CLID ILD Reconstruction Status
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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

Mark Thomson


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