Meson Messes With Standard Model

Scientists for the first time have seen a specific particle of matter spontaneously turn into its antimatter twin--a discovery that might require some rewriting of the fundamental theory that governs nature at the subatomic level.

Particle physics is like studying fine wristwatches by slamming them together to see which parts fall out. Except that the particles set loose by giant accelerators tend to exist for the briefest wisps of time--only billionths or even trillionths of a second. As a result, scientists can only observe the results of the decay of these particles, collecting data on their mass and electrical charge. Most of the time, these properties fit the Standard Model, the grand theory that has defined the nature of matter for nearly 4 decades. But sometimes, researchers see a particle behave in a new way that could crack open the door to an entirely new category of forces governing particle interactions.