Forgotten particle may explain why matter survived the Big Bang

Scientists propose that a long-overlooked heavy neutrino may explain why matter survived the Big Bang, potentially solving a fundamental mystery of the universe's existence. The theory suggests this particle could have left detectable gravitational wave signals. Researchers from the University of Southampton and the Indian Institute of Technology Kanpur found that this 'decoupled' heavy neutrino, previously dismissed as insignificant, may have lived long enough to temporarily dominate the universe's energy density. This shift could have altered conditions allowing matter to outnumber antimatter, published in Physical Review Letters. The particle's influence on temperature conditions involving the Higgs boson may have shaped the matter-antimatter imbalance. While theoretical, the proposed gravitational wave signatures offer a potential avenue for testing this explanation of why the universe contains matter rather than nothing.