Particles of Antimatter
. British physicist Paul Dirac proposed an early theory of particle interactions in 1928. His theory predicted the existence of antiparticles, which combine to form antimatter. Antiparticles have the same mass as their normal particle counterparts, but they have several opposite quantities, such as electric charge and color charge. Color charge determines how particles react with one another under the strong force (the force that holds the nuclei of atoms together, just as electric charge determines how particles react to one another under the electromagnetic force). The antiparticles of fermions are also fermions, and the antiparticles of bosons are bosons. All fermions have antiparticles. The antiparticle of an electron is called the positron . The antiparticle of the proton is the antiproton. The antiproton consists of antiquarks—two up antiquarks and one down antiquark. Antiquarks have the opposite electric and color charges of their counterparts. The antiparticles of neutrinos are...