ROOT Data Analysis Framework Overview

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ROOT Tutorials

In general, my lesson plan was as follows:

  • Show you how to run PROOF (emphasizing the code needed)
    • TChain files together
    • Make template header, code, and PROOF starting files for specific .root data files
    • Troubleshooting PROOF run errors (whether it's your code or the cluster's errors)
  • Basic analysis code
    • Explain online & offline triggers
    • Analysis cut (lots to discuss)
    • Ways to display data (and interpret it)
    • Calculating invariant mass, delta phi, etc.
    • Calculating Accidental Scaling Factor
    • Tag weighting (accidental subtraction)
    • Two calculations for Sideband Subtraction
    • Fitting histograms
    • Cross section (differential and total)
  • Provide sample code and tricks
    • Setup an array (using a for loop or with direct input, depending on the occasion)
    • Reorder things from high to low mass (how to deal with multiple combinations at once)
    • TLorentzVectors
    • Create new .root files
    • Create marcos to print, make GIF's, fit data, etc.
    • TGraphs & TSplines
  • Final Summary
    • Walk you through my analysis for determining the Eta meson cross section
    • Big picture stuff that puts everything all together and hopefully makes it all make sense


Lesson #1

Lesson #1 Video




Lesson #2

Lesson #2 Video



Lesson #3

Lesson #3




Lesson #4

Lesson #4



Lesson #5

Lesson #5


Additional Resource Files

This file can be uploaded in to a personal annex directory on gluey and manipulated with ROOT to plot the TH1D's and TH2D's contained within.

If inside the folder containing the .root file, use the command:

root -l TwoG_jul_16_2021Analysis.root


If you know the path to the file then use:

root -l

TFile *_file0 = TFile::Open("/nfs/direct/annex/mcintyre/AnalysisXII/TwoG/inv_mass/TwoG_jul_16_2021Analysis.root")


or


root -l /nfs/direct/annex/mcintyre/AnalysisXII/TwoG/inv_mass/TwoG_jul_16_2021Analysis.root




These files are the three files needed to run a PROOF session. These files, written in C++, contain basic clean-up cuts for Radphi data analysis as discussed during the tutorial videos. Running a PROOF session on files such as these are how the .root file (listed above) was created.



A GitHub page containing ROOT training material and tutorials given to CERN Summer Students. There is a link to the ROOT introductory course part of the CERN Training Catalogue.



 
Figure 3: A TH1D histogram of the Mandelstam variable t for the two gamma final state sample.