Uncharged atomic nuclear particle. It has a mass slightly greater than a proton. In beta decay, a neutron decays into a proton, an electron, and an anti-neutrino.
- Electron - Text by M. Alan Kazlev
An elementary particle with a unit electrical charge and a mass 1/1837 of the proton. Electrons surround the atom's positively charged nucleus and determine the atom's chemical properties.
- Hadron - Text by Anders Sandberg
Matter particle consisting of quarks or antiquarks. Hadrons are divided into mesons, composed of a quark and an antiquark, and baryons, composed of three quarks or three antiquarks.
- Neuron Star
- Neutrino - Text by M. Alan Kazlev; additions by Adam Getchell
An electrically neutral lepton of spin 1/2 and extremely low mass that interacts only via the weak force and gravity and as a consequence can typically pass unimpeded through ordinary matter. A common popular illustration of this is that a burst of neutrinos could pass through a light year's thickness of lead and still retain better than two thirds of its strength. There are three known varieties in conventional matter, one in each generation of particles, associated with electron, muon, and tau leptons.
- Neutron Star
- Nuclear Reaction - Text by M. Alan Kazlev
A self-perpetuating chain reaction involving the production of heavy nuclei from the fusion of lighter ones, or lighter nuclei from the fission of heavier ones.
- Nucleus, Atomic - Text by M. Alan Kazlev
The central part of an atom, made up of protons and neutrons, and containing nearly all of the atomic mass.
- Proton - Text by M. Alan Kazlev
One of the two basic elementary particles found the atomic nucleus, the other being the neutron. It has a positive charge equal and opposite that of the electron, and a mass similar to the neutron. Protons have a mass of 1.007276 daltons, or 1.6726 = 10-27 kg.
- Quark - Text by M. Alan Kazlev
The fundamental particles of hadronic matter such as protons, neutrons and mesons. There exist six 'flavors' of quarks: up, down, strange, charm, top and bottom. They are confined to hadrons by the strong force.