[ziofill]

Physicist here. I don’t buy some of these distinctions, like the chirality. Chirality is an observable, it’s like saying there are two photons because they can come in two polarizations, but polarization is not an inherent property: it depends on how we measure it. So I could describe any photon in the left/right chiral basis just as well as in the vertical/horizontal basis or any two antipodal points in the Poincaré sphere, so which is the “right one”? Neither. Spin on the other hand (which is where polarization comes from) is well-defined for any photon and it’s always 1 (the astute reader will wonder why the projection of spin 1 does not take 3 eigenvalues 1,0,-1 and it’s because photons are massless so the 0 projection never occurs because there is no rest frame for massless particles).

[gus_massa]

Chirality is a real property of (most) elementary particles. For example the electron with left chirality has a weak hypercharge of -1, but the electron with right chirality has a weak hypercharge of 0. https://en.wikipedia.org/wiki/Weak_hypercharge#Definition In some sense, they are very different particles. Also, only the left version interact with the weak interaction.

[ziofill]

Ah, then I was thinking about helicity

[gus_massa]

I expected the article to explain "helicity" and then say "and chirality is almost the same (for fast particles)", that is good enough for not specialist. There are a few graphics here and there that show helicity, but that paragraph in the text is totally unintelligible and the only conclusion is that there is something with right and left.

[randrus]

When you say “inherent property” I think “immutable” as in “cannot be changed from one chirality/spin to another”.

Is that a useful line to draw?

Not a physicist. Never played one on TV.

[antonvs]

> it’s like saying there are two photons because they can come in two polarizations

The article claimed exactly that! It said, "Not everyone counts these different chiral and polarization states as distinct particle types. Yet it’s logical to do so, because they affect how particles behave and interact."

At one point the author reaches a particle count of 118. This corresponds to the degrees of freedom of the on-shell physical states (polarizations, spin orientations, colors, and antimatter) of all particles in the Standard Model. As you say, it's misleading to call this a count of different particles.

[nok22kon]

chirality is how particles get mass - the Higgs field gives fermions mass by coupling their left and right-chiral parts, causing chirality mixing