> For a particle to be its own antiparticle, it would have to have spin 1/2 This is wrong. Being anti-particle has nothing to do with a particular spin. Photon

> For a particle to be its own antiparticle, it would have to have spin 1/2 This is wrong. Being anti-particle has nothing to do with a particular spin. Photon is anti-photon (which by the way has spin 1).