fundamental particle - a particle that is less complex than an atom; regarded as constituents of all matterantiparticle - a particle that has the same mass as another particle but has opposite values for its other properties; interaction of a particle and its antiparticle results in annihilation and the production of radiant energy hadron - any elementary particle that interacts strongly with other particles lepton - an elementary particle that participates in weak interactions; has a baryon number of 0 particle - a body having finite mass and internal structure but negligible dimensions quark - hypothetical truly fundamental particle in mesons and baryons; there are supposed to be six flavors of quarks (and their antiquarks), which come in pairs; each has an electric charge of +2/3 or -1/3 weakly interacting massive particle, WIMP - a hypothetical subatomic particle of large mass that interacts weakly with ordinary matter through gravitation; postulated as a constituent of the dark matter of the universe atom - (physics and chemistry) the smallest component of an element having the chemical properties of the element |