Asking for a six preon theory

[arivero]

I have reviewed the old thread https://www.physicsforums.com/threa...ow-do-they-fit-into-the-standard-model.76937/
that catalogues preon theories but I am looking for a very specific variant, having only one coloured particle, for instance
$$(d^r, d^g, d^b)$$ of charge -1/3 and five uncoloured preons $$u c t, s b$$ in the fundamental of $SU(5) \supset SU(3) \times SU(2)$, so they could be with charges +2/3 and -1/3 or something so. Composition should be just a pair preon-preon or a pair preon-antipreon

Has anyone read about this sort of preons?

PS: ah, related to this, if someone knows the user https://www.physicsforums.com/members/antiphon.24684/ please send me a message, I want to mention the nomenclature turtles/elephants elsewhere.

 

[Mordred]

There is several different preon models here some are mentioned. It may help your search
What you have above doesn't ring any bells under Pati-Salam but I'm going off memory don't discount that possibility

https://ntnuopen.ntnu.no/ntnu-xmlui/bitstream/handle/11250/247318/740995_FULLTEXT01.pdf

 

[ohwilleke]

Similar but not the same:

Closer: https://arxiv.org/abs/1112.0181

(removed substandard reference)

Also similar: https://www.npl.washington.edu/AV/altvw80.html

 

[arivero]

Indeed very similar! Now I think about, the charge assignment I suggested above fails with one quark of the up type. A closer assignment is change the uncolored preons to have charges 0, 0 , 0, 1 , 1 and surely this is more easy to find in publications. As in other models of mine, pairs preon preon produce the squarks of the standard model, and pairs preon antipreon produce the leptons.

 

[Mordred]

I've been trying to find Pati-Salams original paper " Lepton number as the fourth "color" that isn't behind a pay wall.
The only copy I was able to find is on academia.
https://www.academia.edu/70190384/Lepton_Number_As_the_Fourth_Color
If your a member (free) it's download able.
It should help as the other models are variations resulting from this original paper.

Another aid is
Pati-Salam Ala SO(10) MSSM.
https://arxiv.org/abs/hep-ph/0204097

(Oops SO(10) Ala Pati-Salam must have had a bit of dyslexia hit lol.)
Last link simply is an aid on the groups used by Pati-Salam

 

[arivero]

Hmm I guess it could be said that Georgi Glashow decuplet is a composite of the 5, and the later is one coloured "preon" of charge -1/3 and two uncoloured $$(d^r, d^g, d^b), e, \nu$$
And things are funnier with flipped SU(5)

 

[Vanadium 50]

And things are funnier with flipped SU(5)

Including one of its champions, John Hagelin, who ran for US President multiple times. I think his record vote share was 0.1%.

 

[arivero]

Including one of its champions, John Hagelin, who ran for US President multiple times. I think his record vote share was 0.1%.

LOL I didn't know! But I remember the newspaper reports about the Maharishi effect in the nineties. Well, at least in physics he got to be a person with some impact, citation-wise.

what I was thinking is, consider the fundamental of Georgi Glashow as preons,
$$\bar 5 = (1, 2)_{3} + (\bar 3, 1)_{-2} = (e^+,\nu) + (d_R,d_G,d_B),$$
with Q= T_3 - Y/6 and then the composites in the 10 and 24 (instead of the gauge group)
$$10 = (1, 1)_{−6} + (\bar 3, 1)_4 + (3, 2)_{−1} \to +1, -2/3, (+2/3 , -1/3)$$
$$24 = (1, 1)_0 + (1, 3)_0 + (3, 2)_5 + (\bar 3, 2)_{−5} + (8, 1)_0 \to 0, (1,0,-1), (+4/3, +1/3), (-1/3, -4/3),0$$
$$\bar {10} \to -1, +2/3, (-2/3 , +1/3)$$
look as a complete generation plus extra stuff. I was wondering how it goes with the flipped version, where the electric charge does not add trivially. Or in a flipped-like but with straighforward charge addition, so the 10 gets 4/3 quarks.

 

[Vanadium 50]

Getting back on topic, do people still build preon (preons as actual particles) theories? Why?

(1) It doesn't seem to explain anything new.

(2) You are replacing six fermions, plus color, for what looks like eight (containing color). It doesn't appear appreciably simpler.

(3) You have a problem with extreme fine tuning. Let's say an electron is made up of X and Y preons. Let;s sat they weigh 20 TeV each - that's the order of magnitude limit from experiment. Then they are bound by exactly 39.9999995 TeV.

It seems like preons make things worse, not better.

 

[kodama]

Getting back on topic, do people still build preon (preons as actual particles) theories? Why?

(1) It doesn't seem to explain anything new.


It seems like preons make things worse, not better.

arXiv:1805.03013 (physics)

[Submitted on 30 Apr 2018]

Supersymmetric Preons and the Standard Model​

Risto Raitio

The experimental fact that standard model superpartners have not been observed compels one to consider an alternative implementation for supersymmetry. The basic supermultiplet proposed here consists of a photon and a charged spin 1/2 preon field, and their superpartners. These fields are shown to yield the standard model fermions, Higgs fields and gauge symmetries. Supersymmetry is defined for unbound preons only. Quantum group SLq(2) representations are introduced to classify topologically scalars, preons, quarks and leptons.

Comments:	10 pages, 2 tables
Subjects:	General Physics (physics.gen-ph)
Cite as:	arXiv:1805.03013 [physics.gen-ph]

The experimental fact that standard model superpartners have not been observed compels one to consider an alternative implementation for supersymmetry....Supersymmetry is defined for unbound preons only

He is proposing exact supersymmetry, and only preons are supersymetric, not standard model particles which are composites

all the benefits of unbroken supersymmetry and an explanation why no superpartners at the LHC, because SM particles are not fundamental

 

[arivero]

Yes I think the main idea now is as a subset of "composite models" where we call for compositeness of some particles, as the Higgs or the top quark. In any case, if one try to exclude the "composite higgs" papers, it is a subfield with very small frequency. Not enough authors/year even for a workshop.

https://inspirehep.net/literature?s...n-summary=true&ui-exclude-self-citations=true

The observation of fine-tuning is interesting; we have already an accidental fine-tuning in QCD vs Electroweak, where the QCD scale happens to be also the scale of electroweak masses. Could an extreme fine tuning justify the accidental one?

 

[ohwilleke]

Getting back on topic, do people still build preon (preons as actual particles) theories? Why?

It is so very tempting though.

Our very terminology points huge arrows in this direction by decomposing fundamental particles in the Standard Model into a bunch of discrete properties that are assigned numbers, which exist in some combinations but not others.

The list I've screen shotted doesn't even include QCD color charge, or whether both left and right, or only left or right parity is available, and particle v. antiparticle distinctions.

A b quark looks like a -1/3 charge preon, plus a single color charge preon, plus a spin-1/2 preon, plus a 1/3 baryon number preon, plus a bottomness preon, plus some composite hypercharge and weak hypercharge particles.

It looks like every other puzzle that science has ever presented to us without actually requiring multi-variable calculus and complex analysis to fathom.

It screams at you that there must be a simpler way! All of our other scientific and life experiences tell us that it feels like there should be some clever way to make it flow from something simpler and deeper.

If it worked for myriad molecules and crystals we encounter in everyday life, it worked for the periodic table of the elements, and it worked for the particle zoo of hadrons, then surely there must be a better way to simplify the 104 possible combinations of color charge, mass, electromagnetic charge, weak interaction charge, spin, parity, and particle-antiparticle combinations (including the graviton, and excluding continuous properties like photon frequency and kinetic energy):

* 3 quark generations x 2 quark EM charges x 3 colors each x 2 parity possibilities x particle/antiparticles for each = 72 discrete quark variants.
* 3 charged lepton generations x 2 parity possibilities x particle/antiparticles for each = 12 discrete charged lepton variants
* 3 neutrino generations x 1 parity possibility x particle/antiparticle for each = 6 discrete neutrino variants

for 90 discrete fundamental fermion variants.

The eight color combinations of gluons, the W+ and W- bosons, one Z boson, the Higgs boson, the photon and the (hypothetical graviton) for 14 discrete fundamental bosons variants.

104 fundamental particles in all.

How can 104 discrete variations of anything be fundamental, our intuition screams?

And there is a prize out there to claim: Reducing the number of experimentally determined constants in the Standard Model.

15 masses, 4 CKM parameters, 4 PMNS parameters, 3 coupling constants particular to the Standard Model, G and the cosmological constant in GR, and the speed of light (it was measured before it was defined, which is why it isn't a round number in meters) and Plank's constant for good measure.

Surely there must be a way to trim down the 30 fundamental constants (really a few less, since a few are not independent of each other due to electroweak unification)!

And, it isn't as if the 104 discrete variants of particle types and 30 fundamental constants show no patterns! There are mass hierarchies and textures and alternative parameterizations. There are correlations between the masses and the mixing angles. There are combinations of properties that are allowed, and combinations of properties that aren't. We already have formulas connecting a couple of the coupling constants to a couple of the masses. So, why shouldn't there be more formulas like that?

Even if your preon model cuts down the number of fundamental particles only minimally, if it can provide a way to calculate many more of those 30 experimentally determined physical constants from first principles, that's a huge win that can provide more precision without more experimental measurements!

And, for those who believe that dark matter particles are a thing and that dark energy has substance, or that SUSY is real, or that there might be inflatons or other motley BSM particles, it offers the reward of a path to identify what those BSM particles could be before we discover them experimentally (and in light of the fact that we may never actually be able to observe them experimentally because the experiments are too hard, at least to complete in our lifetime).

The same incentives, with more sophistication, drive GUT models and string theory, which are basically preon theories for grown ups.

We already know things sufficiently fundamental to know what we need to know to apply the Standard Model and GR to all sorts of absurdly hard problems that are at the very limits of our technological abilities with absurd precision, but it is still so unsatisfying and clunky!

So that's "why" people keep working on preon models.

Is it time well spent?

Probably not.

As Vanadium 50 notes, using the same methods that we used to discovery protons, neutrons and quarks, it takes huge contortions for preons to be real without some sort of Higgs field/gravitational field shielding or something similar to hide hugely massive particles as components of much less massive particles.

But there is also a deep sense that this clunky complexity can't be all that there is to know. The data we have is so organized and structured and fits together so well. It looks like a preon problem! And, preon theories are very inexpensive to research using data collected for other purposes. And, highly respected HEP scientists have tried in the past and published their whimsies, before giving up, so it is respectable, up to a point (even if the numerology monster lurks behind every corner and the experimental constraints get tighter every time we review them anew).

As a result, people keep trying that approach, the same way that they try to climb Mount Everest despite the long line of dead bodies that they have to pass by on the way and knowing that their particular quest isn't likely to change the world in any meaningful way. The data is sitting there, staring us in the face, taunting us!

Preon theory, GUT theory, TOE theory, string theory, and lots of other BSM theorizing is ultimately driven by an unwillingness to accept that what we know now is as good as it gets. Preon theories are just the entry level version of the larger quest.

 

[Vanadium 50]

I'm not going to discuss a "revolutionary" paper with 8 cites, 5 of which are self-cites.

Composite Higgs is a special case, as it does explain some things: why the Higgs Yukawa is so close to 1, and the lets call it "discomfort" with fundamenta scalars. And we know from condensed matter that collective modes can produced Higgs-like behavior.

I'll let you invoke the "gotta be something" argument for the electron mass. But there are lots of other particles out there that need a similar degree of fine tuning.

Note that this is an argument against "preons as particles". If you instead use the analogy "preons analogous to magnetic poles", things look better. They still don't help, but you don't have multiple instances of fine tuning.

 

[arivero]

(2) You are replacing six fermions, plus color, for what looks like eight (containing color). It doesn't appear appreciably simpler.

What I was thinking is that partial approaches as the composite Higgs or composite top are into something; so I did time ago my "composite scalar superpartners" -fully zero citations work, not unexpectedly :-) - and so I was thinking here of some preon theory that partly looks as the original theory.

If we say for instance that the 10 of Georgi Glashow SU(5) is a composite extracted out of 5x5 = 15+10 tensor product, we have used three particles (d,e,nu) to explain four. Or, including colour, we have used five particles "d,e,nu" to explain eight "u,d,e,nu". The one I was thinking in the initial post would aim to explain three generations from eight states, so if it exists -it seems not- it also would be an advance in simplicity.

 

[kodama]

does Bilson-Thompson, Sundance (2005). "A topological model of composite preons". arXiv:hep-ph/0503213 count as preons

more recently

[Submitted on 31 May 2021 (v1), last revised 11 Sep 2021 (this version, v4)]
Braided matter interactions in quantum gravity via 1-handle attachment
Niels Gresnigt, Antonino Marciano, Emanuele Zappala

In a topological description of elementary matter proposed by Bilson-Thompson, the leptons and quarks of a single generation, together with the electroweak gauge bosons, are represented as elements of the framed braid group of three ribbons. By identifying these braids with emergent topological excitations of ribbon networks, it has been possible to encode this braid model into the framework of quantum geometry provided by loop quantum gravity. In the case of trivalent networks, it has not been possible to generate particle interactions, because the braids correspond to noiseless subsystems, meaning they commute with the evolution algebra generated by the local Pachner moves. In the case of tetravalent networks, interactions are only possible when the model's original simplicity, in which interactions take place via the composition of braids, is sacrificed. We demonstrate that it possible to preserve both the original classification of fermions, as well as their interaction via the braid product, if we embed the braid in a trivalent scheme, and supplement the local Pachner moves, with a non-local and graph changing 1-handle attachment. Moreover, we use Kauffman-Lins recoupling theory to obtain invariants of braided networks that distinguish topological configurations associated to particles in the Bilson-Thompson model.

Comments: 15 pages, 7 figures. v4: Improvements on exposition. Final version to appear in Phys. Rev. D
Subjects: General Relativity and Quantum Cosmology (gr-qc)

 

[arivero]

Nah, definitely braid groups are outside of the frame.

 

[Vanadium 50]

Do you actually think the universe works this way? I mean, as an experimenter, I look for things I don't believe in and think are unlikely all the time, but that's my job.

As far as explaining flavor, remember, this is what did Technicolor in.

 

[kodama]

Do you actually think the universe works this way? I mean, as an experimenter, I look for things I don't believe in and think are unlikely all the time, but that's my job.

As far as explaining flavor, remember, this is what did Technicolor in.

do you believe in string theory and susy?

 

[Vanadium 50]

do you believe in string theory and susy?

Why does it matter? I measure things.

 

[kodama]

Why does it matter? I measure things.

isn't string theory similar to preons?

 

[Vanadium 50]

Why does it matter? I measure things.

isn't string theory similar to preons?

Huh?

 

[berkeman]

Rhut-rho...

 

[arivero]

In any case, the point with preons is that it depens of how many particles you need. For one generation of the SM, it seems not very useful. For 3 generations, they could be of some help. For 3 generations of susy, it definitely helps if there is some way to reclassify all the degrees of freedom.

 

[kodama]

In any case, the point with preons is that it depens of how many particles you need. For one generation of the SM, it seems not very useful. For 3 generations, they could be of some help. For 3 generations of susy, it definitely helps if there is some way to reclassify all the degrees of freedom.

do preons have to be particles?

 

[renormalize]

do preons have to be particles?

Historically, fundamental physics has progressed through the stages:
$$\text{particles of macroscopic matter}\rightarrow\text{molecules}\rightarrow\text{atoms}\rightarrow\text{electrons and nucleons}\rightarrow\text{leptons and quarks}$$It's been particles all the way down. Why should hypothetical preons be different?

 

[kodama]

Historically, fundamental physics has progressed through the stages:
$$\text{particles of macroscopic matter}\rightarrow\text{molecules}\rightarrow\text{atoms}\rightarrow\text{electrons and nucleons}\rightarrow\text{leptons and quarks}$$It's been particles all the way down. Why should hypothetical preons be different?

Bilson-Thompson preons could be LQG spin networks

 

[arivero]

I think that by "-on" we definitely mean particles. It can be argued if they are "labels", as it was discussed I believe in the first age of the eightfold way.

 

[arivero]

Getting back on topic, do people still build preon (preons as actual particles) theories? Why?

(3) You have a problem with extreme fine tuning. Let's say an electron is made up of X and Y preons. Let;s sat they weigh 20 TeV each - that's the order of magnitude limit from experiment. Then they are bound by exactly 39.9999995 TeV.

Another point I was thinking: 39.9999999 TeV or exactly 40 Tev? Because above electroweak scale, all particles are massless.