Mesons are the associated quantum-field particles that transmit the nuclear force between hadrons that pulls them together into a nucleus.

All mesons are unstable, with the longest-lived lasting for only a few hundredths of a microsecond. Charged mesons decay (sometimes through mediating particles) to form electrons and neutrinos. Uncharged mesons may decay to photons.

Types: Pion Rho meson, Eta and eta prime mesons, Phi meson, J/psi meson, Omega meson, Upsilon meson, Kaon B meson, and D meson.