Answer to Question #120964 in Physics for kashaf

Question

. Do all particles have antiparticles? What about the photon?

Answer 1

In theory, all particles have antiparticles. But some (a truly neutral particle, see https://en.wikipedia.org/wiki/Truly_neutral_particle) particles are their own antiparticles. It means, that such particle and antiparticle can not be distinguished in practice. The photon is indeed one of such particles.

Also the neutrinos might have or do not have distinguishable antiparticles, depending on the theory you stand on: wheather Majorana's one, or Standard Model (see https://en.wikipedia.org/wiki/Majorana_fermion)