There's nothing in the laws of physics that actually requires matter to dominate antimatter, and yet all our observations of the universe suggest that that's the case. But some unexpected behavior by ghostly neutrino particles could solve the antimatter mystery.
The T2K project in Japan is one of the world's foremost neutrino detectors, and it appears to be on the verge of a crucial discovery. However, these experiments have been on hold since the earthquake in March, so the results have to remain provisional until the work can start back up again.
Specifically, it seems to have found evidence that neutrinos can spontaneously change their "flavor", so that a specific particle can be measured as one type of neutrino and then again later as a different type. Physicists have seen evidence of neutrino oscillation in previous experiments, but this would be the first hard evidence for oscillation from muon neutrinos, which are the middle-sized neutrinos, to electron neutrinos, which are the lightest and most common flavor.
Before work had to be suspended, the T2K project had picked up on an excess of electron neutrinos emanating from a beam of what should have been almost exclusively muon neutrinos, which suggests oscillation from one to the other was taking place. The results aren't quite conclusive enough to claim a discovery - and we've seen recently how difficult finding clinching proof can be - but it's definitely a strong sign of this new form of oscillation.