# Bigger anti-matter particles

I have learned about the existence of positrons as a decay product from uranium fission - if I'm not mistaken. Is there any evidence for higher 'mass' anti-matter, or is that mere speculation or rationalisation? i.e. Is the argument that there anti-matter based planets in the universe, or just a soup of positrons?

-
Possible duplicate: physics.stackexchange.com/q/1165/2451 – Qmechanic Aug 16 '12 at 7:21