Wobbling in the history of particle physics – now. Powered by Northrop Grumman

Particle physics is the quest to discover the fundamental components of the universe by analyzing, cataloging and measuring the particles that combine to create everything. It’s no easy task – the variety and variability of these physical firmaments makes them an ever-changing puzzle that can seem completely impenetrable until a new secret is unlocked.

Now, new research on the muon – a small electron-like particle 200 times heavier than its negatively charged cousin – could pave the way for the particle’s next pivot: oscillations.

Standard operation procedure

To help make sense of the universe and how it works, scientists created the Standard Model. It was not an easy task either. As SciTechDaily notes, while the electron was discovered in 1897, the last element in the current framework – the Higgs boson – wasn’t confirmed until 2012.

The model makes it possible to reconcile three of the four fundamental forces: electromagnetism, the strong nuclear force and the weak nuclear force. It also highlights the role of quarks and leptons as the building blocks of all matter, including the familiar trio of protons, neutrons and electrons. Work on the Standard Model has shown that photons play a role in the transport of electromagnetism, while the strong force relies on gluons to ensure the stability of atomic nuclei and the weak force exploits W and Z bosons. to drive the powerful nuclear processes that keep stars burning for billions of years. year.

However, despite its usefulness, the standard model has a blind spot: gravity. While the model does an excellent job of describing which particles underlie the other three fundamental forces, gravity is conspicuously absent. This is because scientists have never been able to link a specific particle to the creation and distribution of gravity. While it plays a vital role in the workings of our universe – whether it’s counteracting the expansive tendencies of nuclear reactions within our sun or keeping our feet firmly planted on planet Earth – this apparently appealing operation simple has historically resisted deep understanding.

But new muon measurements could change all that.

Crack the code

What is important to remember from scientists – and particle physicists in particular – is that they are never satisfied with the status quo. Although the Standard Model provides a starting point for understanding the universe, obvious shortcomings in the current framework mean there is still work to be done. In practice, this work involves finding new approaches to potentially breaking the model by conducting experiments, taking measurements, and then comparing the results to what the model predicts.

The challenge? For years, the model has found the right answers, much to the frustration of physicists who know something is missing. Repeated experiments using different particle approaches have produced precise measurement after precise measurement – ​​so far. Recent follow-up work on earlier muon experiments using more advanced equipment suggests a crack in the current model and raises hope that scientists may finally have found the key to a new revolution in particle physics.

Meet the muon

So what exactly is a muon? Think electron, but heavier. Much heavier – 200 times heavier, in fact. As Science Daily notes, muons and electrons “are essentially tiny magnets with their own magnetic field.” However, unlike electrons, muons are much less stable, existing only a few millionths of a second before decaying. It is also difficult to observe muons, even during their brief stay here, because the vacuum they occupy is not empty.

“It’s your cappuccino-foam version of a vacuum, where there are virtual particles appearing and disappearing all the time,” Lawrence Gibbons, who led the Cornell team involved in the new research, told Science Daily. “And that turns out to affect the strength of a muon’s magnetic field.”

Through work at CERN in 1959, followed by more precise experiments in 1966 and 1969, and then another round at Brookhaven National Laboratory in 1999, the researchers finally found something: a disconnect between the observed magnetic measurements and predicted when the muons made their way into this void. New efforts at Fermilab with more precise and advanced equipment have confirmed these findings – and could pave the way for a much more massive muon impact.

Let’s Get Physics-al

Work at CERN, Brookhaven and Fermilab all focus on the same thing: the g-2 value of the muon, which represents the amount it “wobbles” via vacuum interactions. As Jessica Esquivel, a particle physicist at Fermilab, notes, this oscillation is called the precession frequency.

“When muons enter a magnetic field, they precess or spin like a top,” she told Vox.

To measure precession, efforts at Fermilab used a powerful particle accelerator – capable of creating 20 times more muons than those previously used at CERN – to shoot an intense beam of muons into highly sensitive detectors, which measured their precession frequency. As the Standard Model predicts, this precession occurs when muons collide with virtual particles, which Esquivel describes as “a kind of ghosting of real particles.”

“We have photons going in and out and they’re just kind of like there, but not really there,” she told Vox. However, despite this recurring strangeness, these virtual particles have a physical impact on muon oscillations.

But this is where it gets really weird: Experiments at Fermilab confirm that muons flicker more than they should, according to the Standard Model. Even more exciting? Scientists don’t know why.

Stumbling our way forward

The lack of certainty here is what makes these experimental results so interesting. According to the Standard Model, g-2 muon values ​​are explainable using actual particle interactions and should produce predictable results. However, Fermilab’s efforts suggest that something else is causing this additional oscillation – something outside the current functional framework, as Esquivel and his colleagues told Vox.

And while there have been discussions about this “breaking” of the Standard Model before, it’s more about filling in the details where the data was clearly missing. Esquivel likens it to adding elements to the periodic table.

“Even back then,” she tells Vox, “they had places where they knew an item had to go, but they hadn’t been able to see it yet. That’s basically where we are now. In practice, this movement of muons opens the door to a multitude of potential operations on the particles.This unexpected oscillation could be caused by an interaction with dark matter or long-predicted dark energy particles, or it could help establish a particle-based link with the peripheral fourth fundamental gravitational force.

Esquivel simply explains the impact of this measurement of movement: “It’s once in a lifetime. We are looking for new physics and we are so close that we can taste it. A meal of muons, an extra oscillation – it happens!

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