TTGamma Analysis


Analysis Code

  • Recipe to install and compile the analysis code:
cmsrel CMSSW_5_3_14_patch2
cd CMSSW_5_3_14_patch2/src/
git clone
scram b -j 8
git clone -b V00-00-10
cd TTGamma/test/
make clean

  • To check all the options and sample names available in the code, run the executable with no arguments:

  • Example to run over Skimmed ntuples and produce histograms for each sample. Below the first line will run over the single top t-channel sample with input the muon skim.
./ttgamma t_t muon inputskim >& histos_t_t.log &
./ttgamma data muon inputskim >& histos_data.log &

Plotting Script

  • Recipe to install code to make plots is in this LINK

  • Example to produce a comparison plot. Requires that you have produced histograms for each MC sample and data.

$CMSSW_BASE/src/TTGamma/test/cuyFiles/ -x plot_mu.xml -f "CMS Preliminary" -p "png"


  • Skimmed tuples as input
    • Produce histograms for each sample e.g.
./ttgamma t_s muon inputskim outdir=./histos/ >& histos/histos_t_s.log &
    • See the file named run_histos.csh for the complete list of samples.
    • Produce plots using the script.
    • Pre-selection control plots:
cd cuyFiles -b -q -x plot_mu_pre.xml -p "pdf"
    • Photon selection plots:
cd cuyFiles -b -q -x plot_mu.xml -p "pdf"

*Top Group Synchronization Exercise

* Option to run the synchronization exercise that change a little the default selection:

./ttgamma sync muons outdir=histos


Cutflow table
1 cut: Skim entries: 9097
2 cut: Cleaning entries: 9080
3 cut: HLT entries: 9080
4 cut: GoodPV entries: 9078
5 cut: OneIsoMuon entries: 1095
6 cut: LooseMuVeto entries: 1057
7 cut: LooseEleVeto entries: 953
8 cut: 1Jets entries: 906
9 cut: 2Jets entries: 771
10 cut: 3Jets entries: 598
11 cut: 4Jets entries: 527
12 cut: Onebtag entries: 433


Cutflow table
1 cut: Skim entries: 9097
2 cut: Cleaning entries: 9080
3 cut: HLT entries: 9080
4 cut: GoodPV entries: 9078
5 cut: OneIsoEle entries: 1029
6 cut: LooseMuVeto entries: 913
7 cut: DileptonVeto entries: 896
8 cut: ConvRejection entries: 861
9 cut: 1Jets entries: 798
10 cut: 2Jets entries: 687
11 cut: 3Jets entries: 540
12 cut: 4Jets entries: 483
13 cut: Onebtag entries: 391

  • Recipe to run ttgamma in the Condor batch farm:
# copy these files to your scratch area and edit the files batch.jdl and to use your area:
cp /uscmst1b_scratch/lpc1/cmsroc/yumiceva/TTGamma/condor/batch.jdl .
cp /uscmst1b_scratch/lpc1/cmsroc/yumiceva/TTGamma/condor/ .
# then you can submit jobs using:
# condor_submit batch.jdl

Skimmed Ntuples

  • Location of electron skim:
  • Location of muon skim:
  • To produce a skimmed ntuple:
./ttgamma skim electron outdir=/eos/uscms/store/user/yumiceva/ttgamma/skim/v0/electron/

  • To run in condor, you can use this script along with batch.jdl file:

Analysis Ntuples


  • Recipe to install ggNtuple code here

  • Recipes to run production here

  • My test recipe:
    cmsrel CMSSW_5_3_14_patch1
    cd CMSSW_5_3_14_patch1/src/
    git cms-addpkg PhysicsTools/PatAlgos
    git clone
    git clone
    git clone -b V01-00
    git clone -b V05-03-12-03
    cvs co -r V00-02-05 -d CMGTools/External UserCode/CMG/CMGTools/External
    scram b -j 20

To make CVS work again, you need the following:

setenv CVSROOT ""

  • Location of files at FNAL:

    • Latest version here
    • old version. Full ntuples no skimmed:
data: /uscmst1b_scratch/lpc1/old_scratch/lpceg/yurii/ggNtuples/job_1electron_2012*
mc: /uscmst1b_scratch/lpc1/old_scratch/lpceg/yurii/ggNtuples/GGNtuMC/
mc preskimmed (e+gamma): /uscmst1b_scratch/lpc1/old_scratch/lpceg/yurii/ggNtuples/LepGamDR03SkimMC

  • Code to produce ggNtuples here

  • Ntuple naming convection here

JSON and Pileup files


MC Corrections

PU reweighting

  • Need to compute the input histograms. First, install the lumi scripts by following this recipe
  • Calculate the PU distribution in 2012 data. Notice that MC histogram was produced with 500 bins and 100 pu vertices: -i Cert_190456-208686_8TeV_22Jan2013ReReco_Collisions12_JSON.txt --inputLumiJSON pileup_JSON_DCSONLY_190389-208686_All_2012_pixelcorr.txt --calcMode true --minBiasXsec 69400 --maxPileupBin 100 --numPileupBins 500 MyDataPileupHistogram.root
  • MC ntuples include the PU histogram called "hPU_True" filled with the data from "getTrueNumInteractions" for only bunch crossing 0.
  • We need to extract the MC histograms from the skimmed ntuples to use them in the analysis code. We use the script "" for this task.

Muon Identification and Isolation SF

b-tagging SF


Top quark reference selection


The following is taken from Physics Letters B Volume 713, Issue 2, 21 June 2012, Pages 6890 :

A correction is applied to the isolation variable to account for effects of additional interactions. For charged particles, only those associated with the primary vertex are considered in the isolation variable. For neutral particles, a correction is applied by subtracting the energy deposited in the isolation cone by charged particles not associated with the primary vertex, multiplied by a factor of 0.5. This factor corresponds approximately to the ratio of neutral to charged hadron production in the hadronization process of pile-up interactions. An η, pT, and lepton-flavor dependent threshold on the isolation variable of less than roughly 10% of the candidate pT is applied. To correct for the contribution to the jet energy due to pile-up, a median energy density (ρ) is determined event by event. The pile-up contribution to the jet energy is estimated as the product of ρ and the area of the jet and subsequently subtracted from the jet transverse energy [37]. In the fiducial region for jets of |η| < 4.7, jet energy corrections are also applied as a function of the jet ET and η [38].

Photon ID


  • Papers:
    • Atlas published paper at 7 TeV link
    • Top quark working group report, Snowmass arxiv
    • Constraining couplings of the top quarks to the Z boson in ttbar+Z production at the LHC arxiv
    • QCD corrections to top quark pair production in association with a photon at hadron colliders arxiv
    • Constraining top-Z couplings through ttb+Z production at the LHC, ICHEP presentation pdf
  • Photon Reconstruction, Isolation. Photon Workshop
  • Standard Model cross sections at 8 TeV link
  • Vector boson production paper
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Topic revision: r35 - 2015-06-15 - FranciscoYumiceva
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