Mixed sneutrinos, dark matter, and the CERN LHC

Zachary Thomas, David Tucker-Smith, Neal Weiner

    Research output: Contribution to journalArticle

    Abstract

    We study the phenomenology of supersymmetric models in which gauge-singlet scalars mix with the minimal supersymmetric standard model (MSSM) sneutrinos through weak-scale A terms. After reviewing the constraints on mixed-sneutrino dark matter from measurements of ΩCDM and from direct-detection experiments, we explore mixed-sneutrino signatures relevant to the LHC. For a mixed-sneutrino lightest supersymmetric particle (LSP) and a right-handed slepton next-to-lightest supersymmetric particle (NLSP), decays of the lightest neturalino can produce opposite-sign, same-flavor (OSSF) dileptons with an invariant-mass distribution shifted away from the kinematic end point. This signature is possible for parameters that lead to a cosmologically viable mixed-sneutrino LSP. We also consider signatures that require larger mixing angles than preferred for mixed-sneutrino dark matter, but which are possible regardless of whether a mixed-sneutrino is the LSP. In some parameter regions, the charginos and neutralinos produced in cascades all decay dominantly to the lighter sneutrinos, leading to a kinematic edge in the jet-lepton invariant-mass distribution from the decay chain q∼→χ-q→ν∼*lq, without an OSSF dilepton signature. We explore the possibility of using mass-estimation methods to distinguish this mixed-sneutrino jet-lepton signature from an MSSM one. Finally, we consider signatures associated with Higgs-lepton or Z-lepton production in cascades involving the heavier sneutrinos.

    Original languageEnglish (US)
    Article number115015
    JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
    Volume77
    Issue number11
    DOIs
    StatePublished - Jun 18 2008

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    Dark Matter
    dark matter
    Signature
    signatures
    leptons
    Decay
    mass distribution
    Cascade
    Standard Model
    Kinematics
    cascades
    kinematics
    particle decay
    Invariant
    Right handed
    reviewing
    Phenomenology
    decay
    End point
    Higgs

    ASJC Scopus subject areas

    • Physics and Astronomy(all)
    • Nuclear and High Energy Physics
    • Mathematical Physics

    Cite this

    Mixed sneutrinos, dark matter, and the CERN LHC. / Thomas, Zachary; Tucker-Smith, David; Weiner, Neal.

    In: Physical Review D - Particles, Fields, Gravitation and Cosmology, Vol. 77, No. 11, 115015, 18.06.2008.

    Research output: Contribution to journalArticle

    Thomas, Zachary ; Tucker-Smith, David ; Weiner, Neal. / Mixed sneutrinos, dark matter, and the CERN LHC. In: Physical Review D - Particles, Fields, Gravitation and Cosmology. 2008 ; Vol. 77, No. 11.
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