What are the Predictions for the Higgs Mass in Different Models?

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Discussion Overview

The discussion centers on the predictions for the Higgs mass across various theoretical models, including the Standard Model (SM), Minimal Supersymmetric Standard Model (MSSM), next-to-Minimal Supersymmetric Standard Model (nMSSM), little Higgs, and split supersymmetry. Participants explore the expected mass ranges and the implications of different theoretical frameworks.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant asks for expert predictions regarding the Higgs mass in various models, suggesting a range of 114-1000 GeV and expressing uncertainty about specific model predictions.
  • Another participant states that the SM does not provide a specific prediction but suggests it is lighter than 200 GeV based on electroweak precision fits and heavier than 114 GeV based on LEP searches.
  • The MSSM is mentioned to have a lower limit around 97 GeV and an upper limit of about 130 GeV, with some edge scenarios potentially allowing for lighter masses.
  • The nMSSM is noted to have an upper limit of about 140 GeV, but no lower limit is provided.
  • One participant claims that the little Higgs model is increasingly ruled out, with allowed scenarios becoming more unconventional.
  • Split supersymmetry is mentioned with skepticism regarding its relevance.
  • A participant questions the processes that lead to the unitarity bound on the upper limit in the nMSSM.
  • Another participant clarifies that the bound is derived from the mass matrix rather than unitarity, discussing the relationship between eigenvalues and diagonal entries.
  • Further clarification is provided regarding the upper bound in the nMSSM, linking it to the MSSM and an additional term from singlet coupling to the Higgs.
  • A paper is referenced that may provide additional insights into the topic, particularly regarding the upper bound on lambda.

Areas of Agreement / Disagreement

Participants express varying predictions for the Higgs mass across different models, indicating a lack of consensus. Some models have clearer bounds than others, and there is debate about the relevance and implications of certain models.

Contextual Notes

The discussion includes limitations such as the dependence on specific theoretical assumptions and the lack of consensus on certain predictions. Some participants reference papers and external sources for further exploration of the topic.

jgraber
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Can anyone tell me what the experts expect the Higgs mass to be in various well discussed models?
i.e. SM
MSSM
nMSSM
little Higgs
split supersymmetry
others?

Or do they all just predict 114-1000 GeV?

I think MSSM predicts less than 125 or 130 max.

I have heard rumors that SM predicts near 175,
and also that it predicts 85 plus unspecified corrections.

The others I only know broad ranges or weasel words.

Can anyone help me out?
Pointers to actual sources for any significant predictions would be appreciated.
TIA
Jim Graber
 
Physics news on Phys.org
SM: no prediction, but electroweak precision fits indicate it is lighter than 200GeV. LEP searches indicate it is heavier than 114GeV

MSSM: lower limit as above (there are a few 'edge of parameter space' scenarios where it could be as light as about 97GeV though). Upper limit about 130GeV

NMSSM: upper limit about 140GeV, no lower limit.

little Higgs is pretty much already ruled out. The allowed scenarios are getting increasingly wacky.

Split susy: no idea - why would anyone care?

This talk might be useful to you:
http://www-zeuthen.desy.de/ILC/workshops/ew_workshop/gruenewald.pdf
(slide 20 has the 'rumors' you were talking about)
 
Speaking of the nMssM do you happen to know which processes combine to give the unitarity bound on the upper limit?
 
It isn't a unitarity bound. It is a bound coming directly from the form of the mass matrix. The smallest eigenvalue of a matrix is always less than its smallest diagonal entry.
 
IC, that's interesting (I have hopelessly little knowledge in the nMssM phenomonology other than just the general scheme).. What does the 140 GEV diagonal eigenstate correspond too and how are they able to get the number?
 
It is the usual bound from the MSSM plus an extra term that comes from the singlet coupling to the Higgs.

You might find this paper useful:
http://arxiv.org/abs/hep-ph/0304049

Eq.26 is the appropriate term.

Actually, the upper bound on lambda is unitarity, so I suppose it is indirectly a unitarity bound after all.
 
Last edited:
Thanks, makes a lot of sense now and a good paper as well.
 

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