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Preons! (subquarks, etc...) 
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#1
May2605, 05:54 AM

PF Gold
P: 2,892

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 SLACSPIRES 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, hepph/0309213. It points us to papers from Harari, Shupe, and Fritzsch. The one from Harari is in KEK scans, at http://ccdb3fs.kek.jp/cgibin/img_index?7905333 I believe to remember that Harari work was about three non commuting preons with nice jewish names. 


#2
May2605, 03:40 PM

P: 631

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 vaVohu 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. TTT=positron. 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: ttt=electron vvv=antielectron neutrino ttv, tvt, vtt=three colors of antiu quarks vvt, vtv, tvv=three colors of d quarks. Baryon number (B) and lepton (L) number are not conserved, but BL is conserved. A Baryon number violating process would be U+U>d+positron which in rishons is: TTV+TTV > TVV+TTT Matter and antimatter 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 antipreons. 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: Leptons: Electron neutrino A(BC) Electron B(BC) Muon A(AC) MuNeutron 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) Quarks: u=A(bc) d=B(bc) s=A(ac) c=A(ab) b=B(ab) t=C(ab) 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: W+=Ab W=Ba 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. 


#3
May2605, 03:57 PM

P: 631

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) Subjclass: General Physics A preonbased 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. 


#4
May2605, 05:05 PM

P: 631

Preons! (subquarks, etc...)
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 antipreons, 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 C=y**+y** S=C+Electron Third Generation Tau Neutrino=U,Electron Neutrino, u Tau=Tau Neutrino+Mu Neutrino+Muon T=y***+y*** B=T+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 Photons 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). Comment: 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 parapositronium and orthopostronium. (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 antiY*s, electrons, positrons), electron neutrinos, antielectron 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 antimatter 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 antipreon, 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 


#5
May2605, 05:50 PM

P: 631

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) Subjclass: 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 electronneutrino has a mass of about 4.5 meV. Masses of the muon and tauneutrinos are also estimated. Comment: 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. 


#6
May2605, 06:14 PM

P: 631

Search abstracts (body) in `astroph,condmat,grqc,hepex,heplat,hepph,hepth,mathph,nuclex,nuclth,physics,quantph' in all years (19912005) for occurrences of `Preon'
(28 matches) : 1. hepph/0503213 [abs, ps, pdf, other] : Title: A topological model of composite preons Authors: Sundance O.BilsonThompson Comments: 9 pages, 3 figures, submitted to Phys. Lett. B 2. hepth/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. astroph/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. hepth/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 Journalref: Phys.Rev. D69 (2004) 105010 5. hepth/0308065 [abs, ps, pdf, other] : Title: Little Groups of Preon Branes Authors: H.Mkrtchyan, R.Mkrtchyan Comments: LaTeX, 11 pages Journalref: Mod.Phys.Lett. A18 (2003) 26652672 6. hepth/0212174 [abs, ps, pdf, other] : Title: Brane Content of Branes' States Authors: Ruben Mkrtchyan Comments: Misprints removed, text improved Journalref: Phys.Lett. B558 (2003) 205212 7. hepph/0208135 [abs, ps, pdf, other] : Title: Preon Trinity  A Schematic Model of Leptons, Quarks and Heavy Vector Bosons Authors: JeanJacques Dugne, Sverker Fredriksson, Johan Hansson Comments: 7 pages, epl.cls included, to be publ. in Europhysics Letters Journalref: Europhys.Lett. 57 (2002) 188194 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) Subjclass: General Physics 9. hepth/0201233 [abs, ps, pdf, other] : Title: Generalized Supersymmetries and Composite Structure in MTheory Authors: J. Lukierski (Wroclaw University, Inst. of Theor. Phys.) Comments: LaTeX, 7pages. Talk presented at the XVIth Max Born Symposium ,,Supersymmetries and Quantum Symmetries `01" (2125.09.2001, Karpacz, Poland) and International Nankai Symposium (811.10.2001, Tianjin, China). To be published in the Proceedings of Nankai Symposium, Ed. Ge MoLin and J. Park, Int. J. Mod. Phys. B Journalref: Int.J.Mod.Phys. B16 (2002) 20392046 10. astroph/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. hepph/9909569 [abs, ps, pdf, other] : Title: Preon Trinity  a new model of leptons and quarks Authors: JeanJacques 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. hepph/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. hepph/9901234 [abs, ps, pdf, other] : Title: Quarks, Leptons as FermionBoson Composite Objects and FlavorMixings by Substructure Dynamics Authors: Takeo Matsushima Comments: 37 pages, 3 figures 14. hepph/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) Journalref: Phys.Rev. D58 (1998) 115006 15. astroph/9804219 [abs, ps, pdf, other] : Title: Highest Energy Cosmic Rays Author: Paul H. Frampton Comments: 6 pages. LaTeX. Talk at PASCOS98, Northeastern University 16. hepph/9712522 [abs, ps, pdf, other] : Title: The Excess of HERA High$Q^2$ Events and Leptoquarks in a LeftRight Symmetric Preon Model Authors: Motoo Sekiguchi, Hiroaki Wada, Shin Ishida (Atomic Energy Research Institute, College of Science and Technology, Nihon University) Comments: 7 pages Journalref: Prog.Theor.Phys. 99 (1998) 707712 17. hepph/9712422 [abs, ps, pdf, other] : Title: The Mystery of Flavor Authors: R. D. Peccei (UCLA) Comments: 23 pages, 2 figures, latex document 18. hepph/9712328 [abs, ps, pdf, other] : Title: Proposal of unified fermion texture Authors: W. Krolikowski (Warsaw Univ.) Comments: 29 pages, LaTeX, no figures Journalref: Acta Phys.Polon. B29 (1998) 755782 19. hepph/9711433 [abs, ps, pdf, other] : Title: Vacuum structure, spectrum of excitations and lowenergy phenomenology in chiral preonsubpreon model of elementary particles Authors: O.E.Evnin Comments: 20 LaTeX pages, 8 figures 20. hepph/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 Journalref: Prog.Theor.Phys. 99 (1998) 635648 21. hepph/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. astroph/9709080 [abs, ps, pdf, other] : Title: Longevity and HighestEnergy Cosmic Rays Authors: Paul H. Frampton, Bettina Keszthelyi, Y. Jack Ng Comments: 8 pages, RevTeX Journalref: Int.J.Mod.Phys. D8 (1999) 117122 23. hepph/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 Journalref: Phys.Lett. B396 (1997) 161166 24. hepth/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. hepph/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. hepph/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 Journalref: Phys.Lett. B333 (1994) 364371 27. hepph/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 Journalref: Phys.Rev. D48 (1993) 361369 28. hepph/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 Journalref: Phys. Lett. B301 (1993) 196202 


#7
May2605, 06:16 PM

P: 631

Date: Tue, 22 Mar 2005 08:48:11 GMT (52kb)
http://es.arxiv.org/abs/hepph/0503213 A topological model of composite preons Authors: Sundance O.BilsonThompson Comments: 9 pages, 3 figures, submitted to Phys. Lett. B Reportno: ADP0505/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 subpreons, representing exactly two levels of substructure within quarks and leptons. Description 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 antiparticles) 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: Positron=+++ Electron= Neutrino=000 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=00 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). Bosons These are unbraided triplets: W+=+++ W=  Photon is three untwisted 000s (i.e. neither right nor left) Zo is three countertwists 000s (i.e. both right and left) Mass Mass is not precisely spelled out (reserved for future publications ), 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. Comment: 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. 


#8
May2605, 07:43 PM

P: 631

Note that Yershov, Friedriksson, and BilsomThompson 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 BilsomThompson uses onlyt H+, Ho and H with no antiparticles), although both Yershov and BilsomThompson 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 BilsomThompson's case).
None of Yershov's conclusions require anything more fundamental than the Y particles he proposes, and none of BilsomThompson'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 Yparticles and BilsomThompson'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). BilsomThompson'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. 


#9
May2605, 09:07 PM

P: 631

Various Google Search Results:
Physics Essay volume 10, number 1, 1997, "The ABC Preon Model" by D.J. Larson http://www.dipmat.unipg.it/~bartocci/fis/larson2.htm "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 [preeon]." http://www.hep.wisc.edu/~jnb/poster_...posterbig.html Wikipedia (mostly by yours truly): http://en.wikipedia.org/wiki/Preon 


#10
May2605, 11:59 PM

P: 631

More links:
Lubos Motl on Preons (IMHO making tearing down strawman arguments, rather than fairly addressing the possibility): http://www.lns.cornell.edu/spr/200109/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 http://arxiv.org/abs/hepph/9709227 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 socalled squarks and sleptons, since this SUSY is effective only on the composite scale. 


#11
May2705, 12:46 AM

P: 631

Jongbae Kim 1998 J. Phys. G: Nucl. Part. Phys. 24 18811902
http://www.iop.org/EJ/abstract/09543899/24/10/006 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 and Research Department, ETRI, Yusong PO Box 106, Taejon 305600, 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 quarklepton distinction within a given family. They cannot, however, produce the desired updown distinction or the expected quarklepton 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 leftright, updown and quarklepton 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. 


#12
May2705, 12:53 AM

P: 631

capp.iit.edu/beach04/talks/kalman.ppt 


#13
May2705, 09:43 AM

PF Gold
P: 2,892

Uff! Espectacular review. Let me humbly add the Search Report
http://pdg.lbl.gov/2004/reviews/quarklep_s054.pdf 


#14
May2705, 09:53 AM

PF Gold
P: 2,892

Phys. Rev. D 36, 21022108 (1987). 


#15
May2705, 01:47 PM

Sci Advisor
P: 1,677

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. 


#16
May2705, 02:53 PM

P: 631

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. 


#17
May2705, 05:31 PM

PF Gold
P: 2,892




#18
May2705, 05:59 PM

PF Gold
P: 2,892




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