How a mysterious particle could explain the Universe’s missing antimatter

The universe, as we perceive it, is predominantly composed of matter, including everything from the ground beneath us to distant galaxies. This raises a perplexing question for scientists: If the Big Bang created equal amounts of matter and antimatter, why is antimatter so scarce in our cosmos? Currently, physicists are at a loss for a definitive answer, but many believe that a crucial difference in the behavior of matter and antimatter might explain this mystery. A leading avenue of investigation is focusing on the enigmatic subatomic particle known as the neutrino, which could be pivotal in understanding the matter-antimatter imbalance. Jessica Turner, a theoretical physicist at Durham University in the UK, explains, "While neutrinos may not be the sole explanation for the asymmetry between matter and antimatter, a significant number of theoretical models that address this issue are linked to neutrinos." To clarify, when scientists refer to matter, they mean the ordinary components of the universe—primarily protons and neutrons that form atomic nuclei, along with lighter particles like electrons. Antimatter, despite its sci-fi connotations, is quite similar to regular matter; the primary distinction lies in electric charge. Take the positron, for instance, which is the first antimatter particle discovered: it shares the same mass as an electron but carries a positive charge instead of a negative one. The situation becomes more complex with electrically neutral particles, as seen with photons, which are their own antiparticles, and antineutrons, which differ from neutrons due to their composition of antiquarks instead of quarks.