Neutrinos May Be The Key To Why We Are Surrounded By Matter

In the early Universe, neutrinos interacted strongly with other matter before some of them "decoupled. " The heaviest of these decoupled neutrinos may be the solution to the matter-antimatter cosmic mystery. Neutrinos don't interact strongly with regular matter.

Countless neutrinos stream through us all the time with no effect. In the earliest cosmic moments neutrinos still interacted strongly with protons, neutrons, and electrons.

At about a second after the Big Bang neutrons decoupled from other material particles. In the present epoch these neutrinos play no strong role in the evolution of the Universe, but some of them may be the reason we live in a matter-dominated universe.

In the modern Universe only left-handed neutrinos interact with matter. For matter, the three flavors are associated with the electron, muon, and tauon, which is why neutrinos have three possible masses.

This latest study focuses on the anti-neutrinos with the greatest mass. They argue that since the half-life of these heavy neutrinos is relatively long, they would have decayed well after things like electrons, protons, positrons, and anti-protons formed.

When heavy anti-matter decayed, their by-products kept the Universe a bit warm and annihilated some of the antimatter particles to create neutral photons.

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