Welcome to the Quanta Science podcast.

Each episode we bring you stories about developments in science and mathematics.

I'm Susan Vallett.

Physicists have ruled out a mundane explanation for the strange findings of an old Soviet experiment,

leaving open the possibility that the results

point to a new fundamental particle. That's next.

It's season three of the joy of why, and I still have a lot of questions. Like, what is this thing we call

time? Why does altruism exist? And where is Jan 11? I'm here. Astrophysicist and co-host. Ready for

anything. That's right. I'm bringing in the A team. So brace yourselves. Get ready to learn.

I'm Janelle Levin. I'm Steve Strogatz. And this is Quantum Magazine's podcast,

The Joy of Why. New episodes drop every other Thursday.

Deep in the Caucasus's mountains on the border between Russia and Georgia, an unusual experiment is taking place.

In an underground lab, shielded by a mountain of rock, highly radioactive material sits inside

a vat of liquid gallium, blasting out particles called neutrinos that break the gallium down

into atoms of germanium. The goal is to resolve a little-known

mystery of physics, the gallium anomaly. Ben Jones is a neutrino physicist at the University of

Texas, Arlington. As it stands right now, there are not really compelling, available explanations.

And I would really like to know personally what it's caused by. That's why I think it's a

particularly exciting anomaly. Some three decades ago, in a previous version of the current experiment,

scientists first detected a dearth of the expected germanium atoms that still can't be explained.

Since then, physicists have worked to rule out possible mismeasurements

or inaccuracies that could explain the anomaly. Now they've eliminated another one.

...