Cari Cesarotti
speaker
212 appearances
1 recordings
1 series
first heard Sep 2024
last heard Sep 2024
Cari Cesarotti’s voice in public audio — every appearance, attributed to the second.
Trend
recordings per month · last 12 monthsNo recordings in the last 12 months.Older appearances are listed below; set an alert to hear about the next one.
Appearances
you know, being something that the public really enjoys as much as something like astronomy or biology, where people either see or experience much more of it. Because physics requires, as we are already seeing in this conversation you and I are having, right? Physics requires so much lead up to understanding sort of why it's surprising or exciting or interesting or puzzling, right?
So I think that a lot of this rhetoric comes from the fact that the LHC turned on and we just saw the Higgs boson. And it's kind of a ridiculous sentence to me to say, oh, we just saw the Higgs boson because this was like the linchpin to making sure the standard model was even first order correct.
So, yeah, I mean, like the answer is just that there's not new particles showing up with sort of the unexpected frequency, which they were in sort of the 50s to 80s. And who ordered that was kind of the motto of particle physicists. But to say that that's a failure versus just the field has matured a lot, I think, is underselling all the work that people have done for the past 70 years.
Yeah, absolutely. So sort of the jargon that you might hear people use in particle physics is the hierarchy problem. Um, and if you are not thinking about it all the time, it's kind of easy to write off as, well, is this really a problem? Are you just looking to keep yourselves relevant?
Um, but you know, effectively how I like to describe it is, you know, I, I loved all the sitcoms from the nineties or whatever, where it's like, oh no, like something is going to close unless we find $35,629 and 15 cents. And then behind them, you see the banner that's like talent show grand prize.
35,000 dollars 629 and 13 cents I think that was the same number but yeah like the fact that there are numbers that can that for some reason are so big and yet agree down to such a small accuracy is something that should be fundamental fundamentally puzzling right good so let's let's be a little bit more explicit now you know we've we've
I mean, these days, kind of hard to disentangle, honestly. Yeah, so the hierarchy problem is something specific to understanding the mass of the Higgs boson, which is one of the bosons in the standard model. And the Higgs is the weirdest particle in the standard model by far. It is the only particle that has the properties that it has.
So like I said earlier, a lot of particles sit in three generations. The Higgs boson does not. The Higgs boson stands as a very weird outsider. that you may have heard is responsible for giving particles mass. And if you want to learn all about that, there's a beautiful book by Matt Strassler that you should definitely check out. Very good.
But the Higgs boson gives particles mass, has different what we'll call intrinsic properties. It's called the spin in specific. That doesn't match any other particle. And because of that, effectively, we think that the Higgs boson should have a mass 10 to the 18 times bigger than it does. And so this is the hierarchy problem.
And the hierarchy is just the mass scale that we expect and the mass scale that we see everything else sitting at. And the fact that there's 10 to the 18 differences, I mean, really 10 to the 32, because it's squared and that's the real first principles number. The fact that something can be off by 32 orders of magnitude from our theoretical predictions, where did that come from, right?
So this is definitely questions that when I was in high school, so I was in high school right when I was ending high school when the Higgs boson was discovered. So if you guys want to calculate how old that makes me, please don't. But yeah, I remember having this exact same thought when people were like, oh, but is it the Higgs? You know, did we really discover the Higgs?
And I was like, well, who cares? You discovered a particle and it's right where you thought the Higgs. Like, why do you get to say, oh, is it the Higgs? You know? And the truth is, like you said earlier, is that there are a lot of ways in which we can have actual predictions using frameworks and not just models.
So the model is the thing that the mass that we observe is plugged into versus the theoretical framework is in how we make the predictions. So given the properties that we hypothesized of the Higgs that make it a particle that could in fact give mass to other particles, Then we have the theoretical tools to make a prediction of what the mass should be.
And so basically, because the Higgs matched the properties that we modeled it to have, then we can actually use a theoretical framework to calculate what its mass should have been if things were as simple as we hypothesized to be. So the fact that there is something going on that we don't quite understand is one of the biggest open problems of particle physics to me.
Dark matter is for sure. And I feel like it's kind of unfair for particle physicists to claim this as strictly a particle physics problem because it could be astro, it could be cosmology. There's a lot of different buckets in which you could put the dark matter problem. But certainly if dark matter has a particle description, that is also something that the standard model should try to sort out.
This is the biggest fight I've gotten to with my PhD advisor. Is neutrino mass new physics or not? Because one could argue... that there exists a way to account for neutrino masses in the standard model. But my response to that is you can't do it with only fundamental interactions. You have to have something that happens a little bit more complicated.
Um, so because there does not exist a fundamental interaction term that we can write down for neutrinos that give them mass because they can't, it won't work the same way as the other particles, but the Higgs boson, um, because that that's not true. I think there, that is an example of new physics. However, I don't want to, I don't want to start a fight on that today.
So maybe another day I'd be happy to start a fight, but yeah, neutrino oscillations inherit violation of lepton number. Something else is going on there, right? Absolutely.
Okay. How do I say this without talking about left-handed and right-handed fields?
OK. So what we've seen in the standard model is that there exists left-handed and right-handed fields. And this is sort of the fundamental difference between massless versus massive particles, is the amount of what we call degrees of freedom, which you need to have an object sort of propagate. So for massive particles, they have a left and a right-handed component.
Showing 21–40 of 212 · page 2 of 11
← Previous
Next →