Essay Abstract

Fractional electric charges for quarks are one of the most striking aspects of the Standard Model of particle physics, and are well supported by QED phenomenology. However, it is possible to argue that the fractional nature of the charges is a reflection of the properties of the strong, rather than electric, interaction, and that a different structure is needed at a more fundamental level. In this sense, the fractional charges could be seen as 'emergent', as in the parallel case of the fractional quantum Hall effect. Using the original coloured quark model, first proposed in 1964 and never disproved by experiment, we gain new insights into two areas which have proved to be problematic for physics: the theory of Grand Unification and the application of the Higgs mechanism to the creation of fermion masses.

Author Bio

Educated Manchester University, BSc 1970, PhD 1975, both in physics. Worked in industry (ICI) and as College lecturer. Research Fellow, Physics Department, University of Liverpool since 1987. Hon. Governor Manchester College, Oxford, since 1993.Research work in physics, and history and philosophy of science. Author or editor of approximately 10 books and about 150 other publications. 3 best paper awards at CASYS conferences.

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  • [deleted]

Dear Dr. Rowlands,

What an interesting article! I had no knowledge of the HN formulation and I did not know that the symmetry behind the GMZ formulation could be expressed differently. Perhaps the fact that the LHC has not found anything unexpected will induce people to consider HN again, in order to gain novel insights. Also, your article makes me wonder whether there are not still other ways to express the same symmetry. If so, then that could open up a new theoretical approach to understanding the relation between the fundamental forces.

all the best,

Armin

    • [deleted]

    Dear Dr Rowlands

    I very much enjoyed your essay. As an amateur playing with particle models, I am at the stage where I need to include charge. Your essay asserts that charge is an emergent property, which I agree with, despite my finding charge difficult to understand. Your potential sapping at the basis of fractional charges is very useful and will allow greater freedom.

    Best wishes

    Ben Smith

    Dear Peter,

    I have an idea about Model of quark quasiparticles. In the model quarks are quasiparticles not real particles. Can you look to the model, which is in §12 of the book: Fedosin S.G. The physical theories and infinite nesting of matter. Perm: S.G. Fedosin, 2009-2012, 858 p. ISBN 978-5-9901951-1-0. It is supposed that 6 quarks are composed of 2 phases of nucleonic substance having opposite fractional charge. Then every hadron is some composition of only this 2 phases of nucleonic substance. The model of quark quasiparticles is a consequence of the theory of Infinite Hierarchical Nesting of Matter, which described in my essay. You can also evaluate the substantial models of proton, neutron, electron and atomic nucleus.

    Sergey Fedosin Essay

      • [deleted]

      I have also thought for some time that the fractional charge of quarks is due to a fractional quantum Hall effect. We might assume the "bare theory" of quarks is something like the Han-Nambu model, then a QCD flux F^a_{ij} = D_jA^a_i - D_iA^a_j, i and j spatial coordinates is a QCD chromomagnetic field. The over all QCD flux is across the D-brane which contains a cosmology. The general flux would be a gauge field with G_2 symmetry which decomposes into U(1)xSU(3). Then at low energy this QCD chromomagnetic flux induces the fractional charge on quarks.

      I have not pursued this, largely because I have yet to come to an understanding of this flux. Without a D-brane consideration it seemed as if various monopole type of considerations were needed. However, these ideas were not very workable. In my essay I do reference a paper of mine on a 2-color D-brane theory, which has QCD-like connections. Maybe this or something similar might demonstrate how fractional charges emerged.

      There is of course a question about why quarks are thirds of charge and not fifths or sevenths and so forth. Maybe in the so called multiverse setting there are other spacetime cosmologies with such configurations.

      Cheers LC

        • [deleted]

        Dear Peter,

        I found your essay interesting in many ways. All these fundamental numbers fascinating me, like you.

        I read carefully your essay and i found something intrigued me, when i see this value : 0.25 or 25 %, (sin2θW = 0.25 ) ?

        I am not a physicist and i would like if you take a look to my essay and give me your impression about this value.

        Something fundmental is under this ratio of 25-75 %.

        http://fqxi.org/community/forum/topic/1552

        Thanks

          6 days later
          • [deleted]

          Dear Dr. Rowland,

          A vert nice essay. I especially like the idea from Laughlin that fractional chrges may be an emergent feature a la fractional quantum Hall effect.

          I recall that the Han-Nambu model was equivalent to the standard quark picture, but I thought that the R-ratio might provide a way to distinguish teh two? Briefly the R-ratio is

          R= sigma(e+e- --> q q-bar) / sigma (e+e- --> mu+ mu-)

          i.e. it was the ratio of the total cross section of electron, positron to quark,anti-quark divided by the total cross section for electron, positron to mu-, mu+. This ratio then provides a glimpse into the charge and color assignments. In the standard quark picture for a single quark, anti-quark (u-quark say)

          R= N_c (q_u)^2

          where N_c is the number of colors and q_u is the electric charge of the up-quark. In scatterinng experimetns up to the s-quark mass (but below c-quark) one finds (to tree level)

          R=3(4/9+1/9+1/9) = 2

          Everytime a new energy is reached where a new quark can be created the R-ration jumps so for exmaple when one has an energy to include the c-quark this becomes

          R=3(4/9+1/9+1/9+4/9)=10/3

          This relationship for R (and the first order log corrections) has been tested nd confirmed. What does the Han-Nambu model give for the R-ratio? This might be a tricky test since it depends on the square of the charges and the average of the square is not always the square of the average. In any case it would be a good test of the Han-Nambu model.

          One should also check if the chiral anomaly cancellation of the Standard Model works since this relates the various charges of leptons with quarks in order that the anomaly cancel. However even thhough I did not check this my feeling is that the Han-Nambu model will work for this since in the anomaly (at least to one-loop) the anomaly depends linearly on the various charges rather than quadratically as for the R-ratio.

          Best,

          Doug

            • [deleted]

            Dear Ben

            Thank you for this. I am not sure that I said charge was an emergent concept in itself, but that fractional charges were.

            Best wishes

            Peter

            • [deleted]

            Dear Sergey

            I think it is a valid idea that quarks are quasi-particles rather than actual particles, and I have worked out a quantum mechanical theory of baryon / meson structures which effectively requires this, though I don't yet know how this would relate to what you are suggesting. It is described in my book Zero to Infinity (World Scientific, 2007). I am interested in your ideas on how all the relevant masses, etc, work out and will read this closely.

            Best wishes

            Peter

            • [deleted]

            Dear Lawrence

            Thank you for this. You may be interested in the quantum mechanical aspects of the ideas I have been investigating, which are in my book Zero to Infinity (World Scientific, 2007) and are also outlined in an arXiv paper of 2010 (the only one I published on arXiv that year). Here there is some mathematical development related to QCD fluxes, etc. Maybe this will generate some ideas that you can connect with yours. You may remember that we have met (Berkeley, 2000) and discussed string / brane versions of what I then presented, which I think you subsequently referred to in your Quantum Fluctuations of Spacetime.

            Are you still based in Budapest? I will probably be visiting next year, and maybe we could meet up again to discuss the possibilities.

            Best wishes

            Peter

            • [deleted]

            Dear Doug

            Thank you for this. My quick answer to your question is that I believe any QED measurements will be the same in both representations because the prefect gauge invariance observed in QCD and the massless nature of the gluons means that all possible phases of the QCD exist simultaneously, which means that any particular electric charge structure is only in place for one third of the time, though that third can, of course, never be identified. So, I think that it is the properties of the strong interaction that determine the QED for quarks, just as it is the weak interaction that determines the QED for electrons in the fractional quantum Hall effect.

            Best wishes

            Peter

            • [deleted]

            Dear M. H. Amazigh

            Thank you for your comments. I think it is a perfectly valid thing to look for simple ratios and to expect them to occur in certain circumstances. For example, I have an article somewhere on arXiv about the physical significance of the factor 2 and have written about it also in my book Zero to Infinity (World Scientific, 2007). Numerical factors sometimes emerge from something simpler and more fundamental than the physical thing one is looking at, often some deep symmetry or duality. My own belief is that two numbers occur again and again in physics (and in some other areas of science), and these are 2 and 3. The first usually signifies duality and the second anticommutativity. So, I think the 0.25 for electroweak is probably a number of this kind. I have read through your article and will study it more closely to see how it may relate to this way of thinking.

            Best wishes

            Peter

            • [deleted]

            I am still affiliated with AIAS at U. Budapest, but I have not been in Europe for over 6 years. That position is an ingratis position, so I have to work outside of there. I was working for some time doing work on photovoltaic physics, but that whole industry has gone completely into the tank.

            Gravity is in a sense the square of gauge theory, and in particular in the AdS setting it is the square of SU(3) and SU(4) ~ SU(2,2), which is a "type of QCD" in a twistor framework Two gluons in an entanglement that are color neutral define a spin = 2 particle that has a graviton amplitude. The LHC is going to ramp up the heavy ion work next year at 7 TeV and it will be interesting to see if there are more of these signatures of AdS/black hole-like scattering amplitudes.

            I have though for some time that fractional quark charges are some manifestation of the quantum Hall effect. It may be due to the incidence of a gauge 4-form on the D3-brane, similar to a magnetic field across a material or graphene.

            Cheers LC

            Dear Peter,

            Thanks for your comment.

            You are right, the number 2 indicates something fundamental in the functioning of the Universe.

            These numbers, ratios, these constants we challenge and sharpen our curiosity to get the laws behind them.

            I read your article on arxiv about the significance of the factor 2. I find it interesting and you bring an original perspective.

            I'm working too on the duality of nature and I think we're both on the right way.

            I am preparing to release a book on a comprehensive theory of how the universe and nature works. And I can tell you that I use excessively the duality.

            All the best with your essay

            • [deleted]

            Dear Jataker

            Experiment is the final arbiter, and experiment seems to suggest that quarks are point like particles. The string idea was not a description of the quarks but an early way of describing the strong force before the more sophisticated QCD theory was created. If someone comes up with a new type string theory of the particles involved, that is not relevant to the level of observation I was discussing in my essay. I kept any discussion about exotic models of quarks out of my essay, as it was concerned only with the interpretations of observations involving the Standard Model.

            Best wishes

            Peter

            • [deleted]

            Dear Hải.Caohoàng

            I think your post should have concentrated on making comments on my essay, rather than promoting an alternative theory, which you have every opposrtunity to do in your own essay. You can, of course, refer to this, but the main thrust of your comments should be on what I have written. In any case, I think the results of experiments recently carried out at CERN seem to be against you. There is every probability now that the Higgs boson really does exist, and such experiments are the only sure way we have of testing out the vailidity of our assumptions. My own essay concerns the Standard Model, which has been tested successfully many times over, and does not seek to contradict this. In view of the massive evidence already accumulated in its favour, I think ideas which cannot incorporate the Standard Model are unlikely to add significantly to our knowledge.

            Best wishes

            Peter Rowlands

            • [deleted]

            Meaning of Fractional Electric Charge yo can read i my old essay

            http://www.fqxi.org/community/forum/topic/946

            5 days later

            After studying about 250 essays in this contest, I realize now, how can I assess the level of each submitted work. Accordingly, I rated some essays, including yours.

            Cood luck.

            Sergey Fedosin