1. HG 5: Trigger Study for ttH, H→bb Catrin Bernius (UCL) CPPM, Genova, Glasgow, RAL, RHUL, UCL some outline

2. Catrin Bernius, UCL30.10.2007 2 Trigger items for ttH, H  bb Chris Collins-Tooth (Glasgow), Higgs WG meeting, 18 Nov 07 Menu for L=10 33 cm -2 s -1 Semileptonic channel: mu20i (& higher) and e25i: –the lower the threshold the better –High efficiency is important, but matching between ID and MS necessary to avoid garbage –Combining lepton triggers with missing energy (xeXX), sum jet (jeXX) or total sum (teXX) triggers with aim of lowering lepton threshold

3. Catrin Bernius, UCL30.10.2007 3 Jet trigger studies Fabrizio Parodi (Genova)

4. Catrin Bernius, UCL30.10.2007 4 Trigger efficiencies in semileptonic ttH Signal sample dataset (rel. 12.0.6): –trig1_misal1_mc12_V1_005870.ttH_poslepnu_jj_bb.recon.AOD.v12000601_tid008657 –trig1_misal1_mc12_V1_005871.ttH_neglepnu_jj_bb.recon.AOD.v12000601_tid008658 Trigger items studied: e25i and mu20(i) Efficiencies is caclulated after the preselection: 6 jets with pt>20 GeV, |eta|<5 (NO b-tagging information) 1 isolated lepton with cuts on eta ( 20GeV for muons, >25GeV for electrons) for reconstructed leptons –trigger efficiency should be close to 100% when isolated lepton is reconstructed offline –higher statistics than after higgs reconstruction Efficiency calculated by: –After preselection : e = #(pass trigger & preselection cuts)/#(pass+not pass trigger+preselection cuts)

5. Catrin Bernius, UCL30.10.2007 5 Trigger Efficiency vs p T truth,  truth for e25i Spacepoint bug: non flat efficiencies at L2

6. Catrin Bernius, UCL30.10.2007 6 Trigger Efficiency vs p T truth,  truth for mu20i gap in muon detector (  =0) Barrel / endcap boundary

7. Catrin Bernius, UCL30.10.2007 7 Efficiencies  (lep) = # events where e or  pass e25i or mu20 / # events with e or  from W in truth  (e) = # events where e pass e25i / # events with e from W in truth  (  ) = # events where  pass mu20 / # events with  from W in truth Error on efficiencies ~ ± 0.5% After Preselection  (lep)  (e)  (  ) L189% 91% 87% L2 84% 87% 82% EF 82% 84% 79%

8. Catrin Bernius, UCL30.10.2007 8 m bb with and without trigger Reconstructed Higgs mass with and without trigger selection to check if online selection has “bias“ on crucial variables ttH samplettbb (QCD) sample

9. Catrin Bernius, UCL30.10.2007 9 m bb dependence on electron & muon cuts Check dependence of analysis on selection thresholds (done by varying the offline selection cuts around the nominal thresholds (E T (e)>25GeV,E T (  )>20GeV) by ± 5 GeV ttH samplettbb (QCD) sample

10. Catrin Bernius, UCL30.10.2007 10 Conclusions Something about the trigger menus... In hadronic ttH channel... Combining lepton trigger with jet trigger, b jet trigger... In semileptonic ttH with isolated offline reconstructed lepton, the trigger efficiency for leptons is ~ 82% ± 0.5% –84% for electrons (expected to be higher for rel 13.0.30 after bug fixes) –79% for muons No difference in shape of m bb spectrum of ttH, ttbb(QCD) sample –for analysis done with and without trigger selection –for variation of electron & muon E T cuts by ±5 GeV around the current thresholds

11. Catrin Bernius, UCL30.10.2007 11 Reminder In release 12.0.6: –Muons: only the highest L1 muon threshold fired –e.g.: event with 50GeV muon, L1_MU40 fired (nearest threshold), but L1_MU08, L1_MU10 etc. not passed. –To get correct trigger decision, all higher thresholds need to be checked Isolation is currently not implemented for muons in release 12 –Electrons: level 2 spacepoint bug (FIXED IN RELEASE 13) Problem in reconstruction where tracks aren‘t formed at L2 due to missing code Leads to non-flat efficiencies in eta at L2 Can only be fixed by re-reconstruction from RDO‘s http://indico.cern.ch/getFile.py/access?contribId=52&sessionId=4&resId=0&materi alId=slides&confId=16155 (slide 5)http://indico.cern.ch/getFile.py/access?contribId=52&sessionId=4&resId=0&materi alId=slides&confId=16155 TriggerDecision... INFO TriggerDecision: L1 Trigger Item L1_MU06 did not pass TriggerDecision... INFO TriggerDecision: L1 Trigger Item L1_MU08 did not pass TriggerDecision... INFO TriggerDecision: L1 Trigger Item L1_MU10 did not pass TriggerDecision... INFO TriggerDecision: L1 Trigger Item L1_MU11 is fulfilled TriggerDecision... INFO TriggerDecision: L1 Trigger Item L1_MU20 did not pass TriggerDecision... INFO TriggerDecision: L1 Trigger Item L1_MU40 did not pass

12. Catrin Bernius, UCL30.10.2007 12 Relative e25i efficiencies

13. Catrin Bernius, UCL30.10.2007 13 Relative mu20i efficiencies

14. Catrin Bernius, UCL30.10.2007 14 Trigger Efficiency vs p T truth for e25i

15. Catrin Bernius, UCL30.10.2007 15 BEFORE ttH RECONSTRUCTION Trigger Efficiency vs  truth for e25i Spacepoint bug: non flat efficiencies at L2 (fixed in rel 13)

16. Catrin Bernius, UCL30.10.2007 16 Trigger Efficiency vs p T truth for mu20i

17. Catrin Bernius, UCL30.10.2007 17 BEFORE ttH RECONSTRUCTION Trigger Efficiency vs  truth for mu20i gap in muon detector due to cryostat of LAr Barrel / endcap boundary

18. Catrin Bernius, UCL30.10.2007 18  distribution for muons (EF) gap in muon detector due to cryostat of LAr Barrel / endcap boundary TDR Vol.1

19. Catrin Bernius, UCL30.10.2007 19 Efficiencies  (lep) = # e+  which pass e25i or mu20 / # e+  from W  (e) = # e which pass e25i / # e from W  (  ) = #  which pass mu20 / #  from W Before ttH Reconstruction After Preselection  (lep)  (e)  (  )  (lep)  (e)  (  ) L1 81% 79% 83% 89% 91% 87% L2 70% 67% 73% 84% 87% 82% EF 64% 59% 69% 82% 84% 79% Error on efficiencies ~ ± 0.5%

20. Catrin Bernius, UCL30.10.2007 20 Some numbers...  (lep) = (#e+muons which pass e25i/mu20) / (#e+muons from W)  (e) = (#e which pass e25i) / (#e from W)  (  ) = (#muons which pass mu20) / (#muons from W) After ttH Reconstruction  (lep)  (e)  (  ) L1 87% 91% 82% L2 83% 86% 79% EF 80% 83% 77%