2 Simple use case for mixed event analysis
4 Delta_phi correlation analysis is performed on charged tracks
5 for same and mixed events
6 Author: andreas.morsch@cern.ch
13 #include "AliAODEvent.h"
14 #include "AliAODTrack.h"
15 #include "AliAnalysisTaskPhiCorr.h"
16 #include "AliMultiEventInputHandler.h"
18 ClassImp(AliAnalysisTaskPhiCorr)
20 //________________________________________________________________________
21 AliAnalysisTaskPhiCorr::AliAnalysisTaskPhiCorr(const char *name)
22 : AliAnalysisTaskME(name), fHists(0), fHistDphiCO(0), fHistDphiUC(0)
25 // Define input and output slots here
26 DefineOutput(1, TList::Class());
30 //________________________________________________________________________
31 void AliAnalysisTaskPhiCorr::UserCreateOutputObjects()
36 fHistDphiCO = new TH1F("fHistDPhiCO", "#Delta #Phi distribution", 64, 0., 3.2);
37 fHistDphiCO->GetXaxis()->SetTitle("#Delta#Phi [rad]");
38 fHistDphiCO->GetYaxis()->SetTitle("dN/d#Phi");
39 fHistDphiCO->SetMarkerStyle(kFullCircle);
41 fHistDphiUC = new TH1F("fHistDPhiUC", "#Delta #Phi distribution", 64, 0., 3.2);
42 fHistDphiUC->GetXaxis()->SetTitle("#Delta#Phi [rad]");
43 fHistDphiUC->GetYaxis()->SetTitle("dN/d#Phi");
44 fHistDphiUC->SetMarkerStyle(kOpenCircle);
47 fHists->Add(fHistDphiCO);
48 fHists->Add(fHistDphiUC);
51 //________________________________________________________________________
52 void AliAnalysisTaskPhiCorr::UserExec(Option_t *)
55 // Called for each event
56 // Uncorrelated tracks
57 Int_t nev = fInputHandler->GetBufferSize();
58 Float_t wgt = 1./(nev*(nev-1));
62 for (Int_t iev = 0; iev < nev; iev++) {
63 AliAODEvent* aod = (AliAODEvent*) GetEvent(iev);
64 fMixedEvent.AddEvent(aod);
67 Int_t ntrack = fMixedEvent.GetNumberOfTracks();
69 for (Int_t itr = 0; itr < ntrack -1; itr++) {
70 for (Int_t jtr = itr+1; jtr < ntrack; jtr++) {
71 AliVParticle* track1 = fMixedEvent.GetTrack(itr);
72 AliVParticle* track2 = fMixedEvent.GetTrack(jtr);
73 Int_t iev1 = fMixedEvent.EventIndex(itr);
74 Int_t iev2 = fMixedEvent.EventIndex(jtr);
76 Float_t phi1 = track1->Phi();
77 Float_t phi2 = track2->Phi();
78 Float_t dphi = TMath::Abs(phi1 - phi2);
79 if (dphi > TMath::Pi()) dphi = 2. * TMath::Pi() - dphi;
81 fHistDphiUC->Fill(dphi, wgt);
83 fHistDphiCO->Fill(dphi, 0.5);
92 //________________________________________________________________________
93 void AliAnalysisTaskPhiCorr::Terminate(Option_t *)
95 // Draw result to the screen
96 // Called once at the end of the query
98 TCanvas *c1 = new TCanvas("AliAnalysisTaskPt","Pt",10,10,510,510);
100 fHistDphiCO->DrawCopy("E");
101 fHistDphiUC->DrawCopy("Esame");