Fundamental interaction The gravitational force is attributed to the curvature of spacetime, described by Einstein's general theory of relativity. The other three are discrete quantum fields, and their interactions are mediated by elementary particles described by the Standard Model of particle physics. Within the Standard Model, the strong interaction is carried by a particle called the gluon, and is responsible for quarks binding together to form hadrons, such as protons and neutrons. As a residual effect, it creates the nuclear force that binds the latter particles to form atomic nuclei. The weak interaction is carried by particles called W and Z bosons,
X and Y bosons X and Y bosons In particle physics, the X and Y bosons (sometimes collectively called "X bosons") are hypothetical elementary particles analogous to the W and Z bosons, but corresponding to a new type of force predicted by the Georgi–Glashow model, a grand unified theory. The X and Y bosons couple quarks to leptons, allowing violation of the conservation of baryon number, and thus permitting proton decay. An X boson would have the following decay modes: where the two decay products in each process have opposite chirality, is an up quark, is a down antiquark and is a positron. A