Matter-Antimatter...

Figure 1: See link for descriptions

While quantum mechanics is by now a well-established theory, it nonetheless still fascinates both newcomers and experts alike with unusual phenomena. The paradox of Schrödinger’s cat and the subtleties of the two-slit interference are timeless classics. Another less-familiar quantum effect, the oscillations of neutral mesons (bound states of a quark and an antiquark), has also intrigued legions of physicists for nearly sixty years [1]. These mesons oscillate back and forth between particle and antiparticle states. The theoretical ideas underlying this behavior involve concepts that are woven deeply into the history of particle physics. In Physical Review Letters, the LHCb Collaboration has now reported [2] the first significant single-measurement observation of oscillations in the neutral D -meson system.

American Physical Society: Viewpoint: Observing Matter-Antimatter Oscillations