The results of one of the most anticipated experiments in particle physics have been obtained, and they are about to fulfill the wildest dreams of every researcher: perhaps they can break physics as we know it.
Evidence from the Fermi National Accelerator Laboratory near Chicago appears to point to a tiny subatomic particle known as muon the wobble is much larger than theory predicts. The best explanation, according to physicists, is that the muon pushes types of matter and energy completely unknown to physics.
If the results are correct, this discovery represents a breakthrough in particle physics that did not occur in 50 years, when the dominant theory was first developed to explain subatomic particles. The tiny wobble of a muon, created by the interaction of its own magnetic field or magnetic moment with an external magnetic field, could shake the very foundations of science.
“Today is an unusual day, which not only we, but the entire global physical community have been waiting for so long,” said Graziano Venanzoni, co-speaker of Muon g-2 experiment and physicist of the Italian National Institute of Nuclear Physics, said in a statement…
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Sometimes known as “fat electrons,” muons are similar to their more widely known counterparts, but they are 200 times heavier and radioactively unstable – they decay in just a millionth of a second into electrons and tiny, ghostly, chargeless particles known as neutrinos. Muons also have a property called rotation, which, when combined with their charge, makes them behave as if they were tiny magnets, causing them to wobble like little gyroscopes when they hit a magnetic field.
But today’s results, from an experiment in which physicists sent muons to orbit a superconducting magnetic ring, seem to indicate that the muon vibrates much more than it should. Scientists said the only explanation is the existence of particles that are not yet accounted for by the system of equations that explain all subatomic particles, called the Standard Model, which has remained unchanged since the mid-1970s. The idea is that these exotic particles and their associated energies will push and pull muons inside the ring.
The Fermilab researchers are relatively confident that what they saw (the extra wobble) was a real phenomenon and not some kind of statistical fluke. They gave this confidence a 4.2 sigma figure, which is incredibly close to the 5 sigma threshold at which particle physicists announce a major discovery. (A 5 sigma result suggests that there is a 1 in 3.5 million chance of this happening by accident.)
“This quantity that we are measuring reflects the interactions of a muon with everything else in the universe. But when theorists calculate the same value using all known forces and particles in the Standard Model, we don’t get the same answer, ”Rene Fatemi, a physicist at the University of Kentucky and manager of modeling for the Muon g-2 experiment, said in a statement. “This is compelling evidence that the muon is sensitive to something that is not our best theory.”
However, a competing calculation made by a separate group and published on Wednesday (April 7) in the journal Nature can rob hesitation of its meaning. According to the calculations of this group, which give a much larger value for the most indefinite term in the equation that predicts the rocking motion of the muon, the experimental results are fully consistent with the predictions. Twenty years of chasing particles could have been in vain.
“If our calculations are correct and the new measurements don’t change history, it looks like we don’t need new physics to explain the muon’s magnetic moment — it follows the rules of the Standard Model,” said Zoltan Fodor, professor of physics at the University of Pennsylvania and head of the research group. published an article in Nature, said in a statement…
But Fodor added that given that his group’s prediction was based on a completely different calculation with very different assumptions, their results were far from what had been done. “Our discovery means that there is a contradiction between the previous theoretical results and our new ones. This discrepancy should be understood, ”he said. “In addition, new experimental results may be close to old ones or closer to previous theoretical calculations. We have many years of unrest ahead of us. “
In fact, physicists cannot say unambiguously whether new particles are attracting their muons until they agree on exactly how the 17 existing particles of the Standard Model interact with muons. Until one theory wins, physics remains by a thread.
Originally published on Live Science.