Hadronic Jet Energy Scale Hadronic t-t bar selection and Jet Energy Scale calibration Part I : Accessing the trigger information 09/02 - Menelaos Tsiakiris

Motivation… Main decay modes:  di-lepton: tt bar  lν lν bb 5% (e + μ)  lepton + jets: tt bar  lν qq bb 30% (e + μ)  all hadronic : tt bar  qq qq bb 45% qq bar (10%), gg (90%)  tt bar Dominant quark production mechanism t  Wb (~100%) quarks (light jets) b quark jets (displaced vertices) Pros: + Largest branching ratio + Kinematics that can be fully reconstructed Cons: - very large QCD multijet background challenging for the isolation of the signal - difficulties for triggering

Tools… Atlas offline – Athena  currently on Sample 5012 (QCD) AOD di-jet sample reco. with trigger info trig1_misal1_csc11_ J3_pythia_jetjet.recon.AOD.v Sample 5200 (ttbar) AOD semi-leptonic sample reco. with trigger info trig1_misal1_csc11_ T1_McAtNlo_Jimmy.recon.AOD.v UserAnalysis ( ) package  very basic stuff… Trigger Decision Class (by M.Wielers)  access the trigger information List of predefined trigger menus in release 12 : Contains the trigger menu items as defined at reconstruction. Trigger Menu :  official production CSC-03

About Trigger Decision … Obtains the trigger decision for each event Gives the list of signatures running in each trigger level Implemented from fully functional on 12.0.x From also included in AODs TriggerDecisionMaker TriggerDecisionMaker Algorithm  runs after the trigger steering  determines which HLT or LVL1 items were satisfied  fills the TriggerDecision object TriggerDecision class  User Interface: … bool isDefined(“L1_2J45”) bool isTriggered(“L1_2J45”) bool isTriggerPassed() void print() void printAccepted() … Starting point: Wiki page: Browse CVSView and DoxygenCVSViewDoxygen Methods…

More on Trigger Decision… How-to use: cmt/requirement i) Include the Trigger, in the cmt/requirement  use TrigSteeringEvent TrigSteeringEvent-* Trigger/TrigEvent AnalysisSkeleton.cxx ii) Edit AnalysisSkeleton.cxx  #include "TrigSteeringEvent/TriggerDecision.h" StoreGate iii) Retrieve the trigger decision from StoreGate  /** Get Trigger Decision */ const TriggerDecision* trigDec = 0; MyTriggerDecision StatusCode sc = m_storeGate->retrieve( trigDec, MyTriggerDecision); if( sc.isFailure() || !trigDec) { mLog << MSG::WARNING << "No Trigger Decision found in TDS" << endreq; return StatusCode::SUCCESS; } Need more insight? !!! This is only for handling the MSG service trigDec->isTriggered(“L1_J35”) Returns true/false Default key In case you re-run the trigger hypothesis on an ESD/AOD + MyTriggerDecision+ e.g

Reco container Trigger Decision if (accepted) accepted_histo Fill accepted_histo Truth container findAMatch highest_truth_histo Fill highest_truth_histo Divide Find highest energetic jet Turn – on curve : For a trigger request of: E > 50 GeV The percentage of jets that pass the energy threshold with respect to their true energy E truth My analysis: Per event… Ideal…

jet160 The jet160 item turn-on curves (5012): LVL1: L1_J45 (20GeV) LVL2: L2_ jet160 EF: EF_jet160 !!! “garbage” at low energies !?!?

Reco container Trigger Decision if (accepted) accepted_histo Fill accepted_histo Truth container findAMatch highest_truth_histo Fill highest_truth_histo Divide Find highest energetic jet Offline reconstruction algorithm Trigger Reco Container Trigger reconstruction algorithm Fast solution… Truth container Find highest energetic jet Trigger Decision if (accepted) Divide highest_truth_histo Fill highest_truth_histo accepted_histo Fill accepted_histo

jet160 The jet160 item turn-on curves (5012): The “garbage” are gone… ! But for this sample the jet160 item is not good …. Very few events  next slide

jet160 The jet160 item (5012): Truth distribution Only very few events above 180 GeV

2jet120 The 2jet120 item (5012): LVL1: L1_2J45 LVL2: L2_ jet120L2_jet120 EF: EF_jet120EF_jet120 Note the naming convention for L2 and EF! Still few statistics based

New sample Semi-leptonic ttbar… … just looked at it a few days ago … very few events after 220 GeV ! Truth distribution

The jet160 item on a 5200 sample, 4000 events: 90 – 100% Starts building up after 160 GeV Bit sloppy here… ~ 80% -100% AnalysisSkeleton INFO The L1 J45 : 3987  ~100% AnalysisSkeleton INFO The L2 jet160 : 2281  57% AnalysisSkeleton INFO The EF jet160 : 421  11%

The 2jet120 item (5200) 4000 events: ~ 80% - 90% ~ 50% - 60% Starts to build up only after 120 GeV AnalysisSkeleton INFO The L1 2J45 : 3859  96% AnalysisSkeleton INFO The L2 2jet120 : 1930  48% AnalysisSkeleton INFO The EF 2jet120 : 278  7%

The 3jet65 item (5200) 4000 events: LVL1: L1_3J45 LVL2: L2_ jet65L2_jet65L2_jet65 EF: EF_jet65EF_jet65EF_jet65 ~ 80% - 90% ~ hardly % Again… AnalysisSkeleton INFO The L1 3J45 : 3434  85% AnalysisSkeleton INFO The L2 3jet65 : 2508  63% AnalysisSkeleton INFO The EF 3jet65 : 522  13% ~ 90% !

The 4jet50 item (5200) 4000 events: LVL1: L1_4J45 LVL2: L2_ jet50L2_jet50L2_jet50L2_jet50 EF: EF_jet50EF_jet50EF_jet50EF_jet50 AnalysisSkeleton INFO The L1 2J45 : 2392  60% AnalysisSkeleton INFO The L2 2jet120 : 1771  44% AnalysisSkeleton INFO The EF 2jet120 : 406  10 % No more than 40% ~ 60% - 70% ~ 70 % !!! again 3987 passed LVL1 : 99% 3137 passed LVL2 : 78% 857 passed EF : 21% Total accepted events:

About Jet Energy Scale… The efficiency of the jet triggers depends heavily on the quality of the Jet Energy Scale calibrations in the online system. For the di-jet 5012 sample As an introduction to this study I looked on the JES based on offline reconstruction

JES JES : Fitting each bin of the x-axis with a gaussian and plotting the Constant(height), Mean and Sigma Offset of 2 GeV The distribution is getting wider for high energies (less events ?) 5012 di-jet sample

About Jet Energy Scale… For the ttbar 5200 sample

JES JES : 5200 ttbar sample Not the same as 5012 !

My to-do list … Run the online reconstruction algorithm. (Samples ??) Do the turn-on curves based on the trigger reco. algorithm and improve diagrams (e.g. errors) Examine JES for the online case Look into EventView Trigger package

THANK YOU!