The nuclear magneton is the spin magnetic moment of a Dirac particle, a charged, spin-1/2 elementary particle, with a proton's mass m p, in which anomalous corrections are ignored. The nuclear magneton is μ μ N = e ℏ ℏ 2 m p , where e is the elementary charge, and ħ is the reduced Planck constant. The magnetic moment of such a particle is parallel to its spin. Since the neutron has no charge, it should have no magnetic moment by the analogous expression. The non-zero magnetic moment of the neutron thus indicates that it is not an elementary particle. The sign of the neutron's magnetic moment is that of a negatively charged particle. Similarly, that the magnetic moment of the proton, μ p /⁠ μ N ≈ 2.793 is not almost equal to 1 μ N indicates that it too is not an elementary particle. Protons and neutrons are composed of quarks, and the magnetic moments of the quarks can be used to compute the magnetic moments of the nucleons.