This is a list of all the particles in the current standard model of particle physics and two hypothetical particles that most physicists expect will be discovered: graviton and Higgs. (See also the graphical Particles chart.)
All particles are either fermions or bosons.
Fermions. (half-integer spin 1/2, 3/2, 5/2, etc.) Matter is made of fermions. Fermions obey the exclusion principle; they cannot be in the same place at the same time.
Bosons. (integer spin 0, 1, 2, etc.) Forces are carried by bosons with non-zero spin. Bosons do not obey the exclusion principle; they can pass right through each other.
Elementary particles. Elementary particles are not composed of other particles. The elementary fermions are the quarks and leptons. The elementary bosons are the photon, W and Z bosons, gluon, graviton, and Higgs.
Quarks. (spin 1/2) The protons and neutrons in the nucleus of an atom are made of quarks. There are six types or "flavors" or quarks: down, up, strange, charm, bottom, and top. Each comes in three "color" charges: red, green, and blue.
Leptons. (spin 1/2) The six leptons are the electron and its two heavier sisters, the muon and tau, and the three lightweight neutrinos, the electron neutrino, muon neutrino, and tau neutrino.
Graviton. (spin 2) Gravitons [predicted] carry the gravity force.
Gluon. (spin 1) Gluons carry the strong force, also called the nuclear force or color force. The strong force holds quarks together.
W± and Z bosons. (spin 1) W± and Z bosons carry the weak force. The weak force is responsible for radioactivity.
Photon. (spin 1) Photons carry the eletromagnetic force. Photons are particles of light. Light is an electromagnetic wave.
Higgs. (spin 0) The Higgs boson [predicted] is an excitation the Higgs field. The Higgs field gives other particles their inertial mass.
Electroweak W and B bosons. (spin 1) W1, W2, W3, and B bosons carry the electroweak force. When the electroweak force split into the electromagnetic and weak forces, the W1, W2, W3, B, and Higgs remixed to make W±, Z, photon, and Higgs.
Composite particles. Composite particles (hadrons) are composed of other particles. The main types of composite particles are the baryons and the mesons.
Baryons. (spin 1/2, 3/2) Baryons are fermions composed of three quarks. The most important baryons are the two nucleons: the proton (up-up-down quarks) and the neutron (up-down-down quarks). Some other baryons are the sigma, lambda, xi, delta, and omega-minus.
Mesons. (spin 0, 1) Mesons are bosons composed of a quark and antiquark. Some mesons are the pion, kaon, eta, rho, omega, and phi.
Antiparticles. All particles have a corresponding anti-particle that is identical in many ways but opposite in others; for example, the mass and spin are the same but the charge is opposite. An uncharged particle may be its own anti-particle.
Chirality. Particles may have left-handed or right-handed spins.
There are many new theories, such as supersymmetry theory, supergravity theory, and superstring theory, that postulate additional particles that are not in the standard model of particle physics. Here are some:
Supersymmetric partners. Every standard particle may have a superpartner particle: a fermion for each boson and a boson for each fermion.
|Standard Fermions||spin||Partner Bosons||spin|
|Standard Bosons||spin||Partner Fermions||spin|
|W±, Z||1||wino, zino||1/2|
Other particle names used in supersymmetry:
sparticle: the supersymmetric partner of any particle.
slepton: the partner of a lepton (electron or neutrino).
gaugino: the partner of a gauge boson (photon, W, Z, or gluon).
electroweak wino and bino: the partners of electroweak bosons (W and B).
neutralino: a mixture of neutral particles (photino, zino, and Higgsino, or electroweak wino, bino, and Higgsino).
chargino: a mixture of charged particles (wino and Higgsino).
Strings. String theory postulates that all elementary particles are really tiny strings with different vibration modes.
Sterile neutrino. A particle that has no interactions except gravity.
Graviton variations. The spin 1 graviphoton and the spin 0 graviscalar (also known as the radion or dilaton).
Axion. A particle proposed to expain the the absence of an electrical dipole moment for the neutron. Supersymmetry adds the axino and saxion.
Goldstone boson. A type of spin 0 particle that that is necessary wherever there is a broken symmetry. Supersymmetry adds the goldstino and sgoldstino. The majoron is a type of Goldstone boson.
X and Y bosons. Particles mediating a grand unified force, analogous to the W and Z bosons.
Mirror particles. Particles with left/right (parity) opposite of known particles.
Magnetic monopoles. North and south monopoles, analogous to positive and negative charged particles. Some theories also propose a magnetic photon.
Tachyon. A particle that travels faster than light and backward in time.
Exotic baryons. Fermions composed of three quarks plus other particles. The pentaquark has five quarks.
Exotic mesons. Bosons composed of other particles, but not merely two quarks. The tetraquark has four quarks. The glueball is composed of gluons.
Many quantized states are not real particles, but are conveniently named and treated as if they were real particles. Some are the quantized modes of collections of particles.
Soliton. A stable solitary wave packet arising from a combination of waves. Solitons are found in many physical phenomena, large and small.
Phonon. A quantized sound wave.
Electron hole. The absence of a negatively-charged electron in a semiconductor, treated as if it were a positively-charged particle.
Cooper pair. A pair of electrons (fermions) in a superconductor, treated like a single boson.
Exciton. A bound state of an electron and an electron hole.
Magnon. A quantized spin wave.
Plasmon. A quantized plasma oscillation.
Polaron. A quantized polarization field.
Landau quasiparticle. In a normal metal.
Stoner excitation. In a ferromagnetic metal.
Bogoliubov quasiparticle. In a superconductor.