HG 5: Trigger Study for ttH, Hbb Catrin Bernius (UCL) CPPM, Genova, Glasgow, RAL, RHUL, UCL some outline Catrin Bernius, UCL 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 Catrin Bernius, UCL Jet trigger studies Fabrizio Parodi (Genova) Catrin Bernius, UCL Trigger efficiencies in semileptonic ttH Signal sample dataset (rel ): trig1_misal1_mc12_V1_ ttH_poslepnu_jj_bb.recon.AOD.v _tid trig1_misal1_mc12_V1_ ttH_neglepnu_jj_bb.recon.AOD.v _tid Trigger items studied: e25i and mu20(i) Efficiencies is caclulated after the preselection: 6 jets with pt>20 GeV, |eta|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) Catrin Bernius, UCL Trigger Efficiency vs p T truth, truth for e25i Spacepoint bug: non flat efficiencies at L2 Catrin Bernius, UCL Trigger Efficiency vs p T truth, truth for mu20i gap in muon detector ( =0) Barrel / endcap boundary Catrin Bernius, UCL 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% Catrin Bernius, UCL 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 Catrin Bernius, UCL 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 Catrin Bernius, UCL 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 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 Catrin Bernius, UCL Reminder In release : 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 arent formed at L2 due to missing code Leads to non-flat efficiencies in eta at L2 Can only be fixed by re-reconstruction from RDOsalId=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 Catrin Bernius, UCL Relative e25i efficiencies Catrin Bernius, UCL Relative mu20i efficiencies Catrin Bernius, UCL Trigger Efficiency vs p T truth for e25i Catrin Bernius, UCL BEFORE ttH RECONSTRUCTION Trigger Efficiency vs truth for e25i Spacepoint bug: non flat efficiencies at L2 (fixed in rel 13) Catrin Bernius, UCL Trigger Efficiency vs p T truth for mu20i Catrin Bernius, UCL BEFORE ttH RECONSTRUCTION Trigger Efficiency vs truth for mu20i gap in muon detector due to cryostat of LAr Barrel / endcap boundary Catrin Bernius, UCL distribution for muons (EF) gap in muon detector due to cryostat of LAr Barrel / endcap boundary TDR Vol.1 Catrin Bernius, UCL 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% Catrin Bernius, UCL 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%