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Status of GMSB photons analysis

Status of GMSB photons analysis. Shilei Zang (slzang@pizero.colorado.edu) Bernadette Heyburn, Uriel Nauenberg University of Colorado, Boulder. SUSYBSM WG3/WG4 meeting, 24 Aug. 2007. Outline. Photonic GMSB sample Generator studies for signal events, and comparison with ORCA results

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Status of GMSB photons analysis

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  1. Status of GMSB photons analysis Shilei Zang (slzang@pizero.colorado.edu) Bernadette Heyburn, Uriel Nauenberg University of Colorado, Boulder SUSYBSM WG3/WG4 meeting, 24 Aug. 2007

  2. Outline Photonic GMSB sample Generator studies for signal events, and comparison with ORCA results Reconstructed objects Signal efficiency and background study Summary and next to do

  3. Photonic GMSB Sample • Bob Hirosky’s GMSB sample (prompt photon). Gen-Sim: CMSSW_1_4_6; Dig-Rec: CMSSW_1_5_3. About 8250 events (I used 7999 evts for this report) . • Lmd=100TeV; M_mess=2Lmd; N=1; tanBeta=15; sig(mu)=+1; M_top=175GeV; C_grav=1. (ctau=0.115mm, or ctau=0?) • MSEL=0 and MSUB(244)=1, only gg~g~g generated. (xSection~0.492pb) • Francesco’s GMSB sample (prompt photon). CMKINOSCARORCA • Same GMSB parameters as above Bob’s. • MSEL=39, all SUSY processes included. xSection(total SUSY)~0.439pb; xSection(gg~g~g)~0.05pb. • All the plots on Francesco’s sample are provided by Francesco.

  4. GMSB photons • Experimental signature • high pT photons • large MET due to gravitinos • multi-jets

  5. Generator studies for signal events • Start from generator level in order to check the GMSB sample, compare with ORCA results, and define the selection criteria for the future analysis. • Number of generator photons • PT and Eta of generator photons • MET from gravitinos and from gen • Quarks from SUSY particle • Neutralino’s vertex and flight distance

  6. Number of generator photons • Photons from neutralino decay: • BR of neutralino from Isajet: • BR(LSP+photon)~95% • BR(LSP+Z0)~3% • BR(LSP+ e+e-)~2% • BR(LSP+H0)~10-4% • 95%*95%=90.25% • 2*5%*95%=9.5% • 5%*5%=0.25% 2 photons ~90.14% 1 photon ~9.58% 0 photon ~0.29% Number of photons from NLSP decay per event

  7. PT of generator photons 1st photon CMSSW 2nd photon CMSSW PT(peak)~100GeV PT(peak)~40GeV 71.7% PT>90GeV 79.5% PT>30GeV PT PT 1st photon ORCA 2nd photon ORCA

  8. Eta of generator photons 1st photon CMSSW 2nd photon CMSSW Barrel: |eta|<1.479 ~89% in barrel ~78% in barrel Eta Eta 1st photon ORCA 2nd photon ORCA Eta Eta

  9. MET from gravitinos and from gen MET from neutrinos and gravitinos. CMSSW CMSSW peak~100GeV peak~140GeV ORCA ORCA

  10. MET from gravitinos vs from gen CMSSW

  11. Quarks from SUSY particle • Mother of selected quarks is a SUSY particle. • Sample includes only gg~g~g process, and BR(~gSUSY+qqbar)~98.6%, and 98.6%*98.6%=97.2%. quarks(4,6,8,10)~97% Number of quarks from SUSY decay Type of quarks (pid) 4 quarks ~91.7% u c d s qbar 2 quarks ~3.1% 6 quarks ~4.5% b 0 quark ~0.025% 8 quarks ~0.64% 10 quarks ~0.038%

  12. Number of quarks per event • CMSSW result: Sample includes only gg~g~g process • ORCA result: Sample includes all SUSY processes CMSSW ORCA Number of quarks from SUSY particle

  13. PT and Eta of quarks PT CMSSW PT(peak)~160GeV CMSSW 87.9% PT>100GeV PT Eta ORCA ORCA PT

  14. Neutralino’s Vertex Vx Vy • Vetex smeared with Gauss (sigX=sigY=0.0015cm, sigZ=5.3cm) • Gravitino’s vetex minus Neutralino’s vetex equals exactly zero. So ctau=0 exactly? (ctau should equal 0.1144mm?) Vz

  15. Reconstructed objects • Use SusyAnalyzer under CMSSW_1_5_3 • The reconstructed objects are filtered, cleaned, and driven by SusyAnalyzer. • SusyAnalyzer’s default parameters (cuts) are used: photonEtaMax=2.5; photonPtMin=20GeV; jetPtMin=30GeV. • Multiplicity of jets and photons • PT and eta of jets and photons • MET from Calorimeter and Recoil

  16. Multiplicity of jets/photons and Pt of jets Number of jets Number of photons 62.9% >=2 phorons PT of the1st jet PT of the 2nd jet

  17. PT and Eta of photons 1st photon 2nd photon PT(peak)~100GeV PT(peak)~45GeV PT PT 1st photon 2nd photon Eta Eta

  18. MET from Calorimeter, Recoil, and Gen MetCalo MetRecoil peak~110GeV peak~120GeV mean~1.02 mean~0.81 MetRecoil/MetCalo MetRecoil/MetGen

  19. Signal efficiency • Francesco’s 2 gamma selection: • PT(1st gamma)>90GeV • PT(2nd gamma)>30GeV • Abs(eta)<1.479 for both of the gamma (barrel). • 3022 events selected with Francesco’s 2 gamma selection. • Further require MetRecoil>130GeV  1796 events. • Signal efficiency= 1796/7210 =24.9%

  20. MET distribution after Francesco’s 2 gamma selection Final MET of signal sample

  21. Background study • Francesco listed the following bkg need to analyze: • QCD: 1) qcd jets (0<pT_hat<4000GeV) 2) gamma jet (pT_hat>40GeV) • EW background 1) W+jets and Z+jets (0<pT_hat<2200GeV) 2) ttbar inclusive • Others 1) W+gamma 2) Z+gamma 3) WW, ZZ, WZ • First test with 100000 PhotonJets_Pt_300_500. xSection(bkg)=8.2pb. • xSection(GMSB)=0.492pb. Scale factor: 7999/(100000*0.492/8.2)=1.33

  22. MET of GMSB and Bkg • Further require MetRecoil>130GeV  • Signal efficiency=24.9%; • Bkg(PhotonJets) efficiency = 0.189% MET of PhotonJets_Pt_300_500 (scaled) MET of GMSB

  23. Summary and next to do • Summary • Generator signal events studied to test the sample and compare with ORCA results. CMSSW results are similar as ORCA’s. • Reconstructed objects simply analyzed to understand them and SusyAnalyzer • Tried a background analysis • With Francesco’s cuts, give the efficiency of the signal and of the background sample. • Next to do • Further analyze the reconstructed objects after matching with generator particles. • Find a set of analysis variables to select 2 gamma, and determine the cuts • Generate some GMSB second vertex (not prompt) photons samples. • Establish our analysis strategy for GMSB second vertex photons analysis.

  24. Thank you!

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