Minimum Fermion Content to Account for Standard Model: 12 of 8

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  • #31
arivero said:
about the extra Q=4/3.

Let me review the calculation. Let p,q to be the number of up and down quarks, respectively, and n=4 the number of components of a Dirac spinor.

How many different QCD strings can we built?

charge +4/3: p (p+1) /2
charge +1 : p * q
charge +2/3: q (q+1) /2
charge +1/3: p * q
charge 0: p^2 + q^2
and the same for -1/3, -2/3, -1, -4/3

So how many families of Dirac spinors do we produce if we can apply susy?
exotic \pm 4/3 p*(p+1) /4
electron p*q /2
up q*(q+1)/4
down p*q/2
neutrino: (p^2 + q^2) / 4. I suspect an extra U(1) must be truncated, so perhaps (p^2+q^2-1)/4

Note the down and electron sector work in the same way.

Now, to look for sBootstrap, we just check the table in a worksheet

Code:
p	q	neutr.	e,d	u	exotic
0	1	0	0	0,5	0
1	0	0	0	0	0,5
1	1	0,25	0,5	0,5	0,5
0	2	0,75	0	1,5	0
1	2	1	1	1,5	0,5
2	2	1,75	2	1,5	1,5
2	1	1	1	0,5	1,5
2	0	0,75	0	0	1,5
0	3	2	0	3	0
1	3	2,25	1,5	3	0,5
[B]2	3	3	3	3	1,5[/B]
3	3	4,25	4,5	3	3
3	2	3	3	1,5	3
3	1	2,25	1,5	0,5	3
3	0	2	0	0	3
4	0	3,75	0	0	5
4	1	4	2	0,5	5
4	2	4,75	4	1,5	5
4	3	6	6	3	5
4	4	7,75	8	5	5
3	4	6	6	5	3
2	4	4,75	4	5	1,5
1	4	4	2	5	0,5
0	4	3,75	0	5	0
5	0	6	0	0	7,5
5	1	6,25	2,5	0,5	7,5
5	2	7	5	1,5	7,5
5	3	8,25	7,5	3	7,5
5	4	10	10	5	7,5
5	5	12,25	12,5	7,5	7,5
4	5	10	10	7,5	5
3	5	8,25	7,5	7,5	3
2	5	7	5	7,5	1,5
1	5	6,25	2,5	7,5	0,5
0	5	6	0	7,5	0
...
of course we need to produce at least the initial particles. So the list reduces:

Code:
p	q	neutr.	e,d	u	exotic
[B]2	3	3	3	3	1,5[/B]
3	3	4,25	4,5	3	3
4	4	7,75	8	5	5
3	4	6	6	5	3
2	4	4,75	4	5	1,5
5	4	10	10	5	7,5
5	5	12,25	12,5	7,5	7,5
4	5	10	10	7,5	5
3	5	8,25	7,5	7,5	3
2	5	7	5	7,5	1,5
...
and the configuration of the standard model appears as the simplest and the most symmetric one. So my hope of the existence of additional conditions truncating the exotic states and marking it as unique.

Okay. This all looks great here, and the p=2, q=3 model does appear to reproduce the SM, but how do you actually create a physical limit that will stop it at p=2 and q=3? To show an example, I am going to try to build the fermions from your model here, with the extra constraint that you cannot have more than one heavy quark type involved in a combination; I am also going to use terminology where the highest generation involved is the "p" or the "q". So we can build anything from anything that fits the pattern...

(p=1, q=0) : (uuS) = exotic, (u-uS) = nu_e ?
(p=1, q=1) : (duS) = -d, (d-uS) = e-, (d-dS) = nu_e ?, (-d-dS) = u
(p=1, q=2) : (sdS) = -c, (s-dS) = nu_mu, (s-uS) = mu-, (-s-uS) = s
(p=2, q=1) : (cdS) = -b, (c-dS) = tau+, (c-uS) = nu_tau, (-c-uS) = exotic
(p=1, q=3) : (bdS) = -t, (b-dS) = nu_tau', (b-uS) = tau'-, (-b-uS) = b'
(p=1, q=4) : (b'uS) = -b'', (b'-uS) = tau''-, (b'-dS) = nu_tau'', (-b'-dS) = t'
(p=3, q=1) : (tuS) = exotic, (t-uS) = nu_tau''', (t-dS) = tau'''+, (-t-dS) = b'''
(p=4, q=1) : (t'uS) = exotic, (t'-uS) = nu_tau'''', (t'-dS) = tau''''+, (-t'-dS) = b''''
(p=1, q=5) : (b''uS) = -b''''', (b''-uS) = tau'''''-, (b''-dS) = nu_tau''''', (-b''-dS) = t''

Need I continue further? At first glance, from what mass order seems to emerge so far, it seems it might follow a well known pattern;

p, q
1, 0
1, 1
1, 2
2, 1
1, 3
1, 4
3, 1
4, 1
1, 5
1, 6
1, 7
5, 1
6, 1
7, 1
1, 8
1, 9
1, 10
1, 11
8, 1
9, 1
10, 1
11, 1
12, 1
...

where the "p" types are predecessors of the next type-step in the familiar groupings 1,1,2,3,5,8,13,... and so on (Fibinacci Sequence (sp?)) with "q" types as predecessors in groupings of (Fibinacci + 1, i.e. 2,2,3,4,6,9,14,...) between every "p" type grouping. Thus, if allowed to go into infinite generations, the "p" type quarks will at first become much more massive than "q" type quarks of the same generation, and then suddenly drop below the "q" type quark masses of similar generation as the generations go higher. However, the pattern above suggests that quarks would be arranged, by ascending mass, in this kind of ordering;

u, d, s, c, b, b', t, t', b'', b''', b'''', t'', b''''', b'''''', t''', b''''''', t'''', b(8), b(9), t''''', b(10), t'''''', b(11), t''''''', b(12), b(13), t(8), b(14), b(15), t(9), b(16), t(10), b(17), t(11), b(18), b(19), t(12), b(20), b(21), b...

So, the whole Fibinacci idea kind of breaks down, and then I have very little hope of finding another pattern worth looking for. But to avoid this whole connundrum, it would be very wise to find a way to physically limit the acceptable fermions primarily to the second, third and fourth lines, which could give the three generations. If you impose the limits, somehow, of q > 0 and p + q < 4. This would produce just rows two through four minus the nu_tau entry, and adding the t-quark and nu_tau' from row five; it also eliminates both of the plausible exotics by default, and gives some structure;

0,1 1,1 2,1
0,2 1,2
0,3

The remaining nu_tau' could fill the vacancy left by the elimination of nu_tau in the row above, and would then, essentially, be nu_tau. The new limited list becomes;

(p=0, q=1) : (d-dS) = nu_e, (-d-dS) = u
(p=1, q=1) : (udS) = -d, (u-dS) = e+
(p=0, q=2) : (u-sS) = mu+, (-u-sS) = s
(p=1, q=2) : (dsS) = -c, (d-sS) = nu_mu
(p=2, q=1) : (dcS) = -b, (d-cS) = tau-
(p=0, q=3) : (dbS) = -t, (d-bS) = nu_tau

This gives us all of the SM fermions, with superstrings incorporated. The arrangement requires "q" to not be equal to zero at any time, so that would actually seem to suggest that the down quark is the logical choice for a fundamental particle when compared with the up quark. Hence, you have now reduced everything to composites of d and S, with d being the only justifiable fundamental quark. Both d and S could be thought of as fermions, though, but S has no electric or color charges...

I didn't think I would get such an interesting answer when I started writing this post, it is a little surprising to me, to be honest... I thought the idea would show a serious flaw of some sort if I worked it out. But it still leaves you with the question of how to physically justify those quirky constraints q > 0 and p + q < 4...

You know, I just thought of something, and you're going to hate me for this...

Doesn't this almost equate to my P/N modified rishon model? I mean, with S being completely neutral, it is close to being like the N rishon, and the down quark is complimentary to S the same way as the P rishon is to the N rishon... they could be treated as two slightly-different approaches to obtaining the physical electric charges for composite fermions. Where P and N have certain different features in hypercharge and isospin, it seems that d and S are the fundamental quark and electron-neutrino (from (d-dS) --> S), having hypercharge and isospin units that are normal to the current SM fermions! In this context, (uS) is nothing but a CPT operator for d, turning d to -d, with the idea that the electron-neutrino is a purely supersymmetric particle! Yet, it seems like our two different models are nothing more than two different languages for expressing hypercharge and isospin, with some differences in motivation, to get the same properties that we know the SM fermions to already have. I will give you this; my modified rishon model has rishons with unusual units of isospin, which leave them with sqrt(5)/sqrt(13) of the normal sqrt(I_z^2 + Y^2/2) vector as compared to the natural quarks and leptons in your sBootstrap. But my modified rishon model has 1) a physical motivation for limiting to three generations, as well as 2) an explanation of the structure of vector bosons, while this attempt I made to clarify sBootstrap to myself seems to have none of these features...
 
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  • #32
I am beginning to be intrigued by the idea this model suggests. I want to think about this "sBootstrap" more because I just answered one of my own questions about it by writing it all out on paper, but it is late now, I'm still at my office at the library and its almost midnight here, and my head hurts. I better head home now. See you all here again tomorrow... same place, same time, same bad channel...
 
  • #33
mormonator_rm said:
If you impose the limits, somehow, of q > 0 and p + q < 4. This would produce just rows two through four minus the nu_tau entry, and adding the t-quark and nu_tau' from row five; it also eliminates both of the plausible exotics by default, and gives some structure;

0,1 1,1 2,1
0,2 1,2
0,3

The remaining nu_tau' could fill the vacancy left by the elimination of nu_tau in the row above, and would then, essentially, be nu_tau. The new limited list becomes;

(p=0, q=1) : (d-dS) = nu_e, (-d-dS) = u
(p=1, q=1) : (udS) = -d, (u-dS) = e+
(p=0, q=2) : (u-sS) = mu+, (-u-sS) = s
(p=1, q=2) : (dsS) = -c, (d-sS) = nu_mu
(p=2, q=1) : (dcS) = -b, (d-cS) = tau-
(p=0, q=3) : (dbS) = -t, (d-bS) = nu_tau

---ut it still leaves you with the question of how to physically justify those quirky constraints q > 0 and p + q < 4...

-------------...

You know, I just thought of something, and you're going to hate me for this...

Doesn't this almost equate to my P/N modified rishon model?
Wel, it can be seen as a preon model, so it is not surprising it looks similar.

Now, I am still a bit loss with your new notation for p and q. Also, it seems that it is using the S to get the two spins +1/2 and -1/2 of the fermion. On the other hand, the superBootstrap as I see it relies in susy to produce these two spins, and then it needs not one but two scalar strings for each fermion to be produced. For instance dSs and dSb to produce the -u, dSd and sSs to produce the -c, and sSb and bSb to produce the -t. It is this extra limitation which forces for an minimum of three generations.
 
  • #34
arivero said:
Wel, it can be seen as a preon model, so it is not surprising it looks similar.

Now, I am still a bit loss with your new notation for p and q. Also, it seems that it is using the S to get the two spins +1/2 and -1/2 of the fermion. On the other hand, the superBootstrap as I see it relies in susy to produce these two spins, and then it needs not one but two scalar strings for each fermion to be produced. For instance dSs and dSb to produce the -u, dSd and sSs to produce the -c, and sSb and bSb to produce the -t. It is this extra limitation which forces for an minimum of three generations.

Ehh... okay, I wasn't thinking really along the same lines at all. So you have to be able to amalgamate two different configurations into one known fermion, such as dSs and dSd for -u, or dSb and sSs for -c (I switched the dSd and dSb from your post because that made more sense to me regarding the generations you have assigned). Well, it just doesn't seem very intuitive to me yet, I'll have to read more in-depth. I don't know enough to go much further than this...
 
  • #35
mormonator_rm said:
Well, it just doesn't seem very intuitive to me yet, I'll have to read more in-depth. I don't know enough to go much further than this...
The intuition is that the combination of two quarks into a QCD string is a boson, and the lowest energy state is an scalar (actually, pseudoscalar. But spin 0 anyway). When you use supersymmetry to uplift bosons to fermions, you need to match degrees of freedom. In four dimensions, it means that for each lepton or quark you need two spin 0 particles having the same charge.

I am a bit unsure about how it works in dimension greater than 4, say 10 or 26. For instance in dimension 10... do they match one fermion against eight spin 0 particles? The source of my troubles with higher dimensions is that you seem to need extra symmetries beyond CPT if you want to put some order in the components of a solution of Dirac equation.
 
  • #36
arivero said:
The intuition is that the combination of two quarks into a QCD string is a boson, and the lowest energy state is an scalar (actually, pseudoscalar. But spin 0 anyway). When you use supersymmetry to uplift bosons to fermions, you need to match degrees of freedom. In four dimensions, it means that for each lepton or quark you need two spin 0 particles having the same charge.

I am a bit unsure about how it works in dimension greater than 4, say 10 or 26. For instance in dimension 10... do they match one fermion against eight spin 0 particles? The source of my troubles with higher dimensions is that you seem to need extra symmetries beyond CPT if you want to put some order in the components of a solution of Dirac equation.

Okay. I get it now. I'm sorry, I've been a little out of it lately.

Well, 10 or 26 dimensions should, indeed, be problematic. I would imagine. So, now I see what your getting at, and I see the problem too. Good luck, I can't help you a whole lot because I'm not that keen on String Theory. In all honesty, I tend to try to avoid String Theory because of the background dependence, and because I haven't bothered to study the latest on it in a few years, also because of the background dependence. Basically, I don't like background dependence...
 
  • #37
mormonator_rm said:
In all honesty, I tend to try to avoid String Theory because of the background dependence, and because I haven't bothered to study the latest on it in a few years, also because of the background dependence. Basically, I don't like background dependence...

Yep I have also tryed for years to avoid string theory... and now this thing has imposed itself on my shoulders :frown:
 
  • #38
http://arxiv.org/abs/0804.0637v1
A Complete Classification of Ternary Self-Dual Codes of Length 24
Authors: Masaaki Harada, Akihiro Munemasa
(Submitted on 4 Apr 2008)
----------
http://arxiv.org/abs/0805.2205
Mass formula for self-orthogonal codes over Z_{p^2}
Authors: Rowena A. L. Betty, Akihiro Munemasa
(Submitted on 15 May 2008)
A quaternary code is said to be even if the Euclidean weight of every codeword
is divisible by 8. Every quaternary even code is self-orthogonal.
 
  • #39
What is the relevance of the above papers to this thread? I don't see any.
 
  • #40
Gokul43201 said:
What is the relevance of the above papers to this thread? I don't see any.

I see a far far far one; but perhaps jal would like to explain. Of course, from time to time it is suspected that the 24 in string theory (25-1) and the 24 in lattices have a common origin.
 
  • #41
I doubt very much that my comment could help you.
Rather, you comment would help me.

The title, “Who has 12 of 8?”, seems to solicit an answer that would be based on some of the quantum gravity approaches, which of course is based on how the universe made symmetry and made phase changes. Those two papers seem to cover just about all of the possibilities of making symmetries that could be made.
It appears that the initial symmetry of the universe could have been the Leech Lattice.
The symmetries of confinement have been reduced to within “a hard shell” or “dust bag” and it does not require The Leech Lattice as an explanation.
jal
 
  • #42
Leech Lattice is the Holy Graal of Conway's team. There is some gauss thing, e^{\gamma/8}, for unimodular selfdual whatevers. And of course there is the famous diofantine
\sum_{l=1}^n l^2=m^2.
But one needs a very high level of sphere packing gimnastics to understand the connections; I am afraid I am not trained on it. Someone?
 
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  • #43
12 of 8 = 6 of 16

Perhaps it could be more interesting to consider 6 groups of 16 particles:

-The groups of 6 appear in some perspectives of Lisi gadget

-At all, the fermion cube can be considered as having 16 degrees of freedom, if it includes the spin of each spinor (but not the antiparticle, then it should be 32).

-N=4 SUSY has a 16-plet. And...

-SO(32) heterotic string theory, when compactified down to 4 dimensions via a 6-torus, groups 6 of these 16-plets, and thus 96 scalar fields. Or perhaps the 16 is coming from a U(1)^16 related to the Cartan subalgebra of SO(32). Historically, this is the root of the first conjectured self-duality of string theory, back by Sen in hep-th/9402002.
 
  • #44
12 of 8 = 48*2

arivero said:
-SO(32) heterotic string theory, when compactified down to 4 dimensions via a 6-torus, groups 6 of these 16-plets, and thus 96 scalar fields. Or perhaps the 16 is coming from a U(1)^16 related to the Cartan subalgebra of SO(32). Historically, this is the root of the first conjectured self-duality of string theory, back by Sen in hep-th/9402002.

Other cases:

http://arxiv.org/pdf/hep-th/9604164v2 gets groups of 96 scalars in compactification of M theory to 2 dim, via K3xK3xS1.

hep-th/9508058 "the heterotic string on a Narain torus at a generic point of moduli space is obtained by compactifying the ten-dimensional N = 1 Maxwell/Einstein supergravity theory on a six-torus" and then one gets 96 scalar field there, same as Sen.

hep-th/0411118 gets 48 out of SU(D+1), D=6, and/or " and 48 spinorial 16 of SO(10),
sixteen from each sector", or hep-th/0401114 "NAHE set models have N = 1 spacetime supersymmetry and 48 chiral generarions"

http://arxiv.org/pdf/hep-th/0409132 http://arxiv.org/pdf/hep-th/0501041 hep-ph/9604302 etc (NAHE sets) "projects the above N = 2 spectrum to an N = 1 gravity multiplet, the dilaton chiral multiplet, and 6 untwisted + 48 twisted geometrical chiral multiplets."

Froggart and Nielsen reminder us that "Similarly, including three right-handed neutrinos, the biggest anomaly free subgroup of U(48) is SO(10)". Chou and Wu have tried to produce families from a discrete \Delta 48 family group upon SO(10).

hep-th/9603081v2 describe D-particles with "48 fermionic ones"

d=5, N =8 supergravity is described in a number of papers and it has 48 "symplectic?" Weyl fermions. Eg hep-th/0205235v1 hep-th/9812092. I am kind of amused because I think that Kiritsis book list this content, or a very similar one, for d=4 compactifications.
 
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  • #45


arivero said:
d=5, N =8 supergravity is described in a number of papers and it has 48 "symplectic?" Weyl fermions. Eg hep-th/0205235v1 hep-th/9812092. I am kind of amused because I think that Kiritsis book list this content, or a very similar one, for d=4 compactifications.

Let me confirm that Kiritsis refers to d=4. At the end of section 9.1, page 223, he says that
"describe the toroidal compactification of type II string theory to four dimensions... We compactify in a six torus... The two Majorana-Wey gravitini and fermions give rise to eight D=4 Majorana gravitiny and 48 Spin 1/2 Majorana fermions"
.

I really do not catch it. Does string theory predict the fermion content of the standard model? Then, what are we discussing about?

About NAHE sets, the original preprints of Antoniadis et al circa 1989 are available in KEK. It is sort of intriguing because no connection is done initially to the general statement that relates the number of generations to the euler characteristic of the compactified manifold. It is only later that Faraggi (and see hep-th/0403272) connects them to Z2xZ2 orbifolds and that some papers in the arxiv (eg http://arxiv.org/abs/hep-th/0403058 ) mention the Euler Characteristic of NAHE based models. It is amusing that the NAHE set starts with 48 generations, and then the number goes down to 3 via the orbifolding and Wilson lines. It is unclear to me if the NAHE conditions have already been reformulated as Calabi-Yau, or proved different.

In this context (Faraggi research), Lubos likes to mention hep-ph/9405357 and its prediction of top mass neglecting some near predictions of Ibañez and Alvarez-Gaume teams. In fact, the attempt of prediction via NAHE is already in the original papers.
 
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  • #46
Hmm perhaps the point is that the 48 fermions are Majorana while the SM ones are Weyl. Or perhaps it is that string theoretists are lazy about model building, and they conceded NAHE as being the definitive model, not researching more phenomenology for 30 years.
 
  • #47
A different view on this: to consider 3x(4x8)=4x24 insread of 12x8,

here "3" is the generation number. So there are two arrangements for the 8-plets:

I - labeled via SU(3)xU(1)
II - labeled via CPT.

In the case I, the uncoloured 8-plet contains the electron and the neutrino, and the coloured ones have a pair of quarks u,d

In the case II, the whole "fermion cube" is fit into the 8-plet, and the four 8-plets are labeled via the operations of parity and charge conjugation.

I wonder if there is some duality between I and II.

of course, when we have 3 generations there are an expansion to four 24-plets.

It is funny, but one is left thinking that this string people were in the right path twenty years ago.
 

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