drien Renaud (LAL-Orsay IN2P3/CNRS and Université Paris-Sud) or the Atlas collaboration. Search for supersymmetry via resonant final states with the ATLAS detector HEP2012 – Valparaiso, Chile January 6, 2012 • PRL (arXiv:1103.5559) • EPJC (arXiv:1109.3089) • EPJCL (arXiv:1110.2693)
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Adrien Renaud (LAL-Orsay IN2P3/CNRS and Université Paris-Sud) for the Atlas collaboration. Search for supersymmetry via resonant final states with the.
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Adrien Renaud (LAL-Orsay IN2P3/CNRS and Université Paris-Sud)for the Atlas collaboration.
Search for supersymmetry via resonant final states with the
ATLAS detector
HEP2012 – Valparaiso, Chile January 6, 2012
• PRL (arXiv:1103.5559)• EPJC (arXiv:1109.3089)• EPJCL (arXiv:1110.2693)
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Overview
1) Introduction 2) RPV tau sneutrino search in the eμ final state3) Scalar gluon search in the four jets final state4) Conclusion
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Susy via Resonances ??MSSM:- particles with L or B numbers- renormalizable terms violate L or B
Potential disaster:- much too fast proton decay
RP conservation:- PR = (-1)2S • (-1)3(B-L)
- forbids L and B violating terms- PR= +1 (-1) for SM (SUSY) particles- LSP stable, in all cascade decays, DM
No resonances--> look for an excess in SM tail
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Susy via Resonances ??Beyond MSSM with RP conservation:
Extended supersymmetry: -- minimal ? new pheno ? flavor-violation ? dirac gauginos ? … -- new particles with PR = +1 --> resonances in RP conserved susy !
RP violated susy: -- B and L conservation ? neutrino masses and mixing ? …
-- some of the couplings have to be small --> stable proton
--> Scalar-gluon search
--> RPV tau sneutrino search
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Introduction to RPV Sneutrino search
Search for RPV sneutrino with lepton number violation decay:
- eμ clean signature with low SM background- previous limit from low energy tau branching ratio:
λ’311 < 0.11 and λ312 < 0.07 for Mslepton = Msquark =
100 GeV
λ’311 ≠ 0 and λ312 ≠ 0
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Event Selection
Using L=1.07 fb-1: 2011 dataSingle lepton (e, μ) trigger (100±1%)
Electron:-- pT > 25 GeV-- |η| < 1.37 or 1.42 < |η| < 2.47-- isolated in EM calorimeter-- shower shape requirements
Muon:-- pT > 25 GeV-- |η| < 2.4-- reconstructed in ID and MS-- isolated in the ID
- Exactly one muon and one electron with opposite-sign charge
- No requirements on #jets and ETmiss
Signal generated with HERWIG + JIMMY + NLO k-factor
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Highest invariant mass (662 GeV) eμ event
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Backgrounds Physics backgrounds (real leptons) -- Z/γ*->tau,tau top pair single top WW, WZ, ZZ -- Estimated using MC corrected for data/MC differences
Instrumental background (lepton faked by photon or jet) -- W/Z+γ estimated using MC -- SM multijet and W/Z+jets estimated using data-driven matrix method: 1) Define loose and tight lepton definitions 2) Apply on all events to get NTT,NTL,NLT,NLL
3) Determine efficiency (r) and fake rate (f) for a lepton that has passed the loose definition to also pass the tight definition 4) Solve the 4*4 matrix:
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Data / Background
Kolmogorov-Smirnov test probability: 56%Data consistent with absence of new physics