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Comment by DecoPerson | Hacker News Reader

This new map was super informative to me, a layman. I hadn’t read about chirality in particle physics, and didn’t realize it was a key difference between the fundamental particles.

I really appreciate this new map — it makes the information much more approachable.

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It's also interesting that so far we seem to have certain interactions happening on one side of the model but no analogous phenomena on the other side. That immediately makes me wonder whether there should be something in each "gap", even if we haven't yet encountered it experimentally or hypothesized its existence from the theory, or if not, whether that asymmetry might be a hint that we still haven't got our model quite right.

> Correction: October 23, 2020 The original version of this article stated that left-handed leptons in different generations occasionally interact via the weak force. In fact, though such interactions have been hypothesized, they have not been observed.

Those gaps immediately catch your eye, don't they? Seeing them and thinking "what if there's something we are missing" is exactly what many particle physicists also think. This is why the existence of particles and interactions addressing those gaps have been hypothesized to death and then some. Trying to compare some of these hypothesis with the experiment is a major part of fundamental physics today, second only to measuring the things we know exist more precisely. In many cases the comparison has been performed, and when it has been the conclusion was "if there is something there, then the parameters must be such that our instruments did not measure the effects yet". This is why particle physicists are pushing for better instruments.

what if the absence of the interactions on the right hand side actually contributes to the stability of the universe?

Maybe it does. Maybe it's the key to everything existing as we know it! But it sure would be interesting to understand why, if that is the case. The most reliable models we have for how the natural world works tend to be very simple in their mathematics, as long as we're using the right mathematics to model them.

Right-handed neutrinos are a prime candidate for dark matter. The possibilities and exact contributions depend on whether neutrinos are massive or not.

The article glosses over the fact that massive neutrinos are not part of the mainstream Standard Model, but depend on semi-detached and unconfirmed extensions, such as Majorana spinors and (P)MNS mixing matrix:

https://en.wikipedia.org/wiki/Pontecorvo%E2%80%93Maki%E2%80%...

I agree. My chances of ever understanding the Standard Model are slim at best, but this representation helped to click more parts of it into place for me than any other diagram.

Which leaves, I think: dark matter and dark energy (if they exist), and gravity?

> and gravity?

https://xkcd.com/1489/

Note the mouse-over text :)

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