Any member of a class of subatomic particles that includes protons and neutrons, as well as numerous others such as the Σ+ (sigma-plus) and Ω− (omega-minus) particles. Together with the mesons, baryons form one of the two major classes of subatomic particles, the hadrons. Baryons are composite particles, made up from three quarks, and have a spin of ½. All isolated baryons other than the proton are unstable and decay down to a proton plus other particles. See also Non-baryonic Matter.
Subjects: Astronomy and Astrophysics — Physics.