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B Unelegant, Unnatural, Ugly BSM theme books

  1. Nov 1, 2017 #41

    haushofer

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    I'm still wondering about my earlier question, which I'll repeat here since it seems relevant for this topic:

    To which extent is finetuning (and hence naturalness) an artefact of doing perturbation theory? Are there exactly soluble QFT's which suffer from naturalness/finetuning problems?

    I mean, how would finetuning of the Higgs mass show up in a non-perturbative formulation of the SM?

    I thought the question is appropriate here, so I don't start a new topic. Without wanting to hijack this topic of course ;)
     
  2. Nov 1, 2017 #42

    atyy

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    There is an interesting discussion in https://www.google.com.sg/url?sa=t&...0D0sQFgg6MAY&usg=AOvVaw2-LVf2T6qnYUCeZ5kTGnKa.
     
    Last edited: Nov 1, 2017
  3. Nov 1, 2017 #43
    Great article. The first thing that came to my mind was how come physicists didn't focus more on nonperturbative scheme instead of proposing supersymmetry to handle the quadratic divergences. Supersymmetric particles won't exist in nonperturbative scheme just like virtual particles are just side effect of perturbation theory that is not there in lattice QFT. Unless they think perturbation method could be chosen by nature intrinsically?.


     
  4. Nov 1, 2017 #44

    haushofer

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  5. Nov 1, 2017 #45
    Please share how you understand the paper. There is a passage in page 3 that got me puzzled: "In brief, the quadratic divergences are completely irrelevant for the naturalness and fine-tuning problems involving the physical parameters."

    How do you interpret the statement? Does it mean nonperturbative approach doesn't or does remove the Higgs Hierarchy Problem? And when it mentioned "gauge hierarchy problem".. did it mean the higgs?

    Also the paper was written in 1983.. a time when we still didn't have a cellphone. So it was ancient. Now after more than 30 years.. is there any update to it.. or new jargons being used now.. for example like relativistic mass no longer used now. Something similar in the terms used in the paper? atyy? anyone?

    Thank you.
     
  6. Nov 1, 2017 #46

    atyy

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  7. Nov 2, 2017 #47
    Haushofer mentioning about nonperturbative approach yesterday bothered me a bit about the electron's gyromagnetic ratio that perturbation can produce a value to better than one part in 10^10, or about three parts in 100 billion. I was supposed to mention this yesterday so let me ask about it. After reading the archives about nonperturbative approach. I found this message of yours written in April 4, 2011 in message 78 of https://www.physicsforums.com/threads/non-perturbative-qft-without-virtual-particles.485597/page-4

    rogerl asked: "In Hierarchy Problem, the Higgs can have planck mass because of quantum contributions. So what they do is propose that the virtual particles of Supersymmetric particles can cancel the very large quantum contributions in the Hierarchy Problem. Why do they have to take drastic measure and radical idea just to get rid of the large contribution if virtual particles are just multivariate integrals. Why didn't they just go to lattice methods to solve it?

    atyy replied: "That's an interesting question. I don't know. My understanding is that the underlying theory is given by special relativity, quantum mechanics, Wilsonian renormalization, and the standard model Lagrangian. I would guess that the fine tuning problem is a heuristic argument based on Wilsonian renormalization, so it should have a counterpart in a lattice language.

    Also, is there such a thing as non-perturbative QED? Unless a QFT is asymptotically free or safe, isn't it by definition only perturbatively defined? According to http://www.sciencedirect.com/scienc...02d57ae15e181b9774e884147a99780a&searchtype=a , QED is likely not asymptotically safe. The only question then is how we choose to name the terms in a particular perturbation expansion."

    atyy. It's been 6 long years since you wrote the above. Please update us of your understanding now. So do you think the Higgs Hierarchy Problem has a counterpart in lattice language? And after so many results in the LHC and half a dozen years of pondering about it.. so is there such thing as a non-perturbative QED? What do you think? What's new in your thinking now compared to 2011?
     
  8. Nov 3, 2017 #48
    According to an expert/professor (Demystifier). Finetuning and naturalness are not artifacts of doing perturbation theory. Also for instance, if you study SM on the lattice, you have to choose some UV cutoff on the lattice. The physical quantities may strongly depend on that choice, which can lead to a fine tuning problem.

    So with the nonperturbative approach not a solution of the Higgs Hierarchy Problem and crossed out, we are back to:

    1. Supersymmetry (example of Naturalness)
    2. Extra Dimensions (Randall RS1, RS2)
    3. Natural Finetuning (Lubos')
    4. Multiverse Anthropic principle
    5. Scale Symmetry (is this an example of Naturalness?)

    Let me ask you. When a grenade explode in the ground. Does anyone every ask if it's caused by Naturalness (simply by formula) or by Multiverse? It may sound silly.. is it not. So if we eliminate these three. We have left:

    1. Extra Dimensions (Randall RS1, RS2)
    2. Scale Symmetry (is this an example of Naturalness?)

    If we don't have Extra Dimension. We are left with Scale Symmetry.

    But is an exploding grenade caused by Scale Symmetry where the distances of the grounds and the size of the grenade were created on impact?

    What seems to be missing in the choices are Anthropic principle without Multiverse.. or in other words Intelligent Design.. but let's not use these words as the words automatically denote mindlessness.. let's use the word "programming" instead... that's right.. the Standard Model parameters could be programmed that way instead of coming from naturalness or extra dimensions or multiverse.. is it not?

    What could still solve the Higgs Hierarchy Problem is if the Higgs is a composite.. is this still possible?

    Again someone please share whether scale symmetry is an example of naturalness because I can't decide. Thanks.
     
  9. Nov 17, 2017 at 1:05 AM #49
    @star apple regarding you original question: You can find a list of books in the same spirit as Woit's and Smolin's here, and essays written in a similar spirit here.
     
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