nucleones

Nucleones is not a standard term in contemporary physics. In most scientific contexts, the correct word is nucleon, referring to the constituents of atomic nuclei: the proton and the neutron. When encountered as nucleones, the term is typically a misspelling or an historical variant, and readers should relate it to the nucleon concept.

A nucleon is a baryon—an entity made of three quarks—bound by the strong interaction as described by quantum chromodynamics. The proton consists of two up quarks and one down quark (uud), and the neutron consists of one up and two down quarks (udd). Nucleons have a rest mass of about 938 MeV/c^2 for the proton and 939.6 MeV/c^2 for the neutron; they possess half-integer spin (1/2) and participate in electromagnetic, weak, and strong interactions. The proton carries a positive electric charge (+e), while the neutron is electrically neutral. The typical size of a nucleon is on the order of 0.8 to 0.9 femtometers.

In atomic nuclei, nucleons are held together by the nuclear force, a short-range residual interaction mediated by mesons, which gives nuclei their binding energies and stability. Nucleons are not pointlike but have internal structure, including quarks, gluons, and quantum fluctuations (the sea of quark–antiquark pairs).

In nuclear physics, models such as the shell model and the liquid-drop model describe how nucleons populate energy levels and contribute to nuclear properties. High-energy experiments probe nucleon structure through deep inelastic scattering, revealing parton distributions within nucleons.

See also: baryon, proton, neutron, quantum chromodynamics, nuclear force.