ttbar+gamma Analysis

Introduction/Theory:

Analysis Description:

The initial part of the analysis is related with the generation of events at parton level using MadGraph, the generation will be focused in 13 TeV and it will be done in a 2to7 decay.

Trigger:

• We are using the trigger HLTEle27_WP80_v
• This appear in our code as the HLTIndex[17]

Electron Cuts:

• Number of Electrons >= 1
• Electron Pt > 35 GeV

Muon Cuts:

• Number of Muons >= 1

Photon Cuts:

• Number of Photons >= 1

Analysis Code

Prerequisite

Setup PROOF (In case of need):

• Copy to your area and modify according to your needs the ROOT setup files:

cp ~yumiceva/RooAlias.C ~/.
cp ~yumiceva/RooCMS.C ~/.
cp ~yumiceva/RooLogon.C ~/.
cp ~yumiceva/.rootrc ~/.

• Edit rootrc file to point the PROOF sandbox to your scratch area. Change the line:

Proof.Sandbox: /uscmst1b_scratch/lpc1/cmsroc/yumiceva/proof

CMSSW:

• Set-up a CMSSW release:

cmsrel CMSSW_5_3_14_patch1
cd CMSSW_5_3_14_patch1/src/
cmsenv

Code

• Follow the instructions of the twiki https://twiki.cern.ch/twiki/bin/view/Main/FYumicevaTTGamma:

cd CMSSW_5_3_14_patch1/src/
cmsenv
git init
git clone -b V00-00-18 git@github.com:yumiceva/TTGamma.git

• The package EGamma is required for building the analysis code, this can be copy from Titas Roy (FIT) directory (It is also located as an attached file here, need to be decompressed):

cd CMSSW_5_3_14_patch1/src/
cmsenv
scp -r /uscms_data/d3/troy2012/CMSSW_5_3_14_patch1/src/EGamma/ .

• To build the analysis code, run:

cd CMSSW_5_3_14_patch1/src/
cmsenv
cd TTGamma/test/
make clean
make
mkdir histos

• To check the options and samples available to run the code, execute without any parameters:

./ttgamma

• To check the different input parameters for the executable, open the file run_histos.csh, an example is:

./ttgamma t_t muon inputskim >& histos_t_t.log

Plots

• To compare the histograms created for both the data and the MC samples, the package cuy is used, to obtain it run:

cd CMSSW_5_3_14_patch1/src
git init usercode
cd usercode
git config core.sparsecheckout true
echo "cuy" > .git/info/sparse-checkout
git remote add fxy https://github.com/yumiceva/usercode.git
git pull fxy master
git fetch fxy
git checkout V10-00-07
cd cuy
scram b
cmsenv

• The input options for the cuy.py code are:
  • -b, --batch : Run the program in batch mode, no graphics.
  • -c, --create : Create a XML configuration file from a ROOT file.
  • -e, --example : Generate an example .xml file.
  • -f, --flag : Create a banner.
  • -l, --list : List the objects inside a ROOT file.
  • -O, --OutputFileName : Name of the output ROOT file.
  • -o, -- Output : Output directory.
  • -p, --print : Print the canvas in the specified format (png,ps,eps,pdf,..).
  • -q, --quit : quit the program after producing the plots.
  • -t, --tag : Tag name for the XML configuration file.
  • -v, --verbose : Verbose (More extended) output.
  • -w, --wait : Pause the script after plotting a new superposition of histograms.
  • -x, --xml : XML configuration file.

• To produce the stacking plots (required to have all the histograms of the samples first) run:

cd CMSSW_5_3_14_patch1/src/
cmsenv
cd TTGamma/test/cuyFiles
mkdir plots
cuy.py -q -b -x plot_mu.xml -f "CMS Preliminary" -o plots/ -p "pdf"

• To change which plots are wanted as output and the configuration of the histograms the file plot_mu.xml (In the cuyFiles directory) needs to be modified.

MC-Whizard comparison:

The comparison between the two generators used it for the simulation of events at 8TeV for the ttbar+gamma analysis, MadGraph and Whizard, is presented in the file comparison