1 /**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
7 * Permission to use, copy, modify and distribute this software and its *
8 * documentation strictly for non-commercial purposes is hereby granted *
9 * without fee, provided that the above copyright notice appears in all *
10 * copies and that both the copyright notice and this permission notice *
11 * appear in the supporting documentation. The authors make no claims *
12 * about the suitability of this software for any purpose. It is *
13 * provided "as is" without express or implied warranty. *
14 **************************************************************************/
16 //---------------------------------------------------------------------
17 // Class to find and store the leading particle in event and
18 // store its correlation to associated particles
19 // Author: jgcn@mda.cinvestav.mx
20 //---------------------------------------------------------------------
22 #include <Riostream.h>
24 #include <TClonesArray.h>
25 #include <TLorentzVector.h>
27 #include "AliLeading.h"
28 #include "AliJetReader.h"
29 #include "AliJetReaderHeader.h"
33 ////////////////////////////////////////////////////////////////////////
35 AliLeading::AliLeading()
41 fLeading = new TLorentzVector(0.,0.,0.,0.);
42 fLow = -TMath::Pi()/2.0;
44 fCorr = TArrayI(fnBin);
47 ////////////////////////////////////////////////////////////////////////
49 AliLeading::~AliLeading()
57 ////////////////////////////////////////////////////////////////////////
59 void AliLeading::FindLeading(AliJetReader *reader)
63 // find leading particle in the array of lorentz vectors
64 // lvArray and fill the correlation histogram
68 AliJetReaderHeader* header = reader->GetReaderHeader();
70 TClonesArray* lvArray = reader->GetMomentumArray();
71 Int_t nIn = lvArray->GetEntries();
74 if (fNassoc < 0) return;
79 for (Int_t i = 0; i < nIn; i++){
80 TLorentzVector *lv = (TLorentzVector*) lvArray->At(i);
81 if (lv->Pt() > ptMax &&
82 lv->Eta() > header->GetFiducialEtaMin() &&
83 lv->Eta() < header->GetFiducialEtaMax())
90 // fill correlation array
91 fLeading = (TLorentzVector*) lvArray->At(idxMax);
92 for (Int_t i = 0; i < nIn; i++) {
93 if (i == idxMax) continue;
94 TLorentzVector *lv = (TLorentzVector*) lvArray->At(i);
95 Double_t dphi = fLeading->DeltaPhi(*lv);
96 if (dphi < fLow) dphi = 2.0 * TMath::Pi() + dphi;
97 // find bin and fill array
99 Int_t iBin = (Int_t) TMath::Floor((dphi - fLow)
100 *((Double_t) fnBin) / (2.0 * TMath::Pi()));
101 fCorr.AddAt(fCorr.At(iBin)+1,iBin);
105 ////////////////////////////////////////////////////////////////////////
107 void AliLeading::Reset()
110 // Reset leding particle information
111 fLeading->SetPxPyPzE(0., 0., 0., 0.);
116 ////////////////////////////////////////////////////////////////////////
118 void AliLeading::PrintLeading()
121 // Print leading particle information
123 cout << " No leading particle in this event" << endl;
126 cout << " Leading particle: " << endl;
127 cout << " (px,py,pz,e) = (" << fLeading->Px() << ","
128 << fLeading->Py() << "," << fLeading->Pz() << ","
129 << fLeading->E() << ")" << endl;
130 cout << " (pt,eta,phi) = (" << fLeading->Pt() << ","
131 << fLeading->Eta() << "," << fLeading->Phi() << ")" << endl;
132 cout << " " << fNassoc << " associated particles." << endl;