An Etymological Dictionary of Astronomy and Astrophysics

An uncharged → subatomic particle found in the nucleus of every → atom heavier than → hydrogen. It has a → rest mass of 1.67492 x 10^-24 g, 939.566 → MeV, slightly greater than that of the → proton. The neutron is composed of three → quarks (two down and one up). Although the neutron is electrically neutral,
it owns a → spin of 1/2 and a → magnetic moment; it can therefore interact magnetically with matter. A free neutron is unstable and disintegrates by → beta decay to a proton, an → electron, and → antineutrino of the electron type: n→ p + e^- + ν^__e + 0.7823 MeV. Its → mean life is about 15 minutes. The decay of the neutron is associated with a → quark transformation in which a down quark is converted to an up by the → weak interaction.

See also: From neutro-, a combining form representing → neutral, + → -on a suffix used in the names of → subatomic particles.