Weak interactions, responsible for the instability of all but the least massive fundamental particles in any class. The Standard Model of particle physics is the relativistic quantum field theory of these the strong, electromagnetic, and weak interactions. In such theories, each type of interaction has a characteristic set of force carrier particles associated with quantum excitation of the force field related to that interaction. The carrier particles either appear in intermediate stages or are produced during all particle processes involving that type of interaction. Gluons are the carrier particles of strong interactions.
Photons are the carrier particles of electromagnetic interactions.
W and Z bosons are the carrier particles of weak interactions. The name for the carrier particle of gravitational interactions is the graviton . The status of this particle is still tentative, because the theory is incomplete and there has been no good experimental evidence that they exist. Gravitons are not considered to be a part of the Standard Model. In the Standard Model a fifth interaction type is needed to account for the masses of all particles.