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Exclusive tt analysis using full run II CMS data


This page contain analysis instructions (in development)

On this page:

Usefull Links

  • Exclusive ttbar talk (LHC WG on Forward Physics and Diffraction): link

Data and MC samples

Sample Xsec
/TTJets_TuneCP5_13TeV-amcatnloFXFX-pythia8/RunIIFall17MiniAODv2-PU2017_12Apr2018_94X_mc2017_realistic_v14-v1/MINIAODSIM 832

These samples produced privately and can be found in CERN EOS

Sample Xsec [fb]
/eos/cms/store/cmst3/group/top/exclusive_top/excl_ttbar_QED/MINIAOD/excl_ttbar_WmLep_QED/ 0.064
/eos/cms/store/cmst3/group/top/exclusive_top/excl_ttbar_QED/MINIAOD/excl_ttbar_WpLep_QED/ 0.064

Configuration file can be found in the attachment . It consist of several steps:

  • Simulation with FPMC of exclusive γγ→tt events
  • Interfacing of FPMC output with MadSpin such that only one top quark decays leptonically
  • Interfacing MadSpin output with Pythia8
  • Processing events after hadronization with full CMS detector simulation following by reconstruction
Execute script with correct arguments. The output files will be of a miniAOD.root format.

Stream Lumi
/SingleMuon/Run2017H-17Nov2017-v2/MINIAOD XXX
/HighEGJet/Run2017H-17Nov2017-v1/MINIAOD XXX


Ntuple production

Production is performed using TopLJets2015 analysis package which use PPS reconstruction data.

PPS fast simulation

The full instruction for simulating the forward protons can be found in TaggedProtonsDirectSimulation twiki. The configuration file is attached ( The following lines should be executed (CMSSW should point to your CMSSW setup as explained here):

cd ${CMSSW}/src
eval `scram r -sh`
cd -
cd ${CMSSW_BASE}/../cms-data
export CMSSW_DATA_PATH="/afs"
cd -
cp ${CMSSW_BASE}/src/proton_simulation_validation/settings/2017_postTS2/* .

NOTE: to process miniAOD, one should change the collection name to: cms.InputTag("prunedGenParticles")

Making validation plots


To plot top - anti-top invariant mass from the samples, either directly from tops or from the protons

scram project CMSSW CMSSW_9_4_7
cd CMSSW_9_4_7/src

root -l  /eos/cms/store/cmst3/group/top/exclusive_top/excl_ttbar_QED/MINIAOD/excl_ttbar_WpLep_QED//excl_ttbar_WpLep_QED_663.root
Events->Draw("2*sqrt( (6500.-genpar.pz()[0])*(6500.+genpar.pz()[1]))")

miniAOD with protons

To plot proton pZ vs reconstructed pZ (similarly can be made for ξ):

cd ${CMSSW}/src

root -l  miniAOD_withProtons.root
Events->Draw("proton.pz() : genpar.pz()[0]","proton.pz() > 0")

For more variables see reco::ForwardProton.


To process nanoAODs execute the following:

ln -s /eos/user/m/mpitt/PPS_ttbar/FPMC/Merged/excl_ttbar_WmLep_QED.root MiniEvents.root
python $CMSSW_BASE/src/TopLJets2015/TopAnalysis/scripts/ -i MiniEvents.root -o ntuple.root --njobs 1 -q local --era era2017 -m RunExclusiveTop2020 --skimtree True

PPS reconstruction (data)

Submit to grid

After the local tests are succesfull, one can process all the data on the grid:


execute this and that

-- MichaelPitt - 2019-12-07

  • production of exclusive ttbar events with CMS

Topic attachments
I Attachment History Action Size Date Who Comment
Compressed Zip archivezip r1 manage 17.1 K 2020-01-01 - 15:40 MichaelPitt production of exclusive ttbar events with CMS
Compressed Zip archivezip r2 r1 manage 2.4 K 2020-01-21 - 18:51 MichaelPitt cfg file for FastSim of tagged protons
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Topic revision: r11 - 2020-01-21 - MichaelPitt
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