In particle physics, a real neutral particle is an elementary particle that is its own antiparticle. Known examples include photons, Z bosons, and neutral pions; along with the hypothetical Higgs bosons, 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.
Famous quotes containing the words real, neutral and/or particle:
“There’s always the hyena of morality at the garden gate, and the real wolf at the end of the street.”
—D.H. (David Herbert)
“The United States must be neutral in fact as well as in name.... We must be impartial in thought as well as in action ... a nation that neither sits in judgment upon others nor is disturbed in her own counsels and which keeps herself fit and free to do what is honest and disinterested and truly serviceable for the peace of the world.”
—Woodrow Wilson (1856–1924)
“Each particle is a microcosm, and faithfully renders the likeness of the world.”
—Ralph Waldo Emerson (1803–1882)