spin

spin

Amount of angular momentum associated with a subatomic particle or nucleus. It is measured in multiples of {Planck constant} (h-bar), equal to Planck's constant divided by 2π. Electrons, neutrons, and protons have a spin of ¹⁄₂, for example, while pions and helium nuclei have zero spin. The spin of a complex nucleus is the vector sum of the orbital angular momentum and intrinsic spins of the constituent nucleons. For nuclei of even mass number, the multiple is an integral; for those of odd mass number, it is a half-integer. See also Bose-Einstein statistics, Fermi-Dirac statistics.

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spin

1. Physics

a. the intrinsic angular momentum of an elementary particle or atomic nucleus, as distinguished from any angular momentum resulting from its motion

b. a quantum number determining values of this angular momentum in units of the Dirac constant, having integral or half-integral values.

2. a condition of loss of control of an aircraft or an intentional flight manoeuvre in which the aircraft performs a continuous spiral descent because the angle of maximum lift is less than the angle of incidence

3. (in skating) any of various movements involving spinning rapidly on the spot

4. Informal a short or fast drive, ride, etc., esp in a car, for pleasure

5. Commerce informal a sudden downward trend in prices, values, etc.

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spin [spin]

(mechanics)

Rotation of a body about its axis.

(quantum mechanics)

The intrinsic angular momentum of an elementary particle or nucleus, which exists even when the particle is at rest, as distinguished from orbital angular momentum.

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Spin (quantum mechanics)

The intrinsic angular momentum of a particle. It is that part of the angular momentum of a particle which exists even when the particle is at rest, as distinguished from the orbital angular momentum. The total angular momentum of a particle is the sum of its spin and its orbital angular momentum resulting from its translational motion. The general properties of angular momentum in quantum mechanics imply that spin is quantized in half integral multiples of ħ (=h/2π, where h is Planck's constant); orbital angular momentum is restricted to half even integral multiples of ħ. A particle is said to have spin &frac32;, meaning that its spin angular momentum is &frac32;. See Angular Momentum

A nucleus, atom, or molecule in a particular energy level, or a particular elementary particle, has a definite spin. The spin is an intrinsic or internal characteristic of a particle, along with its mass, charge, and isotopic spin. See Quantum mechanics, Symmetry laws (physics)

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spin - Equivalent to buzz. More common among C and Unix programmers.