The NY Times reports experiments with muons give a pretty clear hint that the standard model of particles and forces is… incomplete.
Scientists are putting to the test the Standard Model, a grand theory that encompasses all of nature’s known particles and forces. Although the Standard Model has successfully predicted the outcome of countless experiments, physicists have long had a hunch that its framework is incomplete. The theory fails to account for gravity, and it also can’t explain dark matter (the glue holding our universe together), or dark energy (the force pulling it apart).
One of many ways that researchers are looking for physics beyond the Standard Model is by studying muons. As heavier cousins of the electron, muons are unstable, surviving just two-millionths of a second before decaying into lighter particles. They also act like tiny bar magnets: Place a muon in a magnetic field, and it will wobble around like a top. The speed of that motion depends on a property of the muon called the magnetic moment, which physicists abbreviate as g.
Short version: an experiment designed to measure “g” has just amassed huge amounts of data, and the initial results show the Standard Model’s predictions don’t match up with what is being detected.
The measurements are sufficiently convincing to be beyond reasonable doubt — and there’s more data to crunch which will further validate and refine the measurements.
While this may seem fairly abstract and distant from mundane concerns, it suggests our understanding of the way the universe is put together is incomplete at a very fundamental level — and that’s a big deal.
Suppose we were still trying to figure out electromagnetism without Maxwell’s equations. We’d still be struggling to advance beyond 1800’s technology.
What this will eventually make possible is impossible to predict. Anti-gravity? Practical fusion? The burden is now on theoretical physicists to figure out how to expand or supplant the Standard Model.
The latest result moves physicists one step closer to a Standard Model showdown. But even if new physics is confirmed to be out there, more work will be needed to figure out what that actually is. The discovery that the known laws of nature are incomplete would lay the foundation for a new generation of experiments, Dr. Keshavarzi said, because it would tell physicists where to look.
It sounds like this could be a good excuse for a Big Bang Theory cast reunion special. It will expand the techno-babble possibilities for all of the assorted Star Trek series out there.
To paraphrase an old observation, the universe is not only stranger than we imagine, it may be stranger than we can imagine. And it may be even stranger than that.
UPDATE 8:20 pm ET 8-10-23:
To pick out some points raised in comments,
- It’s been known for a while that the Standard Model is somewhat less than a universal explanation for life, the universe, and everything. This experiment has found a nifty way to probe those shortcomings.
- This experiment brings hard data to evaluate two different ways of predicting the results. One is a relatively close match; the other not so much. This suggests that figuring out how to apply the Standard Model is an evolving process that needs more work, as does the model itself.
- The results and the methods used to obtain them push the limits of measurement to a high degree of confidence, above and beyond previous experiments.
- Several commenters note observations from the Webb Space Telescope, which can see farther back into time than the Hubble, are showing things about the early universe that should not have been that way based on what our predictions about how it evolved had led us to expect.
- Those and other astronomical observations are a different way of testing what the Standard Model predicts, by attempting to see how predictions about the particles and forces it is based on manifest at the large end of the scale.
- The excitement around all this is because each of these discoveries that show where the Standard Model falls short are pointers to where to start looking for answers.
Science isn’t just about accumulating knowledge; it’s about charting the boundaries of that knowledge in order to explore beyond it, to “boldly go where no one has gone before.”