Regis faculty member part of experiment that could transform understanding of physics

Fred Gray was teaching a class in Science Room 130 on the Regis Northwest Denver Campus when the results of an experiment that could transform our understanding of the laws of physics were released to the public.

Gray, the chair of the Department of Physics and Astronomy, has worked on the experiment for his entire career, from initial research at Brookhaven National Laboratory to the current Muon g-2 experiment with Illinois-based Fermi National Accelerator Laboratory. After he hurried to clean up the lab where he was teaching, he rushed to his office to find the results scientists had wondered about for decades. 

The first results of Muon g-2 (pronounced G minus 2), show strong evidence that the Standard Model — scientists’ best explanation of how the subatomic world works — is incomplete. One implication of the experiment is that new, undiscovered forms of matter or forces might exist outside it. 

In the earlier Brookhaven National Laboratory experiment, the subject of Gray’s 1998 dissertation, “we measured a value that was just a little different than what the Standard Model would predict,” he said. The Muon g-2 experiment came to the same conclusion — marking a major milestone in the effort to solve a mystery in physics.

Since the results of the experiment were released, the team of 200 physicists from seven countries have received international attention and praise, even from Star Wars actor Mark Hamill, who tweeted “Evidence is mounting that the force has been with us … ALWAYS.” Recently, Gray spoke with Colorado Public Radio’s Colorado Matters program and The Denver Post about his role in the experiment.

The experiment worked like this: Focusing magnets helped transport a beam of particles called muons into a storage ring. Once the particles were there, they traveled inside a vacuum chamber via a magnetic field that caused the particles to wobble on their axes, like spinning tops. Because they were moving so quickly, time slowed down for the muons, making the short-lived particles exist long enough for scientists to measure how fast they were spinning.

If a new, undiscovered particle is present, the muons will behave differently than what the Standard Model would predict. That’s exactly what happened at Fermilab — but scientists don’t yet know what types of matter or forces are causing the discrepancy. 

Gray said there are three possible explanations for the discrepancies: that scientists made the same mistake in two different experiments (which Gray said is unlikely), that there’s a problem with the team’s Standard Model calculation or that new, yet-to-be-discovered matter exists.

As scientists continue to release and analyze data, their research could begin to transform our understanding of physics, from the tiny particles scientists are researching at Fermilab to unexplained dark matter in the expanses of the universe. 

“It’s unlikely that we would have to throw out the book on particle physics,” Gray said before the results were released. “But it’s more like we would have to add another chapter, or maybe even another whole volume of the book.” 

During the experiment, which started in 2013, Gray has dedicated weekends and school breaks to working at Fermilab. Regis students began to make an impact on the experiment after Gray secured funding from the National Science Foundation to take students with him to the Chicago-area laboratory. 

Next year, he plans to take a sabbatical to work on the experiment full-time. 

“Over the years, it became clear that this is one of those pieces of science in our field that held the potential to be transformative,” Gray said. “If it’s really right, this may be the key to knowing what physics is out there.”