source: HiSusy/trunk/Delphes/Delphes-3.0.9/examples/Example1.C @ 5

Last change on this file since 5 was 5, checked in by zerwas, 11 years ago

update to Delphes-3.0.9

File size: 1.8 KB
Line 
1/*
2root -l examples/Example1.C\(\"delphes_output.root\"\)
3*/
4
5//------------------------------------------------------------------------------
6
7void Example1(const char *inputFile)
8{
9  gSystem->Load("libDelphes");
10
11  // Create chain of root trees
12  TChain chain("Delphes");
13  chain.Add(inputFile);
14 
15  // Create object of class ExRootTreeReader
16  ExRootTreeReader *treeReader = new ExRootTreeReader(&chain);
17  Long64_t numberOfEntries = treeReader->GetEntries();
18 
19  // Get pointers to branches used in this analysis
20  TClonesArray *branchJet = treeReader->UseBranch("Jet");
21  TClonesArray *branchElectron = treeReader->UseBranch("Electron");
22 
23  // Book histograms
24  TH1 *histJetPT = new TH1F("jet_pt", "jet P_{T}", 100, 0.0, 100.0);
25  TH1 *histMass = new TH1F("mass", "M_{inv}(e_{1}, e_{2})", 100, 40.0, 140.0);
26
27  // Loop over all events
28  for(Int_t entry = 0; entry < numberOfEntries; ++entry)
29  {
30    // Load selected branches with data from specified event
31    treeReader->ReadEntry(entry);
32 
33    // If event contains at least 1 jet
34    if(branchJet->GetEntries() > 0)
35    {
36      // Take first jet
37      Jet *jet = (Jet*) branchJet->At(0);
38     
39      // Plot jet transverse momentum
40      histJetPT->Fill(jet->PT);
41     
42      // Print jet transverse momentum
43      cout << jet->PT << endl;
44    }
45
46    Electron *elec1, *elec2;
47
48    // If event contains at least 2 electrons
49    if(branchElectron->GetEntries() > 1)
50    {
51      // Take first two electrons
52      elec1 = (Electron *) branchElectron->At(0);
53      elec2 = (Electron *) branchElectron->At(1);
54
55      // Plot their invariant mass
56      histMass->Fill(((elec1->P4()) + (elec2->P4())).M());
57    }
58  }
59
60  // Show resulting histograms
61  histJetPT->Draw();
62  histMass->Draw();
63}
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