gauge bosons carry fundamental forces. there are three known gauge bosons, which are elementary particles. for example, the photon carries the electromagnetic force. the three types of gauge bosons are: photons for electromagnetism, gluons (eight kinds) for strong force, and w and z bosons (three kinds) for weak force. other theoretical gauge bosons are predicted, such as gravitons for gravity. the higgs boson is another fundamental particle of a type called a scalar boson.