A new lever on the standard model?

• lprent
• 3 years ago
• Categories: science

For me the most notable thing about the last week hasn’t been the repetitive and ill-informed braying from the opposition about covid-19. It has been about the announcement that Fermilab in the US has partially confirmed that there may be a wobble in the behaviour of muons. The probability of the experimental result being a statistical variation is now 1 in 40,000 – or 4.2 sigma. Not quite up to the 5 sigma – but definitely showing promise of a lever into the 1970s standard model of physics.

The digest that I get from National Geographic editorialised the observation like this:-

By Victoria Jaggard, SCIENCE executive editor

One of the things I love about particle physics is how much scientists really want to find cracks in some of their most widely accepted theories. Doing science means coming up with a hypothesis, testing it, and seeing if the results match your predictions. The more times you come up with the same answer, especially via different types of tests, the more likely it is that the hypothesis is correct. Gather enough evidence for related hypotheses, and you are on the path to developing a theory.

In most fields, having observations match your theory is a big win. But for particle physicists, finding a result that does not match predictions is when things really get interesting.

Specifically, physicists have been hoping for such a mismatch in the foundational theory of particle physics, called the standard model. This is the mathematical framework that describes the subatomic particles and forces that make up the universe. So far, test after test shows particles behaving exactly as the math predicts, and in 2012, experiments at the Large Hadron Collider added another entirely expected brick to the standard model in the form of the Higgs boson. That’s a problem, because the math we have can’t account for a few key components of the universe, including a little thing called gravity. Clearly, something somewhere is off, but we have not been able to put our metaphorical finger on it for decades, and that means our basic understanding of everything around us is flawed.

Now, at last, the latest test at Fermilab in Illinois (pictured above) reveals one particle, the muon, acting funny enough that it has scientists on the edge of their collective chairs. As our Michael Greshko puts it, this odd muon behavior “is a major hint that the universe contains unseen particles and forces beyond our current grasp.” Future tests may not only strengthen the case, but they may also finally show scientists how to get multiple cosmic theories to align and merge.

“This has been a long time coming, this result. Many of us have been working on it for decades,” University of Manchester physicist Mark Lancaster tells Greshko. “It’s more a feeling of relief than anything else.”

National Geographic Newsletter, Science : April 07 2021

You can find a more detailed National Geographic article at “New experiment hints that a particle breaks the known laws of physics“. But that editorial is a close to perfect description of the most scientific striving – and why scientists, especially physicists, are the worlds major sceptics (unlike the people* politely described by Alison Campbell in ‘“doing my own research” & the scientific method‘) . Reputations are made when you prise a new hole in our understanding how our universe works.

Decades down the line, our societies also benefit (often along with a few new problems) from finding and understanding the way that the universe works. For instance, my work as a computer software engineer is, these days, is almost entirely dependent on the understanding of quantum tunnelling. First identified experimentally in 1927 as an unidentified issue and steadily refined as a theory ever since. In future decades this long process is likely to be the key to future transistors like the TFET (tunnel field effect transistor), as this IEEE article explains.

The standard model in physics has now been formalised since the mid-1970s. It has been proving remarkably hard to unthrone in the physics world because it keeps getting experimental results that confirm it. Apart from the irritation mentioned in the editorial above on know that it doesn’t explain some observed phenomenon, it also means that there has been now real lever to allow prise open a better understanding of how things really work.

Down the line of human history it means that it gets harder to build new technologies that allow us to work more subtly with our universe. Rather than using crude and coarse technologies with really annoying side-effects. C02 emissions from burning fossil carbon being the obvious example.