standard model

2 Articles

Have Scientists Stuck The Landing On The Glueball Discovery?

August 12, 2026 by 18 Comments

Exciting discoveries in particle physics are one of those things that it can be easy to get blase about. Some people get caught up in the obvious excitement, while others yawn: “Oh, you found the Higgs Boson, just like Higgs predicted. Call me when you have something new.” Well, if you’re in category B, prepare to yawn while the rest of us break out champagne, because it looks like we’ve finally found the glueball. 

The glueball has got to be one of the oddest particles to fall out of the Standard Model. It’s not a fundamental particle, but its makeup contains no quarks– those itty bits that make up protons and neutrons– nor any leptons like electrons or muons. No, the glueball is a hadron made entirely of bosons: specifically, gluons, the force-carrying particles of the strong nuclear force. It’s also been called gluonium or a gluon-ball, but glueball is more fun.

Try and imagine a proton without any quarks. Remember that inside the proton there are three quarks, held together with force-carrying gluon particles. If you have zero quarks, but enough of those gluons tangled up in the right ways, and you get a tangible, if short lived particle. That’s the glueball, a neutral particle that will decay almost immediatly in to Pions. It works because gluons have ‘colour charge’– the strong nuclear force’s answer to electric charge.

It’s also one of those things that will probably never be seen in nature: odds are, even in the hottest collisions, you’re going to get a quark or two mixed up with your gluon soup. That’s okay; the gluonic state is what we’ve been looking for. As long as the particle is mostly gluons, and behaves as the Standard Model predicts it should, physicists are inclined to call it good enough. The latest candidate to hit “good enough” is X(2370), which fell out of a collision in the Beijing Electron–Positron Collider II (BEPC II), as detected by the Beijing Spectrometer III (BES III). The paper hit ArXiv at the end of July. It’s taken the collaboration this long to make sure of what they were looking at, as they sorted through the terabytes of data an instrument like this generates.

Is this likely to affect you in any way? No. It confirms what we already thought we knew about the universe, and the particle itself is too short-lived to ever exist outside of some very extreme– mostly man-made– environments. On the other hand, it’s an excuse to celebrate scientific discovery, and we’ll take any of those we can, just like when the Muon Magnetic Moment measured in at the expected value, or neutrinos transmuted elements in exactly the way the models said they would. Besides, if we’re really lucky this result will turn out not to be a glueball, but something new and interesting. Then even the most jaded nerds will have reason to celebrate.

Header image: The Bejing III Spectrometer, BESII.

Muon Magnetic Moment Matches Model, Making Major Malaise

April 24, 2026 by 13 Comments

Sometimes, a major discovery is exactly what you were hoping not to find. That’s the case with a team at Penn State who seem to have recently closed the door on any new physics stemming from a longstanding discrepency in the magnetic moment of the muon. It turns out, the model was fine, and we just needed better calculations.

The Muon is a heavier cousin to the electron. Like the electron, it has an intrinsic magnetic moment, but the traditional methods to calculate it did not quite match experiments, which was very exciting because it made us hope our models could be improved. Rather than try the traditional approximation methods for the unsolvable equations, the group at Penn State set up what you can think of as the Quantum Chromodynamic equivalent of a Finite Element Model (FEM) simulation–a grid of discrete steps in space and time. Tiny ones, of course, because the muon, like the electron, is a point-like particle with no lower size limit. In any case, according to their paper in Nature, after a decade of refinement and increasingly expensive supercomputer runs, the mystery can be put to bed. Instead of the discrepancy that so exited physicists 25 years ago when it was first found, theory and experiment now match to 11 digits, or a 0.5 sigma discrepancy, if you prefer.

Statistically, the Standard Model works– and that kind of sucks. It sucks, because it’s the gaps in the model where new physics are possible, and everyone has been pushing at those few gaps for the last 50 years to try and find what might be behind the standard model. Even [Zoltan Fodor], the principle investigator behind this project, is sad to see it work out. Sure, it’s a feather in his cap to get the calculations right at last–but ask anybody in the field, and they’d rather keep the door open to new physics than be right. We were certainly hoping it was something novel, last time the topic came up.

You might think muons are the last thing a hacker would ever encounter, but since there’s a steady rain of them from the sky in the form of cosmic rays, it’s not only easy to interact with them, you can actually put them to practical use– like muon tomography, or navigation indoors and underground.

Header Image Credit: Dani Zemba / Penn State