B mesons

In today's New Scientist, there is an article about flipping particles.

B mesons consist of a bottom quark and an anti-strange quark. It turns out that the bottom becomes an anti-strange and the anti-strange becomes a bottom. This exchange occurs one trillion times a second. The change appears to be mediated by some boson that noone has seen before.

The exchange violates CP conservation.

So the standard model of particle physics may need revision.