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New physics searches with Z(ll) + X + E T miss final state

New physics searches with Z(ll) + X + E T miss final state. N. Panikashvili and D. Harper University of Michigan, US. General Gauge Mediation (GGM) - motivation. Thanks to Shih/Ruderman ArXiv 0911.4130. effort to formulate gauge mediation in the model independent way

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New physics searches with Z(ll) + X + E T miss final state

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  1. New physics searches with Z(ll) + X + ETmiss final state N. Panikashvili and D. Harper University of Michigan, US

  2. General Gauge Mediation (GGM) - motivation Thanks to Shih/Ruderman ArXiv 0911.4130 effort to formulate gauge mediation in the model independent way there is no hierarchy between M of colored states (squarks, gluinos) and uncolored states (wino, bino, higgsinos, sleptons). The discovery of GGM becomes possibile even with early LHC data in regions of parameter space not probed by any Tevatron searches At gauge mediation LSP is gravitino NLSP is lightest neutralino, stau …. Neutralino is mixture of bino, wino and higgsinos If Neutralino is higgsino like, it decays to ~X1 Z + ~G or ~X1 h + ~G and leads to the final states such as ZZ+MET, Zh+MET … We concentrate on the final state: Z(ll) + jets + MET Tevatron limits: Z(ll) + jets + MET Jets + MET

  3. GGM higgsino – like neutralino grid production Thanks to Shih/Ruderman ArXiv 0911.4130 • 40 points (50K each one) which cover M(gluino) from 300GeV to 700GeV and M(higgsinos) from 110GeV up to 690GeV • Parameters of production: • EF: at least one Zll • Details of the grid: • Mass spectrum, LO cross sections, filter efficiency, details of production: https://twiki.cern.ch/twiki/bin/view/AtlasProtected/GGMHiggsinoZGrid

  4. GGM grid – different production mechanism • We investigated the kinematics of the following points we selected 4 points: • M(~g) =300GeV, M(~h)=120GeV • M(~g) =700GeV, M(~h)=120GeV • M(~g) =300GeV, M(~h)=290GeV • M(~g) =700GeV, M(~h)=690GeV

  5. Dominant production:electroweak Dominant production:strongqqbar~g~g, gg~g~g

  6. MC signal cross - section • Prospino 2 • NLO was calculated using 4 different processes

  7. We are using Standard SUSY di-lepton selection In addition we require 81GeV < M(ll) < 101GeV, which defines our preselection Electrons (1fb-1) Muons (689.3pb-1) Event Selection (need an update for 1fb-1)

  8. OS EE tight + ISO + mass (17% - 45%) pre-selection results: efficiency of the MC signal OS MM tight + ISO + mass (6% - 45%) Efficiency (%) Efficiency (%) • Different efficiencies due to different pT spectra • Different pT cuts: pT = 8GeV/10 GeV, pTleading = 20GeV/25 GeV muons/electrons

  9. pre-selection results (MET) • MET depends on the mass of NLSP, the lower mass the lower MET

  10. Large MET region

  11. Signal region 1: MET > 200GeV + inclusive leptons • Significance S/√B S/√B Efficiency (%) Z(ee)+MET>150GeVN(data) = 5N(SM) = 3.1  0.2

  12. pre-selection results (N jets) • Not optimal variable for the GGM searches with dominant weak production mechanism: M(~g) = 700GeV and M(~h) =120GeV

  13. Leading jet pT

  14. Sub-leading jet pT

  15. Improve of the significance in certain region Signal region 2: MET > 100GeV, Njets>3 S/√B Efficiency (%) Z(ee)+MET>100GeVN jets>3N(data) = 20N(SM) = 13.6  0.5 • N(SM) – is from MC only: ttbar, dibosons, single top, inclusive Z • Errors are statistical only

  16. pre-selection results (HT) • HT is useful for points with high M(NLSP) and M(~g)

  17. Signal region3: MET>150GeV HT>350GeV N(data) = 7N(SM) = 4.1  0.2

  18. Effective Mass

  19. Leading lepton pT

  20. N of leptons

  21. Plans • Background estimation - • Systematic • Enlarge GGM parameter space for the case of Wino • submitted

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