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Reference Guide
df102_NanoAODDimuonAnalysis.C File Reference

Detailed Description

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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();
h->GetXaxis()->SetTitleSize(0.04);
h->GetYaxis()->SetTitleSize(0.04);
h->DrawClone();
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}");
c->SaveAs("dimuon_spectrum.pdf");
// Print cut-flow report
report->Print();
}
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 %
Date
August 2018
Author
Stefan Wunsch (KIT, CERN)

Definition in file df102_NanoAODDimuonAnalysis.C.