The real proof could come later this year when the Large Hadron Collider switches on at CERN, near Geneva, Switzerland to finally accidentally cause a rip in the space-time continuum, swallowing everything on Earth and ultimately destroying the universe itself. B-sub-s meson @ Wikipedia. Observation of Bs-Bsbar Oscillations. Press release: Fermilab's CDF scientists make it official: They have discovered the quick-change behavior of the B-sub-s meson, which switches between matter and antimatter 3 trillion times a second.
Flipping particle could explain missing antimatter - In its early days, the cosmos was apparently a cauldron of radiation & equal amounts of matter and antimatter. As it cooled, all the antimatter supposedly was annihilated in collisions with matter - but for some reason the proportions ended up lopsided, allowing some of the matter to form the elements, stars and galaxies we see today. The precise reason for this is unknown to physics, perhaps until now.