18 August 2005

Modern Physics: Preons.

I'm interested in preon theory, which considers the possibility that many or all of the particles in the standard model of particle physics may not be fundamental. Indeed, I am the principal author of the Wikipedia article on the topic and have also discussed it at the physics forums.

Let me first be clear: Preon theory is not the prevailing mainstream view in particle physics. The mainstream view is that the standard model particles are (or at least mostly are) fundamental. Honestly, I'm not sure myself if preon theory will or will not prove to be true. But, as string theory develops more doubters, I think it will be an obvious direction for non-string theory investigators and theorists.

Many critics of preon theory base their criticisms on poor efforts at formulating a preon theory. In the interest of preventing people from offering strawman arguments I'm offering here some of the positive features of what I believe to be the most promising preon theory currently extant with references to the relevant papers on the subject:

Yershov's Preon Theory.

Yershov as of March of 2003 has described a substructure for the standard model that provides charge, spin, and mass numbers, as well as structural formulas for:

a) All varieties of existing quarks and anti-quarks.
b) All generations and types of electrons including antiparticles.
c) All generations and types of neutrinos including antiparticles.
d) W+, W-, Z, polarized photon and all of the gluons, i.e. all spin-1 particles.
e) A map to the mass of higher generation particles.
f) A formula for calculating masses that is quite accurate for both Fermions and in a modified form Bosons.
g) Only a couple of parameters to put in experimentally (one Fermion mass and one W mass) (although the combinations of particles used to create higher order particles is itself a free parameter).
h) It does it all in 4D unlike superstring theory.
i) It does not predict the abundance of non-observed particles suggested by supersymmetry theories.

His theory starts with just three kinds of particles (some of his illustrations depict them as little arrows) which are identical except for chromodynamic color, and their antiparticles. All fermions are combinations of three preon structures Yershov calls Y particles. In more depth, his theory plays out as follows:

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).


(1) 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 have masses that almost completely cancel out.
(2) The model predicts the left handedness of the neutrino and the asymmetry between the lifetimes of para-positronium and ortho-postronium.
(3) 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.
(4) This model assumes that the world is made up of equal amounts of matter and anti-matter at the Y particle level.
(5) Gravity appears to be delegated to the curvature of space, a la GR.
(6) While charged preon doublets are considered confined, neutral preon doublets (i.e. a preon and its antipreon) are suggestively labeled suggesting that they are candidates for the gluon. The would, like the photon, be massless and chargeless, and would consist of both a preon and an anti-preon, with three possible colors each.

Mass Prediction Table

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

His theory needs some modest tweaks to take dynamics into account, but it is still remarkably good for a Preon Theory.

The First Paper

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.

The Second Paper

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.


Anonymous said...

Yershov's Preon Theory & Bilson-Thompson & LQG & mass prediction


it's my understanding that Yershov's Preon Theory can predict particle masses a priori and his paper also describes second and third generation particles, whereas Bilson-Thompson only the first generation.

Is it compatible or derivable from Bilson-Thompson's theory, http://arxiv.org/abs/hep-ph/0503213 which apparently can be derived from LQG spin networks.

Yershov paper here http://arxiv.org/abs/physics/0207120 seems to make points of contact with Bilson-Thompson. Could Bilson-Thompson ribbon model make use of Yershov's Preon model to predict particle masses?

Incidentally, John Baez or Lee Smolin will Bilson-Thompsonplan to publish papers mapping out the remainder of the SM? His paper were only for first generation.

Has there been any there been any indications Bilson-Thompson might publish an article along with Yershov?

What would be cool would be starting with spin networks, which give rise both to general relavitivity and the standard model, you can map out the entire standard model using preons and predict particle masses.

"Yershov Properties of space can be used for explanation of some patterns of nature. For example, topology of space might be responsible for the enigmatic spectrum of masses of quarks and leptons, which so far has not been explained. Here we consider a topological structure discovered in 1882 by F.C.Klein and show that properties of this structure necessarily lead to formation of a set of secondary topological structures, number of which matches the number of known fundamental particles. Some features of these structures can be related to quantum numbers and masses of the particles"

Andrew Oh-Willeke said...

Good discussion can be found here.

Anonymous said...

Dear Andrew,

would you like to contribute your summary of Yeshov and Bilson and Frerickson's preon model to wiki?


mike lawrence said...

An interesting discussion (even if I'm a few years late!). I have developed a preon theory that goes beyond Yershov's model, although there are some interesting similarities. I would love to explain it here, although it's a bit long. It's at www.pbtsm.co.uk and look for the short one page preview 'Ring Theory in a Nutshell' or the full file 'Underlying Nature of Mechanics and Matter'. Hope you find it interesting.