Matter‐antimatter asymmetry

New experiments on the decay of an $η°$ meson into $π+,$ $π−$ and $π0$ find no statistically significant asymmetry between matter and antimatter. An earlier experiment by Paolo Franzini and his collaborators at Columbia and Stony Brook (PHYSICS TODAY, August, page 71) found an asymmetry of $7.2%±2.8%,$ implying a violation of charge‐conjugation invariance in intermediate‐strength interactions.