Meson to muons: ultra-rare decay

You know that matter is made of protons, neutrons, and electrons. Technically, matter is made of many, many more subatomic particles — so many that physicists refer to them all as the particle zoo.

Now, scientists at the European nuclear research facility CERN have reported evidence of an extremely rare phenomenon in which one kind of subatomic particle transforms into two other particles. The finding could offer a more precise way to test our understanding of how our universe and its particles work.