Evidence for a particle that's its own antiparticle

Most of the discussion is here:

https://news.ycombinator.com/item?id=14839427

At this moment there are also two comments here: https://news.ycombinator.com/item?id=14817322

And there's another comment here: https://news.ycombinator.com/item?id=14818725

There are also other submissions:

https://news.ycombinator.com/item?id=14817206

https://news.ycombinator.com/item?id=14840123