Particle Physics Glossary

A particle with the same mass as its counterpart but opposite quantum numbers such as electric charge.

The weakening of the strong force at very short distances or high energies.

A composite particle made of three quarks, such as the proton or neutron.

A particle with integer spin that obeys Bose-Einstein statistics. Includes force-carrying gauge bosons and the Higgs boson.

The European Organization for Nuclear Research, the world's largest particle physics laboratory, located near Geneva, Switzerland.

The charge associated with the strong force carried by quarks (red, green, blue) and gluons.

The phenomenon in QCD where quarks and gluons cannot exist as free particles.

A principle stating that a particular measurable property of a system remains constant over time.

The violation of the combined charge conjugation ($C$) and parity ($P$) symmetry in certain weak force interactions.

A measure of the probability that a specific scattering or interaction process will occur between particles.

A hypothetical form of matter that does not emit or absorb light but exerts gravitational effects on visible matter.

The unified description of the electromagnetic and weak nuclear forces at high energies.

A particle with half-integer spin that obeys the Pauli exclusion principle. All matter particles (quarks and leptons) are fermions.

A graphical representation of the mathematical expressions describing particle interactions in quantum field theory.

A boson that mediates a fundamental force: photon (EM), $W$/$Z$ (weak), gluon (strong).

The massless gauge boson that mediates the strong nuclear force between quarks.

A composite particle made of quarks held together by the strong force. Includes baryons and mesons.

A scalar field permeating all of space whose interaction with particles gives them mass.

An elementary particle that does not participate in the strong interaction, such as electrons and neutrinos.

A hadron composed of one quark and one antiquark.

An electrically neutral lepton with very small mass that interacts only via the weak force and gravity.

The theoretical framework combining quantum mechanics and special relativity in which particles are excitations of underlying fields.

An elementary particle and fundamental constituent of matter that experiences all four fundamental forces.

The theory describing all known elementary particles and three of the four fundamental forces of nature.

A proposed extension of the Standard Model that predicts a partner particle for each known particle with different spin.