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Encyclopedia :: encyclopedia : Spin (physics) (Site not responding. Last check: 2007-10-09) |
 | | The spin of composite particles, such as protons, neutrons, atomic nuclei, and atoms, is made up of the spins of the constituent particles, plus the orbital angular momentum of their motions around one another. |
 | | This is understood to refer to the spin of the lowest-energy internal state of the composite particle (i.e., a given spin and orbital configuration of the constituents). |
 | | It is not always easy to deduce the spin of a composite particle from first principles; for example, even though we know that the proton is a spin-1/2 particle, the question of how this spin is distributed among the three internal quarks and the surrounding gluons is an active area of research. |
| www.hallencyclopedia.com /Spin_(physics) (1923 words) |
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