In
quantum mechanics, a
boson (, ) is a particle that follows
Bose–Einstein statistics. Bosons make up one of the two classes of
particles, the other being
fermions. The name boson was coined by
Paul Dirac to commemorate the contribution of the
Indian physicist
Satyendra Nath Bose in developing, with Einstein,
Bose–Einstein statistics—which theorizes the characteristics of elementary particles. Examples of bosons include fundamental particles such as photons, gluons, and W and Z bosons (the four force-carrying
gauge bosons of the
Standard Model), the recently discovered
Higgs boson, and the still-theoretical
graviton of quantum gravity; composite particles (e.g.
mesons and stable nuclei of even
mass number such as
deuterium (with one proton and one neutron, mass number = 2),
helium-4, or
lead-208); and some
quasiparticles (e.g.
Cooper pairs,
plasmons, and
phonons).