The Higgs Boson mass prediction for LHC: string theory's prediction v.s preon theory

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Main Question or Discussion Point

Thanks Lubos,

Dear Lubos,
Does string theory offer a concrete prediction for the mass of the higgs boson?

Thanks
Dan

PS would you mind if I cross-post your response at sci.physics or PF?
dan | 10.01.06 - 5:58 pm | #

Dear dan,

string theorists - just like everyone else - are unable to give a unique prediction for the Higgs mass at this moment although more particular models are more concrete.

The lower bound is 114 GeV because they have not yet been seen, an upper bound may be derived from the need to restore the unitarity of the elastic scattering of pairs of W bosons, and is below 800 GeV or so.

Supersymmetric theories (or supersymmetric vacua in string theory) predict the lightest Higgs to be much lighter than 800 GeV, typically below 200 GeV. A lot of extra information can be derived from the renormalization group running - a dependence of similar parameters on the characteristic energy scale of the experiment.

For example, there exists another lower theoretical bound from the condition that the Higgs doesn't become a tachyone at higher energy scales. That would destabilize the vacuum which would be a worse catastrophe than global warming.

Please feel free to share anything I write here.

Have a nice evening
Lubos
Lubos Motl | Homepage | 10.01.06 - 9:36 pm | #


Hi Dan,



On Sunday 01 Oct 2006 23:00, you wrote:

> I've been looking at your articles, including
> http://arxiv.org/abs/physics/0301034, I'm wondering if
> you have a prediction for the Higgs Boson mass-energy,
> which may be seen at LHC.
>

Yes, indeed, from my model you can predict
the higgs mass. But this prediction is rather
embarrassing: NONE, because the particle masses
in this model are energies of the moving and
oscillating particle constituents (preons).
From this point of view the preon could be
regarded as the higgs since it is the preon
that gives particles their masses.

On the other hand, when you look at the complete
set of structures that emerge under the supposed
symmetry of the basic field, you will find that
this set could be one-to-one mapped to the variety
of known particles. There are some extra particles
that appear in my model, but they are neutral closed
shells, which could only be identified with WIMPs.
So, there are no candidates for the higgs particle
in my model, unless you take seriously the idea
of identifying the higgs and preons (indeed,
the preon is the only unidentified particle in my
model and, like higgs, it corresponds to a scalar field
permeating the whole universe). However, it follows
from my model that preons cannon be found in free
states, unless when the energy becomes comparable
to that of the initial state of the universe. Therefore,
my model predicts that higgs will likely not to be
seen at LHC.

Ragards,

Vladimir

--
 

Answers and Replies

  • #2
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Dear Lubos, I've posted your response over at PF,

Since proton decay experiments have ruled out GUT models SU(5), SO(10), SUSY GUT SU(5),

I have another question: some preon models do not predict the higgs boson. Consider arXiv:hep-ph/9709227. "Higgs pain? Take a preon".
Some preon theorists feel that the Higgs field/higgs boson is unnecessary in their preon model. It is unclear to me what effect the Higgs boson, should it be discovered, would have on these preon models.

If TEV/CERN/LHC, and others experiments fail to show the Higgs Bosons, to the extent HEP people feel the Higgs boson has been ruled out,

What would be the implications for susy and susy string theory? What about the implications to SUSY string theory of TEV/CERN/LHC not-seeing SUSY-partners? (other than you losing your $10k bet) :)


Dan
 
  • #3
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The answer to the first question should be clear from Motl's response - if the Higgs isn't seen (in some form) by 1TeV, it is dead. But then of course, we will have something else to play with.

The second question about SUSY was answered in this thread:
https://www.physicsforums.com/showthread.php?t=133032

Basically, string theory has no need for low energy SUSY, so there would be no direct implication. (It would of course remove a major motivation for SUSY, so could hurt string theory indirectly.)
 
  • #4
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Dear Dan,

nope. The experiments have only ruled out the minimal (simplest, minimal matter content) SU(5) model and some other simple models. There are still models, including those with SU(5) and SUSY, that are alive because they predict a longer proton lifetime. Many of us, including me, still believe that a GUT at high energies is more likely than 50%.

The paper about Higgs pain is, as far as I can say, complete nonsense. There's no quantum field theory in it at all. It is a kindergarden game of gluing particles without understanding what math actually describes the particles in the real world.

Some Higgs must exist to make the WW scattering unitary. It might just be composite or quickly decaying but it can't be completely absent. Every physicist worth the name knows that.

Seeing no Higgs would be a shock not only for SUSY theorists. But something new would have to be seen anyway. The Standard Model with the known particles and interactions but without Higgs is simply inconsistent because it gives probabilities outside the 0%,100% range for certain processes.

My bet is only $1k not $10k.

Best
Lubos

-- incidentally this paper
arxiv.org/abs/hep-ph/0302272

suggests SUSY SU(5) have been ruled out.
 
  • #5
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Severian said:
The answer to the first question should be clear from Motl's response - if the Higgs isn't seen (in some form) by 1TeV, it is dead. But then of course, we will have something else to play with.

The second question about SUSY was answered in this thread:
https://www.physicsforums.com/showthread.php?t=133032

Basically, string theory has no need for low energy SUSY, so there would be no direct implication. (It would of course remove a major motivation for SUSY, so could hurt string theory indirectly.)
I was wondering if string theory can concoct some scenario and remain viable, as they did with the discovery of deSitter space with the KKLT mechanism, should LHC not find the Higgs boson.

I should perhaps respond in the other thread but planck-scale SUSY breaking might have implications in disagreement with observation, although I suppose with string theory, all things are possible.

Incidentally Yershov did respond to your question, did you find it satisfactory?
 
Last edited:
  • #6
Kea
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bananan said:
I was wondering if string theory can concoct some scenario and remain viable, as they did with the discovery of deSitter space with the KKLT mechanism, should LHC not find the Higgs boson.
Easily - by taking on board an M-theory that uses preons.

:smile:
 
  • #7
176
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Kea said:
Easily - by taking on board an M-theory that uses preons.

:smile:
I think that a SUSY-level preon theory with an unbroken SUSY with preon and SUSY-preon partner would be more simple than MSSM and no need to explain SUSY-breaking.


Lubos doesn't like idea.
 

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