PlanetPhysics/Gauge Bosons 2

Gauge bosons are (quantum) [[../Particle/|particles]] of zero or integer [[../QuarkAntiquarkPair/|spin]] (i.e., bosons or particles that follow the Bose-Einstein statistics) which act as the carriers of the four fundamental forces of nature. Thus, the major gauge boson classes are: photons, W and Z bosons/[[../Neutralinos/|Higgs bosons]], [[../ExtendedQuantumSymmetries/|gluons]] and gravitons , that are carriers of, respectively, electromagnetic interactions, (electro[[../WeakNuclearForce/|)weak interactions]] (W and Z), [[../QuarkAntiquarkPair/|strong interactions]] and gravitational ones.

Unlike photons and (W,Z) bosons, the [[../Vectors/|scalar]] massive Higgs bosons (spin-0) and (massless) gravitons (spin-2 bosons) are yet to be observed, and are thus considered hypothetical. Therefore, the [[../QuarkAntiquarkPair/|Standard Model of physics]] currently includes only photons, W, Z bosons and gluons.

In quantum gauge theories, gauge bosons are the quanta of gauge [[../CosmologicalConstant/|fields]]. There are distinct gauge (symmetry) [[../TrivialGroupoid/|groups]] associated with each class of gauge bosons. Thus, the gauge group of electromagnetic interactions in [[../QED/|quantum electrodynamics]] ([[../QED/|QED]]) is the unitary [[../TopologicalOrder2/|symmetry group]] $U(1)$ as it has only one gauge boson --the photon. On the other hand, in [[../QuantumChromodynamicsQCD/|quantum chromodynamics (QCD)]] the gauge group is the special unitary group $SU(3)$ corresponding to the eight different [[../QuarkAntiquarkPair/|gluon]] [[../Bijective/|types]] (distinguished by their quantum [[../QuarkAntiquarkPair/|flavors]]) which are responsible for the strong interactions.

Note also that not all bosons are field carriers, and thus there are many more bosons besides the gauge bosons, such as: the deuteron, all nuclei of either zero or integer spin, Cooper (electron) pairs and all quasi-particles of either zero or integer spin.