At the Big Bang, why didn’t matter and antimatter cancel each other out?
The latest findings come from scientists at the ALPHA experiment at CERN near Geneva, who report in the journal Nature that they were able to suspend atoms of the antimatter equivalent of hydrogen, antihydrogen, for hundreds of hours in a vacuum. Doing so allowed them to observe that in antihydrogen—which is composed of an antiproton and a positron, the electron’s antiparticle—jumps in energy levels known as the Lamb shift were identical to those seen in hydrogen. This symmetry rules out one of the possible answers to the matter-antimatter discrepancy.
Jonathan O’Callaghan, “Physicists Come Closer to Answering Question of Antimatter’s Scarcity” at Scientific American
We are told that thousands of anti-hydrogen atoms have now been captured and stored, though it isn’t easy.