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Exploring W/Z+Jets in Electron Channel for Particle Physics Research

Investigate W/Z+Jets in electron channel at the USCMS First Physics Workshop for precise luminosity monitoring and detector calibration.These events are crucial for pQCD studies, providing insight into unexplored LHC regimes with unique boson mass scales. Address irreducible backgrounds for SM processes and new physics searches, such as top production, SUSY, and Higgs searches using datasets from CSA07 and ALPGEN simulations. Explore electron selection, jet removal strategies, and key event parameters like electron Pt, Jet Pt, MET, and W transverse mass. Witness Z mass peaks even in events with 5 jets, showcasing the experiment's capabilities.

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Exploring W/Z+Jets in Electron Channel for Particle Physics Research

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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 Electron Pt Pt (GeV) Christos Lazaridis USCMS First Physics Workshop

  16. 1st/2nd Jet Pt Christos Lazaridis USCMS First Physics Workshop

  17. 3rd/4th Jet Pt Christos Lazaridis USCMS First Physics Workshop

  18. MET MET(GeV) (GeV) Christos Lazaridis USCMS First Physics Workshop

  19. W Transverse Mass Mt,W calculated based on electron and MET information Christos Lazaridis USCMS First Physics Workshop

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