The news has made the rounds that the T2K experiment in Japan discovered evidence for an asymmetry in the behaviour of neutrinos and antineutrinos. The violation of this symmetry (CP-symmetry) seems to be almost as large as possible which is why the experiment was able to gather the data faster than initially thought.
More data is still needed for a definitive discovery which will still require some years to gather.
However, if this hint turns out to be true (and it seems most physicists expect that it will) then it will provide new directions for beyond-Standard-Model physics.
As usual, you can best read about it in Quanta (with an earlier discussion some years ago when this effect first turned up here). Nature and Interactions also have worthwhile articles, while CernCourier has a bit more technical coverage (with some explanation as to what such a result would hint at theoretically here).