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Preons! (subquarks, etc )

  1. May 26, 2005 #1


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    I do not like composite models of quarks and leptons; they seem to me just as decomposition of phonemes: it can be done, but it is not linguistic. Still, I could be wrong. Another PF inhabiatant, Carl Brannen, likes them enough to have developed his own model. And I'd guess he is not the only one around here.

    So I would like to use this thread first to review the work already done and published on "preon" models. Some papers are old, thus sometimes it helps to search for them in spires instead of ArXiV because, beside extensive citation search, Spires keeps pointers to the KEK, Fnal and CERN preprint services. You can go to Spires from any ArXiV:hep- preprint by clicking the SLAC-SPIRES HEP tag.

    The main spires trick is "find a Einstein and date 1905"

    A first clue, because it is recent, is Sverker Fredriksson Preon Prophecies by the Standard Model, hep-ph/0309213. It points us to papers from Harari, Shupe, and Fritzsch.

    The one from Harari is in KEK scans, at http://ccdb3fs.kek.jp/cgi-bin/img_index?7905333 [Broken] I believe to remember that Harari work was about three non commuting preons with nice jewish names.
    Last edited by a moderator: May 2, 2017
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  3. May 26, 2005 #2


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    I'll just take a moment to summarize Fredriksson and Harari's models, since both are intriguing and delightful in their own ways (I'll deviate from standard notation and show antiparticles with lower case to save a lot of Texing):

    Harari (April 1979):
    Two rishon (which means "primary" in Hebrew). They are T (Third for charge 1/3e or Tohu from "unformed" in Hebrew in Genesis) and V (Vanishes for charge 0 or va-Vohu which means "void" in Hebrew in Genesis). All leptons and all flavors of quarks are three rishon combinations. Three preon groups have spin 1/2.

    VVV=electron neutrino
    TTV, TVT and VTT=three colors of u quarks.
    TVV, VTV and VVT=three colors of d antiquarks.

    Each rishon has antiparticles. Hence:

    vvv=anti-electron neutrino
    ttv, tvt, vtt=three colors of anti-u quarks
    vvt, vtv, tvv=three colors of d quarks.

    Baryon number (B) and lepton (L) number are not conserved, but B-L is conserved.

    A Baryon number violating process would be U+U-->d+positron which in rishons is:

    Matter and anti-matter are equally abundant in nature.

    The W+=TTTVVV
    The W-=tttvvv

    Higher generation leptons and quarks are presumed to be excited states of first generation leptons and quarks. Mass is not explained.

    Fredriksson (September 2003):

    Three kinds of preons. I'll depart from his Greek notation and render them as ABC for the preons and abc for the anti-preons. A and B have charge +1/3 C has charge -2/3. Preons have spin 1/2. Unlike preons have spin zero.

    Leptons and quarks are three preon combinations. They are further broken into a lone preon and a dipreon in each case:

    Electron neutrino A(BC)
    Electron B(BC)
    Muon A(AC)
    Mu-Neutron B(AC)
    Tau Neutrino A(AB)
    Tau B(AB)

    Proposed First Kappa Neutrino C(BC)
    Proposed Second Kappa Neutrino C(AB)
    Proposed Kappa Electron C(AC)


    Proposed h=C(bc)
    Proposed g=C(bc)
    Proposed X=B(ac) (charge -4/3, possibly unphysical)

    No Higgs particles. Bb dipreons can annihilate and produce Aa dipreons.

    Weak Carrier Bosons:

    Z and proposed Z'=Aa
    Proposed Z' and Z=Bb
    Proposed Z" and proposed Z'=Cc
    Proposed Z*=Ac
    Proposed z*=Ca
    Proposed W+'=Cb
    Proposed W-'=Bc

    Mass is not fully explained.
    Last edited: May 26, 2005
  4. May 26, 2005 #3


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    Another preon paper: http://es.arxiv.org/abs/physics/0207120

    Fermions as topological objects
    Authors: V. N. Yershov
    Comments: Latex2e, 20 pages, 12 figures, 3 tables, (V8: formulae compactified)
    Subj-class: General Physics

    A preon-based composite model of fermions is discussed. The preon is regarded as a topological object with three degrees of freedom in a dual (3+1)-dimensional manifold. It is shown that dualism of this manifold gives rise to a set of preon structures, which resemble three families of fermions. The number of preons in each structure is readily associated with its mass. Although just a sketch, our model predicts masses of fermions to an accuracy of about $10^{-6}$ without using experimental input parameters.
  5. May 26, 2005 #4


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    Yershov (March 2003):

    Fundamental Particles:

    The fundamental particle is the Preon, which has a charge of -1/9th in electron units. A Preon has a mass of 1/9th in electron units. Preon antiparticles also exist. Preons come in three colors (red, green and blue, if you like).

    First Order Structure:

    Preons can form charged or neutral doublets. Doublets are not stable. They promptly form Y particles composed of three preons, one of each color (in my notation "Y"), or three anti-preons, one of each color (in my notation "y"). A Y particle has a charge and mass of one third of an electron. Y particles have one preon on each color but are polarized (like a water molecule) with one color more prominent than the others.

    Higher Order Structure:

    First Generation
    Electron Neutrino=6Yy (36 preons, 0 charge, 0 mass)
    Electron=3y (9 preons, -9 charge, 9 mass)
    Y*=Electron Neutrino+Y (39 preons, -3 charge, 39 mass)
    U=y*,Electron Neutrino,y* (114 preons (39+36+39), +6 charge, 78 mass (39+39))
    D=U,Electron Neutrino,Electron (114+36+9=159 preons, -3 charge, 78+36+9=123 mass)

    Second Generation
    Mu Neutrino=Y*,Electron Neutrino, y*
    Muon=Mu Neutrino+Electron Neutrion,Electron

    Third Generation
    Tau Neutrino=U,Electron Neutrino, u
    Tau=Tau Neutrino+Mu Neutrino+Muon

    Note: a Y**=U,Electron Neutrino,U,Electron Neutrino,Electron and
    a Heavy Neutrino=6Y*y*, and an Ultra Heavy Neutrino=3(y*,Heavy Neutrino,U),Electron and a Y***=an Ultra Heavy Neutrio,Y

    It appears from the notation, although the author doesn't quite come out and say it, that a photon=Yy, but has no mass or charge because the antiparticles has a mass that cancels out. This does, however, appear to explain the polarization of light (see equation 10 at page 9 and the table at page 12).


    This model is notable because:
    (1) It predicts the masses of all known particles to considerable accuracy. Of course, it also correctly assigns spin and charge numbers to all known particles.
    (2) The model used a formula to determine the mass of composite particles which is not simply a sum of masses, which is along the line of the sum of the component part masses divided by the sum of the reciprocal masses of the particles. Neutrally charged neutrino components do not contribute significantly to mass -- Y's and y's has masses that almost completely cancel out.
    (3) The model predicts the left handedness of the neutrino and the asymmetry between the lifetimes of para-positronium and ortho-postronium.
    (4) Six kinds of Ys (one for each color and charge combination, all with the same charge and mass magnitude) are used to produce left and right handed versions of eight kinds of particles (three Y*s, three anti-Y*s, electrons, positrons), electron neutrinos, anti-electron neutrinos, and two polarizations of photons for a total of 20 kinds of particles.
    (5) This model assumes that the world is made up of equal amounts of matter and anti-matter at the Y particle level.
    (6) Gravity appears to be delegated to the curvature of space, a la GR.
    (7) While charged preon doublets are considered confined, neutral preon doublets (i.e. a preon and its antipreon) are suggestively labeled [tex]g^0[/tex] suggesting that they are candidates for the gluon. The [tex]g^0[/tex] would, like the photon, be massless and chargeless, and would consist of both a preon and an anti-preon, with three possible colors each.

    Table For My Favorite G,pi,e theorist

    Predicted Mass (preon units;mass of proton=1 units) Experiment
    electron=9 preon units; 0.0005446175 mp; 0.0005446170232(12) mp
    u quark=78 preon units; 0.004720019 mp; 0.0047 mp
    d quark=123 preon units; 0.007443106 mp; 0.0074 mp
    muon=1860.9118 preon units; 0.11260946 mp; 0.1126095173 (34) mp
    c quark=27122.89 preon units; 1.641289 mp; 1.6 mp
    s quark=2745.37 preon units; 0.1661307 mp; .16 mp
    tau=31297.11 preon units; 1.893884 mp; 1.8939(3) mp
    t quark=3122289 preon units; 188.9392 mp; 189 mp
    b quark=75813.33 preon units; 4.587696 mp; 5.2 mp

    mp/me=1836.1510 vs. 1836.1526675(39) experiment
    Last edited: May 27, 2005
  6. May 26, 2005 #5


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    More Yershov: http://es.arxiv.org/abs/physics/0301034

    Date: Thu, 16 Jan 2003 09:54:57 GMT (18kb)
    Date (revised v2): Fri, 7 Mar 2003 18:07:30 GMT (18kb)

    Neutrino masses and the structure of the weak gauge boson
    Authors: V.N.Yershov
    Comments: LaTex2e, 4 pages (V2: minor linguistical corrections)
    Subj-class: General Physics

    It is supposed that the electron neutrino mass is related to the structures and masses of the $W^\pm$ and $Z^0$ bosons. Using a composite model of fermions (described elsewhere), it is shown that the massless neutrino is not consistent with the high values of the experimental masses of $W^\pm$ and $Z^0$. Consistency can be achieved on the assumption that the electron-neutrino has a mass of about 4.5 meV. Masses of the muon- and tau-neutrinos are also estimated.


    Basically, the assumption is that the composite mass formula for bosons is the inverse of the composite mass formula for fermions. The preon formulas for W+, W-, and Zo is set forth and the entire scheme in briefly recapped in a page or so. The experimental value of the W under the boson formula is used to establish the Z and neutrino masses, which should be nearly neutral under the original rest mass formula used for fermions.

    The W-=electron neutrino, electron.
    The W+=electron neutrino, postitron.
    The Z=W+,W-.
    Last edited: May 26, 2005
  7. May 26, 2005 #6


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    Search abstracts (body) in `astro-ph,cond-mat,gr-qc,hep-ex,hep-lat,hep-ph,hep-th,math-ph,nucl-ex,nucl-th,physics,quant-ph' in all years (1991-2005) for occurrences of `Preon'
    (28 matches) :
    1. hep-ph/0503213 [abs, ps, pdf, other] :
    Title: A topological model of composite preons
    Authors: Sundance O.Bilson-Thompson
    Comments: 9 pages, 3 figures, submitted to Phys. Lett. B

    2. hep-th/0501115 [abs, ps, pdf, other] :
    Title: BPS preons in supergravity and higher spin theories. An overview from the hill of twistor appraoch
    Authors: Igor A. Bandos
    Comments: 30 pages, LaTeX, AIPProc style, Contribution to the Procs. of XIX Max Born Symposium. V2: References added, citations completed

    3. astro-ph/0410417 [abs, ps, pdf, other] :
    Title: Preon stars: a new class of cosmic compact objects
    Authors: J. Hansson, F. Sandin
    Comments: 10 pages, 3 figures

    4. hep-th/0312266 [abs, ps, pdf, other] :
    Title: On BPS preons, generalized holonomies and D=11 supergravities
    Authors: I.A. Bandos, J.A. de Azcarraga, J.M. Izquierdo, M. Picon, O. Varela
    Comments: 11 pages, RevTeX Typos corrected, a short note and references added
    Journal-ref: Phys.Rev. D69 (2004) 105010

    5. hep-th/0308065 [abs, ps, pdf, other] :
    Title: Little Groups of Preon Branes
    Authors: H.Mkrtchyan, R.Mkrtchyan
    Comments: LaTeX, 11 pages
    Journal-ref: Mod.Phys.Lett. A18 (2003) 2665-2672

    6. hep-th/0212174 [abs, ps, pdf, other] :
    Title: Brane Content of Branes' States
    Authors: Ruben Mkrtchyan
    Comments: Misprints removed, text improved
    Journal-ref: Phys.Lett. B558 (2003) 205-212

    7. hep-ph/0208135 [abs, ps, pdf, other] :
    Title: Preon Trinity - A Schematic Model of Leptons, Quarks and Heavy Vector Bosons
    Authors: Jean-Jacques Dugne, Sverker Fredriksson, Johan Hansson
    Comments: 7 pages, epl.cls included, to be publ. in Europhysics Letters
    Journal-ref: Europhys.Lett. 57 (2002) 188-194

    8. physics/0207120 [abs, ps, pdf, other] :
    Title: Fermions as topological objects
    Authors: V. N. Yershov
    Comments: Latex2e, 20 pages, 12 figures, 3 tables, (V8: formulae compactified)
    Subj-class: General Physics

    9. hep-th/0201233 [abs, ps, pdf, other] :
    Title: Generalized Supersymmetries and Composite Structure in M-Theory
    Authors: J. Lukierski (Wroclaw University, Inst. of Theor. Phys.)
    Comments: LaTeX, 7pages. Talk presented at the XVI-th Max Born Symposium ,,Supersymmetries and Quantum Symmetries `01" (21-25.09.2001, Karpacz, Poland) and International Nankai Symposium (8-11.10.2001, Tianjin, China). To be published in the Proceedings of Nankai Symposium, Ed. Ge Mo-Lin and J. Park, Int. J. Mod. Phys. B
    Journal-ref: Int.J.Mod.Phys. B16 (2002) 2039-2046

    10. astro-ph/9912555 [abs, ps, pdf, other] :
    Title: The Cosmological Consequences of the Preon Structure of Matter
    Authors: Vladimir Burdyuzha (1), Grigory Vereshkov (2), Olga Lalakulich (2), Yuri Ponomarev (1) ((1) Astro Space Center of Lebedev Physical Institute of Russian Academy of Sciences, Moscow, Russia, (2) Rostov State University, Rostov on Don, Russia)
    Comments: LaTex 2.09, 9 pages

    11. hep-ph/9909569 [abs, ps, pdf, other] :
    Title: Preon Trinity - a new model of leptons and quarks
    Authors: Jean-Jacques Dugne, Sverker Fredriksson, Johan Hansson, Enrico Predazzi
    Comments: 12 pages Latex, no figures; to be published in the Proceedings of Beyond 99, Tegernsee, Germany, June 1999

    12. hep-ph/9907531 [abs, ps, pdf, other] :
    Title: Preons, Dark Matter and the Production of Early Cosmological Structures
    Authors: V. Burdyuzha (1), O. Lalakulich (2), Yu. Ponomarev (1), G. Vereshkov (2) ((1) Astro Space Center of Lebedev Physical Institute of Russian Academy of Sciences, (2) Rostov State University)
    Comments: LaTeX 2.09, 13 pages, 1 Postscript figure

    13. hep-ph/9901234 [abs, ps, pdf, other] :
    Title: Quarks, Leptons as Fermion-Boson Composite Objects and Flavor-Mixings by Substructure Dynamics
    Authors: Takeo Matsushima
    Comments: 37 pages, 3 figures

    14. hep-ph/9810494 [abs, ps, pdf, other] :
    Title: Unity of Forces at the Preon Level with new Gauge Symmetries
    Author: M.K.Parida (Phys.Dept.,North Eastern Hill Univ.,Shillong, India)
    Comments: 41 pages, Latex, with five figures, To appear in Phys.Rev.D58(1998)
    Journal-ref: Phys.Rev. D58 (1998) 115006

    15. astro-ph/9804219 [abs, ps, pdf, other] :
    Title: Highest Energy Cosmic Rays
    Author: Paul H. Frampton
    Comments: 6 pages. LaTeX. Talk at PASCOS-98, Northeastern University

    16. hep-ph/9712522 [abs, ps, pdf, other] :
    Title: The Excess of HERA High$-Q^2$ Events and Leptoquarks in a Left-Right Symmetric Preon Model
    Authors: Motoo Sekiguchi, Hiroaki Wada, Shin Ishida (Atomic Energy Research Institute, College of Science and Technology, Nihon University)
    Comments: 7 pages
    Journal-ref: Prog.Theor.Phys. 99 (1998) 707-712

    17. hep-ph/9712422 [abs, ps, pdf, other] :
    Title: The Mystery of Flavor
    Authors: R. D. Peccei (UCLA)
    Comments: 23 pages, 2 figures, latex document

    18. hep-ph/9712328 [abs, ps, pdf, other] :
    Title: Proposal of unified fermion texture
    Authors: W. Krolikowski (Warsaw Univ.)
    Comments: 29 pages, LaTeX, no figures
    Journal-ref: Acta Phys.Polon. B29 (1998) 755-782

    19. hep-ph/9711433 [abs, ps, pdf, other] :
    Title: Vacuum structure, spectrum of excitations and low-energy phenomenology in chiral preon-subpreon model of elementary particles
    Authors: O.E.Evnin
    Comments: 20 LaTeX pages, 8 figures

    20. hep-ph/9711342 [abs, ps, pdf, other] :
    Title: A Composite Model of Quarks with the `Effective Supersymmetry'
    Author: Nobuchika Okada
    Comments: 22 pages, uses REVTEX macro, revised manuscript to be published in Prog. Theor. Phys
    Journal-ref: Prog.Theor.Phys. 99 (1998) 635-648

    21. hep-ph/9709227 [abs, ps, pdf, other] :
    Title: Higgs Pain? Take a Preon!
    Authors: J.-J. Dugne, S. Fredriksson, J. Hansson, E. Predazzi
    Comments: The preon contents of some quarks and leptons have been changed in order to achieve a more consistent scheme. A few new comments have been added. 13 pages, LaTeX, no figures. To be published in Proc. of the Meeting on 'The Fundamental Structure of Matter' and 'Tests of the Electroweak Symmetry Breaking', Ouranoupolis, Greece, May 1997

    22. astro-ph/9709080 [abs, ps, pdf, other] :
    Title: Longevity and Highest-Energy Cosmic Rays
    Authors: Paul H. Frampton, Bettina Keszthelyi, Y. Jack Ng
    Comments: 8 pages, RevTeX
    Journal-ref: Int.J.Mod.Phys. D8 (1999) 117-122

    23. hep-ph/9611343 [abs, ps, pdf, other] :
    Title: A Supersymmetric Composite Model of Quarks and Leptons
    Authors: Markus A. Luty, Rabindra N. Mohapatra
    Comments: 10 pages, LaTeX 2e
    Journal-ref: Phys.Lett. B396 (1997) 161-166

    24. hep-th/9610190 [abs, ps, pdf, other] :
    Title: Frustrated SU(4) as the Preonic Precursor of the Standard Model
    Author: Stephen L. Adler
    Comments: 36 pages, plain TEX, no figures

    25. hep-ph/9603437 [abs, ps, pdf, other] :
    Title: Need for Two Vectorlike Families in SUSY Composite Models
    Author: H. Stremnitzer (Univ. of Vienna)
    Comments: 6 pages, LaTeX, no macros needed

    26. hep-ph/9405372 [abs, ps, pdf, other] :
    Title: An Automatic Invisible Axion In The SUSY Preon Model
    Authors: K.S. Babu, Kiwoon Choi, J.C. Pati, X. Zhang
    Comments: (TeX file) 16 Pages
    Journal-ref: Phys.Lett. B333 (1994) 364-371

    27. hep-ph/9212275 [abs, ps, pdf, other] :
    Title: Light fermions in composite models
    Authors: S. Yu. Khlebnikov, R. D. Peccei
    Comments: 22 pages, 2 figures not included, latex, UCLA/92/TEP/49
    Journal-ref: Phys.Rev. D48 (1993) 361-369

    28. hep-ph/9211288 [abs, ps, pdf, other] :
    Title: Flavor Changing Neutral Currents in a Realistic Composite Technicolor Model
    Authors: Christopher D. Carone, Rowan T. Hamilton (Lyman Laboratory of Physics, Harvard University, Cambridge, MA 02138)
    Comments: 16 pages, LaTeX + embedded PicTeX figures requiring prepictex, pictex, and postpictex inputs. HUTP.STY included
    Journal-ref: Phys. Lett. B301 (1993) 196-202
  8. May 26, 2005 #7


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    Date: Tue, 22 Mar 2005 08:48:11 GMT (52kb)

    A topological model of composite preons
    Authors: Sundance O.Bilson-Thompson
    Comments: 9 pages, 3 figures, submitted to Phys. Lett. B
    Report-no: ADP-05-05/T615

    We present a modification of the preon model proposed independently by Shupe and Harari. A basic dynamics is developed by treating the binding of preons as topological in nature and identifying the substructure of quarks, leptons and gauge bosons with elements of the braid group B_3. Topological considerations and a straightforward set of assumptions lead directly to behaviour consistent with much of the known phenomenology of the Standard Model. The preons of this model may be viewed as composite in nature, and composed of sub-preons, representing exactly two levels of substructure within quarks and leptons.


    This is a clean version of Harari's approach.

    It proposed that two basic types of particles (basically, half loops) called U and E can combine in types UU, EE, or EU=UE. The pairs are called Helons which in turn are labeled H+, H- and Ho (I will omit the H's and just show the signs and use upper and lower case to denote particles and anti-particles)

    Helons form into either braided or unbraided triplets, which cannot contain both a + and a - at the same time. Braided triplets corrospond to fermions by the following formula:

    First Generation Leptons:
    First Generation Quarks
    Blue U=++0
    Blue d=00+
    Blue u=--0
    Blue D=00-
    Red U=+0+
    Red d=0+0
    Red u=-0-
    Red D=0-0
    Green U=0++
    Green d=+00
    Green u=0--
    Green D=-00

    All fermions can be either right or left handed. The neutrino is its own antiparticle but still has handiness (right or left).

    These are unbraided triplets:
    W-= ---
    Photon is three untwisted 000s (i.e. neither right nor left)
    Zo is three countertwists 000s (i.e. both right and left)

    Mass is not precisely spelled out (reserved for future publications :wink: ), but it is a product of aggregate twistiness and possibly also charge. Thus, a photon, which is completely untwisted, is massless, while twisted charged particles are more massive.

    Second and further generation particles are not spelled out, but proposed basically to have additional twists beyond those absolutely necessary to create their characteristics.

    QCD Color
    QCD color effects are explained by the requirement that baryons be viewed as stacks of quarks and that each set of three subcomponents must have the same aggregate charge helon charge.


    This has the virtue of creating a model that closely maps to the standard model in charge, color, and parity constraints, and establishing the experimentally discovered number of particles without excess or shortage (although it isn't clear how this model of the photon handles the varied properties of a photon like polarization and frequency) with a great deal of simplicity.

    It fails, however, in this iteration to explain particle masses, and it is hard to see how so simple a set of triplets could produce the complex mass structures which actually exist.
    Last edited: May 26, 2005
  9. May 26, 2005 #8


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    Note that Yershov, Friedriksson, and Bilsom-Thompson all "independently" come to the conclusion that the level of structure immediately below the standard model must have multiple types of components (Yershov says three colors of Ys with antiparticles, Fredriksson with three kinds of particles with antiparticles, while Bilsom-Thompson uses onlyt H+, Ho and H- with no antiparticles), although both Yershov and Bilsom-Thompson note that this fairly simple typology can be derived by one more level of an even simpler structure (three kinds of preons in Yershov's case, two kinds of tweedles in Bilsom-Thompson's case).

    None of Yershov's conclusions require anything more fundamental than the Y particles he proposes, and none of Bilsom-Thompson's conclusions require anything more fundamental than the Helons. The strong indication is that neither preons (or preon doublets) nor tweedles could be experimentally discovered, and that even Yershov's Y-particles and Bilsom-Thompson's Helons would be confined at all times.

    But, Yershov's success with the mass problem suggests that he is closer to the right track in terms of particle structure (although, while he claims that there are no free parameters in his theory, in fact, the theory hardly necessitates the particle structures he proposes in the absence of data).

    Fredriksson's approach seems, at face value, the lease compellling of the three. Unlike Yershov's approach it does not explain particle mass, and it doesn't seem as transparent.

    Fredriksson's approach predicts a fourth generation of particles (the Kappa Electron, Kappa Neutrino, H quark, G quark, another heavy neutrino, a possibly unphysical X quark, 4 new Zs and 2 new Ws).

    Bilsom-Thompson's approach could produce additional generations beyond the three that we observe, at least among fermions, without apparent limit. But, each particle appears as if it should fit in a generation.

    Yershov's approach also predicts large numbers of extremely short lived or confined particles such as the Y*, Y**, Y***, two preon doublets, and two types of heavy neutrinos. It is also not at all obvious that his set of possible particles is complete, although his topological approach makes not all combinations of particles physically possible, and appears at first glance to dispense with the need for a Higgs boson.
    Last edited: May 26, 2005
  10. May 26, 2005 #9


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    Various Google Search Results:

    Physics Essay volume 10, number 1, 1997, "The A-B-C Preon Model" by D.J. Larson
    http://www.dipmat.unipg.it/~bartocci/fis/larson2.htm [Broken]

    "James N. Bellinger, author
    Atoms are made of a nucleus and electrons; nuclei are made of protons and neutrons, and these are made of quarks and gluons. We can ask if the quarks (and electrons) are themselves made of something even smaller, which we usually call preons [pree-on]." http://www.hep.wisc.edu/~jnb/poster_group/posterbig.html

    Wikipedia (mostly by yours truly): http://en.wikipedia.org/wiki/Preon
    Last edited by a moderator: May 2, 2017
  11. May 26, 2005 #10


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    More links:

    Lubos Motl on Preons (IMHO making tearing down strawman arguments, rather than fairly addressing the possibility): http://www.lns.cornell.edu/spr/2001-09/msg0035261.html

    From: Sverker Fredriksson [view email]
    Date: Wed, 3 Sep 1997 10:52:21 GMT (12kb)
    Date (revised): Mon, 29 Sep 1997 14:47:02 GMT
    Date (revised): Tue, 4 Nov 1997 16:30:13 GMT
    Higgs Pain? Take a Preon!
    Authors: J.-J. Dugne, S. Fredriksson, J. Hansson, E. Predazzi
    Comments: The preon contents of some quarks and leptons have been changed in order to achieve a more consistent scheme. A few new comments have been added. 13 pages, LaTeX, no figures. To be published in Proc. of the Meeting on 'The Fundamental Structure of Matter' and 'Tests of the Electroweak Symmetry Breaking', Ouranoupolis, Greece, May 1997

    The Higgs mechanism is the favourite cure for the main problem with electroweak unification, namely how to reconcile a gauge theory with the need for massive gauge bosons. This problem does not exist in preon models for quark and lepton substructure with composite $Z^0$ and $W$s, which, consequently, also avoid all other theoretical complications and paradoxes with the Higgs mechanism. We present a new, minimal preon model, which explains the family structure, and predicts several new, heavy quarks, leptons and vector bosons. Our preons obey a phenomenological supersymmetry, but without so-called squarks and sleptons, since this SUSY is effective only on the composite scale.
  12. May 27, 2005 #11


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    Jongbae Kim 1998 J. Phys. G: Nucl. Part. Phys. 24 1881-1902

    Explanation of the masses of quarks and leptons in a supersymmetric preon model
    Jongbae Kim
    Department of Physics, University of Maryland, College Park, MD 20742, USA
    Research Department, ETRI, Yusong PO Box 106, Taejon 305-600, South Korea
    Received 8 December 1997
    Print publication: Issue 10 (October 1998)

    Abstract. We have studied whether the radiative effects including gauge and Yukawa interaction corrections can improve the phenomenological consequences on the masses of quarks and leptons in the supersymmetric preon model. Our study shows that pure renormalization effects in the region from the metacolour scale to the electroweak scale produce quark-lepton distinction within a given family. They cannot, however, produce the desired up-down distinction or the expected quark-lepton asymmetry in the effective hierarchy parameter of the up, down and lepton sectors. It also shows that the pure radiative corrections cannot explain the `fine structure' effects exhibited by . These lead us to conclude that the symmetry structure of the preon theory cannot strictly respect left-right, up-down and quark-lepton symmetries near and below the Planck scale. This subsequently implies the symmetry both as regards unification of couplings near the Planck scale in the model and as regards its possible origin from a superstring theory.
  13. May 27, 2005 #12


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    Fermilab Mass Paradox issues: http://www.npl.washington.edu/AV/altvw80.html

    Power point on Why Quarks Cannot Be Fundamental Particles:

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  14. May 27, 2005 #13


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  15. May 27, 2005 #14


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    For a lot of time, I had though that Technicolor and preons were one and the same research line. I would like to blame to this kind of titles, instead of acknowledging my own lack of familiarity with the field. But on other hand the buzzwords "composite technicolor" were used time ago by the Mallinckrodt chair, in http://dx.doi.org/10.1016/0550-3213(87)90638-9 [Broken] and
    Phys. Rev. D 36, 2102-2108 (1987).
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  16. May 27, 2005 #15


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    The problem with preon models is always the same thing. Namely, you have to match T'Hooft Anomaly conditions exactly, and control fcncs to observed levels, and this severely constrains the possible phenomological models you can write down.

    When you add SUSY to the mix, afaik its nearly impossible as you end up with badly divergent helicity violating terms.
  17. May 27, 2005 #16


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    SUSY is well on its way to the toilet of physics history. It simply predicts too many supersymmetric partners that the evidence does not support the existence of. It is a classic example of the looks pretty, but doesn't work fad in modern physics. Preon theory is, if anything, primarily a solid argument for why SUSY particles should not exist and are not necessary.

    Also, constraints are not necessarily a bad thing. You need just one phenomological model to work and you'd like to have it be unique.
  18. May 27, 2005 #17


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    Too many arbitrary choosing in the preon structure. Surely it does not survive GIGO (Garbage In, Garbage Out) tests. A paper cited by Yeshov, physics/0109024, has the same problem (pages 44 and 45).
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  19. May 27, 2005 #18


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    Still, model builders keep trying. Here is one 1997 susy preon (superpreons?) model from Nima: http://arxiv.org/abs/hep-ph/9712389
  20. May 28, 2005 #19


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    That paper by Nima is not really a realistic model, but more an early attempt at solving the susy breaking problem. The gauge embedding used would lead to serious theoretical problems (landau poles near the composite scale) not to mention being ugly.

    It also breaks perturbative unification and I suspect there is problems with the usual triangle and striangle anomaly matching conditions (but I may be wrong on that).

    However it does illustrate some of the problems of field theory. when you embed the standard model into some larger gauge group (say SU(N) where N --> infinity), the cat is out of the bag so to speak. There is usually a few choices (eg complicated) representations whereby you can push problems to higher and higher scales somewhat arbitrarily.
  21. Jun 9, 2005 #20


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    Several Preon papers at a 1986 physics conference are found here:
    http://www.phys.vt.edu/~ippap/publications/hep86.html [Broken]

    and 1985 here:
    http://www.phys.vt.edu/~ippap/publications/hep85.html [Broken]
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