A tiny, wobbly μ meson had just shaken the particle physics to its core
This is a top-down view of the equipment used in the Fermilab G-2 experiment. The experiment used μ meson bundles, electronic racks, and superconducting magnetic storage loops cooled to minus 450 degrees Fahrenheit (minus 267 degrees Celsius) to study meson jitter. (Image credit: Reidar Hahn/FermiLab).
One of the high-profile particle physics experiments is coming out, and they may fulfill every researcher's most fanatical dream: because they may break our impression of physics.
Evidence presented by the Fermi National Accelerator Laboratory near Chicago suggests that tiny subatomic particles known as μ mesons oscillate far more than theoretically predicted. According to physicists, the best explanation is that μ mesons are propelled by completely unknown matter and energy in physics.
If these results are true, then the discovery represents a breakthrough that has never been seen in five decades in particle physics. Fifty years ago, the dominant theory to explain subatomic particles was first proposed — that the tiny oscillations of μ mesons are produced by the interaction of their internal magnetic field or magnetic moment with the external magnetic field. According to this, today's discoveries may shake the foundations of science.
In a statement, Graziano Venanzoni, a physicist at the National Institute of Nuclear Physics in Italy, co-spokesperson for the Muon g-2 experiment, said: "Today is an extraordinary day, and we and the entire international physics community have been eagerly awaiting the arrival of this day for a long time."
μ mesons are sometimes referred to as "fat electrons." It is similar in appearance to their well-known close relatives, but weighs two hundred times more than them and is radioactively unstable. μ mesons decay into electrons and tiny ghostly, uncharged particles, or neutrinos, in less than a millionth of a second. μ mesons also have a spin characteristic. When they bind to an electric charge, they behave like tiny magnets. When they fall into a magnetic field, they swing like a small gyroscope.
Today's results are derived from an experiment. In this experiment, physicists let the μ meson rotate around the superconducting magnetic ring, and the experimental results seem to show that the oscillation of the μ meson is far more frequent than it should be. Scientists in the field of research say the only explanation for the results is that the particle's existence cannot yet be used to explain all subatomic equations, the so-called Standard Model. This model has not changed since the mid-1970s. This model suggests that these exotic exotic particles and the energy they bring will push and pull the μ mesons inside the ring.
Researchers at Fermilab are pretty sure that the extra jitter they see is a real phenomenon, not a statistical accident. Because they added a numerical value to the "4.2 Sigma" confidence level, making it very close to the major discovery announced by particle physicists, the 5 Sigma threshold. (The results of 5 Sigma show that the chance of it happening is one in 3.5 million.) )
Renee Fatemi, a physicist at the University of Kentucky, and the simulation manager of the Muon G-2 experiment said in a statement: "The amount we measured reflects the interaction of μ mesons with other matter in the universe. But when theorists use all the known forces and particles in the Standard Model to calculate the same amounts, the answers we get are different. This is a powerful proof that μ mesons are quite sensitive to matter that does not exist in our standard field."
However, a competitive calculation published in the journal Nature by an independent team of researchers could deprive this particle of its importance. According to the team' calculations, the values of the most indeterminate terms in the equations that predict the wobbling motion of the μ mesons are even larger. The results of the experiment are exactly the same as the predictions, which means that two decades of efforts in particle tracing may be futile.
Zoltan Fodor, a professor of physics at Penn State University-----, who led the research team in the paper published in the journal Nature, said in a statement: "If our calculations are correct and the new measurements do not change the outcome of the story, it proves that we hardly need any new physics to explain whether the μ meson strictly follows this magnetic moment controlled by the Standard Model." ”
But Fodor added that given that his team's predictions were based on different calculations and very different assumptions, their results were far from certain. To this end, he said: "Our findings mean that there is a contradiction between the previous theoretical results and our new results, but this contradiction should be understood." In addition, the results of new experiments may be closer to the old results, or closer to previous theoretical calculations. This means that there is still a long period of heart-palpitating years to be discovered in the future. ”
Essentially, physicists can only conclusively determine whether the entirely new particle is pulling μ if they can first confirm how the existing 17 Standard Model particles interact with μ. Until a theory can be finally confirmed, physics will not be able to maintain its relative equilibrium.
BY: livescience
FY: Meng Fanyu
If there is any infringement of the relevant content, please contact the author to delete it after the work is published
Please also obtain authorization to reprint, and pay attention to maintaining completeness and indicating source