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ensabah6
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The neutralino is the lightest supersymmetric stable particle, and is a good dark matter candidate. Some theories like MSSM predicts the LHC has enough energy to produce neutralinos, which can be indirectly detected by missing energy in collisions.
Neutralinos are predicted to be abundant and stable based on SUSY-GUT big bang, enough to be dark matter.
It may be the supersymmetry breaking scale is so high that LHC may not be able to produce neutralinos.
The successor of Cryogenic Dark Matter Search CDMS II is Super-CDMS, with the sensitivity to detect neutralinos over its parameter space in most popular SUSY models. Hence, even at higher than LHC energies, the big bang should have produced neutralinos and these should be detectable. Ref below. In addition to Super-CDMS are other direct and indirect detection experiments that can detect neutralinos over its expected parameter space.
R-parity is required in most phenomenologically acceptable SUSY models, no R-parity leads to predictions in conflict with experiment esp baryon number and lepton number conservation.
So my question is if neither LHC, nor SuperCDMS, nor other direct and indirect experiments, such that say 3-bar or 4-bar, they can be said to not exist (in much the same way as SU(5) and SO(10) GUT experiments have been ruled out based on predicted proton lifetime)
is SUSY still possible? If several independent lines of research (i.e LHC, SuperCDMS, other detection experiments, even Tevatron)
rules out neutralinos as predicted by the minimal (MSSM), the next-to-minimal (NMSSM) and the nearly minimal (nMSSM), is there any reason to think R-parity conserving SUSY is a symmetry of nature?
http://www.telegraph.co.uk/science/science-news/3351261/Large-Hadron-Collider-What-will-it-find.html
Eva Silverstein, Stanford University, USA
'I'd be extremely puzzled if they don't find the Higgs, but wouldn't be devastated if they didn't come up with evidence for supersymmetry. Some of my intuition comes from string theory, an appealing candidate for a theory of all the forces of nature. According to many - perhaps most - versions of string theory, supersymmetry does not hold good at the energies probed by the LHC, so its discovery might require further explanation from this point of view. On the other hand, supersymmetry fits well with some existing observations, and it will be spectacular to finally learn whether it arises.'
String theorists like Eva Silverstein can rationalize away any null result from LHC on the grounds LHC isn't enough energy, and the SUSY breaking scale is above EW scale, but what about neutralino non-detection via SuperCDMS?
ref
http://arxiv4.library.cornell.edu/abs/1005.0761
SUSY dark matter in light of CDMS II results: a comparative study for different models
Authors: Junjie Cao, Ken-ichi Hikasa, Wenyu Wang, Jin Min Yang, Li-Xin Yu
(Submitted on 5 May 2010)
Abstract: We perform a comparative study of the neutralino dark matter scattering on nucleon in three popular supersymmetric models: the minimal (MSSM), the next-to-minimal (NMSSM) and the nearly minimal (nMSSM). First, we give the predictions of the elastic cross section by scanning over the parameter space allowed by various direct and indirect constraints, which are from the measurement of the cosmic dark matter relic density, the collider search for Higgs boson and sparticles, the precision electroweak measurements and the muon anomalous magnetic moment. Then we demonstrate the property of the allowed parameter space with/without the new limits from CDMS II. We obtain the following observations: (i) For each model the new CDMS limits can exclude a large part of the parameter space allowed by current collider constraints; (ii) The property of the allowed parameter space is similar for MSSM and NMSSM, but quite different for nMSSM; (iii) The future SuperCDMS can cover most part of the allowed parameter space for each model.
Neutralinos are predicted to be abundant and stable based on SUSY-GUT big bang, enough to be dark matter.
It may be the supersymmetry breaking scale is so high that LHC may not be able to produce neutralinos.
The successor of Cryogenic Dark Matter Search CDMS II is Super-CDMS, with the sensitivity to detect neutralinos over its parameter space in most popular SUSY models. Hence, even at higher than LHC energies, the big bang should have produced neutralinos and these should be detectable. Ref below. In addition to Super-CDMS are other direct and indirect detection experiments that can detect neutralinos over its expected parameter space.
R-parity is required in most phenomenologically acceptable SUSY models, no R-parity leads to predictions in conflict with experiment esp baryon number and lepton number conservation.
So my question is if neither LHC, nor SuperCDMS, nor other direct and indirect experiments, such that say 3-bar or 4-bar, they can be said to not exist (in much the same way as SU(5) and SO(10) GUT experiments have been ruled out based on predicted proton lifetime)
is SUSY still possible? If several independent lines of research (i.e LHC, SuperCDMS, other detection experiments, even Tevatron)
rules out neutralinos as predicted by the minimal (MSSM), the next-to-minimal (NMSSM) and the nearly minimal (nMSSM), is there any reason to think R-parity conserving SUSY is a symmetry of nature?
http://www.telegraph.co.uk/science/science-news/3351261/Large-Hadron-Collider-What-will-it-find.html
Eva Silverstein, Stanford University, USA
'I'd be extremely puzzled if they don't find the Higgs, but wouldn't be devastated if they didn't come up with evidence for supersymmetry. Some of my intuition comes from string theory, an appealing candidate for a theory of all the forces of nature. According to many - perhaps most - versions of string theory, supersymmetry does not hold good at the energies probed by the LHC, so its discovery might require further explanation from this point of view. On the other hand, supersymmetry fits well with some existing observations, and it will be spectacular to finally learn whether it arises.'
String theorists like Eva Silverstein can rationalize away any null result from LHC on the grounds LHC isn't enough energy, and the SUSY breaking scale is above EW scale, but what about neutralino non-detection via SuperCDMS?
ref
http://arxiv4.library.cornell.edu/abs/1005.0761
SUSY dark matter in light of CDMS II results: a comparative study for different models
Authors: Junjie Cao, Ken-ichi Hikasa, Wenyu Wang, Jin Min Yang, Li-Xin Yu
(Submitted on 5 May 2010)
Abstract: We perform a comparative study of the neutralino dark matter scattering on nucleon in three popular supersymmetric models: the minimal (MSSM), the next-to-minimal (NMSSM) and the nearly minimal (nMSSM). First, we give the predictions of the elastic cross section by scanning over the parameter space allowed by various direct and indirect constraints, which are from the measurement of the cosmic dark matter relic density, the collider search for Higgs boson and sparticles, the precision electroweak measurements and the muon anomalous magnetic moment. Then we demonstrate the property of the allowed parameter space with/without the new limits from CDMS II. We obtain the following observations: (i) For each model the new CDMS limits can exclude a large part of the parameter space allowed by current collider constraints; (ii) The property of the allowed parameter space is similar for MSSM and NMSSM, but quite different for nMSSM; (iii) The future SuperCDMS can cover most part of the allowed parameter space for each model.
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