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W/Z + Jets in the electron channel

W/Z + Jets in the electron channel. Christos Lazaridis Kira Grogg University of Wisconsin-Madison. USCMS First Physics Workshop Fermilab, October 11-13, 2007. W/Z + Jets. High cross section makes them useful… as a precise luminosity monitor as a high-statistics detector calibration tool

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W/Z + Jets in the electron channel

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  1. W/Z + Jets in the electron channel Christos Lazaridis Kira Grogg University of Wisconsin-Madison USCMS First Physics Workshop Fermilab, October 11-13, 2007

  2. W/Z + Jets • High cross section makes them useful… • as a precise luminosity monitor • as a high-statistics detector calibration tool • to demonstrate the performance of the CMS experiment • Good test of pQCD at high Q2 • LHC will reach a regime never probed before! • The mass of the bosons provide the necessary hard scale to perform pQCD calculations • W/Z+Jets are irreducible backgrounds for interesting SM processes (top production) and top searches for new physics (SUSY and Higgs searches) Christos Lazaridis USCMS First Physics Workshop

  3. Datasets • Used data produced for CSA07 • Z+N jets, N = 0…5 • W+N jets, N = 0…5 • ALPGEN 2.12 • GEN-SIM: 1_4_6 • DIGI-RECO: 1_6_0 https://twiki.cern.ch/twiki/bin/view/Main/AlpgenSummer07 Christos Lazaridis USCMS First Physics Workshop

  4. Selecting Zee events Christos Lazaridis USCMS First Physics Workshop

  5. L1 Objects L1 trigger keeps electrons above 63GeV Et: 7-bit value in linear scale (.5GeV resolution) Christos Lazaridis USCMS First Physics Workshop

  6. Highest Electron Pt Christos Lazaridis USCMS First Physics Workshop

  7. Electrons Pt Christos Lazaridis USCMS First Physics Workshop

  8. Removing Electrons from Jets collection Keeping jets that don’t have a nearby electron within a cone ΔR<0.15… Pt,e/Pt,Jet Keeping >0.85 ΔR Jet-Closest e Keeping >0.15 …and the ratio Pt,electron/Pt,Jet > .85 Christos Lazaridis USCMS First Physics Workshop

  9. Jet #1 Pt Christos Lazaridis USCMS First Physics Workshop

  10. Jet #2 Pt Christos Lazaridis USCMS First Physics Workshop

  11. Jet #3 Pt Christos Lazaridis USCMS First Physics Workshop

  12. Z Invariant Mass We can see a Z mass peak even with 5 Jet events! (in theory) Christos Lazaridis USCMS First Physics Workshop

  13. Z Pt Christos Lazaridis USCMS First Physics Workshop

  14. Selecting W events Christos Lazaridis USCMS First Physics Workshop

  15. Electron Pt Christos Lazaridis USCMS First Physics Workshop

  16. 1st Jet Pt Christos Lazaridis USCMS First Physics Workshop

  17. 2nd/3rd Jet Pt Christos Lazaridis USCMS First Physics Workshop

  18. MET • MET ≈0.5 mW (40 GeV) Christos Lazaridis USCMS First Physics Workshop

  19. W Transverse Mass cuts: pT,e >15 GeV MET > 30 GeV Mt,W calculated based on electron and MET information Christos Lazaridis USCMS First Physics Workshop

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