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.
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And you can think about this, I think, with sort of relativity is the best way to sort of understand it. So if you have something that's got angular momentum, let's say that it's turning to the right. If something is massive, then you as an observer can boost yourself either in front or behind of that object. And if you are in front, you see it turning one way.
And if you're behind, you see it turning a different way. So you need to have an object that allows to spin both to the right and to the left to be able to describe that in nature. However, if the object is massless, then it is traveling at the speed of light. And there does not exist a valid frame in which you can boost to flip that spin.
This is why you don't need both a left and a right-handed spinning degree of freedom to describe these particles. In our standard model, we have left and right-handed degrees of freedom for all of the quarks and the electron and the muon, which is my favorite particle, and the tau. But we do not have that for the neutrinos. For the neutrinos, we only have left-handed field components.
So if they were to get mass, you would need to have either two neutrinos and two Higgs interacting, which is different from the fermions, which is just one Higgs and two of the fermions. But that's something that we have not been able to verify if this is right.
So neutrinos could be what we either call Majorana fermions, where they don't have to have this left and right-handed story, or they can be Dirac, where they do have a left and right-handed story, and we just haven't found the right-handed component of the neutrino yet.
I don't know if that was way too technical or not.
Exactly.
Yes.
Yeah, so if you want it to basically have the same sort of mechanism as the other fermions in the standard model, which would make sense because, again, as physicists, the thing that we say is beautiful is symmetry. If you want it to have a left-handed and right-handed component, then we just need to find a new particle that is the right-handed neutrino.
And then it could get its math through the Higgs, and things could be similar but a bit different to the rest of the standard model. The other option that I said before to do perhaps what's Majorana, Fermion instead, is that you don't need the left and the right-handed. Is that the neutrino, you just need the one degree of freedom in the neutrino.
And then if you have two of those degrees of freedom put together, stitched together with two Higgs's, then you can also... have the same sort of mass giving mechanism. But again, that would look very different from the standard model.
So the fact that all the particles get their mass one way, except for this one kind of particle, which gets their mass a different way, that's still a very interesting question. And to understand how that came to be is something that would require further study.
Yeah, and we haven't found something that's, we haven't, yeah, we haven't found definitive evidence that a single fundamental interaction could explain this. And I think, you know, as particle physicists, we love when there is a functional description, which again, is the standard model. But to have a fundamental description, that's really, I think that's really what we all chase.
Oh, absolutely. Yeah. So this puzzle comes in a bunch of different names. I think to kind of put all of them into sort of one area that we could describe it, it's kind of the question of flavor physics. So, you know, I don't suspect particles have that different of taste, but what do I know? So flavor is just sort of another name that we give to particles to describe everything.
how properties are different. So, you know, charge is the one that we all learn in school and that we're most familiar with because there's plus and minus charge. But particles have a lot of properties and we just kind of need names for them. So flavor is the name that we tend to give the different generations of particles. So muons are a different flavor than electrons.
Again, how they taste is not something I can comment on. But yeah, so we call this sort of the flavor physics is sort of the study of understanding why the different generations behave a bit differently.
Sean, if I knew.
And the Nobel Prizes would come showering upon me.
Yeah, so supersymmetry is a pretty well-named thing in particle physics. It's like taking the symmetries that we have, but then more. So it's supersymmetry. And basically, it's adding one extra symmetry into sort of our description of spacetime itself.
And then the consequences of that tend to be in the simplest description of it is that all the particles we've seen in the standard model have what we call very cutely superpartners. And basically they're the same particle with very similar properties, except for fermions become bosons and bosons become fermions. So supersymmetry was an amazing idea for a lot of reasons.
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