Discovery Could Help Answer One of the Most Puzzling Questions in Physics

One of the most vexing problems in physics is the matter-antimatter asymmetry. Simply put: why is there something rather than nothing?

When the universe was created in the Big Bang, equal amounts of matter and antimatter should have been produced. Matter and antimatter annihilate each other on contact, converting to energy. If the amounts were truly equal, everything should have cancelled out, leaving a universe of nothing but radiation.

Obviously that didnt happen. We exist. The universe is full of matter – stars, planets, you and me. Antimatter is vanishingly rare. Something broke the symmetry, and figuring out what that something is remains one of physics great unsolved mysteries.

New research may have brought us closer to an answer. Scientists studying certain particle decay processes have observed asymmetries that could help explain how matter came to dominate. The details are technical – involving CP violation in specific meson decays – but the implications are profound.

CERN has a good explainer on the asymmetry problem for those wanting to dig deeper.

The discovery doesnt fully solve the puzzle. The observed asymmetries arent large enough to account for all the matter in the universe. But theyre a piece of the puzzle, and every piece matters when youre trying to understand why existence exists. What strikes me about this kind of research is how it connects the infinitely small to the infinitely large. Particle physics experiments done in underground laboratories tell us about the first moments after the Big Bang. The behaviour of subatomic particles explains why galaxies exist.

Thats rather extraordinary when you think about it.