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:
“The real American type can never be a ballet dancer. The legs are too long, the body too supple and the spirit too free for this school of affected grace and toe walking.”
—Isadora Duncan (1878–1927)
“The seashore is a sort of neutral ground, a most advantageous point from which to contemplate this world. It is even a trivial place. The waves forever rolling to the land are too far-traveled and untamable to be familiar. Creeping along the endless beach amid the sun-squall and the foam, it occurs to us that we, too, are the product of sea-slime.”
—Henry David Thoreau (1817–1862)
“Experience is never limited, and it is never complete; it is an immense sensibility, a kind of huge spider-web of the finest silken threads suspended in the chamber of consciousness, and catching every air-borne particle in its tissue.”
—Henry James (1843–1916)