How Many Elementary Particles Are There, Really? • Hacker News Board

Re: How Many Elementary Particles Are There, Really?

#61

Post by dpark » Sat, Jun 27, 2026, 5:18 PM UTC

Noaidi wrote: post #25

GroksBarnacles wrote: post #12

Earlier quoted context omitted.

A wave is already what we call a manifestation of a field, maybe I skimmed too quickly but I don't get the author's breakthrough point.

Yes, the field is the substrate. "I insist upon the view that 'all is waves'." Letter to John Lighton Synge (9 November 1959), as quoted by Walter Moore in Schrödinger: Life and Thought (1989) ISBN 0521437679 It is not a breakthrough, it is just something we refuse to see, something that was known for a century. "All is a wave" is the unifying principle. I am no mathematician, but the math needs to start with that fu…

> I am no mathematician, but the math needs to start with that fundamental principle.

This is a weird sort of hubris. “I’m not qualified to do this job but I can certainly tell you how it needs to be done.”

> And if everything is a wave there are no discrete quantities beyond our definition of what constitutes the end, or borders, of the wave.

This is not true in multiple ways. First, it’s known that these particles exhibit quantum behavior. This is measured and confirmed over and over. Many measures are in fact quantized.

Second, existing as a wave does not mean no discrete quantities. Even in everyday materials we observe situations like standing waves that are effectively quantized.

https://en.wikipedia.org/wiki/Standing_wave

Re: How Many Elementary Particles Are There, Really?

#62

Post by ziofill » Sat, Jun 27, 2026, 5:21 PM UTC

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).

Re: How Many Elementary Particles Are There, Really?

#63

Post by tsimionescu » Sat, Jun 27, 2026, 5:29 PM UTC

GistNoesis wrote: post #59

tsimionescu wrote: post #31

Earlier quoted context omitted.

Well, why would there be fewer than N? There is no general principle that we can impose on the world, it just is, we can only discover what the laws and components of the world are (hopefully). I'm not claiming it's impossible for there to be fewer fields than we think right now. But there is no reason to believe there should be.

Elegance. It's Occam's razor. If we can do with only one field, it's probably it. It's inductive and abductive reasoning. The one field, and it has lot of mathematical characteristics which makes it unique on its own, and also it is the only one that has a chance to fit, is the e8 field popularized by Garrett Lisi. If a universe were to be designed based using the e8 Lie algebra as an elemental field, it would look a…

Occam's razor has nothing to do with this, it only applies once you have multiple competing theories - you can't use Occam's razor to decide that a theory "should" exist.

Currently, we don't have any theory that works that's any simpler than the SM. So that's the theory that Occam's razor currently tells us must be true, as it's the simplest alternative that actually works.

Re: How Many Elementary Particles Are There, Really?

#64

Post by Sniffnoy » Sat, Jun 27, 2026, 5:32 PM UTC

I feel like you ought to be go lower than 17, down to 9, by not counting the 3 generations of fermions as distinct (so you've just got up-type quark, down-type quark, electron-type particle, and neutrino). After all, if they can mix with one another, should they really be considered entirely different particles?

Re: How Many Elementary Particles Are There, Really?

#65

Post by ndsipa_pomu » Sat, Jun 27, 2026, 5:36 PM UTC

Sniffnoy wrote: post #64

I feel like you ought to be go lower than 17, down to 9, by not counting the 3 generations of fermions as distinct (so you've just got up-type quark, down-type quark, electron-type particle, and neutrino). After all, if they can mix with one another, should they really be considered entirely different particles?

There's different behaviour between the 3 generations though as a muon will decay whereas an electron won't.

Re: How Many Elementary Particles Are There, Really?

#66

Post by aeonik » Sat, Jun 27, 2026, 5:45 PM UTC

ndsipa_pomu wrote: post #65

Sniffnoy wrote: post #64

I feel like you ought to be go lower than 17, down to 9, by not counting the 3 generations of fermions as distinct (so you've just got up-type quark, down-type quark, electron-type particle, and neutrino). After all, if they can mix with one another, should they really be considered entirely different particles?

There's different behaviour between the 3 generations though as a muon will decay whereas an electron won't.

We don't know that electrons don't decay for sure.

If we live in a false vacuum, for example, that could allow them to decay.

Re: How Many Elementary Particles Are There, Really?

#67

Post by HarHarVeryFunny » Sat, Jun 27, 2026, 5:45 PM UTC

frutiger wrote: post #39

HarHarVeryFunny wrote: post #26

Earlier quoted context omitted.

But of course one can then question why are there exactly N different types of fields, with their specific types of interaction (at least in our universe)? Why should we suppose that this is the most fundamental description of reality, rather than being emergent from something else?

> But of course one can then question why are there exactly N different types of fields, with their specific types of interaction (at least in our universe)? Even that has a (still unsatisfactory) answer. Poincaré symmetry imposes constraints on the kinds of fields we can have. Gauge symmetry shows us how they may couple. There are still some arbitrary selections of the possible permutations that nature has “picked”.

Interesting, but (way out of my depth here) why do these symmetries have to exist?

It would be much more satisfying (not that nature exists to be satisfying) if we could explain our universe starting from some universal constraints on things that must be true of any non-random mechanistic universe, plus some set of (This seems about as close as we could get to explaining our universe... Basically saying that god flipped a coin marked A and B, and it come down A so here we are. Maybe god kept on flipping sets of coins and created a whole bunch of other universes too, whose physics we could also derive.... and maybe one day visit and confirm.

Re: How Many Elementary Particles Are There, Really?

#68

Post by d4ng » Sat, Jun 27, 2026, 5:48 PM UTC

sva_ wrote: post #58

d4ng wrote: post #52

Earlier quoted context omitted.

It's a reasonably sized prime number regardless of base.

> reasonably sized prime number I feel like you're alluding to something but won't say to what? Maybe something like the 'fine-tuned universe' hypothesis?

Actually I’m not alluding to anything specific. I just wondered whether the 17ness of wallpaper groups and fundamental particles was some sort of mapping from a related common object. Obviously a long shot as previously mentioned.

Re: How Many Elementary Particles Are There, Really?

#69

Post by ndsipa_pomu » Sat, Jun 27, 2026, 5:53 PM UTC

aeonik wrote: post #66

ndsipa_pomu wrote: post #65

Earlier quoted context omitted.

There's different behaviour between the 3 generations though as a muon will decay whereas an electron won't.

We don't know that electrons don't decay for sure. If we live in a false vacuum, for example, that could allow them to decay.

> We don't know that electrons don't decay for sure.

However, we don't expect electrons to decay as we don't know what they would decay into i.e. there doesn't seem to be anything plausible with a lower energy configuration.

> If we live in a false vacuum, for example, that could allow them to decay.

Possibly, but that's quite speculative and if our vacuum does decay, then there's a good chance we wouldn't be around to see the differences.

Re: How Many Elementary Particles Are There, Really?

#70

Post by behringer » Sat, Jun 27, 2026, 6:13 PM UTC

HarHarVeryFunny wrote: post #67

frutiger wrote: post #39

Earlier quoted context omitted.

> But of course one can then question why are there exactly N different types of fields, with their specific types of interaction (at least in our universe)? Even that has a (still unsatisfactory) answer. Poincaré symmetry imposes constraints on the kinds of fields we can have. Gauge symmetry shows us how they may couple. There are still some arbitrary selections of the possible permutations that nature has “picked”.

Interesting, but (way out of my depth here) why do these symmetries have to exist? It would be much more satisfying (not that nature exists to be satisfying) if we could explain our universe starting from some universal constraints on things that must be true of any non-random mechanistic universe, plus some set of ( This seems about as close as we could get to explaining our universe... Basically saying that god fli…

You might not want to visit because it's probable you would explode or have some other horrific death due to incompatibility between your fields and theirs.