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Natural Solution to the Supersymmetry Electroweak Fine-Tuning Problem. Tianjun Li Institute of Theoretical Physics, Chinese Academy of Sciences Yellow Mountain, May 9, 2014. Outline. I. Introduction II. The SUSY EW Fine-Tuning Problem III. The MSSM with the Heavy LSP IV. No-Scale F-SU(5) - PowerPoint PPT Presentation
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Natural Solution to the Supersymmetry Electroweak Fine-Tuning Problem
Tianjun Li
Institute of Theoretical Physics, Chinese Academy of Sciences
Yellow Mountain, May 9, 2014
Outline
• I. Introduction• II. The SUSY EW Fine-Tuning Problem• III. The MSSM with the Heavy LSP• IV. No-Scale F-SU(5)• V. General Natural Solution• VI. Summary
I. Introduction
Gauge Hierarchy Problem
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Gauge Coupling Unification
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BICEP2
• The inflation scale is the GUT scale.
• The inflaton potential: non-renormalized theorem for superpotential.
• M^2_{EW} \sim M_{\nu} H
II. SUSY EW Fine-Tuning Problem
• Higgs Boson Mass
• LHC SUSY Search
• Fine-Tuning Problem
• Stops: Enhancing Higgs mass
•Correct the quartic coupling and enhance Higgs boson mass
•Stop maximal mixing relaxing the little hierachy problem•Without large stop mixing, we need •10 TeV stops, rendering a fine-tuning
%01.0~/~/ 2222~ ZZH mmmmtu
•Tree-level upper bound: Z-boson mass mZ = 91.7 GeV•In the MSSM, Higgs quatic coupling at tree-level•is determined by EW gauge couplings
222~6)tan/(t
mAX tt •Stop maximal/large mixing can improves it by about two orders
•The Lightest CP-Even Higgs Boson Mass
LHC SUSY Search
• Gluino and squark masses around 1.7 TeV
in the CMSSM and mSUGRA.
• Gluino mass low bound is around 1.3 TeV.
• Stop/sbottom mass low bounds are around 600 GeV.
• If the LSP is heavy, all the bounds can be relaxed.
mSUGRA/CMSSM
•Gluino 1.4TeV
•Squark 1.8TeV
•https://twiki.cern.ch/twiki/bin/view/AtlasPublic/CombinedSummaryPlots#SusyGttSummary
Simplified model: MET+jets
•ATLAS-CONF-2013-047
•Gluino 1.8TeV
•Squark 1.8TeV
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Supersymmetric SMs
• Displaced Supersymmetry
• Double Invisible Supersymmetry
III. The MSSM with Heavy LSP
Phenomenological Constraints
• The anomalous magetic momentum of the muon
• Higgs boson mass
• LHCb
Parameter Scan
IV. No-Scale F-SU(5)
Flipped SU(5) Model
No-Scale Supergravity
Supergravity Potential:
Natural Solution to EW SUSY Fine-Tuning
Natural Solution to EW SUSY Fine-Tuning
No-Scale F-SU(5)
• \mu problem: Giudice-Masiero (GM) mechanism
• All the mass parameters are proportional to
Natural Solution to the EWFT problem:
V. General Natural Solution
• Only one chiral superfield or modulus breaks supersymmetry.
• All the supersymmetry breaking soft terms are
proportional to gravitino mass.• \mu term is generated via the GM mechanism after
supersymmetry breaking in the MSSM or NMSSM.
• No-scale supergravity or M-theory on S^1/Z_2.
VI. Summary
• The MSSM with Heavy LSP
• If all the mass parameters arise from gravitino mass, the fine-tuning will be order one.
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