One simple measure threatens to bring all of physics to its knees

One simple measure threatens to bring all of physics to its knees

The models upon which modern physics is based have been painstakingly assembled for centuries, but all it takes is a grain of subatomic sand to disrupt this well-oiled machine.

Particle physics is definitely a very thankless science. After decades of meticulous measurements, CERN teams have just hit what looks very much like a major scientific impasse; Could the standard model of particle physics, one of the pillars of our modern science, be on the brink of being shattered?

This bold question is worth asking when looking at a study that today made the front page of the prestigious journal Science; physicists at CERN have just realized that one of the fundamental particles, the W boson, was actually significantly heavier than previously thought.

However, like all the properties of particles, this mass is far from negligible. It is a determining element of what is popularly called the Standard Model. It is a catalog of concepts and theories that describe the behavior of the most fundamental units of our universe and the forces that govern them.

If this model holds up, it is because all the elements that belong to it are intimately linked by different well-defined mathematical relationships; they were first theorized before being confirmed experimentally.

The cursed piece of a huge invisible puzzle

The objective of this process is to constitute a solid scientific base which serves as a basis for lots of very different work. But there is a flip side; if only one of these elements does not correspond, the whole structure can collapse like a house of cards.

It’s a problem that puzzle enthusiasts know all too well; there’s nothing worse than getting to the end before realizing that the last piece doesn’t match the remaining slot. This necessarily means that there are other elements that are not in their place either.

In any case, this is what the researchers behind the study explicitly suggest. “If it’s real, and it’s not a statistical bias or a computational misunderstanding, that’s a huge thing.”, says Harry Cliff, a particle physicist at Cambridge.

His colleague Ashutosh V. Kotwal, the coordinator of the research project, shares his interpretation. According to him, there is asignificant strain” between these results and the standard model. In other words, fundamental physics is coming to a crossroads.

And for good reason: even if the researchers were wrong about its mass, they continue to think that this famous W boson is one of the most important particles in the dynamics of our universe. He is one of the main players in the weak interaction; without going into detail, it is one of the fundamental forces that govern the architecture of the universe as a whole. “Nothing in the Universe that we observe around us, in all its richness and complexity, could exist without the weak interaction”, insists Kotwal.

In a puzzle, if a single piece of the puzzle does not match, the entire final image is called into question. And so it is with the Standard Model of particle physics. © PIRO4D – Pixabay

The Standard Model shows its limits

This apparent inconsistency, among the most remarkable to date, adds to a list of a few sticking points with observable reality. There’s no denying that the Standard Model as it’s defined today is beginning to falter, and that’s an exciting and terrifying prospect for researchers.

Indeed, they know full well that the standard model is not perfect. The main concern is that he has a hard time getting along with the general relativity defined by Albert Einstein (see our article here). If the latter is perfect for explaining how things work on a very large scale, it does not work at all on the subatomic scale. For example, in this standard model, nothing makes it possible to explain the gravitational forces so well described by general relativity.

The objective is therefore to fill the gaping void between these two models. We will then be able to arrive at a unified and global theory called “of the Whole”; a goal that Einstein chased throughout his career. However, the missing pieces of the puzzle are probably hidden in these still obscure breaking points. And this new inconsistency on the mass of the W boson is undoubtedly one of them.

It’s not not necessarily bad news for physicists; it’s more of a double-edged sword. On one side, it’s an additional track that allows you to push the models to their breaking point to discover their limits; an approach that will perhaps contribute to the emergence of a true Theory of Everything. But as exhilarating as they are, these discoveries are also quite terrifying. Because at present, this also means that many works have potentially been carried out on the basis of a model that is at best inaccurate, and at worst significantly distorted.

Ideally, work of this kind will one day allow us to find the pieces that we still lack to understand the functioning of the universe as a whole, at all scales. © Casey Horner – Unsplash

Confirmations, then explanations expected

This discovery is therefore only a first step; you will now have to confirm it several times to avoid finding yourself in this situation again. It will then be a question of determining the exact consequences. But in any case, the authors of the study are already expecting particularly heated debates.

It’s either a major discovery or a problem in the data”, summarizes Jan Stark, director of research at the CNRS, while evoking the “quite tense discussions” who await discipline at the turn. But in order to finally be able to arrive at the long-awaited answers, these confrontations will be essential.

If we’re going to announce something like “We’ve broken the Standard Model,” it’s going to take a lot more than a single measurement from a single experiment.”, hammers Cliff. But that’s good, because the team has not planned to let go. “We’ll follow the clues to the end, and we’ll find out what it all means”, concludes Kotwal with determination.

The text of the study is available here.

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