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Study of Z+Jets background to SUSY LM1 Point

Study of Z+Jets background to SUSY LM1 Point. Huseyin Topakli University of Ç ukurova Anwar Bhatti University of Rockefeller Gheorghe Lungu University of Rockefeller 12-02-08 JetMet Topology Group Meeting. INTRODUCTION.

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Study of Z+Jets background to SUSY LM1 Point

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  1. Study of Z+Jets background to SUSY LM1 Point Huseyin Topakli University of Çukurova Anwar Bhatti University of Rockefeller Gheorghe Lungu University of Rockefeller 12-02-08 JetMet Topology Group Meeting

  2. INTRODUCTION • The Minimal Supersymmetry Model (MSSM) is the minimal extension of the Standard Model (SM) particle content. Its gauge sector is fully determined by Supersymmetry. The mSUGRA model of supersymmetry is determined by 5 free parameters defined at the Grand Unification (GUT) scale. The free parameters are In the SUSY signal sample the large MET is resulting from the two lightest neutralinos in the final states. The missing transverse energy plus multi-jets final state has been a canonical signature for SUSY searches.

  3. Susy LM1 Point Mgluino ~600 GeV Msquark ~ 550 GeV Xsec ~42 pb Low mass test points were chosen to evaluate the sensitivity to SUSY signals in the early period of the LHC but above the Tevatron reach. 250 60

  4. Decays. In the SUSY signal sample The large MET is resulting from The two lightest neutralinos in the final states.

  5. Estimation of Z->nunu+Jets using Z->mumu+Jets. • The ratio will be use to normalize the Z+Jets Monte Carlo predictions. • When we collect real data, the normalization procedure will be credible if the MEt shape in the simulation for Z->nunu+2Jets is in good agrement with the MEt shape in the Z->mumu+2Jets data. (a) (b)

  6. Elektroweak Background Component (Z+Jets) • Major Background: QCD, ttbr, • Events with large and 3 jets in the final state are expected from (3. jet originating from the hadronik decay) process.

  7. HT,MHT, HT+MHT Distributions for QCD, LM1 and Z->NuNu Samples.

  8. Analysis Setup. • CMSSW_1_6_7 was used • and samples are CSA07 samples. • 11 pt bins were used for (0-1TeV) (Pt=20-30,80-120,120-170 were not able to run) • 13 pt bins were used for (0-1TeV) (Pt=50-80 is not available) • LM1 Susy Sample was generated by Gheorghe Lungu with CMSSW_1_5_2

  9. Muon Cuts.(Z->mumu+Jets Pt=30-50GeV) • Pt and Eta cuts applied to each reconstructed muons in order to • efficently select the signal and reject the background effects. Pt>7GeV |Eta|<2.4

  10. Z From Muon Pairs(Pt=30-50GeV). Z mass cut is |ZMass-91.2|<10GeV

  11. Pt and Eta distributions of CaloJets and CorrCaloJets.(Pt=30-50GeV) • Eta and Phi cuts were applied to calojets. Pt>14GeV and |Eta|<3. “rawJets” “CorrJets” Pt Mean is ~24.5 GeV before corrections, after the corrections Pt mean is ~28.5GeV. Pt is increased ~17% due to corrections. |JetEta|<3

  12. Pt of Leading (Cor)CaloJets. No Zmass cut Zmass Window • The blue curve is indicated that Pt is calculated from Zmass window.

  13. Pt of Second (Cor)CaloJets. No Zmass Cut Zmass wind

  14. Pt of Third (Cor)CaloJets. No Zmass Zmass Wind

  15. HT of (Cor)CaloJets. No Zmass Cut Zmass Win

  16. MHT of (Cor)CaloJets.. Red curves indicates that No Zmass cut. Blue curves indicates that from Z mass window. From Met Object

  17. Xsec_Vs_Lead(Cor)CaloJetPt Due to missing Pt range (80-120,120-170GeV)

  18. XSec_Vs_Second(Cor)CaloJetPt. XSec_Vs_Thrd(Cor)CaloJetPt.

  19. XSec_Vs_HT(Cor)CalJets

  20. XSec_Vs_MHT(Cor)CalJets If JetsSize>=2 and MHT>100GeV

  21. missEt From CaloMet Obj.

  22. Next Things. • Use corrected muons • Use the Type-I Met correction • Use Z->ee+Jets samples.

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