess stay tuned. You have the

1009
00:46:30,040 --> 00:46:32,880
Speaker 1: large Headron collider. You just upgraded it, right, you're running

1010
00:46:32,880 --> 00:46:35,440
Speaker 1: that maybe faster than it had been before.

1011
00:46:35,600 --> 00:46:38,239
Speaker 2: Yeah, that's right. We're getting more and more collisions every time,

1012
00:46:38,320 --> 00:46:41,120
Speaker 2: and more protons in every collision, and we're going to

1013
00:46:41,239 --> 00:46:43,120
Speaker 2: run it for another ten issue, and we're going to

1014
00:46:43,200 --> 00:46:46,279
Speaker 2: run it for decades longer and collect huge piles of

1015
00:46:46,320 --> 00:46:48,840
Speaker 2: events and sift through them for evidence to see if

1016
00:46:48,840 --> 00:46:51,200
Speaker 2: the Higgs is doing something weird, because we can measure

1017
00:46:51,200 --> 00:46:53,360
Speaker 2: the higgs boson mass in all sorts of different ways

1018
00:46:53,560 --> 00:46:55,640
Speaker 2: when it decaysed to photons, or in it decays to

1019
00:46:55,680 --> 00:46:58,080
Speaker 2: bottom quarks or in the case to w bosons, and

1020
00:46:58,120 --> 00:47:00,640
Speaker 2: we can also compare those against each other. Does the

1021
00:47:00,680 --> 00:47:02,960
Speaker 2: Higgs look heavier when it turns into a photon or

1022
00:47:03,000 --> 00:47:05,360
Speaker 2: when it turns into quarks, or when it turns into w's.

1023
00:47:05,640 --> 00:47:08,560
Speaker 2: If there's any disagreement there, that's another hint that something

1024
00:47:08,600 --> 00:47:09,440
Speaker 2: new is going on.

1025
00:47:09,920 --> 00:47:11,320
Speaker 1: Wait, the mask can change.

1026
00:47:11,760 --> 00:47:13,640
Speaker 2: The mass should be the same no matter how you

1027
00:47:13,680 --> 00:47:15,879
Speaker 2: measure it. It should be the same if it turns

1028
00:47:15,880 --> 00:47:17,719
Speaker 2: into photons, or if it turns into b's orf it

1029
00:47:17,760 --> 00:47:20,480
Speaker 2: turns into w's. But if there's something else going on,

1030
00:47:20,520 --> 00:47:22,480
Speaker 2: if it's not the Higgs that we thought it was,

1031
00:47:22,680 --> 00:47:24,120
Speaker 2: or if there's more than one higgs, or if there

1032
00:47:24,160 --> 00:47:27,480
Speaker 2: are other particles getting involved. Then you might measure different

1033
00:47:27,480 --> 00:47:29,680
Speaker 2: masses in those different decay modes, and that would be

1034
00:47:29,680 --> 00:47:32,120
Speaker 2: a signed this something else going on you don't understand.

1035
00:47:32,280 --> 00:47:34,160
Speaker 1: Could be that the Higgs boson is actually made out

1036
00:47:34,160 --> 00:47:36,000
Speaker 1: of white chocolate, not dark travel.

1037
00:47:37,719 --> 00:47:40,360
Speaker 2: It's been Santus present to himself all this time.

1038
00:47:40,280 --> 00:47:45,400
Speaker 1: All this time. That's right, it's the clos hypothesis. Should

1039
00:47:45,440 --> 00:47:48,759
Speaker 1: have been the clouds field. Yeah, the Clawson, there you go,

1040
00:47:49,080 --> 00:47:53,760
Speaker 1: the Sandton. All right. Well, a lot of interesting questions

1041
00:47:53,880 --> 00:47:56,880
Speaker 1: talking about and thinking about in this fundamental particle of

1042
00:47:56,920 --> 00:47:58,960
Speaker 1: the universe. I guess the next time you step on

1043
00:47:58,960 --> 00:48:01,480
Speaker 1: a scale, think about you're measuring what your mass is,

1044
00:48:01,840 --> 00:48:05,160
Speaker 1: and think about how many virtual or real Higgs Bosons

1045
00:48:05,239 --> 00:48:07,600
Speaker 1: are flying all around you and inside of you.

1046
00:48:07,719 --> 00:48:10,480
Speaker 2: And how this is just one step in our understanding

1047
00:48:10,600 --> 00:48:13,279
Speaker 2: of the universe. We have this crazy model we put

1048
00:48:13,320 --> 00:48:15,359
Speaker 2: together on our heads and it makes predictions and it

1049
00:48:15,400 --> 00:48:17,600
Speaker 2: has blank spaces in it. Then me go out and

1050
00:48:17,680 --> 00:48:20,440
Speaker 2: confront the actual universe and see if we can get

1051
00:48:20,480 --> 00:48:23,520
Speaker 2: this model to describe everything that we experience.

1052
00:48:23,760 --> 00:48:26,600
Speaker 1: So thanks for joining us, see you next time.

1053
00:48:34,520 --> 00:48:37,320
Speaker 2: Thanks for listening, and remember that Daniel and Jorge explain

1054
00:48:37,400 --> 00:48:41,399
Speaker 2: the universe is a production of iHeartRadio. For more podcasts

1055
00:48:41,400 --> 00:48:46,040
Speaker 2: from iHeartRadio, visit the iHeartRadio app, Apple Podcasts, or wherever

1056
00:48:46,120 --> 00:48:47,840
Speaker 2: you listen to your favorite shows.