Monitoring of L1Calo EM
Efficiencies
Hardeep Bansil
University of Birmingham
L1Calo Joint Meeting, CERN
19/10/2011
Contents
• EM efficiencies
• Running at Tier 0
• Recent offline studies
• Next steps
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Calculating Efficiencies
• Efficiencies calculated for L1 electromagnetic trigger items as
to determine L1Calo (CP) performance
– Function of ET – turn on curve
– Function of η and φ – efficiency map
R  ( ) 2  ( ) 2
eγ raw
cluster
0.15
EM ROI
• Calculated from raw offline clusters of electrons
and photons and matching them to EmTau RoIs
• Raw cluster ET, η, φ determined using energy weighting of
CaloCells that make up calibrated CaloCluster
 (L1_EM x) 
Offline Cluster & R to RoI  0.15 & RoI passes L1_EM x
Offline Cluster
• Can be calculated as a function of each data taking period
(similar to most offline analyses)
• Transition region between EM barrel and endcap excluded
(1.37 < |η| < 1.52)
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Jet ‘Tag and Probe’ v1
• Need to use an independent trigger to collect data sample
• Existing method of obtaining a data sample was by asking
that events triggered on L1_J*
• Then use Jet ‘Tag and Probe’ method to make independent
– Electrons and photons can also be reconstructed as jets within L1Calo
so need to find another L1_J* RoI in the event (Δr > 0.4 away) so that
they can be studied
Please note these are not real events!
Candidate ignored
Candidate studied
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2011 Plans
•
2010: Offline framework produced nice efficiencies, showed L1Calo
worked well in triggering on electrons and photons and where towers had
reduced performance
10 GeV clusters, EM5
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•
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EM14, 2010 Period E-I
2011: Get efficiencies to support existing tools in terms of identifying
towers with reduced performance and making information available to
those are interested in it
Run on Tier 0 for every run + offline for every period
Adjust databases retrospectively if poor performance regions found
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Tier 0 Analysis
•
Code migrated to TrigT1CaloMonitoring, currently using Athena 17.0.4.5
but changing rapidly
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•
Can be found at: EmEfficienciesMonTool
Thanks to Juraj and Pete Faulkner for their help
Available for a few months but noticed more after Muon Trigger ‘issues’
Trimmed code to keep only the important information for efficiencies of
each L1 EM trigger
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–
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Efficiency maps with different raw cluster energies cuts (10, 20, 30 GeV)
Turn-on curves
Plots used to make these efficiencies (numerators and denominators)
Trigger towers affected by known issues or bad calorimeter problems (very few
thankfully!)
•
If downloading a Tier 0 DQ root file, the path to finding the plots is:
•
Currently running on different streams (each stream configured to have
its own trigger strategies for unbiased event selection)
/run_XXXXXX/L1Calo/Reco/EmEfficiencies/
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JetTauEtmiss – Events triggered on jets use Tag and Probe
Muon – Events triggered on muons, independent of calorimeters
Egamma – Events triggered on electrons and photons, biased results so drop this
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Tier 0 Analysis
•
Results from JetTauEtmiss stream, run 190933
L1_EM12 Turn on curve
L1_EM7 Eff. Map (20 GeV clusters)
Errors are
symmetric,
not binomial
•
Results look good (especially for a single run), best option is to make plots
available to L1Calo shifters. Show all plots available but suggest only a
selection of plots at different thresholds to look at
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–
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1D: EM7, EM14, EM30
2D: EM5 with 10 GeV clusters, EM12 with 20 GeV clusters, EM16 with 30 GeV clusters
Physics streams will take to long for shifters to see, need to use Express
stream for faster results
Need an appropriate strategy to work with Express stream as well as to
make results with JetTauEtmiss stream work better (need to be careful of
tau triggered events)
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Jet ‘Tag and Probe’ v2
• New method for events with jets works on assumption that
highest energy Jet_ROI is the one that triggered the event as
inclusive single jet triggers are used
– Using ET8x8 energy for comparison of Jet_ROIs
– Still ask that electron / photon Δr > 0.4 away for highest ET ROI
– Not worrying if probe electrons / photons near jet now
Please note these are not real events!
Candidate ignored
Candidates studied
• Trigger matching to HLT objects is another option but more
complex than this
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Offline studies on Trigger Selection
•
Moved to AthenaProduction-17.0.4.4 (match with Tier 0)
–
Changing from major revisions of Athena is never easy but L1Calo twiki helpful
•
Tests using Express stream ESDs, yet to test with JetTauEtmiss and Muon
•
Ask that event triggered at EF level (no particular trigger selection)
•
Next ask which chains have triggered event
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– Odd events do not meet this requirement
– Currently check L1_EM/L1_J as well to understand chains
Use chain without problems
Use chain with more checks
Do not use chain
Muons
MBTS, RD0, etc.
Single-jet triggers
Multi-jet triggers
Electrons
Photons
Taus
Missing Et (significance)
Single jets based on Jet ‘Tag and Probe’ v2, not worrying about multi-jet
trigger chains yet (make a small contribution to total sample)
For local tests, from 220 events:
All possible EM candidates = 7299, after trigger chain cuts = 4058
(These candidates would still need to pass eγ selection criteria)
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Next steps
• Complete studies of trigger selection offline and test at Tier 0
– Run with larger selection of files and streams
– Improve understanding of composition of different streams
• Get efficiency plots used in online monitoring
– Important for getting regions of poor performance updated in
databases and for physics studies
– Improve clarity of plots on DQ Web page
• Document this analysis
• Adapt analysis for other offline objects relevant to L1Calo
Any suggestions welcome!
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