Stau Coannihilation, Compressed Spectrum and SUSY Discovery at the LHC

Abstract

The lack of observation of supersymmetry thus far implies that the weak supersymmetry scale is larger than what was thought before the LHC era. This observation is strengthened by the Higgs boson mass measurement at $\sim 125$ GeV which within supersymmetric models implies a large loop correction and a weak supersymmetry scale lying in the several TeV region. In addition if neutralino is the dark matter, its relic density puts further constraints on models often requiring coannihilation to reduce the neutralino relic density to be consistent with experimental observation. The coannihilation in turn implies that the mass gap between the LSP and the NLSP will be small leading to softer final states and making the observation of supersymmetry challenging. In this work we investigate stau coannihilation models within supergravity grand unified models and the potential of discovery of such models at the LHC in the post Higgs boson discovery era. We utilize a variety of signal regions to optimize the discovery of supersymmetry in the stau coannihilation region. In the analysis presented we impose the relic density constraint as well as the constraint of the Higgs boson mass. The range of sparticle masses discoverable up to the optimal integrated luminosity of the HL-LHC is investigated. It is found that the mass difference between the stau and the neutralino does not exceed $\sim 20$ GeV over the entire mass range of the models explored. Thus the discovery of a supersymmetric signal arising from the stau coannihilation region will also provide a measurement of the neutralino mass. The direct detection of neutralino dark matter is analyzed within the class of stau coannihilation models investigated. The analysis is extended to include multi-particle coannihilation where stau along with chargino and the second neutralino enter in the stau coannihilation process.

32 pages, 12 figures

References in corpus (23)

• Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC
• Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC
• PYTHIA 6.4 Physics and Manual
• The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations
• Ultralight scalars as cosmological dark matter
• micrOMEGAs4.1: two dark matter candidates
• The Higgs sector of the phenomenological MSSM in the light of the Higgs boson discovery
• Non-universal gaugino masses from non-singlet F-terms in non-minimal unified models
• Constraining the Natural MSSM through tunneling to color-breaking vacua at zero and non-zero temperature
• Implications of the Higgs Boson Discovery for mSUGRA
• GUT-inspired SUSY and the muon g-2 anomaly: prospects for LHC 14 TeV
• The Landscape of Sparticle Mass Hierarchies and Their Signature Space at the LHC
• Supersymmetric Higgs and Radiative Electroweak breaking
• Determining the Dark Matter Relic Density in the Minimal Supergravity Stau-Neutralino Coannihilation Region at the Large Hadron Collider
• Light Higgses at the Tevatron and at the LHC and Observable Dark Matter in SUGRA and D Branes
• Revisiting fine-tuning in the MSSM
• An Ultralight Axion in Supersymmetry and Strings and Cosmology at Small Scales
• Low Mass Gluino within the Sparticle Landscape, Implications for Dark Matter, and Early Discovery Prospects at LHC-7
• Mixed Neutralino Dark Matter in Nonuniversal Gaugino Mass Models
• Supergravity gauge theories strike back: There is no crisis for SUSY but a new collider may be required for discovery
• Non-universal gaugino and scalar masses, hadronically quiet trileptons and the Large Hadron Collider
• Sparticle Mass Hierarchies, Simplified Models from SUGRA Unification, and Benchmarks for LHC Run-II SUSY Searches
• SUSY model and dark matter determination in the compressed-spectrum region at the ILC

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• Gluino-SUGRA scenarios in light of FNAL muon g-2 anomaly
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• Leptonic WIMP Coannihilation and the Current Dark Matter Search Strategy
• Supersymmetry at a 28 TeV hadron collider: HE-LHC
• Naturalness, the Hyperbolic Branch and Prospects for the Observation of Charged Higgs at High Luminosity LHC and 27 TeV LHC
• Detecting hidden sector dark matter at HL-LHC and HE-LHC via long-lived stau decays
• Supergravity Models with 50-100 TeV Scalars, SUSY Discovery at the LHC and Gravitino Decay Constraints
• Mixed hidden sector/visible sector dark matter and observation of CP odd Higgs at HL-LHC and HE-LHC
• On the coverage of neutralino dark matter in coannihilations at the upgraded LHC
• Vacuum stability in stau-neutralino coannihilation in MSSM
• Sensitivity Reach on the Heavy Neutral Leptons and $\tau$-Neutrino Mixing $|U_{\tau N}{|}^2$ at the HL-LHC
• Corrections to Yukawa couplings from higher dimensional operators in a natural SUSY $\mathsf{SO}(10)$ and HL-LHC implications
• LHC phenomenology with hidden sector dark matter: a long-lived stau and heavy Higgs in an observable range
• High Energy Physics and Cosmology at the Unification Frontier: Opportunities and Challenges in the coming years
• A Stronger Case for Superunification Post Higgs Boson Discovery
• Connecting Particle Physics and Cosmology: Measuring the Dark Matter Relic Density in Compressed Supersymmetry at the LHC