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B Is supersymmetry dead?

  1. Dec 14, 2017 #1

    wolram

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  2. jcsd
  3. Dec 14, 2017 #2

    lekh2003

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    Quite the opposite. Super-symmetry is a plausible theory. The problem is that we do not have the resources to find this particles. Massive amounts of energy are required and we don't have it.

    Just because we can't see it doesn't mean it might not be there.
     
  4. Dec 14, 2017 #3

    haushofer

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    Well, no, but the same goes for faries and goblins.

    The plausability of SUSY depends heavily on theoretical argument of which we know they served us very well in the past. But the lack of experimental findings should make you doubt the validity of these lessons from the past.
     
  5. Dec 14, 2017 #4

    lekh2003

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    That's an interesting approach, but that's the beauty of a theory. It is perfectly correct until proven wrong.
     
  6. Dec 14, 2017 #5

    wolram

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  7. Dec 14, 2017 #6

    MathematicalPhysicist

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    Nothing really dies, you'll find reincarnations of this and that in every new theory.

    My problem is with the notion of "particles", every theory suggest new particles, does that mean there are infinite number of particles?
    Does that mean that as you partition space you'll find more and more particles?

    I mean in the far future I can see even greater particles' colliders, heck some may say the universe began as such an experiment (big bang).
    (Obviously as I believe there's no beginning, it's just another experiment).
     
  8. Dec 15, 2017 #7

    bapowell

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    Perfectly correct? No, it's just "not wrong".
     
  9. Dec 15, 2017 #8

    haushofer

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    In which sense? Mathematically or correct as in "describes our reality"?
     
  10. Dec 15, 2017 #9

    lekh2003

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    Once an idea has the status of being "not wrong", it is called a theory. A theory is a theory and just that, not a fixed idea, which is called a law.

    Super symmetry physicists have not called super symmetry a law but a theory. They are entitled to a theory. And it could be wrong but that's because its a theory.
     
  11. Dec 15, 2017 #10

    bapowell

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    This is not what a theory is. This is a "theory" the way creationists dismiss evolution as "just a theory", as in, just a proposed, hypothetical, untested set of ideas. No, a scientific theory is a rigorously-tested collection of ideas, well-supported by evidence. (see https://www.scientificamerican.com/article/just-a-theory-7-misused-science-words/)
     
  12. Dec 15, 2017 #11

    lekh2003

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    Ok, I guess we can then say the validity of supersymmetry is dependent on how you treat the evidence.
     
  13. Dec 15, 2017 #12

    bapowell

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    Yes. As with any scientific proposal, its success depends on how well it squares with the evidence.
     
  14. Dec 15, 2017 #13

    PAllen

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    I would say supersymmetry is an attractive hypothesis, not a theory at all. Similarly for all BSM and quantum gravity proposals. Of course, attractiveness is in the eye of the beholder. To me, supersymmetry proposal is attractive. Over time, the tense of the last sentence’s verb may change, if evidence fails to materialize.

    I don’t think the picture has changed much from the following honest review by someone who finds the proposal attractive:

    https://arxiv.org/abs/1309.0528

    [edit: I add the following link for no other reason than its title:

    https://arxiv.org/abs/1106.2164
    ]
     
    Last edited: Dec 15, 2017
  15. Dec 15, 2017 #14

    Urs Schreiber

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    There was never any theory with deeper motivation that predicted the low-energy supersymmetry that is being highly constrained by LHC data. Even though, after a few decades, people behaved as if there is something in string theory that picks CY compactifications that yield low energy supersymmetry in the effective 4d-theory, in fact there is no such mechanism known in the theory.

    There is one theory which predicts high energy supersymmetry: Namely it is a theorem that 1) assuming that particles are string excitations and 2) the existence of fermions in the string spectrum implies high-energy local target space supersymmetry, aka supergravity (which is different from the low energy supersymmetry constrained by LHC data). E.g. Duff: "The status of local supersymmetry" (hep-th/0403160).

    Of course this does not imply that local/high energy supersymmetry is realized in nature, but it is good to be aware of the difference. There is a faint bit of preference for high energy supersymmetry from the Planck data: according to this.
     
  16. Dec 15, 2017 #15

    PAllen

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    Can you get very high energy supersymmetry to help with the hierarchy problem and provide plausible candidate particles for dark matter?
     
  17. Dec 16, 2017 #16
    ... and, in my opinion, multiverse nonsense as well.
     
  18. Dec 17, 2017 #17

    haushofer

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    Well, this is not the topic to discuss the multiverse, but the plausibility of scientific hypotheses is of course not the same as hypotheses from fantasy novels.

    And yes, the multiverse is science, whether it makes you feel uncomfortable or not.
     
  19. Dec 17, 2017 #18

    MathematicalPhysicist

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    And in other universes, fairies and goblins may be a reality... :->
     
  20. Dec 17, 2017 #19

    haushofer

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    If they are solutions to the underlying equations :P
     
  21. Dec 17, 2017 #20

    MathematicalPhysicist

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    What are the equations which their solutions dictate our existence?
     
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