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A Does Peter Woit's solution of Higgs' naturalness problem work?

  1. Aug 14, 2016 #1
    Does Peter Woits solution Higgs naturalness problem work?

    "http://www.math.columbia.edu/~woit/wordpress/?p=5667

    Conventional wisdom in the particle theory for about 30 years has been that the Standard Model has a huge “hierarchy” or “naturalness” problem, the solution to which is supposed to appear at the LHC via SUSY or some other new BSM physics. With no SUSY or other BSM physics appearing at the LHC, this conventional wisdom is now moving towards claims that fundamental physics has been shown by the LHC to be “unnatural”, with parameters that are environmental, artifacts of our position in the multiverse generated by the anthropic landscape of string theory.

    It seems to me that a much more logical conclusion to draw would be that the LHC has just shown that the hierarchy/naturalness argument was mistaken. I’ve never understood why people found it convincing, and have often argued about this here on the blog. From the “hierarchy” angle, the problem is why the ratio of the electroweak-breaking scale to the GUT or Planck scale is such a small number, but we don’t actually have any evidence for GUT physics or for quantum gravitational physics, so no good reason to be sure that such high scales are relevant to anything or the cause of a hierarchy problem. From the “naturalness” side, while the theory is renormalizable, one can worry about the sensitivity to high energies of its cutoff dependence, but it’s unclear to me why one should be that concerned about this. More worrisome is that the Higgs sector introduces most of the undetermined parameters of the SM, a much more serious defect of the standard theory

    He starts off with:

    is there a Higgs naturalness problem?

    •For decades the HEP community has asserted that naturalness is the central issue
    •Simply put, we have assumed that either EWSB is natural, in which case we need to explain why, or that it is fine-tuned, in which case we also need to explain why
    •I will argue that this is a false dichotomy,and that LHC results are hinting at a third path

    then explains the standard dogma about quadratic sensitivity to the cutoff. He argues that the solution to this problem lies in properly understanding the scaling behavior of the Higgs, following ideas that go back at least to W. Bardeen in 1995 (see here). The fact that the renormalization group flow of the quartic term in the Higgs potential takes it to zero at high energies is interpreted as a suggestion that the right UV boundary condition is that the Higgs potential vanish.."

    so Woit's proposed solution to the hierarchy angle is that
    1- there is no GUT scale, no GUT unification, no GUT superheavy particles for the Higgs to couple to, driving up its mass and
    2- the planck scale is irrelevant to the Higgs. QG is irrelevant to the Higgs sector

    it's worth noting that the particle associated with gravity, the graviton is presumably massless like photon and gluon, and the higgs does not couple to them.

    Higgs physics is sensitive to cut-off but there is no GUT or Planck scale that serves as a cut-off. The top quark is the heaviest particle the Higgs couples to.

    Higgs mass of 126 GEV is the result of quantum interactions with only the particles, fermions and WZ bosons of the SM, and possibly dark matter and light weight particles.

    Does Peter Woit solution work?

    Suppose there are no super heavy particles above the EW scale, planck scale gravity does not couple with Higgs, and other particles like dark matter are ultra-light, less than 1 uev, like hypothetical axions and ultralight scalars. Is Higgs stable at 126 gev? ie there are many more particles yet to be discovered, and do couple to the Higgs, but they are all ultralight, less than 1 uev. The top quark is the heaviest fundamental particle
     
  2. jcsd
  3. Aug 15, 2016 #2
    One thing that comes to mind - mini black holes. There should be virtual black hole states, heavier than any SM particle, which can couple to the Higgs...
     
  4. Aug 15, 2016 #3
    Higgs doesn't couple to gravitons
     
  5. Aug 15, 2016 #4

    Haelfix

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    Science Advisor

    In general relativity any particle that carries a nonzero stress energy tensor will gravitate. This includes the Photon, the Gluon and the Higgs.

    Anyway, suppose you left out gravity (and forgot forever about trying to solve all the other problems of the standard model, like the lack of dark matter, the matter/antimatter asymmetry, the cp problems, the why questions, etc) and sent your UV cutoff to infinity. You would then logically need to explain a much harder problem, namely how to deal with the UV singularities that are unremovable in perturbation series (Landau poles, resummation divergences, etc etc).

    Anyway, more generally attempting to set boundary conditions in the renormalization group of the standard model (for instance by insisting the CFT remains undeformed) is akin to postulating a form of new physics anyway, as it necessarily involves a clever conspiracy or a hidden symmetry of nature and does not on the face of it make much sense. In a sense all you are doing is shifting the miraculous cancellations around.
     
  6. Aug 15, 2016 #5
    in other posts Woit's solution is higgs conformal invariance

    "(and forgot forever about trying to solve all the other problems of the standard model, like the lack of dark matter, the matter/antimatter asymmetry, the cp problems, the why questions, etc) "

    the new particles to explain this is at the weak scale, a hidden sector at the weak scale or much lighter,
    in this scenario the top quark is the heaviest fundamental particle the Higgs couples to.

    "You would then logically need to explain a much harder problem, namely how to deal with the UV singularities that are unremovable in perturbation series (Landau poles, resummation divergences, etc etc)."

    perhaps a theory of quantum gravity like loop quantum gravity with a physical cutoff is the answer or better understanding of nonperturbative physics.

    LHC hasn't found any of the SUSY that was supposed to stablize the Higgs. This is the nightmare scenario.

    If SUSY is broken at much higher energies say GUT or planck scale, to evade falsification of LHC Nightmare of only finding the Higgs, wouldn't such superheavy SUSY partners create stability problems for the Higgs at 126 gev?

    in effect, if SUSY doesn't stablize the Higgs and is broken at a higher energy, with superheavy susy partners, they would make Higgs naturalness problem worse.

    "Anyway, more generally attempting to set boundary conditions in the renormalization group of the standard model (for instance by insisting the CFT remains undeformed) is akin to postulating a form of new physics anyway, as it necessarily involves a clever conspiracy or a hidden symmetry of nature and does not on the face of it make much sense. In a sense all you are doing is shifting the miraculous cancellations around."

    Woit et al, do think there is a theory of quantum gravity out there, perhaps loop quantum gravity. so shifting it until a complete self-consistent theory of gravity. Loop gravity proposes a physical cut-off

    Woit is obviously not a fan of string theory.
     
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