Logo ROOT  
Reference Guide
df102_NanoAODDimuonAnalysis.C File Reference

Detailed Description

View in nbviewer Open in SWAN
Show how NanoAOD files can be processed with RDataFrame.

This tutorial illustrates how NanoAOD files can be processed with ROOT dataframes. The NanoAOD-like input files are filled with 66 mio. events from CMS OpenData containing muon candidates part of 2012 dataset (DOI: 10.7483/OPENDATA.CMS.YLIC.86ZZ and DOI: 10.7483/OPENDATA.CMS.M5AD.Y3V3). The macro matches muon pairs and produces an histogram of the dimuon mass spectrum showing resonances up to the Z mass. Note that the bump at 30 GeV is not a resonance but a trigger effect.

More details about the dataset can be found on the CERN Open Data portal.

#include "ROOT/RVec.hxx"
#include "TCanvas.h"
#include "TH1D.h"
#include "TLatex.h"
#include "TStyle.h"
using namespace ROOT::VecOps;
// Enable multi-threading
// Create dataframe from NanoAOD files
ROOT::RDataFrame df("Events", "root://eospublic.cern.ch//eos/opendata/cms/derived-data/AOD2NanoAODOutreachTool/Run2012BC_DoubleMuParked_Muons.root");
// For simplicity, select only events with exactly two muons and require opposite charge
auto df_2mu = df.Filter("nMuon == 2", "Events with exactly two muons");
auto df_os = df_2mu.Filter("Muon_charge[0] != Muon_charge[1]", "Muons with opposite charge");
// Compute invariant mass of the dimuon system
auto df_mass = df_os.Define("Dimuon_mass", InvariantMass<float>, {"Muon_pt", "Muon_eta", "Muon_phi", "Muon_mass"});
// Make histogram of dimuon mass spectrum. Note how we can set title and axis labels in one go
auto h = df_mass.Histo1D({"Dimuon_mass", "Dimuon mass;m_{#mu#mu} (GeV);N_{Events}", 30000, 0.25, 300}, "Dimuon_mass");
// Request cut-flow report
auto report = df_mass.Report();
// Produce plot
auto c = new TCanvas("c", "", 800, 700);
c->SetLogx(); c->SetLogy();
TLatex label; label.SetNDC(true);
label.DrawLatex(0.175, 0.740, "#eta");
label.DrawLatex(0.205, 0.775, "#rho,#omega");
label.DrawLatex(0.270, 0.740, "#phi");
label.DrawLatex(0.400, 0.800, "J/#psi");
label.DrawLatex(0.415, 0.670, "#psi'");
label.DrawLatex(0.485, 0.700, "Y(1,2,3S)");
label.DrawLatex(0.755, 0.680, "Z");
label.SetTextSize(0.040); label.DrawLatex(0.100, 0.920, "#bf{CMS Open Data}");
label.SetTextSize(0.030); label.DrawLatex(0.630, 0.920, "#sqrt{s} = 8 TeV, L_{int} = 11.6 fb^{-1}");
// Print cut-flow report
int main()
#define c(i)
Definition: RSha256.hxx:101
#define h(i)
Definition: RSha256.hxx:106
R__EXTERN TStyle * gStyle
Definition: TStyle.h:414
int main(int argc, char *argv[])
Definition: cef_main.cxx:54
ROOT's RDataFrame offers a modern, high-level interface for analysis of data stored in TTree ,...
Definition: RDataFrame.hxx:40
virtual void SetTextFont(Font_t tfont=62)
Set the text font.
Definition: TAttText.h:46
virtual void SetTextSize(Float_t tsize=1)
Set the text size.
Definition: TAttText.h:47
The Canvas class.
Definition: TCanvas.h:23
To draw Mathematical Formula.
Definition: TLatex.h:18
TLatex * DrawLatex(Double_t x, Double_t y, const char *text)
Make a copy of this object with the new parameters And copy object attributes.
Definition: TLatex.cxx:1928
void SetOptStat(Int_t stat=1)
The type of information printed in the histogram statistics box can be selected via the parameter mod...
Definition: TStyle.cxx:1589
virtual void SetNDC(Bool_t isNDC=kTRUE)
Set NDC mode on if isNDC = kTRUE, off otherwise.
Definition: TText.cxx:813
void EnableImplicitMT(UInt_t numthreads=0)
Enable ROOT's implicit multi-threading for all objects and methods that provide an internal paralleli...
Definition: TROOT.cxx:527
Events with exactly two muons: pass=31104343 all=61540413 -- eff=50.54 % cumulative eff=50.54 %
Muons with opposite charge: pass=24067843 all=31104343 -- eff=77.38 % cumulative eff=39.11 %
August 2018
Stefan Wunsch (KIT, CERN)

Definition in file df102_NanoAODDimuonAnalysis.C.