What Fermi Laboratory’s muon finding means for physics

Muons, described as extra huge, much less secure cousins of the electron—”fats electrons,” if you’ll—had been thought unlikely to upend the ideas of contemporary physics till 2001, when researchers at Brookhaven National Laboratory in New York noticed the particles behaving surprisingly. Roughly 200-fold heavier and way more radioactive than electrons, muons defied theoretical predictions when immersed in a magnetic subject, showing to be pushed and pulled in magnetic moments that would not be accounted for. Whereas inconclusive on the time, the experiment and its outcomes have tantalized physicists ever since.

Muon g-2 particle storage ring within the MC-1 Constructing. [Photo: Cindy Arnold/Fermilab]

Earlier this yr, a distinct set of researchers at Fermi Nationwide Accelerator Laboratory in Illinois lastly calculated the outcomes of a long-running experiment to measure the muon’s magnetism extra exactly. Muons in a magnetic subject, they discovered, once more wobbled in a means that was inconsistent with theoretical predictions, this time by a margin with a statistical significance of 4.2 sigma. Twenty years in the past, Brookhaven scientists had reached a statistical significance of three.3 sigma, which means there was a 1 in 1,000 likelihood the outcomes had been a fluke; at 4.2 sigma, that likelihood turns into 1 in 40,000. At 5 sigma, which is the brink for formally acknowledged discoveries, it stands at 1 in 3.5 million.

With this most up-to-date finding, scientists are rising more and more assured that the blanket Standard Model—which is the prevailing principle for the structure of the universe—is lacking one thing: a layer that might clarify the muon’s irregularities. By probing this gap within the material, they hope to make clear a lot of unexplained phenomena that fall outdoors the Commonplace Mannequin, together with such mysteries because the existence of dark matter and dark energy. As physicists at the moment perceive it, any particle taking pictures via area, reminiscent of a muon, is being acted upon by an infinite variety of “digital” particles current throughout the quantum realm, making a magnetic tickle of types—however the deviations recorded at Fermi and Brookhaven recommend there could also be yet one more invisible power of nature, ready to be found.

Earlier than all that, experimental outcomes must be dropped at the 5-sigma threshold with additional testing. However some scientists have already got eyes on the long run.


“I’m very excited,” Fabiola Gianotti, the director-general of CERN, told the New York Times of the latest finding. “I really feel like this tiny wobble could shake the foundations of what we thought we knew.”