EE Jet Analysis Code

Installation

Prerequisites

To start running, you will need a few things

1. CERN ROOT with RooFit enabled
   • we need to link to it
   • make sure root-config is in PATH variable
2. RooUnfold
   • go https://gitlab.cern.ch/RooUnfold/RooUnfold#building-the-library and follow the instructions
3. fastjet
   • go to fastjet.fr and install it somewhere!
   • make sure fastjet-config is in PATH variable
4. helper codes
   • go clone this https://github.com/FHead/fheadhelpercode somewhere
   • Set environment variable RootMacrosBase to point to the RootMacros folder
5. (optional) pythia8 installation

CompileRootMacro script

The script itself is in the fheadhelpercode/RootMacros directory

First make sure this script is in your PATH variable, then modify it to use the correct flags, directories, etc

You can see a bunch of if/else statement, add one for your machine and modify accordingly

Compile stuff

Go to fheadhelpercode/RootMacros/Code and do

bash Compile

Then come back here and go into CommonCode. And do

mkdir library
make

Samples

Then you need a bunch of samples.

Make a Samples folder and put the corresponding files as follows

Samples/
   ALEPH/
      *.root
   ALEPHMC/
      *.root
   HERWIG7/
      run_00/
         *.root
      run_01/
         *.root
      ...
   HERWIG715/
      run_00/
         *.root
      ...
   SHERPA/
      run_00/
         *.root
      ...

And then copy the PurePythia91.root into MCStudies/23417_PythiaWholeEvent/ folder. (or generate it with make RunPythiaOnShell if you have pythia8 installed)

Ask Yi where to find the root files

Now we're ready to run things!

Code overview

The code is modularized, with a two-layer folder convention. The parent folder is the rough category of the code, and the subfolders are the units of code that each does something specific. And then we link them together. There are makefiles that helps with tasks that we need to run over and over again.

The most important ones to start with are the MCStudies folder which contains simulation-based jet calibration code, and DataStudies folder which does the data-simulation difference. The JetCorrection folder contains all the calibration constants that are used by later code. Since they are derived already, we do not usually need to run it again unless we want to rederive things with new jet clustering algorithm.

Then the actual analysis code is in UnfoldingStudies. Looking into the makefile, we can see a number of steps.

1. JetClustering: from reconstructed particles we cluster jets and write into intermediate format
2. UnfoldPreparation: from the output of the previous step, we prepare input files for unfolding step
3. NominalUnfold: actual unfold!
4. MCIterationScan: optimize unfolding parameters for simulation-based samples
5. DataIterationScan: optimize for data
6. LeadingJetCorrection: derive leading jet corrections
7. Systematics: fill in all the different systematics and prepare for the final result
8. FinalPlot: make pretty plots!

To start and run, we should do

make RunAllQuick

and wait until it finishes. If everything is set up correctly, we should see a bunch of pretty plots being generated!