Scientists Propose Heaviest Decoupled Right-Handed Neutrino Explains Matter-Antimatter Asymmetry

The Cosmic Matter-Antimatter Imbalance

The modern universe is predominantly composed of matter, with only trace amounts of antimatter. This presents a significant cosmological puzzle, as theoretical models predict that equal quantities of matter and antimatter should have formed during the Big Bang. When matter and antimatter particles meet, they annihilate each other, making the current matter dominance an unexplained phenomenon.

Introducing the Decoupled Right-Handed Neutrino

A new study in Physical Review Letters proposes that the heaviest decoupled right-handed neutrino (RHN) could resolve this asymmetry. This particle, which existed in the early universe, is part of the minimal seesaw model that accounts for the origin of modern neutrinos. Researchers suggest that this specific RHN, previously overlooked, could have altered the universe's expansion and affected the matter-antimatter balance.

An Overlooked Particle

Rishav Roshan, a co-author of the study from the University of Southampton, noted that this decoupled right-handed neutrino has been present in scientific literature for a long time but received little attention. Its interactions with regular matter are very weak, making it nearly invisible to current experimental methods. Many researchers have focused on lighter neutrinos, considering the heavier states less relevant due to their minimal influence.

Future Experimental Verification

The scientists predict that their hypothesis regarding the heaviest decoupled right-handed neutrino could be experimentally tested in the future. This would provide a way to confirm the role of this particle in explaining the fundamental composition of the universe.