Right now, as you’re reading this sentence, mysterious subatomic forces are passing through you.

At least that’s the suggestion from findings, published in April 2021, of a massive experiment conducted at the US Department of Energy’s Fermi National Accelerator Laboratory (Fermilab) in Illinois.

“Over the last 50 years, our understanding of the subatomic world has become really amazing,” says BU Professor of Physics Lee Roberts, cofounder of the experiment and a coauthor on the analysis of the Fermilab results. “But there are a number of questions we still don’t understand.”

The Fermilab experiment, called Muon g-2, detected particles called muons behaving slightly differently than currently accepted physics theories—known altogether as the Standard Model of physics—would predict. That slight deviation indicates that other particles or forces not accounted for by the Standard Model are influencing the muons’ magnetism, suggesting an invisible presence that exists beyond the current reaches of science.

At Fermilab, a huge donut-shaped machine—embedded with electronics and circuitry custom-built in the BU Electronics Design Facility by Postdoctoral Research Associate James Mott and engineers Eric Hazen and Dan Gastler—uses strong magnetic fields to trap the muons in a magnetic racetrack as the particles travel at close to the speed of light. Muons are about 200 times heavier than electrons and can be detected and measured very precisely.

The experiment’s findings were analyzed with the help of more than 200 scientists from 35 institutions in seven countries, including Roberts as well as BU Professors of Physics Robert Carey and James Miller; Postdoctoral Research Associates Nam Tran and Andy Edmonds; and provided the data for graduate student Nick Kinnaird’s PhD dissertation. It’s a breakthrough moment for the field, which has spent decades developing increasingly sensitive detectors and technologies to investigate the unseen particles and forces that make up our material world and beings.

This new finding, Roberts says, “reveals strong evidence for something new beyond what we currently know.”