Bosons, along with fermions and leptons complete the 'zoo' of elementary particles.
Bosons are another class of particles that are responsible for mediating the fundamental forces (mediate in this context basically means that the boson allows the force to function). They are also known as carrier particles. The Standard Model accounts for the electromagnetic, strong, and weak forces, but does not yet explain the force of gravity. All bosons have an integer spin.
The photon, the particle of light, is the boson that mediates the electromagnetic force. The photon has a spin of +1, a charge of 0, and no mass whatsoever. Oddly, the photon acts as its own antiparticle.
The W- boson (charge -1) and its antiparticle W+ (charge -1) mediate the weak nuclear force. The W bosons have a mass about eighty thousand times that of the up quark. Both have a spin of +1. The Z boson also mediates the weak force, but has no charge. The Z boson is about ninety thousand times as massive as the up quark. It is because the masses of the W and Z bosons are so large that the range of the weak force is limited to the atomic nucleus.
The gluon rounds out the list of found elementary bosons. The gluon is the carrier particle for the strong force. Like the photon, the gluon carries no charge and is probably massless. The gluon has an additional property called color charge, which has nothing to do with electric charge. The complex interactions resulting from color charge in gluons is what confines quarks together to make composite particles like neutrons and protons. Unlike photons, quarks and gluons are never found by themselves under natural conditions. Under extreme temperatures and pressures, quarks and gluons can be liberated into a quark-gluon plasma. The gluon like the photon, is its own antiparticle.
The Higgs boson is a theoretical particle predicted by the Standard Model but has yet to be observed. If found, the Higgs boson would help explain the origin of mass in other elementary particles.
