Truly neutral particle

In particle physics, a real neutral particle is an elementary particle that is its own antiparticle. Known examples include photons, Z bosons, Higgs bosons, and neutral pions; along with the hypothetical neutralinos, sterile neutrinos, and gravitons (if they exist).

The electromagnetic charge, weak charge, and strong charge of such a particle must be the same as that of its antiparticle. In the case of the electric and strong charges, this implies that the charge must be zero.

For a spin-1/2 particle such as the (hypothetical) neutralino, being a real neutral particle means being a Majorana fermion.

• http://www.worldscinet.com/ijmpe/13/1302/S0218301304002272.html
• http://link.aps.org/doi/10.1103/PhysRevLett.109.131102
• pdglive.lbl.gov
• http://pdg.lbl.gov/2007/tables/gxxx.pdf