Physicists have proposed a new answer to one of the oldest questions in science: why does anything exist at all? A team from the University of Southampton and the Indian Institute of Technology Kanpur says a long-overlooked particle could explain how matter survived the birth of the universe.
Current theory says matter and antimatter should have wiped each other out in the early universe, leaving behind nothing but energy. The researchers argue that a little-studied relative of the neutrino, called a “decoupled” heavy neutrino, tilted the balance. Because it decays very slowly, the particle survived long enough after the Big Bang to briefly dominate the energy of the universe and trigger a period in which matter took over, study author Dr Rishav Roshan said.
The paper has been published in the journal Physical Review Letters. Roshan said most theories ignored the particle because its interactions were considered too weak to have any effect, a judgment he now calls a mistake.
Other explanations for the matter-antimatter imbalance remain on the table, and the mechanism has not been directly observed. But the researchers say the forgotten neutrino deserves a place in the debate over why the universe favoured matter at all.
Source: Phys.org
