What is half a spin?

[michellemfry]

Hey Mike, at the moment all I care about is that that son of yours is snatched from the jaws of danger. Tell me that is true and I can talk neutrinos all day.

[HIGGSBOSONS]

Some Phenomenas In Nature Cannot Be Observed Directly By Viewing It Like Spin In Classical Physics. Suppose If You See A Fast Moving And Spin Ball Which Is Too Small To Recongnized It Completely. So Feel That Ball Is Simmply Moving Through The Space Not Spining Because It Is Too Fast To Obsreve. But That Effect Can Be Observe When This Interact With Some Other Matter. The Motion Of Such Ball Give Us Clue About New Concept Like Spin.

[Slaviks]

Hi, there!

The term "spin" in quantum mechanics referes to the intrinsic angular momentum of a particle (which may be elementrary, liek electron or neutrino, or composed, like an atom or a golf ball). In this sense neutrino "spins" exactly like a spining golf ball.

There are elegant mathematical reasons [representation theory of SO(3) group] which imply that angular momentum of any isolated object is quantized -- that is, can assume only values that are multiples of hbar/2. For small objects (like elementary particles), the angular momentum is "small integer" * (1/2) * hbar, and angluar momentum quantization has pronounced effects.

For large objects the corresponding integer is HUGE and descrete effects of spin are unobservable.


Nothing misterious about spin!