1 ////////////////////////////////////////////////////////////////////////////////
3 /// AliFemtoModelGausRinvFreezeOutGenerator - freeze-out ///
4 /// coordinates generator, generating a 3D gaussian ellipsoid in LCMS ///
5 /// Authors: Adam Kisiel kisiel@mps.ohio-state.edu ///
7 ////////////////////////////////////////////////////////////////////////////////
9 ClassImp(AliFemtoModelGausRinvFreezeOutGenerator, 1)
13 #include "AliFemtoModelGausRinvFreezeOutGenerator.h"
14 #include "Model/AliFemtoModelHiddenInfo.h"
15 #include "AliFemtoLorentzVector.h"
17 //_______________________
18 AliFemtoModelGausRinvFreezeOutGenerator::AliFemtoModelGausRinvFreezeOutGenerator() :
21 // Default constructor
22 fRandom = new TRandom2();
25 //_______________________
26 AliFemtoModelGausRinvFreezeOutGenerator::AliFemtoModelGausRinvFreezeOutGenerator(const AliFemtoModelGausRinvFreezeOutGenerator &aModel):
30 fRandom = new TRandom2();
31 SetSizeInv(aModel.GetSizeInv());
33 //_______________________
34 AliFemtoModelGausRinvFreezeOutGenerator::~AliFemtoModelGausRinvFreezeOutGenerator()
36 if (fRandom) delete fRandom;
38 //_______________________
39 void AliFemtoModelGausRinvFreezeOutGenerator::GenerateFreezeOut(AliFemtoPair *aPair)
41 // Generate two particle emission points with respect
42 // to their pair momentum
43 // The source is the 3D Gaussian ellipsoid in the LCMS frame
44 AliFemtoModelHiddenInfo *inf1 = (AliFemtoModelHiddenInfo *) aPair->track1()->HiddenInfo();
45 AliFemtoModelHiddenInfo *inf2 = (AliFemtoModelHiddenInfo *) aPair->track2()->HiddenInfo();
47 if ((!inf1) || (!inf2)) { cout << "Hidden info not created! " << endl; exit(kFALSE); }
49 // Calculate sum momenta
50 Double_t tPx = inf1->GetTrueMomentum()->x() + inf2->GetTrueMomentum()->x();
51 Double_t tPy = inf1->GetTrueMomentum()->y() + inf2->GetTrueMomentum()->y();
52 Double_t tPz = inf1->GetTrueMomentum()->z() + inf2->GetTrueMomentum()->z();
53 Double_t tM1 = inf1->GetMass();
54 Double_t tM2 = inf2->GetMass();
55 Double_t tE1 = sqrt(tM1*tM1 + inf1->GetTrueMomentum()->mag2());
56 Double_t tE2 = sqrt(tM2*tM2 + inf2->GetTrueMomentum()->mag2());
57 Double_t tEs = tE1 + tE2;
59 Double_t tPt = sqrt(tPx*tPx + tPy*tPy);
60 Double_t tMt = sqrt(tEs*tEs - tPz*tPz);
62 // Generate positions in PRF from a Gaussian
63 Double_t tROutS = fRandom->Gaus(0,fSizeInv); // reuse of long
64 Double_t tRSideS = fRandom->Gaus(0,fSizeInv);
65 Double_t tRLongS = fRandom->Gaus(0,fSizeInv);
68 Double_t tBetat = tPt/tMt;
69 Double_t tGammat = 1.0/sqrt(1.0-tBetat*tBetat);
71 Double_t tBetaz = tPz/tEs;
72 Double_t tGammaz = 1.0/sqrt(1.0-tBetaz*tBetaz);
74 Double_t tROut = tGammat * (tROutS + tBetat * tRTimeS);
75 Double_t tDtL = tGammat * (tRTimeS + tBetat * tROutS);
76 Double_t tRSide = tRSideS;
78 Double_t tRLong = tGammaz * (tRLongS + tBetaz * tDtL);
79 Double_t tDt = tGammaz * (tDtL + tBetaz * tRLongS);
84 Double_t tXout = tROut*tPx-tRSide*tPy;
85 Double_t tXside = tROut*tPy+tRSide*tPx;
86 Double_t tXlong = tRLong;
87 Double_t tXtime = tDt;
89 if (!(inf1->GetEmissionPoint())) {
90 AliFemtoLorentzVector tPos(0,0,0,0);
91 inf1->SetEmissionPoint(&tPos);
94 inf1->SetEmissionPoint(0,0,0,0);
95 if (!(inf2->GetEmissionPoint())) {
96 AliFemtoLorentzVector tPos(tXout,tXside,tXlong,tXtime);
97 inf2->SetEmissionPoint(&tPos);
100 inf2->SetEmissionPoint(tXout, tXside, tXlong, tXtime);
103 //_______________________
104 void AliFemtoModelGausRinvFreezeOutGenerator::SetSizeInv(Double_t aSizeInv)
108 //_______________________
109 Double_t AliFemtoModelGausRinvFreezeOutGenerator::GetSizeInv() const
113 //_______________________
114 AliFemtoModelFreezeOutGenerator* AliFemtoModelGausRinvFreezeOutGenerator::Clone() const
116 return GetGenerator();
118 //_______________________
119 inline AliFemtoModelFreezeOutGenerator* AliFemtoModelGausRinvFreezeOutGenerator::GetGenerator() const
121 AliFemtoModelFreezeOutGenerator* tModel = new AliFemtoModelGausRinvFreezeOutGenerator(*this);