Why didn’t the universe annihilate itself moments after the big bang? A new finding at Cern on the French-Swiss border brings us closer to answering this fundamental question about why matter dominates over its opposite – antimatter.
Much of what we see in everyday life is made up of matter. But antimatter exists in much smaller quantities. Matter and antimatter are almost direct opposites. Matter particles have an antimatter counterpart that has the same mass, but the opposite electric charge. For example, the matter proton particle is partnered by the antimatter antiproton, while the matter electron is partnered by the antimatter positron.
However, the symmetry in behaviour between matter and antimatter is not perfect. In a paper published this week in Nature, the team working on an experiment at Cern, called LHCb, has reported that it has discovered differences in the rate at which matter particles called baryons decay relative to the rate of their antimatter counterparts. In particle physics, decay refers to the process where unstable subatomic particles transform into two or more lighter, more stable particles.
