The odd behaviour of a subatomic particle may shake up physics
- New findings about the muon make scientist suspect the existence of an unknown particle or force
- An experiment studying the ‘wobble’ of particles moving through a magnetic field saw results that varied greatly from predictions based on the Standard Model
The peculiar wobble of a subatomic particle called a muon in a US laboratory experiment is making scientists increasingly suspect they are missing something in their understanding of physics – perhaps some unknown particle or force.
Researchers on Thursday announced new findings about the muon (pronounced MEW-on), a magnetic and negatively charged particle similar to its cousin the electron but 200 times more massive, in their experiment at the US Energy Department’s Fermi National Accelerator Laboratory in Batavia, Illinois.
The experiment studied the wobble of muons as they travelled through a magnetic field. The muon, like the electron, has a tiny internal magnet that causes it to wobble – or, technically speaking, “precess” – like the axis of a spinning top while in a magnetic field.
But the wobble’s speed, as measured in the experiment, varied considerably from what was predicted based on the Standard Model of particle physics, the theory that explains how the basic building blocks of matter interact, governed by four fundamental forces in the universe.
The new findings, building on data released in 2021, continue to hint at some mysterious factor at play as the researchers try to sort out the discrepancy between the theoretical prediction and the actual experimental results.