Spin for elementary particles and composite particles

But does it make sense to talk about the "spin" of all types of Particle? The target snippet tells us spin is 'carried by elementary particles' and 'carried by ... composite particles (hadrons)'. That last bit seems to imply that not all composite particles have spin. And we also don't know yet whether there are types of particles other than composite and elementary (the physicists among you might already have thought of pseudo-particles). So to be safe, the multiplicity of spin:Spin in Particle is set to [0..1], but where it is known to definitely apply it is redefined to have multiplicity [1], such as in ElementaryParticle and Hadron.

Note that if a particle has spin with value 0 it still "has" a defined spin!

The snippet also does not actually say that an Atom can have spin, only that an AtomicNucleus can. Further down the same Wikipedia page it says, however:

Wikipedia: 'a helium atom in the ground state has spin 0 and behaves like a boson, even though the quarks and electrons which make it up are all fermions.'

Let's leave that matter for now, our main focus at this stage is on elementary particles (and primarily first leptons).

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Leptons and interactions

Notes

[POLICY, STYLE]{STRICT} Webel Parsing Analysis «pa» diagrams are NOT intended as final presentation diagrams! They serve merely to traceably elicit model elements, which may then be shown in other (typically much tidier) presentation diagrams elsewhere.

[DISPLAY, STYLE, TIP]{SUGGESTED} Webel Parsing Analysis: If the dashed-line "anchors" from your «snippet» ElementGroup symbols to elicited elements make a «pa» Parsing Analysis Diagram (PAD) too hard to read, try making them light grey using symbol properties.

Snippets (quotes/extracts)

In quantum mechanics and particle physics, spin is an intrinsic form of angular momentum carried by elementary particles, composite particles (hadrons), and atomic nuclei.

a helium atom in the ground state has spin 0 and behaves like a boson, even though the quarks and electrons which make it up are all fermions.