Delta baryon
The Delta baryons (or baryons, also called Delta resonances) are a family of subatomic particle made of three up or down quarks (u or d quarks), the same constituent quarks that make up the more familiar protons and neutrons. Properties Four closely related baryons exist: (constituent quarks: uuu), (uud), (udd), and (ddd), which respectively carry an electric charge of , , , and . The baryons have a mass of about ; their third component of isospin and they are required to have an intrinsic spin of or higher (half-integer units). Ordinary nucleons (symbol N, meaning either a proton or neutron), by contrast, have a mass of about , and both intrinsic spin and isospin of . The (uud) and (udd) particles are higher-mass spin-excitations of the proton (, uud) and neutron (, udd), respectively. The and , however, have no direct nucleon analogues: For example, even though their charges are identical and their masses are similar, the (ddd), is not closely related to the antiproton (, ). The Delta states discussed here are only the lowest-mass quantum excitations of the proton and neutron. At higher spins, additional higher mass Delta states appear, all defined by having constant or isospin