PWG2/FEMTOSCOPY/AliFemto/AliFemtoModelGausLCMSFreezeOutGenerator.cxx

   1 ////////////////////////////////////////////////////////////////////////////////
   2 ///                                                                          ///
   3 /// AliFemtoModelGausLCMSFreezeOutGenerator - freeze-out                     ///
   4 /// coordinates generator, generating a 3D gaussian ellipsoid in LCMS        ///
   5 /// Authors: Adam Kisiel kisiel@mps.ohio-state.edu                           ///
   6 ///                                                                          ///
   7 ////////////////////////////////////////////////////////////////////////////////
   8 #ifdef __ROOT__
   9   ClassImp(AliFemtoModelGausLCMSFreezeOutGenerator, 1)
  10 #endif
  11
  12 #include "math.h"
  13 #include "AliFemtoModelGausLCMSFreezeOutGenerator.h"
  14 #include "AliFemtoModelHiddenInfo.h"
  15 #include "AliFemtoLorentzVector.h"
  16
  17 //_______________________
  18 AliFemtoModelGausLCMSFreezeOutGenerator::AliFemtoModelGausLCMSFreezeOutGenerator() :
  19   fSizeOut(0), fSizeSide(0), fSizeLong(0)
  20 {
  21   // Default constructor
  22   fRandom = new TRandom2();
  23 }
  24
  25 //_______________________
  26 AliFemtoModelGausLCMSFreezeOutGenerator::AliFemtoModelGausLCMSFreezeOutGenerator(const AliFemtoModelGausLCMSFreezeOutGenerator &aModel):
  27   AliFemtoModelFreezeOutGenerator(aModel),
  28   fSizeOut(0), fSizeSide(0), fSizeLong(0)
  29 {
  30   // Copy constructor
  31   fRandom = new TRandom2();
  32   SetSizeOut(aModel.GetSizeOut());
  33   SetSizeSide(aModel.GetSizeSide());
  34   SetSizeLong(aModel.GetSizeLong());
  35 }
  36 //_______________________
  37 AliFemtoModelGausLCMSFreezeOutGenerator::~AliFemtoModelGausLCMSFreezeOutGenerator()
  38 {
  39   if (fRandom) delete fRandom;
  40 }
  41 //_______________________
  42 void AliFemtoModelGausLCMSFreezeOutGenerator::GenerateFreezeOut(AliFemtoPair *aPair)
  43 {
  44   // Generate two particle emission points with respect
  45   // to their pair momentum
  46   // The source is the 3D Gaussian ellipsoid in the LCMS frame
  47   AliFemtoModelHiddenInfo *inf1 = (AliFemtoModelHiddenInfo *) aPair->Track1()->HiddenInfo();
  48   AliFemtoModelHiddenInfo *inf2 = (AliFemtoModelHiddenInfo *) aPair->Track2()->HiddenInfo();
  49
  50   if ((!inf1) || (!inf2)) { cout << "Hidden info not created! "  << endl; exit(kFALSE); }
  51
  52   Double_t tPx = inf1->GetTrueMomentum()->x() + inf2->GetTrueMomentum()->x();
  53   Double_t tPy = inf1->GetTrueMomentum()->y() + inf2->GetTrueMomentum()->y();
  54   Double_t tPz = inf1->GetTrueMomentum()->z() + inf2->GetTrueMomentum()->z();
  55   Double_t tM1 = inf1->GetMass();
  56   Double_t tM2 = inf2->GetMass();
  57   Double_t tE1 = sqrt(tM1*tM1 + inf1->GetTrueMomentum()->mag2());
  58   Double_t tE2 = sqrt(tM2*tM2 + inf2->GetTrueMomentum()->mag2());
  59   Double_t tEs = tE1 + tE2;
  60
  61   Double_t tPt = sqrt(tPx*tPx + tPy*tPy);
  62
  63   Double_t tRout = fRandom->Gaus(0.0, fSizeOut);
  64   Double_t tRside = fRandom->Gaus(0.0, fSizeSide);
  65   Double_t tRlong = fRandom->Gaus(0.0, fSizeLong);
  66
  67   Double_t tXout = (tPx * tRout + tPy * tRside)/tPt;
  68   Double_t tXside = (tPy * tRout - tPx * tRside)/tPt;
  69
  70   Double_t tBetaz = tPz/tEs;
  71   Double_t tGammaz = 1.0/TMath::Sqrt(1-tBetaz*tBetaz);
  72
  73   Double_t tXlong = tGammaz * (tRlong + tBetaz * 0);
  74   Double_t tXtime = tGammaz * (0 + tBetaz * tRlong);
  75
  76   if (!(inf1->GetEmissionPoint())) {
  77     AliFemtoLorentzVector *tPos = new AliFemtoLorentzVector(0,0,0,0);
  78     inf1->SetEmissionPoint(tPos);
  79   }
  80   else
  81     inf1->SetEmissionPoint(0,0,0,0);
  82   if (!(inf2->GetEmissionPoint())) {
  83     AliFemtoLorentzVector *tPos = new AliFemtoLorentzVector(tXout,tXside,tXlong,tXtime);
  84     inf2->SetEmissionPoint(tPos);
  85   }
  86   else
  87     inf2->SetEmissionPoint(tXout, tXside, tXlong, tXtime);
  88 }
  89
  90 //_______________________
  91 void AliFemtoModelGausLCMSFreezeOutGenerator::SetSizeOut(Double_t aSizeOut)
  92 {
  93   fSizeOut = aSizeOut;
  94 }
  95 //_______________________
  96 void AliFemtoModelGausLCMSFreezeOutGenerator::SetSizeSide(Double_t aSizeSide)
  97 {
  98   fSizeSide = aSizeSide;
  99 }
 100 //_______________________
 101 void AliFemtoModelGausLCMSFreezeOutGenerator::SetSizeLong(Double_t aSizeLong)
 102 {
 103   fSizeLong = aSizeLong;
 104 }
 105
 106 //_______________________
 107 Double_t AliFemtoModelGausLCMSFreezeOutGenerator::GetSizeOut() const
 108 {
 109   return fSizeOut;
 110 }
 111 //_______________________
 112 Double_t AliFemtoModelGausLCMSFreezeOutGenerator::GetSizeSide() const
 113 {
 114   return fSizeSide;
 115 }
 116 //_______________________
 117 Double_t AliFemtoModelGausLCMSFreezeOutGenerator::GetSizeLong() const
 118 {
 119   return fSizeLong;
 120 }
 121 //_______________________
 122 AliFemtoModelFreezeOutGenerator* AliFemtoModelGausLCMSFreezeOutGenerator::Clone() const
 123 {
 124   return GetGenerator();
 125 }
 126 //_______________________
 127 AliFemtoModelFreezeOutGenerator* AliFemtoModelGausLCMSFreezeOutGenerator::GetGenerator() const
 128 {
 129   AliFemtoModelFreezeOutGenerator* tModel = new AliFemtoModelGausLCMSFreezeOutGenerator(*this); return tModel;
 130 }