1. H->WW->lνlν Analysis - Improvements and results - - Data and MC - Higgs Working group meeting, 6 January 2011 Magda Chełstowska & Rosemarie Aben

2. 2 Topics Improvements in analysis Used dataset and selections Cutflow μμ- and ee-channel for data and MC Results for μμ-channel, data and MC Results for ee-channel, data and MC Conclusions and outlook

3. 33 Analysis improvements 1 and 2 jet channels added MC signal sample analysis (smearing, event reweighting,..) Proper ee-channel analysis Implemented all cuts and selections for the cut flow, including topological cuts and overlap removal

4. 4 Used samples Dataset used for ee-channel (3.5M events processed): data10_7TeV.00167776.physics_Egamma.merge.NTUP_SMEW. f299_m639_p273_tid185741_00 Dataset used for μμ-channel (3.2M events processed): user10.HaijunYang.data10_7TeV.00167776.physics_Muons.merge.AOD. f299_m639.D3PD_v15.6.13.2_tag-00-05-10 Dataset used for MC (0.2M events processed): mc09_7TeV.109074.McAtNlo_JIMMY_H160_WpWm_lnunu.merge. NTUP_SMEW.e526_s765_s767_r1306_p273_tid1787XX_00 These samples are currently used for the “acceptance challenge”: to see if every group finds the same cut flow. Twiki acceptance challenge: twiki.cern.ch/twiki/bin/view/AtlasProtected/HiggsWWdilConfNote2011WinterA C2

5. 5 Baseline selection For MC: event reweighting (new) GRL for periods A-I from SMWW group Primary vertex selection Event cleaning Trigger requirement: Data: EF_mu13_MG_tight and EF_e15_medium MC: L1_MU10 and L1_EM14 (new) Exactly two leptons First leading lepton pt > 20 GeV Two leptons have opposite charge Δ z0 (l1,l2) < 0.8 mm removed M ll > 15 GeV Z mass veto: |M ll -M Z | > 10 GeV MET > 30 GeV MC trigger: Should use EF_e15_medium and EF_mu10_MG (luminosity reweighted triggers). However EF_e15_medium is not filled in the sample we currently need to use.

6. 6 Additional baseline selection Overlap removal: ΔR(e-mu) Keep muon, remove electron ΔR(e-e) Keep higher pt electron, remove lower pt electron ΔR(e-jet) Keep electron, remove jet Additional to the exactly 2 leptons cut: In μμ-channel: require no electrons! In ee-channel: require no muons (muon and staco)!

7. 7 Jet selection Used algorithm: AntiKt4H1TopoJet Basic selections: Pt > 20 GeV, |η| < 4.5, jet veto: |η|<2.5 && JVF < 0.7 0 jet selection: Pt ll > 30 GeV 1 jet selection: Reject jet with SV0 > 5.70 Pt total < 30 GeV Z -> ττ veto 2 jet selection: (ask for at least 2 jets) η (j1) * η (j2) < 0 Δη > 2.5 Mjj > 250 GeV No additional jets with pt > 25 GeV && |η| < 3.2 Plus the one jet selections

8. 8 Muon selection For both MuID and StaCo: Pt > 15 GeV |η|<2.4 ≥ 1 pixel hit && ≥ 6 SCT hits on the ID track For |η| 5 and n TRT outliers < 0.9 n total For |η| ≥ 1.9. If n total > 5, then require n TRT outliers < 0.9 n total |z0| < 10 mm (new) d0 significance < 10 etcone30/Pt < 0.15 Ptcone30/pt < 0.1 Additional cuts for StaCo muons: (changed) χ 2 match < 150 |P MS,extrap. -P ID | > -0.4Pt ID and Pt MS,extrap. < 50 GeV Added for MC: pt smearing according to MCP procedure

9. 99 Electron selection Author 1 or 3 (egamma) Pt(cluster) > 15 GeV |η(cluster)|<2.47, exclusion of crack region: 1.37<|η(cluster)|<1.52 OTX cleaning cut Robuster tight quality for 0,1,2 jet analysis (changed) |z0| < 10 mm (new) d0 significance < 10 etcone30/Pt < 0.15 Ptcone30/pt < 0.1 Added: Electron energy scale correction for data

10. 10 Selection to take into account the Higgs decay topology. To be applied after the jet selections. Optimization in progress. Different cuts for high (> 170 GeV) and low Higgs masses Used M(Higgs) in acceptance challenge is 160 GeV M ll < 50 (65) GeV for low (high) mass and M ll < 80 GeV for 2jet analysis Δ Φ (ll) < 1.3 (1.8) for low (high) mass 0.75*M(Higgs) < m T < M(Higgs) Topological selections (new)

11. 11 Cut flow μμ- and ee-channels Data Cut:μμ(StaCo) μμ(MuID) ee Total 323088132308813531698 GRL 310579031057903397349 Vertex 304509030450903388200 Event cleaning 304360030424303384910 Trigger 830918 8305301215950 2 leptons 2236 24121062 Leading lepton Pt 2150 2309 1037 Opposite sign 215023091022 InvMass cut 213322941019 Z mass veto cut 327354180 MET cut 9118 0jet cut 000 0jet + topo000 1jet cuts 321 1jet + topo 000 2jet cuts 001 2jet + topo000

12. 12 Cut flow μμ- and ee-channels MC Cut:μμ(StaCo) μμ(MuID) ee Total 194745194745194745 Event Weight176673 176673176673 Vertex 176658176658176658 Event cleaning 176063176063176063 Trigger108611 108611 121505 2 leptons24351 25401 11118 Leading lepton Pt 24209 25259 11081 Opposite sign 242092525910860 InvMass cut230132402710399 Z mass veto 22256 2325110017 MET cut 20074209618991 0jet cut 11419119205359 0jet + topo476449752365 1jet cuts 5367 55922290 1jet + topo 195120481296 2jet cuts 325342147 2jet + topo14615565

13. 13 Results Data and MC Plots for data (separate for 1,2 jet analysis): - After 2 lepton cut - After baseline selection - After 1 jet cuts Plots for MC (separate 0,1,2 jet analysis): - After baseline selection - After (0,1,2) jet cuts - After topological selection Results for following variables: transverse mass, invariant mass, pt of leading lepton, pt of both leptons, Δφ between both leptons. We only show plots for staco muons since these are alike the ones for muid muons and the staco muons are currently used for the acceptance challenge. NB. Data and MC results not yet comparable, since it only concerns the MC signal sample at the moment (no lumi renormalisation, nor bg) NB. 2jet channel plots have a log scale on the vertical axis for MC. Added: plots with data results compared for muid and staco after 2good lepton cut. For data: no events left after 0 jet cuts, so no plots. 2 jet analysis also not plotted for μμ- channel because of lack of statistics.

14. 14 Transverse Mass Data 1 jet, staco μμ ee 1 jet, muidstaco vs muid 1 jet2 jet

15. 15 Transverse Mass MC 1 jet0 jet2 jet μμ ee

16. 16 Invariant Mass Data μμ ee 1 jet, staco1 jet, muidstaco vs muid 1 jet2 jet

17. 17 Invariant Mass MC 1 jet0 jet2 jet μμ ee

18. 18 Pt leading lepton Data μμ ee 1 jet, staco1 jet, muidstaco vs muid 1 jet2 jet

19. 19 Pt leading lepton MC 1 jet0 jet2 jet μμ ee Updated: double peak structure was due to bug in code.

20. 20 Pt ll Data μμ ee 1 jet, staco1 jet, muidstaco vs muid 1 jet2 jet

21. 21 Pt ll MC 1 jet0 jet2 jet μμ ee

22. 22 Δφ ll Data μμ ee 1 jet, staco1 jet, muidstaco vs muid 1 jet2 jet

23. 23 Δφ ll MC 1 jet0 jet2 jet μμ ee

24. 24 Conclusions and outlook Results that were obtained before the latest selection changes were in agreement with other groups. Code is adapted to improved selections. Awaiting the results of the other groups for comparison. ToDo: eμ-channel (update: code is updated for this channel now) Write out all the variables that pass our selections at each stage to a tree and then to an ntuple. Running over MC background samples, merging these with signal sample and reweighting the luminosity, so that comparison for data and MC is possible Find a Higgs in the MC by running on all datasets on the grid.

25. 25 Back up: to be aware of Check 2 nd lepton if 1 st lepton is affected by the isolation criterion Since we veto on events with extra leptons, it can happen that we lose events in which an isolated electron is coming from a b-jet. Find a solution for this… Z->tautau veto Signed pt in MCP recommendation, find out if this can cause problems. Other comments?