Science Friday - CERN finds a new particle + News alerts for the cosmos

Episode Date: March 30, 2026

Researchers at the Large Hadron Collider in Switzerland have announced that they discovered a new subatomic particle. Roughly four times more massive than a standard proton, this short-lived piece of matter called Ξcc⁺(Xi-cc-plus) is like an extra-heavy proton, researchers say. Physicist Hassan Jawahery joins Host Flora Lichtman to unpack how the particle was found, and what its discovery means for theoretical physics.  Then, astronomer Eric Bellm describes a new alert system that could flag potentially significant changes in the southern night sky in real time. On its first night of testing at the Rubin Observatory in Chile, the system fired off 800,000 alerts. Guests: Dr. Hassan Jawahery is a distinguished university professor at the University of Maryland and a member of the LHCb consortium.  Dr. Eric Bellm is alert product group lead for the Rubin Observatory and a research associate professor at the University of Washington. Transcripts for each episode are available within 1-3 days at sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

Hi, it's Laura Lixman, and you're listening to Science Friday. Heads up, subatomic lovers, a new particle just dropped. Researchers at the Large Hadron Collider in Switzerland announced that they have discovered something like an extra heavy proton. Here to tell us what that means is Hassan Jawa Harry, a member of the LHCB experiment. Welcome, Hassan. Thank you. Thanks for the invitation. I'm happy to talk about the LHCB resolved. Yeah, so describe this new little.

particle for us. It's been described as it like a proton. What is it exactly? So that's actually a very good description which you put there as a heavy proton. So what's been discovered by LHCB is the first observation of a composite particle which contains two charm quarks and a down quark. So it's a proton-like particle because ordinary proton, contains actually two up quarks and one down quark. So in this particle, the two up quarks have been replaced by the charm quark, and the charmed quark being so heavy, makes this particle about four times heavier than the ordinary proton.

Put the finding in context. I mean, is this like discovering a new species of frog or an astronomer finding a new exoplanet or, you know, even more fundamental than that? So I think, yes, what you just described is really more of a, finding an extra planet, we haven't discovered a new fundamental particles, but these particles are made up of fundamental particles. The fundamental particles here are the quarks. We are all made up of quarks, but the kind of quarks which participate in the structure

of the ordinary matter are the lightest ones, which we call them up and down quark. Those are relatively light, and they form, for example, the proton is made up of two up quark and one down quark, and a neutron is made up of two up, and a neutron is made up of two. two down quark and one up quark. Everything else which we see around us, in the stars, in the galaxies, and so on are made up of the same quarks. In this case, we've seen a particle which is made up of a heavy quark. Normally we don't have those quarks in nature.

They are only produced in very high energy collisions of particles, and they were around when the universe was formed at the very early time after the Big Bank. After that, we have to make them in the lab. And so the laws of nature, the laws that we've discovered about these constituents, the way they interact with each other, suggests that there should be a proton-like object made up of these quarks. The fact that we see the properties corresponding to the predictions based on our theory is very important because it gives us insight into how accurate these theoretical foundations are. Yes, I was going to ask that.

I mean, is this particle something you expected to find, or is the data ahead of the theory in this case? So, yeah, that's a very good question. And if this particle was expected to be found and in fact its mass and some of its properties were predicted. And the fact that we see it now is really have to do with the fact that these are very heavy objects. So we have to improve our experimental sensitivity to see it. You upgraded the machine, basically. Yeah, that's right. Okay, so how long does this particle exist?

So, yeah, the difference between this particle as even though we call it a proton-like, proton lives forever, as far as we know. The lifetime is known to be more than 10 to the 31, set years or so on. But this particle made up of heavy cork only lives a few trillion of a second, actually less than less than a few trillion trillion of a second. Lives fast, dies young. Yeah. So it doesn't really live long enough to form any object, for example, an atom made of it or something beyond that. But the fact that we see them shows that the laws which we understand about how the quarks interact are as we expect them to. Well, does this particle tell you anything new about the forces that bind these fundamental particles together, you know, bind quarks together?

But that's something that we will eventually extract from them because we don't still know all their properties. So we have seen it. They are the right mass. And we have seen that this lifetime is short. But we haven't seen all the other properties. So there are many other properties that we have to study when we have a larger fraction of them. And that's why the experiments we've been running for years. When we do that, then we might actually discover effects, which will tell us aspects of the theories that we know.

So we are not there yet, but that's one of the goals. What comes next? Do you just crank up the power knob? So, yeah, we will be running for many years, and eventually what we want to see in this line of research is another particle which is another proton-like objects which will have two charm quarks and a strange quark. But one of the major line of research in LACB is to study the B quark.

And that is at the core of one of the biggest mysteries that we have in nature. which is why even though the universe seem to have been produced symmetric between matter and antimatter at a very early time. Yet, the universe is all made up of matter rather than antimatter. And so what happened to all that antimatter? So really, the biggest mission of LHCB is to uncover the reason behind that. I can't wait to follow along. Thanks, Hassan. Thank you.

Dr. Hassan Jawa-Hari is a distinguished university professor at the University of Maryland and a member of the LHCB Consortium. After the break, turning from the ultra-small to the ultra-big, getting news alerts for the entire universe. Stick around. There's news alerts, emergency alerts, and now we bring you astronomy alerts. The Rubin Observatory, you know it, the telescope on a mountaintop in Chile, aims to take a movie of the entire southern sky. every night. And it recently tested its own alert system to give astronomers a heads up when the telescope spots an unusual change in the sky. Guess how many times it went ding that first night? 800,000. Here to tell us why we shouldn't silence those alerts is Dr. Eric Bellum. He's head of the

group that developed the alert system for Rubin. Hey, Eric. Hi, Laura. Thanks for having me. Thanks for being here. I'm picturing some grad student just having their phone blowing up 800,000 times. Is that mental image correct? I hope not. The Rubin Alert stream is, as you said, it's extremely large. But typically a scientist who is trying to find things to follow up in real time is only interested in a relatively small handful. So they're going to try to filter down that huge stream of notifications to just a handful that are of interest to them. Okay, so what kinds of things trigger an alert? Anything that we see that is moving or changing or brightening in the sky. And so astrophysically, that includes things like asteroids,

the exploding stars like supernovae, variable stars that are brightening and dimming, as well as rare types of all of those things. And how fast do the alerts come? Just in a couple of minutes after the image is taken. We're trying to make sure that scientists can very rapidly follow. follow up the things that they care about. Well, I wondered, like, in that hundreds of thousands of alerts that first night, were there any real, like, wow, I can't believe this is their things? We're just getting started, and so scientists are sort of tuning their algorithms to find the things they most care about.

So it's a little early to say. There definitely were some asteroids that folks noticed were rotating very rapidly. So that was one of the things that came out of that first night's observations. So how does this alert system actually work? What's the flow of data? Yeah, so Rubin is down in Chile, and every 30 seconds, it takes an image of the night sky, and that image is transmitted over fiber optic networks up to California, where at the Stanford linear accelerator center, there's a data facility that processes the images. And then we compare it against a stack of images from that position of the sky where we had previously observed in So by differencing those two images, we're able to find anything that is changing from the previous stack of images. Were you surprised by the volume? No. We're expecting actually an even larger volume once we're up to full operation, something like 7 million alerts a night total. I mean, there must be an art to filtering down to the most important things.

I mean, what's the trickiest part about building an alert system like this? Yeah, the filtering is the most challenging part. That's where the art and the practice and the experience come in. The challenge is to tune the criteria so that you can pick out the thing you most care about without being overwhelmed by hundreds or thousands of other objects that you have to sort through on your way to finding the thing you really are interested. Well, I mean, is there machine learning involved? Like, will the alerts become more and more precise as you go along?

Yes, we definitely use machine learning both in the production of the alerts and scientists as well use various classification algorithms, just like perhaps your email client or something tries to pick out the emails you most care about. And those are things we're going to be tuning up in the next weeks and months as the survey sort of scales up. That does seem like the sort of operative problem, that you have so much data coming in that figuring out which data to pay attention to seems very important. Does it feel like a lot of pressure, Eric? Yeah. Certainly for these things that may be fading away quickly or disappearing, there is a challenge to try to find it in real time while you can still follow it up. And that's why we have this real-time alert stream to make sure that scientists have the best opportunity.

Do the alerts go to people or are they telling, you know, a telescope somewhere else to turn on or look at a particular thing? There definitely are fully automated systems that will take the alert stream and follow it up in real time based on some preset. criteria. There also are scientists who may have telescope time that they've been awarded, who really want to put their eyes on the data before they commit to using that telescope time. So I would say it's still most common that at the end of the procedure, there's a human somewhere in the loop saying, yes, this is the event I really want to see. Let me trigger the Helplice telescope or James Webb Space Telescope to follow it up. Is this for professional academic astronomers only, or are you interested in, you know, amateurs using this as well?

Our first goal is, again, to make discoveries about the universe. And so professional astronomers are our first audience. But there definitely is room for amateurs to contribute. And Rubin has a large education and public outreach team that is planning some specific projects around the alert stream that can help highlight objects that amateurs might be interested in following up. Okay. Can I sign up? And then, like, Like, will it actually ding my phone? Because this is the kind of news alert I feel like I need in my life. I don't know if you need millions of them every night.

But, yes, I think there will be facilities that you can get a summary, at least, of the previous night's discoveries. I do feel like it would be very cool to get a news alert or, you know, an astronomical alert that was like new black hole nearby. Yes, absolutely. I agree. Dr. Eric Bellum is the alert product group lead for the Rubin Observatory. and a research associate professor at the University of Washington. Thanks, Eric. Thanks, Lori. This episode was produced by Charles Bergquist,

and if you've got questions about the universe, big or small, we want to know about them. Please give us a call. The listener line is always open. 8774-Syfry, 8774-Syfry. I hope you have a charmed day. I'm Flora Lichten. Thank you for listening.