PWG2/FEMTOSCOPY/AliFemto/AliFemtoModelWeightGeneratorBasic.cxx

   1 ////////////////////////////////////////////////////////////////////////////////
   2 ///                                                                          ///
   3 /// AliFemtoModelWeightGeneratorBasic -  basic femtoscopic weight generator  ///
   4 /// only return a simple                                                          ///
   5 /// Authors: Adam Kisiel kisiel@mps.ohio-state.edu                           ///
   6 ///                                                                          ///
   7 ////////////////////////////////////////////////////////////////////////////////
   8 #ifdef __ROOT__
   9   ClassImp(AliFemtoModelWeightGeneratorBasic, 1)
  10 #endif
  11
  12 #include "AliFemtoModelWeightGeneratorBasic.h"
  13 #include "AliFemtoModelHiddenInfo.h"
  14
  15 //________________________
  16 AliFemtoModelWeightGeneratorBasic::AliFemtoModelWeightGeneratorBasic():
  17   AliFemtoModelWeightGenerator()
  18 {
  19   /* no-op */
  20 }
  21 //________________________
  22 AliFemtoModelWeightGeneratorBasic::AliFemtoModelWeightGeneratorBasic(const AliFemtoModelWeightGeneratorBasic &aModel) :
  23   AliFemtoModelWeightGenerator(aModel)
  24 {
  25   /* no-op */
  26 }
  27
  28 //________________________
  29 AliFemtoModelWeightGeneratorBasic::~AliFemtoModelWeightGeneratorBasic()
  30 {
  31   /* no-op */
  32 }
  33
  34 //________________________
  35 Double_t AliFemtoModelWeightGeneratorBasic::GenerateWeight(AliFemtoPair *aPair)
  36 {
  37   // Generate a simple femtoscopic weight coming only from
  38   // quantum statistics - symmetrization or anti-symmetrization
  39   // of the pair wave function
  40
  41   // Get hidden information pointers
  42   AliFemtoModelHiddenInfo *inf1 = (AliFemtoModelHiddenInfo *) aPair->Track1()->HiddenInfo();
  43   AliFemtoModelHiddenInfo *inf2 = (AliFemtoModelHiddenInfo *) aPair->Track2()->HiddenInfo();
  44
  45   // Calculate pair variables
  46   Double_t tPx = inf1->GetTrueMomentum()->x()+inf2->GetTrueMomentum()->x();
  47   Double_t tPy = inf1->GetTrueMomentum()->y()+inf2->GetTrueMomentum()->y();
  48   Double_t tPz = inf1->GetTrueMomentum()->z()+inf2->GetTrueMomentum()->z();
  49   //  double tE  = inf1->GetTrueMomentum()->e +inf2->GetTrueMomentum()->.e;
  50   Double_t tM1 = inf1->GetMass();
  51   Double_t tM2 = inf2->GetMass();
  52   Double_t tE1 = sqrt(tM1*tM1 + inf1->GetTrueMomentum()->mag2());
  53   Double_t tE2 = sqrt(tM2*tM2 + inf2->GetTrueMomentum()->mag2());
  54   Double_t tE  = tE1 + tE2;
  55   Double_t tPt = tPx*tPx + tPy*tPy;
  56   Double_t tMt = tE*tE - tPz*tPz;//mCVK;
  57   Double_t tM  = sqrt(tMt - tPt);
  58   tMt = sqrt(tMt);
  59   tPt = sqrt(tPt);
  60   Double_t tBetat = tPt/tMt;
  61
  62   // Boost to LCMS
  63   Double_t tBeta = tPz/tE;
  64   Double_t tGamma = tE/tMt;
  65   fKStarLong = tGamma * (inf1->GetTrueMomentum()->z() - tBeta * tE1);
  66   Double_t tE1L = tGamma * (tE1  - tBeta * inf1->GetTrueMomentum()->z());
  67
  68   // Transform positions to LCMS
  69 //   Double_t tP1zl = tGamma * (inf1->GetEmissionPoint()->z() - tBeta * inf1->GetEmissionPoint()->t());
  70 //   Double_t tP1tl = tGamma * (inf1->GetEmissionPoint()->t() - tBeta * inf1->GetEmissionPoint()->z());
  71
  72 //   Double_t tP2zl = tGamma * (inf2->GetEmissionPoint()->z() - tBeta * inf2->GetEmissionPoint()->t());
  73 //   Double_t tP2tl = tGamma * (inf2->GetEmissionPoint()->t() - tBeta * inf2->GetEmissionPoint()->z());
  74
  75 //   Double_t tP1pzl = tGamma * (inf1->GetTrueMomentum()->z() - tBeta * tE1);
  76 //   Double_t tP1el  = tGamma * (tE1  - tBeta * inf1->GetTrueMomentum()->z());
  77
  78 //   Double_t tP2pzl = tGamma * (inf2->GetTrueMomentum()->z() - tBeta * tE2);
  79 //   Double_t tP2el  = tGamma * (tE2  - tBeta * inf2->GetTrueMomentum()->z());
  80
  81   // Rotate in transverse plane
  82   fKStarOut  = ( inf1->GetTrueMomentum()->x()*tPx + inf1->GetTrueMomentum()->y()*tPy)/tPt;
  83   fKStarSide = (-inf1->GetTrueMomentum()->x()*tPy + inf1->GetTrueMomentum()->y()*tPx)/tPt;
  84
  85 //   Double_t tP1pxl = fKStarOut;
  86 //   Double_t tP1pyl = fKStarSide;
  87
  88 //   Double_t tP2pxl = (inf2->GetTrueMomentum()->x()*tPx + inf2->GetTrueMomentum()->y()*tPy)/tPt;
  89 //   Double_t tP2pyl = (inf2->GetTrueMomentum()->y()*tPx - inf2->GetTrueMomentum()->x()*tPy)/tPt;;
  90
  91 //   Double_t tKO = tP1pxl - tP2pxl;
  92 //   Double_t tKS = tP1pyl - tP2pyl;
  93 //   Double_t tKL = tP1pzl - tP2pzl;
  94 //   Double_t tDE = tP1el  - tP2el;
  95
  96   // save the rotated coordinates in LCMS variables
  97 //   Double_t tP1xl = ( inf1->GetEmissionPoint()->x()*tPx + inf1->GetEmissionPoint()->y()*tPy)/tPt;
  98 //   Double_t tP1yl = (-inf1->GetEmissionPoint()->x()*tPy + inf1->GetEmissionPoint()->y()*tPx)/tPt;
  99
 100 //   Double_t tP2xl = ( inf2->GetEmissionPoint()->x()*tPx + inf2->GetEmissionPoint()->y()*tPy)/tPt;
 101 //   Double_t tP2yl = (-inf2->GetEmissionPoint()->x()*tPy + inf2->GetEmissionPoint()->y()*tPx)/tPt;
 102
 103   // Boost to pair cms
 104   fKStarOut = tMt/tM * (fKStarOut - tPt/tMt * tE1L);
 105
 106   tBetat = tPt/tMt;
 107 //   Double_t tGammat = 1.0/sqrt(1.0-tBetat*tBetat);
 108
 109 //   Double_t tP1xp = tGammat*(tP1xl - tBetat*tP1tl);
 110 //   Double_t tP1tp = tGammat*(tP1tl - tBetat*tP1xl);
 111
 112 //   Double_t tP2xp = tGammat*(tP2xl - tBetat*tP2tl);
 113 //   Double_t tP2tp = tGammat*(tP2tl - tBetat*tP2xl);
 114
 115 //   Double_t tRO = (tP1xl - tP2xl)/0.197327;
 116 //   Double_t tRS = (tP1yl - tP2yl)/0.197327;
 117 //   Double_t tRL = (tP1zl - tP2zl)/0.197327;
 118 //   Double_t tDT = (tP1tl - tP2tl)/0.197327;
 119
 120   Double_t tDX = inf1->GetEmissionPoint()->x()-inf2->GetEmissionPoint()->x();
 121   Double_t tDY = inf1->GetEmissionPoint()->y()-inf2->GetEmissionPoint()->y();
 122   Double_t tRLong = inf1->GetEmissionPoint()->z()-inf2->GetEmissionPoint()->z();
 123   Double_t tDTime = inf1->GetEmissionPoint()->t()-inf2->GetEmissionPoint()->t();
 124
 125   Double_t tROut = (tDX*tPx + tDY*tPy)/tPt;
 126   Double_t tRSide = (-tDX*tPy + tDY*tPx)/tPt;
 127
 128   fRStarSide = tRSide;
 129   Double_t tRSS = fRStarSide/0.197327;
 130
 131   fRStarLong = tGamma*(tRLong - tBeta* tDTime);
 132   Double_t tDTimePairLCMS = tGamma*(tDTime - tBeta* tRLong);
 133
 134   Double_t tRLS = fRStarLong/0.197327;
 135   tBeta = tPt/tMt;
 136   tGamma = tMt/tM;
 137
 138   fRStarOut = tGamma*(tROut - tBeta* tDTimePairLCMS);
 139   Double_t tROS = fRStarOut/0.197327;
 140 //   Double_t tDTimePairCMS = tGamma*(tDTimePairLCMS - tBeta* tROut);
 141   fRStar = ::sqrt(fRStarOut*fRStarOut + fRStarSide*fRStarSide +
 142                            fRStarLong*fRStarLong);
 143   fKStar = ::sqrt(fKStarOut*fKStarOut + fKStarSide*fKStarSide + fKStarLong*fKStarLong);
 144 //   Double_t tRSt = fRStar/0.197327;
 145
 146   if ((fPairType == AliFemtoModelWeightGenerator::fgkPionPlusPionPlus) || (fPairType == AliFemtoModelWeightGenerator::fgkKaonPlusKaonPlus))
 147     return 1.0 + cos (2*(fKStarOut * tROS + fKStarSide * tRSS + fKStarLong * tRLS));
 148   else if (fPairType == AliFemtoModelWeightGenerator::fgkProtonProton)
 149     return 1.0 - 0.5 * cos (2*(fKStarOut * tROS + fKStarSide * tRSS + fKStarLong * tRLS));
 150   else
 151     return 1.0;
 152 }
 153
 154 //________________________
 155 void     AliFemtoModelWeightGeneratorBasic::SetPairType(Int_t aPairType)
 156 {
 157   AliFemtoModelWeightGenerator::SetPairType(aPairType);
 158 }
 159 //________________________
 160 void     AliFemtoModelWeightGeneratorBasic::SetPairTypeFromPair(AliFemtoPair *aPair)
 161 {
 162   AliFemtoModelWeightGenerator::SetPairTypeFromPair(aPair);
 163 }
 164 //________________________
 165 Int_t    AliFemtoModelWeightGeneratorBasic::GetPairType()
 166 {
 167   return AliFemtoModelWeightGenerator::GetPairType();
 168 }
 169 //________________________
 170 AliFemtoModelWeightGenerator* AliFemtoModelWeightGeneratorBasic::Clone() const
 171 {
 172   return GetGenerator();
 173 }
 174 //________________________
 175 AliFemtoModelWeightGenerator* AliFemtoModelWeightGeneratorBasic::GetGenerator() const
 176 {
 177   AliFemtoModelWeightGeneratorBasic *tGen = new AliFemtoModelWeightGeneratorBasic(*this);
 178   return tGen;
 179 }