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Stalemate, or a victory for string theory?

  1. Oct 9, 2007 #1


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    As some PF followers are aware, last year I have been wondering, against my own preferences, if there was a possibility of using string theory straightforwardly (no AdS/CFT) in the QCD word. Today I have abstracted my comments into sections 3 and 4 of http://lanl.arxiv.org/abs/0710.1526.

    Basically, I proof that if it were possible to do such implementation in a way that the fermionic side of the superstring is elementary but the bosonic side is QCD, then supersymmetry implies that there are three generations of leptons and quarks, and of them five light quarks and one massive quark (respect to the electroweak scale).

    Thus string theory could be able to "predict", given the colour times electroweak group as input, the number of generations and the existence of a massive top quark. Moreover, it could seem that the colour group is also fixed to be SU(3).

    Well, it is the case that a couple weeks ago I was posting a thread with the title "Greene surrenders", referring to the failure of string theory to establish itself as a model of HEP particles. Then it was counter-argued than it was not a failure of string theory because nowadays its goal is to be a theory of quantum gravity.

    So what about a situation, say hypothetical if not the one of my preprint, where string theory happens to give some information directly (no RG running, no duality) in the electroweak scale? Should it be a triumph of string theory, or should it be a defeat because it is not in the Planck scale anymore? Sort of stalemate?
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  3. Oct 9, 2007 #2


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    I cannot say if your paper will give any aid or comfort to the string-minded among us, but I was gratified to see that it has a nice big link to Physics Forums in the first paragraph of the introduction.

    If only more papers on arxiv would begin by citing PF it would greatly enhance our dignity, solemnity and feeling of importance :smile:

    BTW I didn't understand the all the complaining that came on your thread about the Steinhardt-Greene conversation gem. The point was the comic irony. The conversation is about the backlash to inflated claims (unique and ultimate: "only this...only that...final theory of everything"). To briefly paraphrase: one of them whines about the backlash. The other says it's due to previous overhype. "You mean string was overhyped?" "Yes, sure." (no reply)

    Great conversation! People should read the whole thing:

    Several who commented on that thread seemed quite worked up and not at all amused.
    Last edited: Oct 9, 2007
  4. Oct 9, 2007 #3


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    It was obliged :approve:. If it becomes a main discovery, it must be pointed out that it developed along PF, between and by the inhabitants of PF.

    So am I afraid about the reception of my argument. Time ago it had been a triumph to show that by pivoting in supersymmetry and dual models, the standard model group implies three generations and a massive top quark. But nowadays it could be an attack against String Quantum Gravity, or an attempt to induce an split in string theory: quarkists versus plankists. The Maldacena way does not have this problem, because AdS sits in one place and QCD in the other. But here all the meat is in the HEP side.
    Last edited: Oct 10, 2007
  5. Oct 10, 2007 #4


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    Congratulations on the new arXiv upload, and thanks for mentioning me.

    I've moved my efforts on Koide over to WordPress, which now allows LaTeX in their blogs. This gives me better control over content, and I like the ability to easily put in color drawings:

    Recently, I've been working on "that damned number", the angle 12.7324 degrees that Koide refers to, but that I like to write in radians as 0.22222204714(23), or that's what I remember.

    The approach I've been following is that of the QED calculation where you sum over soft bosons and end up replacing the vertex "iQ" with an iQ exp(i Q). This makes the fundamental coupling constant be about 2/9.

    To do this, I have to sum up a bunch of qubit Feynman diagrams. So I wrote a java applet to do this for me. The simpler modes work, but the rest are iffy:

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