# Metadata Source URL:: https://en.wikipedia.org/wiki/Meson Topics:: #physic --- # Meson - Wikipedia ## Highlights > [!quote]+ Updated on 310822_075216 > > In particle physics, mesons (/ˈmiːzɒnz/ or /ˈmɛzɒnz/) are hadronic subatomic particles composed of an equal number of quarks and antiquarks, usually one of each, bound together by strong interactions. Because mesons are composed of quark subparticles, they have a meaningful physical size, a diameter of roughly one femtometre (10−15 m),[1] which is about 0.6 times the size of a proton or neutron. All mesons are unstable, with the longest-lived lasting for only a few hundredths of a microsecond. Heavier mesons decay to lighter mesons and ultimately to stable electrons, neutrinos and photons.