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Reference Guide
df102_NanoAODDimuonAnalysis.C File Reference

Detailed Description

Show how NanoAOD files can be processed with RDataFrame.

View in nbviewer Open in SWAN 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.

Some more details about the dataset:

  • It contains about 66 millions events (muon and electron collections, plus some other information, e.g. about primary vertices)
  • It spans two compressed ROOT files located on EOS for about a total size of 7.5 GB.
#include "ROOT/RVec.hxx"
#include "TCanvas.h"
#include "TH1D.h"
#include "TLatex.h"
#include "Math/Vector4D.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/root-eos/cms_opendata_2012_nanoaod/Run2012B_DoubleMuParked.root",
"root://eospublic.cern.ch//eos/root-eos/cms_opendata_2012_nanoaod/Run2012C_DoubleMuParked.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
auto h = df_mass.Histo1D({"Dimuon_mass", "Dimuon_mass", 30000, 0.25, 300}, "Dimuon_mass");
// Request cut-flow report
auto report = df_mass.Report();
// Produce plot
gStyle->SetOptStat(0); gStyle->SetTextFont(42);
auto c = new TCanvas("c", "", 800, 700);
c->SetLogx(); c->SetLogy();
h->SetTitle("");
h->GetXaxis()->SetTitle("m_{#mu#mu} (GeV)"); h->GetXaxis()->SetTitleSize(0.04);
h->GetYaxis()->SetTitle("N_{Events}"); 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()
{
}
Events with exactly two muons: pass=33370298 all=66128870 -- eff=50.46 % cumulative eff=50.46 %
Muons with opposite charge: pass=25794885 all=33370298 -- eff=77.30 % cumulative eff=39.01 %
Date
August 2018
Author
Stefan Wunsch (KIT, CERN)

Definition in file df102_NanoAODDimuonAnalysis.C.

c
#define c(i)
Definition: RSha256.hxx:119
TStyle.h
TLatex::DrawLatex
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:1927
TLatex
Definition: TLatex.h:18
ROOT::RDF::RInterface::Filter
RInterface< RDFDetail::RFilter< F, Proxied >, DS_t > Filter(F f, const ColumnNames_t &columns={}, std::string_view name="")
Append a filter to the call graph.
Definition: RInterface.hxx:187
TCanvas.h
RVec.hxx
ROOT::RDataFrame
ROOT's RDataFrame offers a high level interface for analyses of data stored in TTrees,...
Definition: RDataFrame.hxx:42
RDataFrame.hxx
ROOT::EnableImplicitMT
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:523
TText::SetNDC
virtual void SetNDC(Bool_t isNDC=kTRUE)
Set NDC mode on if isNDC = kTRUE, off otherwise.
Definition: TText.cxx:813
gStyle
R__EXTERN TStyle * gStyle
Definition: TStyle.h:412
h
#define h(i)
Definition: RSha256.hxx:124
main
int main(int argc, char **argv)
Definition: histspeedtest.cxx:752
df102_NanoAODDimuonAnalysis
Definition: df102_NanoAODDimuonAnalysis.py:1
TStyle::SetOptStat
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:1592
TCanvas
Definition: TCanvas.h:23
TLatex.h
Vector4D.h
ROOT::VecOps
Definition: RVec.hxx:53
TH1D.h