The best explanation, physicists say, is that the muon is being influenced by forms of matter and energy that are not yet known to science, but which may nevertheless affect the nature and evolution of the universe. The new work, they said, could eventually lead to a breakthrough in our understanding of the universe more dramatic than the heralded discovery in 2012 of the Higgs boson, a particle that imbues other particles with mass. Muons are akin to electrons but far heavier. When muons were subjected to an intense magnetic field in experiments performed at the Fermi National Accelerator Laboratory, or Fermilab, in Batavia, Illinois, they wobbled like spinning tops in a manner slightly but stubbornly and inexplicably inconsistent with the most precise calculations currently available. The results confirmed results in similar experiments at the Brookhaven National Laboratory in 2001 that have tantalized physicists ever since. “This quantity we measure reflects the interactions of the muon with everything else in the universe,” said Renee Fatemi, a physicist at the University of Kentucky. “This is strong evidence that the muon is sensitive to something that is not in our best theory.”