Proton, Neutron, Electron ... Demon?

A team of scientists at the University of Illinois accidentally proved a long-standing theory. It happened when they fired a stream of electrons at a piece of strontium ruthenate. They wanted to learn why the metal acted like a superconductor without actually being one. Instead, they summoned a demon.

A demon particle, that is.

No, this isn’t a horror movie plot. Rather, it’s particle physics. That's the study of the universe’s tiniest building blocks. Those in the field study atoms to explore the interactions between protons, electrons, and neutrons. Sometimes, they see something we can’t explain. That’s what happened to David Pines in 1956.

Pines wanted to learn more about superconductors. He wanted to know why they hold and transmit electricity without losing any charge. Pines noticed that electrons moved in strange ways in some superconductors. His theory was that there must be a particle pushing on them that humans couldn't see. It was chargeless and massless. But, he said, it caused — ready for it? — Distinct Electron Movement (DEM). Pines took that DEM and put an -ON on it.

Thus, DEMON particles were born.

The theory of demon particles was finally proved this month. It stayed a theory so long because they are so hard to observe.

“We basically laughed (the theory) off,” Ali Husain said in a press statement. But they “saw” the demon moving around in the stream when they measured the energy given off by their electrons. 

“It speaks to the importance of just measuring stuff,” the study's co-author said. “Most big discoveries are not planned. You go look somewhere new and see what’s there.”

Photo from Wikimedia Commons courtesy LG Ultralink.

Reflect: What do you think makes science exciting, and how can unexpected discoveries change our understanding of the world?