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I recently heard the statement$^1$ that quark confinement is evidence for the indivisibility of quarks (i.e. that they are indeed fundamental and have no substructure), but I don't see any reason why this should be true. Is there any merit to this statement?


$^1$ Science and Dissent in Post-Mao China: The Politics of Knowledge" by H. Lyman Miller, p162.

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  • $\begingroup$ Source? Perhaps "Private communication"? :D $\endgroup$ – innisfree Nov 29 '15 at 8:44
  • $\begingroup$ Actually a book on Chinese science: "Science and Dissent in Post-Mao China: The Politics of Knowledge" by H. Lyman Miller. There's a limited preview on Google Books (books.google.com/books?id=pMISfv1SoaYC), and you can find several references to the "problem of quark confinement" (page 162 for example) but no explanation as to what quark confinement has to do with possible quark substructure. I tried searching around but couldn't find anything related, yet she makes repeated reference to the problem as if it was a well-known one. $\endgroup$ – JotThisDown Nov 29 '15 at 9:25
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Here is a review from the particle data group of searches for compositeness for quarks and leptons. . It is from 2001 but I suppose that they are not updating it since it gives the basic parameters for their table of limits for quark and lepton compositeness (2015).

In the review the word "confinement" does not appear, as it necessarily would have, if confinement were a necessary and sufficient reason for the elementary nature of the quarks. There is no evidence that quarks are not confined at present. There are theories where quark decays will violate baryon number conservation, thus leading to proton decay, but that is another story not involving confinement.

As the link provided is from twenty years ago, from within another physics subculture, probably it has to do with a particular theoretical proposal that has not emerged in the western story line of quark compositeness. I would trust the western version, as our experimental results are surely valid.

Here is a review of theory on confinement

Quark Confinement: The Hard Problem of Hadron Physics

"Compositeness" is not found within it either. It does speak of :

It is odd to have a complete theory of one of the four well established forces of nature the strong nuclear force and still not have general agreement, after more than thirty years of effort, on how that force really works at long distances.

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    $\begingroup$ This is slightly chauvinistic, west is best etc. The "western version" and cumulative work that lead to results in PDG were developed by physicists all over the world. $\endgroup$ – innisfree Nov 29 '15 at 12:38
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    $\begingroup$ Yes, but within the western culture, starting from Newton. Not to worry, with their higher average IQ now that the chinese have lost most of their ideology shackles they will probably not only catch up, but leave us behind :). Already it seems the next big colider will be in China $\endgroup$ – anna v Nov 29 '15 at 12:44
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    $\begingroup$ Science was not born in the west, in the 17th century by Newton and co (!?). We don't need nationalism in science, nor should we want it - we don't have to compete with one and other in blocks determined political boundaries. $\endgroup$ – innisfree Nov 29 '15 at 12:58
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    $\begingroup$ we do not have to, but it has happened,humans being humans. And it is not nationalism, rather to coin a word "culturalism" , which unfortunately exists between groups of people. $\endgroup$ – anna v Nov 29 '15 at 13:02
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    $\begingroup$ no, no such divisions inevitably exist between scientists of different backgrounds $\endgroup$ – innisfree Nov 29 '15 at 13:10
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The answer is no, confinement does not logically imply indivisibility. There are models of particle physics -- generally known as preon models -- in which quarks are composite.

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