Example 6: Run Delphes with Nsubjettiness and pile-up
=====================================================

1. Start from the original configuration file:

  cp /afs/cern.ch/user/s/selvaggi/public/delphes_tuto/delphes_card_FCC_basic.tcl examples/delphes_card_FCC_nsub.tcl

2. Replace the "GenJetFinder" and "FastJetFinder" modules with new Nsubjettiness configuration in the "delphes_card_FCC_nsub.tcl" configuration file:


module FastJetFinder GenJetFinder {
  set InputArray Delphes/stableParticles

  set OutputArray jets
 
  set JetAlgorithm 7
  set ParameterR 1.0

  set ComputeNsubjettiness 1
  set Beta 1.0
  set AxisMode 1
  
  set JetPTMin 500.0


}

module FastJetFinder FastJetFinder {

 set InputArray EFlowMerger/eflow

 set OutputArray jets

  set JetAlgorithm 7
  set ParameterR 1.0

  set ComputeNsubjettiness 1
  set Beta 1.0
  set AxisMode 1
  
  set JetPTMin 500.0
}


Also comment out branches in the TreeWriter section that are not needed for this short study (to reduce output size):


module TreeWriter TreeWriter {

# add Branch InputArray BranchName BranchClass
#  add Branch Delphes/allParticles Particle GenParticle
  add Branch GenJetFinder/jets GenJet Jet

#  add Branch ChargedHadronMomentumSmearing/chargedHadrons ChargedHadron Track
#  add Branch Hcal/eflowNeutralHadrons NeutralHadron Tower
#  add Branch Ecal/eflowPhotons Photon Photon

#  add Branch ElectronEnergySmearing/electrons Electron Electron
#  add Branch MuonMomentumSmearing/muons Muon Muon
  add Branch JetEnergyScale/jets Jet Jet
  add Branch MissingET/momentum MissingET MissingET
  add Branch ScalarHT/energy ScalarHT ScalarHT
}




3. Prepare configuration file to run with pile-up

   cp examples/delphes_card_FCC_nsub.tcl examples/delphes_card_FCC_nsub_pu.tcl

    
4. Edit "examples/delphes_card_FCC_nsub_pu.tcl" including pile-up simulation, and charged hadron subtraction. 

set ExecutionPath {

  PileUpMerger
  ParticlePropagator
  …

  Hcal
  TrackPileUpSubtractor
   
  ... 

}

module PileUpMerger PileUpMerger {
  
  set InputArray Delphes/stableParticles

  set ParticleOutputArray stableParticles
  set VertexOutputArray vertices

  # pre-generated minbias input file
  set PileUpFile MinBias.pileup

  # average expected pile up
  set MeanPileUp 20

  # maximum spread in the beam direction in m
  set ZVertexSpread 0.10

  # maximum spread in time in s
  set TVertexSpread 1.5E-09

  # vertex smearing formula f(z,t) (z,t need to be respectively given in m,s)

  set VertexDistributionFormula {exp(-(t^2/(2*(0.05/2.99792458E8*exp(-(z^2/(2*(0.05)^2))))^2)))}

}
  
module ParticlePropagator ParticlePropagator {
  set InputArray PileUpMerger/stableParticles
  …
}
 


module TrackPileUpSubtractor TrackPileUpSubtractor {
# add InputArray InputArray OutputArray
  add InputArray ImpactParameterSmearing/tracks tracks

  set VertexInputArray PileUpMerger/vertices
  # assume perfect pile-up subtraction for tracks with |z| > fZVertexResolution
  # Z vertex resolution in m
  set ZVertexResolution 0.0001
}


module Merger EFlowMerger {
# add InputArray InputArray
  add InputArray TrackPileUpSubtractor/tracks
  add InputArray Ecal/eflowPhotons
  add InputArray Hcal/eflowNeutralHadrons
  set OutputArray eflow
}

(be careful, you need to REPLACE the existing EFlowMerger module with the above)




5. Copy the Minimum Bias file locally (used for pile-up merging)

  cp /afs/cern.ch/user/s/selvaggi/public/delphes_tuto/MinBias.pileup .


6. Run both configurations (with and without pile-up) on boosted QCD and ttbar events. This might take a while (to speed this up consider running them in parallel) …

./DelphesSTDHEP examples/delphes_card_FCC_nsub.tcl qcd_0pu.root /afs/cern.ch/user/s/selvaggi/public/delphes_tuto/qcd_100tev.hep
./DelphesSTDHEP examples/delphes_card_FCC_nsub.tcl tt_0pu.root /afs/cern.ch/user/s/selvaggi/public/delphes_tuto/tt_100tev.hep
./DelphesSTDHEP examples/delphes_card_FCC_nsub_pu.tcl qcd_20pu.root /afs/cern.ch/user/s/selvaggi/public/delphes_tuto/qcd_100tev.hep
./DelphesSTDHEP examples/delphes_card_FCC_nsub_pu.tcl tt_20pu.root /afs/cern.ch/user/s/selvaggi/public/delphes_tuto/tt_100tev.hep

If you want to submit them all in parallel, do:

cp /afs/cern.ch/user/s/selvaggi/public/delphes_tuto/submit.sh .
./submit.sh

7. Compare N-subjettiness

cp /afs/cern.ch/user/s/selvaggi/public/delphes_tuto/Nsub.C .
root -l -b -q Nsub.C'("qcd_0pu.root", "histo_qcd_0pu.root")'
root -l -b -q  Nsub.C'("qcd_20pu.root", "histo_qcd_20pu.root")'
root -l -b -q Nsub.C'("tt_0pu.root", "histo_tt_0pu.root")'
root -l -b -q  Nsub.C'("tt_20pu.root", "histo_tt_20pu.root")'

(produces root files with histograms)

cp /afs/cern.ch/user/s/selvaggi/public/delphes_tuto/plots_nsub.C .
root -b -q plots_nsub.C'("histo_qcd_0pu.root","histo_tt_0pu.root","histo_qcd_20pu.root","histo_tt_20pu.root")'
display nsub_plots.png