W( → eν)+jets electron selection

1. W(→eν)+jetselectron selection Kira Grogg UW-Madison 03 June, 2009 K. Grogg, UW-Madison

2. Outline • Goals & Samples • S/√(S+B) and Efficiency of electron variables for 0, 1, 2, 3+ jets • All plots use progressive cuts: σiηiη→ Δφin → Δηin→ CombRelIso • S/√(S+B) and Efficiency of electron variables for bins of HT • All plots use progressive cuts: σiηiη→ Δφin → Δηin→ CombRelIso • HT = Sum of ET of electrons and all jets • S/√(S+B) and Efficiency of electron variables vs number of jets in the event • Electron pT & η, MET, W mT, W pT, jet pT & η for 1, 2, 3, 4+ jets • Using ID cuts based on W+1 jets K. Grogg, UW-Madison

3. Goals • Long term • W + jets cross section measurement in 200 pb-1 • Investigate W pT spectrum, jet ET and multiplicity distributions • Short term • Determine appropriate electron selection for W+ ≥1 jet events • Events with more jets have higher QCD backgrounds • Jet is an iterativeCone5 Particle Flow jets of pT > 15 GeV K. Grogg, UW-Madison

4. Signal + Background Samples • W+jets • Cross section 40 nb-1 • /Wjets/Summer08_IDEAL_V11_redigi_v1/GEN-SIM-RECO • QCD • Cross section X-Y - 20-30: 0.40 mb-1, 30-80: 0.10 mb-1, 80-170: 1.9*103 mb-1 • /QCD_Emenriched_PtXtoY/Summer08 _IDEAL_V11_redigi_v2/GEN-SIM-RECO • Z+jets • Cross section 3.7 nb-1 • /ZJets/Summer08_IDEAL_V11_redigi_v1/GEN-SIM-RECO • Ttbar+jets • Cross section 317 pb-1 • /TtJets/Summer08_IDEAL_V11_redigi_v1/GEN-SIM-RECO • Using PAT and Particle Flow with CMSSW_2_2_9 UW-Madison

5. Electron ID cuts • Three types looked at • V9 tuned cuts for W→eν • Given in 12 May General EWK meeting • http://indico.cern.ch/materialDisplay.py?contribId=3&materialId=slides&confId=56236 • V11 tuned cuts for W→eν • CMS AN 2009/98 • Also in 22 May EWK electrons meeting • http://indico.cern.ch/materialDisplay.py?contribId=0&materialId=slides&confId=56256 • My cuts tuned for W+1 jets K. Grogg, UW-Madison

6. S/√(S+B) & Efficiency for e ID cuts, by # of jets • Barrel Electrons • -- 0 jets • -- 1 jet • -- 2 jets • -- 3+ jets | V9 cuts | V11 cuts | My cuts | V11 cuts | V9 cuts σiηiη Δφin Δηin K. Grogg, UW-Madison

7. S/√(S+B) & Efficiency for e ID cuts, by # of jets • Endcap Electrons • -- 0 jets • -- 1 jet • -- 2 jets • -- 3+ jets | V9 cuts | V11 cuts | My cuts σiηiη Δφin Δηin K. Grogg, UW-Madison

8. S/√(S+B) & Efficiency for e ID cuts, by HT • Barrel Electrons • HT < 50 • 50 < HT < 100 • 100 < HT < 200 • HT > 200 | V9 cuts | V11 cuts | My cuts | My cuts | V9 cuts σiηiη Δφin Δηin K. Grogg, UW-Madison

9. S/√(S+B) & Efficiency for e ID cuts, by HT • Endcap Electrons • HT < 50 • 50 < HT < 100 • 100 < HT < 200 • HT > 200 | V9 cuts | V11 cuts | My cuts | My cuts | V9 cuts σiηiη Δφin Δηin K. Grogg, UW-Madison

10. S/√(S+B) & Efficiency for iso cuts, by Jets and HT After making My Id cuts By jet By HT 0 jets 1 jet 2 jets 3+ jets HT < 50 50 < HT < 100 100 < HT < 200 HT > 200 CombRelIso CombRelIso K. Grogg, UW-Madison

11. ID S/√(S+B) by number of jets • Cuts are progressive • --- V9 Cuts • --- V11 Cuts • --- My Cuts σiηiη S/√(S+B) of σiηiη My cuts and V9 cuts have better S/√(S+B) # PF jets in event Δφin Δηin S/√(S+B) of Δηin S/√(S+B) of Δφin # PF jets in event # PF jets in event K. Grogg, UW-Madison

12. ID Efficiency by number of jets • Cuts are progressive • --- V9 Cuts • --- V11 Cuts • --- My Cuts Efficiency of σiηiη σiηiη My cuts have worse efficiency V11 cuts have best (overall looser) # PF jets in event Efficiency of Δφin Efficiency of Δηin Δφin Δηin # PF jets in event # PF jets in event K. Grogg, UW-Madison

13. Iso Efficiency and S/√(S+B) by number of jets • ID cuts have been applied • --- V9 Cuts • --- V11 Cuts • --- My Cuts S/√(S+B) Efficiency CombRelIso CombRelIso My cuts and V9 cuts have slightly better S/√(S+B) than V11 cuts My cuts and V9 cuts have worse efficiency than V11 cuts K. Grogg, UW-Madison

14. Comparison of ID cuts For W+≥1 jets events, 200 pb-1 • For V11 samples, the W→eν cuts tuned for V9 have the best S/√(S+B) for W+≥1 jets events K. Grogg, UW-Madison

15. Expected events for 200 pb-1, √s = 10 Tev • Selection • Electron |η| < 2.4, pT > 20 • V9 tuned electron ID cuts • Electron CombRelIso < 0.1 • No 2nd electron • W transverse mass window: 55 < mT < 105 K. Grogg, UW-Madison

16. Electron pT for 1, 2, 3, 4+ jets K. Grogg, UW-Madison

17. Electron η for 1, 2, 3, 4+ jets K. Grogg, UW-Madison

18. MET for 1, 2, 3, 4+ jet events MET, 1 reco jet MET, 2 reco jets MET, 3 reco jets K. Grogg, UW-Madison

19. W mT for 1, 2, 3, 4+ jet events mT, 1 reco jet mT, 2 reco jets mT, 3 reco jets K. Grogg, UW-Madison

20. W pT for 1, 2, 3, 4+ jet events pT, 1 reco jet pT, 2 reco jets pT, 3 reco jets K. Grogg, UW-Madison

21. Jet pT for 1, 2, 3, 4+ jets K. Grogg, UW-Madison

22. Jet Y for 1, 2, 3, 4 jets K. Grogg, UW-Madison

23. Conclusions/Next steps • W+≥1 jet events need looser ID cuts than W→eν events • Will use ID cuts based on W→eν V9 tuned cuts • Given in General EWK talk 12 May, 2009 • Overall acceptance of full electron selection: 48-54% • Overall acceptance including mT window: 33-41% • Moving on… • Reduce top background • Reconstruct invariant mass of two jets • In progress K. Grogg, UW-Madison

24. Backup K. Grogg, UW-Madison

25. Electron ID cut values • Values for V9, V11, and My cuts K. Grogg, UW-Madison

26. H/E cut removed • H/E cuts doesn’t greatly reduce background for the amount of signal lost • No longer used in the robust electron ID Barrel S/√(S+B) & Efficiency Endcap S/√(S+B) & Efficiency K. Grogg, UW-Madison

27. Investigating high pT Efficiency loss W+jets 30 < elec pT < 50 W+jets elec pT < 30 W+jets above elec pT > 50 QCD QCD not binned – doesn’t change with electron pT • Can’t improve high pT cuts without allowing more background • New W→eν cuts don’t use H/E Δφinand Δηin don’t have high pT dependence UW-Madison