Hypothetical heavy neutrino may explain matter asymmetry

Researchers from the University of Southampton and the Indian Institute of Technology Kanpur have proposed a new theory to explain why the universe contains matter instead of being a void of radiation. The study, published in Physical Review Letters, suggests that a previously overlooked hypothetical particle may have played a decisive role in the early cosmos.

According to the research, a decoupled heavy right-handed neutrino, possessing a mass approximately 100 trillion times that of a proton, may have temporarily dominated the energy density of the early universe. This particle could have survived long enough to accelerate cosmic expansion and delay critical particle interactions.

This mechanism addresses the fundamental mystery of matter-antimatter asymmetry. While the Big Bang should have produced equal amounts of matter and antimatter, which would have resulted in total annihilation, the presence of this heavy neutrino may have altered the conditions necessary for matter to prevail over antimatter, allowing for the formation of stars, planets, and life.