
How did the proton get its spin? - dnetesn
https://science.energy.gov/news/featured-articles/2017/03-29-17/
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danbruc
Is there any picture that can provide some intuition about intrinsic spin? To
me it seems kind of tempting to think about it as charge, even though not a
scalar one. But the connection with orbital angular momentum seems to somewhat
ruin simply thinking about it as a charge.

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jeffwass
You could crudely think of intrinsic spin as the particle spinning about its
own axis. This was what physicists originally thought, and why it's called
'spin'. Though we've since learned this is not an accurate view.

Otherwise you can think of spin as an angular momentum that's "just there",
and restricted to a few quantized values.

Electrons are spin-1/2 fermions, and their intrinsic-spin angular momentum can
only have values of +/\- hbar/2\. Ie, in whatever direction you measure the
electron's spin, you'll observe it either clockwise or counterclockwise around
that axis, with value one-half hbar.

Things get interesting in an atom, where the orbiting electron has an orbital
angular momentum in addition to its spin angular momentum. And angular momenta
interact in peculiar ways. (Link below).

In a simple hydrogen you'll also have interactions between the spin of the
single electron with the spin of the proton. In other atoms, say helium, there
will be further interactions between the two electrons.

[https://ocw.mit.edu/courses/physics/8-05-quantum-physics-
ii-...](https://ocw.mit.edu/courses/physics/8-05-quantum-physics-ii-
fall-2013/lecture-notes/MIT8_05F13_Chap_10.pdf)

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andrewflnr

      There's one major source that researchers haven't
      yet explored: orbital angular momentum.
    

You mean quantum spin might come from things actually spinning? What a
shocker! Just when I had gotten used to the idea of quantum spin being
basically an unknowable abstract quantity...

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dang
Url changed from
[https://phys.org/news/2017-03-proton.html](https://phys.org/news/2017-03-proton.html),
which points to this.

