Meson

Meson, subatomic particle of a family called hadrons, which act via a strong nuclear force that holds together an atomic nucleus. Mesons are unstable particles that decay; they carry a positive, negative, or neutral electric charge. They consist of a quark and an antiquark. Mesons include pions (or pi-mesons), upsilon particles, k-mesons (or kaons), and psi particles (or J particles). British physicist Cecil Powell discovered the meson (1947) in cosmic radiation.

See also: Hadron; Quark.