Given that they have no charge, this further elucidates what Orodruin said (if I understood it correctly). So, if I'm on the right track in understanding it, then again it would boil down to the annihilation being a lower (lowest possible?) energy state of the system. As for what they become, I...
So, you are saying the mass and charge are merely consequences of them being anti-particle partners, and they annihilate because they are anti-particle partners, not the other way around. If I understand what you are saying, it is not that the opposite charge and same mass causes them to...
I did a forum search and couldn't find this, so forgive me if my search skills were insufficient to find a previous explanation of this.
But, I'm a bit confused as to why merely having the same mass but opposite charge would cause, for example, an electron and positron to annihilate each other...