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CLID ILD Reconstruction Status. Mark Thomson University of Cambridge. This Talk. Status of CLIC_ILD reconstruction path one outstanding cross-check we are ready to tag a release (see Andre’s talk) This is the final chance to comment on Detector timing assumptions

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CLID ILD Reconstruction Status

Mark Thomson

University of Cambridge

this talk
This Talk
  • Status of CLIC_ILD reconstruction path
    • one outstanding cross-check
    • we are ready to tag a release (see Andre’s talk)
  • This is the final chance to comment on
    • Detector timing assumptions
    • PFO timing selection cuts
    • DST format
  • Thanks to many people
    • in particular, Andre for keeping on top of all the small fixes
    • Erik, Jacopo, Jean-Jacques for finding bugs/features
    • Stephane for producing files with overlay

Mark Thomson

tracking with overlay
Tracking with Overlay
  • At last meeting still some questions regarding tracking efficiency
  • with overlay
  • Ran a quick sanity check:
    • fire 10 GeVmuons in random directions
    • use full background overlay
    • define efficiency “is there a reconstructed track within 0.1 GeV
    • of 10 GeV which is associated with the MC “physics muon”

Histo = MC muon

Point = reco 10 GeV track


Mark Thomson


Q [deg]

  • Limited statistics (no time), but no indication of major problems
    • Hint of something at 10 degrees: FTD geometry ?
    • Only 2 tracks from ~1000 with q>7 degrees not reconstructed

Mark Thomson

detector assumptions
Detector Assumptions
  • Calorimeters
    • Assume all hits have a timestamp
      • currently no smearing of hit times, assumed ~ 2 ns
    • Assume two hit separation limited to 20 ns
      • Hits within 20 ns are merged (use time for highest ph hit)
    • For ECAL/HCAL endcap reconstruction integrate over 10 ns
    • For HCAL barrel integrate over 100 ns
  • Silicon
    • Integrate over time window of 10 ns
    • No accounting for multiple hit capability
      • occupancies fairly low
  • TPC
    • Integrate over full bunch-train
    • Require a matched Si hit in the above 10 ns window
    • For looping tracks, also require arrival at ECAL within 50 ns

Defines input to event reconstruction

Mark Thomson

overlay reconstruction
Overlay Reconstruction
  • Can now routinely process events with overlay !!!
    • few minutes per event
    • overlay 60 BXs gamma gamma -> hadrons (limited by fortranPatRec)
      • believe to be a good approximation
      • accounts for almost all calorimeter background
      • + TPC PatRec is not an issue (see ALICE reconstruction)
  • Compare overlay/non-overlay processing for 1 TeV Z event

1.4 TeV of background (reconstructed particles) !

Mark Thomson

pfo selection
PFO Selection
  • Reconstruction performed at the full overlay level
  • Then apply optional cluster-based timing cuts
  • Since clusters contain many hits, mean cluster time known well
    • assuming single hit resolution of ~ ns implies offline cluster
    • times typically known to much better than 1 ns
    • LHC experience suggests this is realistic
  • e.g. HCAL endcap (where occupancy is high)


Background peaks

Around 5ns, i.e. half of

the 10ns window


Mark Thomson

  • Offline cluster time cuts applied in: CLICPFOSelector
    • calculates a robust mean charge-weighted time for each cluster
    • (finds median time, rejects outlying 10 % of hits)
    • applies cuts at PFO level
    • different cuts for Photons, Neutral hadrons and charged hadrons
    • if enough hits, time obtained from ECAL
  • A priori, not clear how extreme the timing cuts should be
    • Requirements may depend on physics analysis
    • Part of our study is to determine what is required !
    • Hence run three versions of CLICPFOSelector
      • Default, Loose cuts, Tight cuts
    • For physics analysis, have four possible sets of PFOs
      • PandorPFANewPFOS
      • SelectedPandoraPFANewPFOs
      • LooseSelectedPandoraPFANewPFOs
      • TightSelectedPandoraPFANewPFOs

Mark Thomson

pfo based timing cuts
PFO-based Timing Cuts
  • For each PFO type define two levels of timing cuts (tight, loose)

Default cuts:

Mark Thomson


Loose cuts:

Mark Thomson


Tight cuts:

Mark Thomson


1.4 TeV of background !

Mark Thomson


0.3 TeV of background

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0.2 TeV of background

Mark Thomson


0.1 TeV of background

Mark Thomson

aod format
AOD Format
  • Since last meeting, implemented AOD (DST) writing
    • greatly simplified based on LCIO subsets
    • now only write out MC particles for Physics event
    • (not the overlayed background)
  • Collections kept
    • tracks
    • clusters
    • pfos (x4)
    • pfo -> mc relation
    • skimmed mc particles from physics event
  • Flavour tagging left to the analysis groups

Mark Thomson

aod for single muon overlay
AOD for single muon + overlay



LooseSelectedPandoraPFANewPFOsReconstructedParticle 222


PandoraPFANewClusters Cluster 751


RecoMCTruthLinkLCRelation 942

SelectedLDCTracks Track 701


TightSelectedPandoraPFANewPFOsReconstructedParticle 48

Note: MC relations in AOD have to be used with care

only “physics event” MCParticles are retained in AOD

Mark Thomson

using pfo mc relations
Using PFO - MC relations

LCCollection * col = evt->getCollection(m_inputMcParticleCollection.c_str());

intnelem = col->getNumberOfElements();

for (intiMc=0; iMc<= col->getNumberOfElements(); ++iMc){

MCParticle * pMc = dynamic_cast<MCParticle*>(col->getElementAt(iMc));



LCObjectVecobjectVec = m_pfoToMcNavigator->getRelatedToObjects(pPfo);

if (objectVec.size() > 0) {

for(unsignedintimc = 0; imc < objectVec.size(); imc++){

MCParticle * pMC = dynamic_cast<MCParticle*>(objectVec[imc]);

// since only saving skimmed set of MC particles,

// check pMC points to an existing object








Mark Thomson

status of ild reconstruction
Status of ILD Reconstruction
  • After
    • all code included in IlcSoft v11-pre02
    • will ask DESY make tag very soon
  • Default “steering” files in StandardConfig/clic_cdr
    • clic_ild_cdr_steering.xml
    • clic_ild_cdr_steering_overlay.xml
    • clic_ild_cdr_pandora_settings.xml
    • clic_ild_cdr.gear
  • Plan is to process events with and without overlay to help to
  • assess impact of background
    • non-overlay version is almost identical to overlay version

Mark Thomson

f inal steering files
final steering files

NBackground = 0.0

NBackground = 3.2


<processor name="MyOverlayTiming"/>

<processor name="MyCLICCDRMaterialDB"/>

<processor name="MyTPCDigiProcessor"/>

<processor name="MyLEPTrackingProcessor"/>

<processor name="MyVTXDigiProcessor"/>

<processor name="MyNewFTDDigiProcessor"/>

<processor name="MyETDDigiProcessor"/>

<processor name="MyILDCaloDigi"/>

<processor name="MySimpleMuonDigi"/>

<processor name="MySiliconTrackingCLIC"/>

<processor name="MyFullLDCTracking"/>

<processor name="MyCLICTrackSelector"/>

<processor name="MyV0Finder"/>

<processor name="MyKinkFinder"/>

<processor name="MyMarlinPandora"/>

<processor name="MyRecoMcTruthLinker"/>

<processor name="MyLCIOOutputProcessor"/>

<processor name="MyDstWriter"/>


Including calo

timing cuts

Overlay version only

MC Skimming for DST

Write REC file

Write AOD

Mark Thomson

remaining issues
Remaining Issues


*Need to request a tagged release of ILCSoft

Mark Thomson