In classical physics, a vacuum is a complete void—a real manifestation of nothingness. But quantum physics says that vacant area isn’t actually empty. Instead, it’s buzzing with “virtual” particles blipping out and in of existence too shortly to be detected. Scientists know that these digital particles are there as a result of they measurably tweak the qualities of normal particles.

One key property these effervescent particles change is the miniscule magnetic area generated by a single electron, often called its magnetic second. In idea, if scientists might account for all of the forms of digital particles that exist, they may run the maths and determine precisely how skewed the electron’s magnetic second must be from swimming on this digital particle pool. With exact sufficient devices, they may examine their work in opposition to actuality. Determining this worth as precisely as potential would assist physicists nail down precisely which digital particles are toying with the electron’s magnetic second—a few of which could belong to a veiled sector of our universe, the place, for instance, the ever-elusive dark matter resides. 

In February, 4 researchers at Northwestern University introduced they’d finished simply that. Their results, revealed in Physical Review Letters, report the electron magnetic second with staggering precision: 14 digits previous the decimal level, and greater than twice as precise because the previous measurement in 2008. 

That may appear to be going overboard. But there’s far more than mathematical accuracy at stake. By measuring the magnetic second, scientists are testing the theoretical linchpin of particle physics: the usual mannequin. Like a physics model of the periodic desk, it’s laid out as a chart of all of the particles identified in nature: the subatomic ones making up matter, like quarks and electrons, and people who carry or mediate forces, like gluons and photons. The mannequin additionally comes with a algorithm for a way these particles behave.

But physicists know the standard model is incomplete—it’s more likely to be lacking some parts. Predictions primarily based on the mannequin typically don’t line up with observations of the true universe. It can’t clarify key conundrums like how the universe inflated to its present dimension after the Big Bang, and even the way it can exist in any respect—full of matter, and mostly absent of the antimatter that ought to have canceled it out. Nor does the mannequin say something concerning the dark matter gluing galaxies collectively, or the dark energy spurring cosmic expansion. Perhaps its most flagrant flaw is the shortcoming to account for gravity. Incredibly exact measurements of identified particles are due to this fact key to determining what’s lacking as a result of they assist physicists zero in on gaps in the usual mannequin. 

“The standard model is our best description of physical reality,” says Gerald Gabrielse, a physicist at Northwestern University who coauthored the brand new examine, in addition to the 2008 end result. “It’s a highly successful theory in that it can predict essentially everything we can measure and test on Earth—but it gets the universe wrong.” 

In reality, essentially the most exact prediction the usual mannequin makes is the worth of the electron’s magnetic second. If the anticipated magnetic second doesn’t match up with what’s seen in experiments, the discrepancy might be a clue that there are undiscovered digital particles at play. “I always say that nature tells you what equations are correct,” says Xing Fan, a physicist at Northwestern University who spearheaded the examine as a Harvard University graduate scholar. “And the only way you can test it is if you compare your theory to the real world.”