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4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
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18 // Class to generate correlated Heavy Flavor hadron pairs (one or several pairs
19 // per event) using paramtrized kinematics of quark pairs from some generator
20 // and quark fragmentation functions.
21 // Is a generalisation of AliGenParam class for correlated pairs of hadrons.
22 // In this version quark pairs and fragmentation functions are obtained from
23 // ~2.10^6 Pythia6.214 events generated with kCharmppMNRwmi & kBeautyppMNRwmi,
24 // CTEQ5L PDF and Pt_hard = 2.76 GeV/c for p-p collisions at 7, 10 and 14 TeV,
25 // and with kCharmppMNR (Pt_hard = 2.10 GeV/c) & kBeautyppMNR (Pt_hard = 2.75 GeV/c),
26 // CTEQ4L PDF for Pb-Pb at 3.94 TeV, for p-Pb & Pb-p at 8.8 TeV.
27 // Decays are performed by Pythia.
28 // Author: S. Grigoryan, LPC Clermont-Fd & YerPhI, Smbat.Grigoryan@cern.ch
29 // July 07: added quarks in the stack (B. Vulpescu)
30 // April 09: added energy choice between 10 and 14 TeV (S. Grigoryan)
31 // Sept 09: added hadron pair composition probabilities via 2D histo (X.M. Zhang)
32 // Oct 09: added energy choice between 7, 10, 14 TeV (for p-p), 4 TeV (for Pb-Pb),
33 // 9 TeV (for p-Pb) and -9 TeV (for Pb-p) (S. Grigoryan)
34 // April 10: removed "static" from definition of some variables (B. Vulpescu)
35 // May 11: added Flag for transportation of background particles while using
36 // SetForceDecay() function (L. Manceau)
37 // June 11: added modifications allowing the setting of cuts on HF-hadron children.
38 // Quarks, hadrons and decay particles are loaded in the stack outside the loop
39 // of HF-hadrons, when the cuts on their children are satisfied (L. Manceau)
40 // Oct 11: added Pb-Pb at 2.76 TeV (S. Grigoryan)
42 //-------------------------------------------------------------------------
43 // How it works (for the given flavor and p-p energy):
45 // 1) Reads QQbar kinematical grid (TTree) from the Input file and generates
46 // quark pairs according to the weights of the cells.
47 // It is a 5D grid in y1,y2,pt1,pt2 and deltaphi, with occupancy weights
48 // of the cells obtained from Pythia (see details in GetQuarkPair).
49 // 2) Reads "soft" and "hard" fragmentation functions (12 2D-histograms each,
50 // for 12 pt bins) from the Input file, applies to quarks and produces hadrons
51 // (only lower states, with proportions of species obtained from Pythia).
52 // Fragmentation functions are the same for all hadron species and depend
53 // on 2 variables - light cone energy-momentum fractions:
54 // z1=(E_H + Pz_H)/(E_Q + Pz_Q), z2=(E_H - Pz_H)/(E_Q - Pz_Q).
55 // "soft" & "hard" FFs correspond to "slower" & "faster" quark of a pair
56 // (see details in GetHadronPair). Fragmentation does not depend on p-p energy.
57 // 3) Decays the hadrons and saves all the particles in the event stack in the
58 // following order: HF hadron from Q, then its decay products, then HF hadron
59 // from Qbar, then its decay productes, then next HF hadon pair (if any)
60 // in the same way, etc...
61 // 4) It is fast, e.g., generates the same number of events with a beauty pair
62 // ~15 times faster than AliGenPythia with kBeautyppMNRwmi (w/o tracking)
64 // An Input file for each quark flavor and p-p energy is in EVGEN/dataCorrHF/
65 // One can use also user-defined Input files.
67 // More details could be found in my presentation at DiMuonNet Workshop, Dec 2006:
68 // http://www-dapnia.cea.fr/Sphn/Alice/DiMuonNet.
70 //-------------------------------------------------------------------------
73 // add the following typical lines in Config.C
75 if (!strcmp(option,"corr")) {
76 // An example for correlated charm or beauty hadron pair production at 14 TeV
78 // AliGenCorrHF *gener = new AliGenCorrHF(1, 4, 14); // for charm, 1 pair per event
79 AliGenCorrHF *gener = new AliGenCorrHF(1, 5, 14); // for beauty, 1 pair per event
81 gener->SetMomentumRange(0,9999);
82 gener->SetCutOnChild(0); // 1/0 means cuts on children enable/disable
83 gener->SetChildThetaRange(171.0,178.0);
84 gener->SetOrigin(0,0,0); //vertex position
85 gener->SetSigma(0,0,0); //Sigma in (X,Y,Z) (cm) on IP position
86 gener->SetForceDecay(kSemiMuonic);
87 gener->SetTrackingFlag(0);
91 // and in aliroot do e.g. gAlice->Run(10,"Config.C") to produce 10 events.
92 // One can include AliGenCorrHF in an AliGenCocktail generator.
93 //--------------------------------------------------------------------------
95 #include <Riostream.h>
97 #include <TClonesArray.h>
98 #include <TDatabasePDG.h>
101 #include <TLorentzVector.h>
103 #include <TParticle.h>
104 #include <TParticlePDG.h>
108 #include <TVirtualMC.h>
109 #include <TVector3.h>
111 #include "AliGenCorrHF.h"
113 #include "AliConst.h"
114 #include "AliDecayer.h"
117 #include "AliGenEventHeader.h"
119 ClassImp(AliGenCorrHF)
123 <img src="picts/AliGenCorrHF.gif">
127 Double_t AliGenCorrHF::fgdph[19] = {0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180};
128 Double_t AliGenCorrHF::fgy[31] = {-10,-7, -6.5, -6, -5.5, -5, -4.5, -4, -3.5, -3, -2.5, -2,- 1.5, -1, -0.5, 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 10};
129 Double_t AliGenCorrHF::fgpt[51] = {0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.6, 7.2, 7.8, 8.4, 9, 9.6, 10.3, 11.1, 12, 13, 14, 15, 16, 17, 18, 19, 20.1, 21.5, 23, 24.5, 26, 27.5, 29.1, 31, 33, 35, 37, 39.2, 42, 45, 48, 51, 55.2, 60, 65, 71, 81, 100};
130 Int_t AliGenCorrHF::fgnptbins = 12;
131 Double_t AliGenCorrHF::fgptbmin[12] = {0, 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 7, 9};
132 Double_t AliGenCorrHF::fgptbmax[12] = {0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 7, 9, 100};
134 //____________________________________________________________
135 AliGenCorrHF::AliGenCorrHF():
146 // Default constructor
149 //____________________________________________________________
150 AliGenCorrHF::AliGenCorrHF(Int_t npart, Int_t idquark, Int_t energy):
162 // Constructor using particle number, quark type, energy & default InputFile
166 fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/BeautyPP7PythiaMNRwmi.root";
167 else if (fEnergy == 10)
168 fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/BeautyPP10PythiaMNRwmi.root";
169 else if (fEnergy == 14)
170 fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/BeautyPP14PythiaMNRwmi.root";
171 else if (fEnergy == 3)
172 fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/BeautyPbPb276PythiaMNR.root";
173 else if (fEnergy == 4)
174 fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/BeautyPbPb394PythiaMNR.root";
175 else if (fEnergy == 9 || fEnergy == -9)
176 fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/BeautyPPb88PythiaMNR.root";
177 else fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/BeautyPbPb394PythiaMNR.root";
182 fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/CharmPP7PythiaMNRwmi.root";
183 else if (fEnergy == 10)
184 fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/CharmPP10PythiaMNRwmi.root";
185 else if (fEnergy == 14)
186 fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/CharmPP14PythiaMNRwmi.root";
187 else if (fEnergy == 3)
188 fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/CharmPbPb276PythiaMNR.root";
189 else if (fEnergy == 4)
190 fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/CharmPbPb394PythiaMNR.root";
191 else if (fEnergy == 9 || fEnergy == -9)
192 fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/CharmPPb88PythiaMNR.root";
193 else fFileName = "$ALICE_ROOT/EVGEN/dataCorrHF/CharmPbPb394PythiaMNR.root";
196 fTitle= "Generator for correlated pairs of HF hadrons";
199 for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
202 SetChildMomentumRange();
205 SetChildThetaRange();
208 //___________________________________________________________________
209 AliGenCorrHF::AliGenCorrHF(char* tname, Int_t npart, Int_t idquark, Int_t energy):
221 // Constructor using particle number, quark type, energy & user-defined InputFile
223 if (fQuark != 5) fQuark = 4;
224 fName = "UserDefined";
225 fTitle= "Generator for correlated pairs of HF hadrons";
228 for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
231 SetChildMomentumRange();
234 SetChildThetaRange();
237 //____________________________________________________________
238 AliGenCorrHF::~AliGenCorrHF()
244 //____________________________________________________________
245 void AliGenCorrHF::Init()
248 AliInfo(Form("Number of HF-hadron pairs = %d",fNpart));
249 AliInfo(Form(" QQbar kinematics and fragm. functions from: %s",fFileName.Data() ));
250 fFile = TFile::Open(fFileName.Data());
251 if(!fFile->IsOpen()){
252 AliError(Form("Could not open file %s",fFileName.Data() ));
255 ComputeIntegral(fFile);
257 fParentWeight = 1./fNpart; // fNpart is number of HF-hadron pairs
259 // particle decay related initialization
261 if (gMC) fDecayer = gMC->GetDecayer();
262 fDecayer->SetForceDecay(fForceDecay);
268 //____________________________________________________________
269 void AliGenCorrHF::Generate()
272 // Generate fNpart of correlated HF hadron pairs per event
273 // in the the desired theta and momentum windows (phi = 0 - 2pi).
276 // Reinitialize decayer
278 fDecayer->SetForceDecay(fForceDecay);
281 Float_t polar[2][3]; // Polarisation of the parent particle (for GEANT tracking)
282 Float_t origin0[2][3]; // Origin of the generated parent particle (for GEANT tracking)
283 Float_t pt, pl, ptot; // Transverse, logitudinal and total momenta of the parent particle
284 Float_t phi, theta; // Phi and theta spherical angles of the parent particle momentum
285 Float_t p[2][3]; // Momenta
286 Int_t nt, i, j, ihad, ipa, ipa0, ipa1, ihadron[2], iquark[2];
287 Float_t wgtp[2], wgtch[2], random[6];
288 Float_t pq[2][3], pc[3]; // Momenta of the two quarks
289 Double_t tanhy2, qm = 0;
291 Double_t dphi=0, ptq[2], yq[2], pth[2], plh[2], ph[2], phih[2], phiq[2];
293 Int_t** pSelected = new Int_t* [2];
294 Int_t** trackIt = new Int_t* [2];
296 for (i=0; i<2; i++) {
305 for (j=0; j<3; j++) polar[i][j]=0;
308 // same quarks mass as in the fragmentation functions
309 if (fQuark == 4) qm = 1.20;
312 TClonesArray *particleshad1 = new TClonesArray("TParticle",1000);
313 TClonesArray *particleshad2 = new TClonesArray("TParticle",1000);
315 TList *particleslist = new TList();
316 particleslist->Add(particleshad1);
317 particleslist->Add(particleshad2);
319 TDatabasePDG *pDataBase = TDatabasePDG::Instance();
321 // Calculating vertex position per event
322 if (fVertexSmear==kPerEvent) {
325 for (j=0;j<3;j++) origin0[i][j]=fVertex[j];
330 for (j=0;j<3;j++) origin0[i][j]=fOrigin[j];
338 // Generating fNpart HF-hadron pairs
341 while (ipa<2*fNpart) {
343 GetQuarkPair(fFile, fgIntegral, yq[0], yq[1], ptq[0], ptq[1], dphi);
345 GetHadronPair(fFile, fQuark, yq[0], yq[1], ptq[0], ptq[1], ihadron[0], ihadron[1], plh[0], plh[1], pth[0], pth[1]);
347 if (fEnergy == 9 || fEnergy == -9) { // boost particles from c.m.s. to ALICE lab frame
348 Double_t dyBoost = 0.47;
349 Double_t beta = TMath::TanH(dyBoost);
350 Double_t gamma = 1./TMath::Sqrt((1.-beta)*(1.+beta));
351 Double_t gb = gamma * beta;
354 plh[0] = gb * TMath::Sqrt(plh[0]*plh[0] + pth[0]*pth[0]) + gamma * plh[0];
355 plh[1] = gb * TMath::Sqrt(plh[1]*plh[1] + pth[1]*pth[1]) + gamma * plh[1];
364 // Cuts from AliGenerator
367 theta=TMath::ATan2(pth[0],plh[0]);
368 if (theta<fThetaMin || theta>fThetaMax) continue;
369 theta=TMath::ATan2(pth[1],plh[1]);
370 if (theta<fThetaMin || theta>fThetaMax) continue;
373 ph[0]=TMath::Sqrt(pth[0]*pth[0]+plh[0]*plh[0]);
374 if (ph[0]<fPMin || ph[0]>fPMax) continue;
375 ph[1]=TMath::Sqrt(pth[1]*pth[1]+plh[1]*plh[1]);
376 if (ph[1]<fPMin || ph[1]>fPMax) continue;
378 // Add the quarks in the stack
380 phiq[0] = Rndm()*k2PI;
382 phiq[1] = phiq[0] + dphi*kDegrad;
384 phiq[1] = phiq[0] - dphi*kDegrad;
386 if (phiq[1] > k2PI) phiq[1] -= k2PI;
387 if (phiq[1] < 0 ) phiq[1] += k2PI;
394 TVector2 qvect1 = TVector2();
395 TVector2 qvect2 = TVector2();
396 qvect1.SetMagPhi(ptq[0],phiq[0]);
397 qvect2.SetMagPhi(ptq[1],phiq[1]);
398 pq[0][0] = qvect1.Px();
399 pq[0][1] = qvect1.Py();
400 pq[1][0] = qvect2.Px();
401 pq[1][1] = qvect2.Py();
404 tanhy2 = TMath::TanH(yq[0]);
406 pq[0][2] = TMath::Sqrt((ptq[0]*ptq[0]+qm*qm)*tanhy2/(1-tanhy2));
407 pq[0][2] = TMath::Sign((Double_t)pq[0][2],yq[0]);
408 tanhy2 = TMath::TanH(yq[1]);
410 pq[1][2] = TMath::Sqrt((ptq[1]*ptq[1]+qm*qm)*tanhy2/(1-tanhy2));
411 pq[1][2] = TMath::Sign((Double_t)pq[1][2],yq[1]);
413 // Here we assume that |phi_H1 - phi_H2| = |phi_Q1 - phi_Q2| = dphi
414 // which is a good approximation for heavy flavors in Pythia
415 // ... moreover, same phi angles as for the quarks ...
422 for (ihad = 0; ihad < 2; ihad++) {
428 fChildWeight=(fDecayer->GetPartialBranchingRatio(ihadron[ihad]))*fParentWeight;
429 wgtp[ihad]=fParentWeight;
430 wgtch[ihad]=fChildWeight;
431 TParticlePDG *particle = pDataBase->GetParticle(ihadron[ihad]);
432 Float_t am = particle->Mass();
436 ptot=TMath::Sqrt(pt*pt+pl*pl);
438 p[ihad][0]=pt*TMath::Cos(phi);
439 p[ihad][1]=pt*TMath::Sin(phi);
442 if(fVertexSmear==kPerTrack) {
446 fOrigin[j]+fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
447 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
451 // Looking at fForceDecay :
452 // if fForceDecay != none Primary particle decays using
453 // AliPythia and children are tracked by GEANT
455 // if fForceDecay == none Primary particle is tracked by GEANT
456 // (In the latest, make sure that GEANT actually does all the decays you want)
458 if (fForceDecay != kNoDecay) {
459 // Using lujet to decay particle
460 Float_t energy=TMath::Sqrt(ptot*ptot+am*am);
461 TLorentzVector pmom(p[ihad][0], p[ihad][1], p[ihad][2], energy);
462 fDecayer->Decay(ihadron[ihad],&pmom);
464 // select decay particles
466 np[ihad]=fDecayer->ImportParticles((TClonesArray *)particleslist->At(ihad));
468 // Selecting GeometryAcceptance for particles fPdgCodeParticleforAcceptanceCut;
470 if (fGeometryAcceptance)
471 if (!CheckAcceptanceGeometry(np[ihad],(TClonesArray*)particleslist->At(ihad))) continue;
473 trackIt[ihad] = new Int_t [np[ihad]];
474 pSelected[ihad] = new Int_t [np[ihad]];
475 Int_t* pFlag = new Int_t [np[ihad]];
477 for (i=0; i<np[ihad]; i++) {
479 pSelected[ihad][i] = 0;
483 TParticle* iparticle = 0;
486 for (i = 1; i<np[ihad] ; i++) {
487 trackIt[ihad][i] = 1;
489 (TParticle *) ((TClonesArray *) particleslist->At(ihad))->At(i);
490 Int_t kf = iparticle->GetPdgCode();
491 Int_t ks = iparticle->GetStatusCode();
494 ipF = iparticle->GetFirstDaughter();
495 ipL = iparticle->GetLastDaughter();
496 if (ipF > 0) for (j=ipF-1; j<ipL; j++) pFlag[j]=1;
500 // flag decay products of particles with long life-time (c tau > .3 mum)
502 Double_t lifeTime = fDecayer->GetLifetime(kf);
503 if (lifeTime > (Double_t) fMaxLifeTime) {
504 ipF = iparticle->GetFirstDaughter();
505 ipL = iparticle->GetLastDaughter();
506 if (ipF > 0) for (j=ipF-1; j<ipL; j++) pFlag[j]=1;
508 trackIt[ihad][i] = 0;
509 pSelected[ihad][i] = 1;
514 if ((ChildSelected(TMath::Abs(kf)) || fForceDecay == kAll || fSelectAll) && trackIt[ihad][i])
517 pc[0]=iparticle->Px();
518 pc[1]=iparticle->Py();
519 pc[2]=iparticle->Pz();
520 //printf("px %f py %f pz %f\n",pc[0],pc[1],pc[2]);
521 Bool_t childok = KinematicSelection(iparticle, 1);
523 pSelected[ihad][i] = 1;
530 pSelected[ihad][i] = 1;
532 } // if child selection
534 } // decay particle loop
535 } // if decay products
537 if ((fCutOnChild && ncsel[ihad] >0) || !fCutOnChild) ipa1++;
539 if (pFlag) delete[] pFlag;
541 } // kinematic selection
542 else // nodecay option, so parent will be tracked by GEANT (pions, kaons, eta, omegas, baryons)
545 PushTrack(fTrackIt,-1,ihadron[ihad],p[ihad],origin0[ihad],polar[ihad],0,kPPrimary,nt,wgtp[ihad]);
554 if (pSelected[ihad]) delete pSelected[ihad];
555 if (trackIt[ihad]) delete trackIt[ihad];
556 particleshad1->Clear();
557 particleshad2->Clear();
559 }//go out of loop and generate new pair if at least one hadron is rejected
560 } // hadron pair loop
565 if(fForceDecay != kNoDecay){
566 for(ihad=0;ihad<2;ihad++){
568 //load tracks in the stack if both hadrons of the pair accepted
569 LoadTracks(iquark[ihad],pq[ihad],ihadron[ihad],p[ihad],np[ihad],
570 (TClonesArray *)particleslist->At(ihad),origin0[ihad],
571 polar[ihad],wgtp[ihad],wgtch[ihad],nt,ncsel[ihad],
572 pSelected[ihad],trackIt[ihad]);
574 if (pSelected[ihad]) delete pSelected[ihad];
575 if (trackIt[ihad]) delete trackIt[ihad];
578 particleshad1->Clear();
579 particleshad2->Clear();
582 } // while (ipa<2*fNpart) loop
584 SetHighWaterMark(nt);
586 AliGenEventHeader* header = new AliGenEventHeader("CorrHF");
587 header->SetPrimaryVertex(fVertex);
588 header->SetNProduced(fNprimaries);
592 delete particleshad1;
593 delete particleshad2;
594 delete particleslist;
599 //____________________________________________________________________________________
600 void AliGenCorrHF::IpCharm(TH2F *hProbHH, Int_t &pdg3, Int_t &pdg4)
602 // Composition of a lower state charm hadron pair from a ccbar quark pair
603 Int_t pdgH[] = {411, 421, 431, 4122, 4132, 4232, 4332};
606 hProbHH->GetRandom2(id3, id4);
607 pdg3 = pdgH[(Int_t)TMath::Floor(id3)];
608 pdg4 = -1*pdgH[(Int_t)TMath::Floor(id4)];
613 void AliGenCorrHF::IpBeauty(TH2F *hProbHH, Int_t &pdg3, Int_t &pdg4)
615 // Composition of a lower state beauty hadron pair from a bbbar quark pair
616 // B-Bbar mixing will be done by Pythia at their decay point
617 Int_t pdgH[] = {511, 521, 531, 5122, 5132, 5232, 5332};
620 hProbHH->GetRandom2(id3, id4);
621 pdg3 = pdgH[(Int_t)TMath::Floor(id3)];
622 pdg4 = -1*pdgH[(Int_t)TMath::Floor(id4)];
624 if ( (pdg3== 511) || (pdg3== 521) || (pdg3== 531) ) pdg3 *= -1;
625 if ( (pdg4==-511) || (pdg4==-521) || (pdg4==-531) ) pdg4 *= -1;
630 //____________________________________________________________________________________
631 Double_t AliGenCorrHF::ComputeIntegral(TFile* fG) // needed by GetQuarkPair
633 // Read QQbar kinematical 5D grid's cell occupancy weights
634 Int_t cell[6]; // cell[6]={wght,iy1,iy2,ipt1,ipt2,idph}
635 TTree* tG = (TTree*) fG->Get("tGqq");
636 tG->GetBranch("cell")->SetAddress(&cell);
637 Int_t nbins = tG->GetEntries();
639 // delete previously computed integral (if any)
640 if(fgIntegral) delete [] fgIntegral;
642 fgIntegral = new Double_t[nbins+1];
645 for(bin=0;bin<nbins;bin++) {
647 fgIntegral[bin+1] = fgIntegral[bin] + cell[0];
649 // Normalize integral to 1
650 if (fgIntegral[nbins] == 0 ) {
653 for (bin=1;bin<=nbins;bin++) fgIntegral[bin] /= fgIntegral[nbins];
655 return fgIntegral[nbins];
659 //____________________________________________________________________________________
660 void AliGenCorrHF::GetQuarkPair(TFile* fG, Double_t* fInt, Double_t &y1, Double_t &y2, Double_t &pt1, Double_t &pt2, Double_t &dphi)
661 // modification of ROOT's TH3::GetRandom3 for 5D
663 // Read QQbar kinematical 5D grid's cell coordinates
664 Int_t cell[6]; // cell[6]={wght,iy1,iy2,ipt1,ipt2,idph}
665 TTree* tG = (TTree*) fG->Get("tGqq");
666 tG->GetBranch("cell")->SetAddress(&cell);
667 Int_t nbins = tG->GetEntries();
669 gRandom->RndmArray(6,rand);
670 Int_t ibin = TMath::BinarySearch(nbins,fInt,rand[0]);
672 y1 = fgy[cell[1]] + (fgy[cell[1]+1]-fgy[cell[1]])*rand[1];
673 y2 = fgy[cell[2]] + (fgy[cell[2]+1]-fgy[cell[2]])*rand[2];
674 pt1 = fgpt[cell[3]] + (fgpt[cell[3]+1]-fgpt[cell[3]])*rand[3];
675 pt2 = fgpt[cell[4]] + (fgpt[cell[4]+1]-fgpt[cell[4]])*rand[4];
676 dphi = fgdph[cell[5]]+ (fgdph[cell[5]+1]-fgdph[cell[5]])*rand[5];
679 //____________________________________________________________________________________
680 void AliGenCorrHF::GetHadronPair(TFile* fG, Int_t idq, Double_t y1, Double_t y2, Double_t pt1, Double_t pt2, Int_t &id3, Int_t &id4, Double_t &pz3, Double_t &pz4, Double_t &pt3, Double_t &pt4)
682 // Generate a hadron pair
683 void (*fIpParaFunc)(TH2F *, Int_t &, Int_t &);//Pointer to hadron pair composition function
684 fIpParaFunc = IpCharm;
685 Double_t mq = 1.2; // c & b quark masses (used in AliPythia)
687 fIpParaFunc = IpBeauty;
694 Double_t pz1, pz2, e1, e2, mh, ptemp, rand[2];
696 TH2F *h2h[12], *h2s[12], *hProbHH; // hard & soft fragmentation and HH-probability functions
697 for (Int_t ipt = 0; ipt<fgnptbins; ipt++) {
698 snprintf(tag,100, "h2h_pt%d",ipt);
699 h2h[ipt] = (TH2F*) fG->Get(tag);
700 snprintf(tag,100, "h2s_pt%d",ipt);
701 h2s[ipt] = (TH2F*) fG->Get(tag);
705 for (Int_t ipt = 0; ipt<fgnptbins; ipt++) {
706 if(pt1 >= fgptbmin[ipt] && pt1 < fgptbmax[ipt])
707 h2h[ipt]->GetRandom2(z11, z21);
708 if(pt2 >= fgptbmin[ipt] && pt2 < fgptbmax[ipt])
709 h2h[ipt]->GetRandom2(z12, z22);
713 if (TMath::Abs(y1) > TMath::Abs(y2)) {
714 for (Int_t ipt = 0; ipt<fgnptbins; ipt++) {
715 if(pt1 >= fgptbmin[ipt] && pt1 < fgptbmax[ipt])
716 h2h[ipt]->GetRandom2(z11, z21);
717 if(pt2 >= fgptbmin[ipt] && pt2 < fgptbmax[ipt])
718 h2s[ipt]->GetRandom2(z12, z22);
722 for (Int_t ipt = 0; ipt<fgnptbins; ipt++) {
723 if(pt1 >= fgptbmin[ipt] && pt1 < fgptbmax[ipt])
724 h2s[ipt]->GetRandom2(z11, z21);
725 if(pt2 >= fgptbmin[ipt] && pt2 < fgptbmax[ipt])
726 h2h[ipt]->GetRandom2(z12, z22);
730 gRandom->RndmArray(2,rand);
731 ptemp = TMath::Sqrt(pt1*pt1 + mq*mq);
732 pz1 = ptemp*TMath::SinH(y1);
733 e1 = ptemp*TMath::CosH(y1);
734 ptemp = TMath::Sqrt(pt2*pt2 + mq*mq);
735 pz2 = ptemp*TMath::SinH(y2);
736 e2 = ptemp*TMath::CosH(y2);
738 hProbHH = (TH2F*)fG->Get("hProbHH");
739 fIpParaFunc(hProbHH, id3, id4);
740 mh = TDatabasePDG::Instance()->GetParticle(id3)->Mass();
741 ptemp = z11*z21*(e1*e1-pz1*pz1) - mh*mh;
742 if (idq==5) pt3 = pt1; // an approximation at low pt, try better
743 else pt3 = rand[0]; // pt3=pt1 gives less D-hadrons at low pt
744 if (ptemp > 0) pt3 = TMath::Sqrt(ptemp);
745 if (pz1 > 0) pz3 = (z11*(e1 + pz1) - z21*(e1 - pz1)) / 2;
746 else pz3 = (z21*(e1 + pz1) - z11*(e1 - pz1)) / 2;
747 e1 = TMath::Sqrt(pz3*pz3 + pt3*pt3 + mh*mh);
749 mh = TDatabasePDG::Instance()->GetParticle(id4)->Mass();
750 ptemp = z12*z22*(e2*e2-pz2*pz2) - mh*mh;
751 if (idq==5) pt4 = pt2; // an approximation at low pt, try better
753 if (ptemp > 0) pt4 = TMath::Sqrt(ptemp);
754 if (pz2 > 0) pz4 = (z12*(e2 + pz2) - z22*(e2 - pz2)) / 2;
755 else pz4 = (z22*(e2 + pz2) - z12*(e2 - pz2)) / 2;
756 e2 = TMath::Sqrt(pz4*pz4 + pt4*pt4 + mh*mh);
758 // small corr. instead of using Frag. Func. depending on yQ (in addition to ptQ)
759 Float_t ycorr = 0.2, y3, y4;
760 gRandom->RndmArray(2,rand);
761 y3 = 0.5 * TMath::Log((e1 + pz3 + 1.e-13)/(e1 - pz3 + 1.e-13));
762 y4 = 0.5 * TMath::Log((e2 + pz4 + 1.e-13)/(e2 - pz4 + 1.e-13));
763 if(TMath::Abs(y3)<ycorr && TMath::Abs(y4)<ycorr && rand[0]>0.5) {
764 ptemp = TMath::Sqrt((e1-pz3)*(e1+pz3));
765 y3 = 4*(1 - 2*rand[1]);
766 pz3 = ptemp*TMath::SinH(y3);
772 //____________________________________________________________________________________
773 void AliGenCorrHF::LoadTracks(Int_t iquark, Float_t *pq,
774 Int_t iPart, Float_t *p,
775 Int_t np, TClonesArray *particles,
776 Float_t *origin0, Float_t *polar,
777 Float_t wgtp, Float_t wgtch,
778 Int_t &nt, Int_t ncsel, Int_t *pSelected,
782 Int_t* pParent = new Int_t[np];
783 Float_t pc[3], och[3];
786 for(i=0;i<np;i++) pParent[i]=-1;
788 if ((fCutOnChild && ncsel >0) || !fCutOnChild){
791 PushTrack(0, -1, iquark, pq, origin0, polar, 0, kPPrimary, nt, wgtp);
795 PushTrack(0, ntq, iPart, p, origin0, polar, 0, kPDecay, nt, wgtp);
801 for (i = 1; i < np; i++) {
804 TParticle* iparticle = (TParticle *) particles->At(i);
805 Int_t kf = iparticle->GetPdgCode();
806 Int_t jpa = iparticle->GetFirstMother()-1;
808 och[0] = origin0[0]+iparticle->Vx()/10;
809 och[1] = origin0[1]+iparticle->Vy()/10;
810 och[2] = origin0[2]+iparticle->Vz()/10;
811 pc[0] = iparticle->Px();
812 pc[1] = iparticle->Py();
813 pc[2] = iparticle->Pz();
816 iparent = pParent[jpa];
821 PushTrack(fTrackIt*trackIt[i], iparent, kf,
823 0, kPDecay, nt, wgtch);
831 if (pParent) delete[] pParent;