AYESHA RASCOE, HOST:
It's true. Muons - you know, those subatomic particles, also known as fat electrons - wobble faster than we suspected. By we, of course, I mean they - the particle physicists obsessed with things like that. Researchers at the U.S. Department of Energy's Fermi National Accelerator Lab in Batavia, Ill., marked a major achievement earlier this month. They measured the magnetic wobble of a muon with greater precision than ever before - as in, there's only a 1 in 3.5 million chance that what they observed was a fluke.
And this extra wobble tests the holy grail of particle physics known as the Standard Model, which is a theory that explains everything we know about subatomic particles - basically the building blocks of the universe and how they interact. It could also mean that there is a new dimension or a fifth force of nature in play. That's big news, or it sounded like big news to me. To tell us more about this amazing subatomic world, we're joined by Esra Barlas Yucel, postdoctoral researcher at the University of Illinois at Urbana-Champaign and a researcher at the Fermilab. Welcome to the show.
ESRA BARLAS YUCEL: Thanks, Ayesha. Thanks for having me here.
RASCOE: So these muons - they have these tiny magnets, and they sort of spin in that magnetic field. Why is this extra wobble in this itty-bitty particle important?
YUCEL: Because it could tell us new things about the physics we know so far. We have a model that explains every particles and every interactions in the world that we have known so far - the Standard Model. But we know that there are some missing things, missing pieces in this theory. So that's why you need to look for some specific interactions or properties of the particle in an experiment. And that's what we are doing.
RASCOE: I read that it could point to a new force of nature in addition to the gravitational, electromagnetic, strong and weak nuclear forces. So there could be a fifth one, or there could be a new dimension.
YUCEL: Yeah, there are some popular ideas, some suspects on describing this discrepancy. And one of them, as you say, could be a fifth force of nature that we don't know yet. Other ideas that explains this extra wobble is the presence of a maybe new exotic particle. Maybe, as you say, it's a new dimension. One of the other popular idea is that the theory known as supersymmetry. It basically tells us that every subatomic particle has a partner. There are so many ideas.
RASCOE: You said that you have to do experiments to try to figure out what the new dimension or force would be. Do we have a way to look at that, or is that a challenge to prove what this could be?
YUCEL: Yeah, the work is not done yet. We are - OK, drinking our champagnes and celebrating - whoa, we have a new physics. But we don't have how to design those new experiments to show or to find out those new unknown facts. So we have a lot of work to even design or think about new way of showing the proof of new physics that will complete the Standard Model at the end.
RASCOE: Do you think that when we look at the Standard Model now that you have this information that doesn't fit in it - are we going to see the Standard Model be tweaked? The Standard Model is something that you guys use to help explain a lot. Will that have some changes?
YUCEL: Yes, definitely. There are so many other theories that depends on the result. So they are also eagerly waiting for the final showdown in 2025.
RASCOE: Is that the final time to recreate what happened in this experiment to prove that it wasn't a fluke?
YUCEL: So we have published almost half of our data. We have another set of data that is going to be published in 2025. So that's the last chunk of data we have at Fermilab. At the same time, the Standard Model calculations, which are being calculated by the Theory Initiative - it's another group - they will also update their numbers in 2025. So that will be the final showdown.
RASCOE: OK, OK (laughter).
YUCEL: We will see if the discrepancy is still there or not. So that's why we are really excited to see that how the theory number will also evolve in the next two years. So that will tell us the final word, I suppose.
RASCOE: We'll have to have you back on when the final showdown happens in 2025 (laughter).
YUCEL: Yeah, sure. I would be happy to.
RASCOE: That's Esra Barlas Yucel, postdoctoral researcher at the University of Illinois at Urbana-Champaign. Thank you so much for speaking with us today.
YUCEL: Thanks for having me. It was really fun. Transcript provided by NPR, Copyright NPR.
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