STEER/AliCascadeComparison.C

   1 /****************************************************************************
   2  *           Very important, delicate and rather obscure macro.             *
   3  *                                                                          *
   4  *               Creates list of "findable" cascades,                       *
   5  *             calculates efficiency, resolutions etc.                      *
   6  *                                                                          *
   7  *  Origin: Christian Kuhn, IReS, Strasbourg, christian.kuhn@ires.in2p3.fr  *
   8  ****************************************************************************/
   9
  10 #include <TPDGCode.h>
  11 #if !defined(__CINT__) || defined(__MAKECINT__)
  12   #include <TMath.h>
  13   #include <TError.h>
  14   #include <Riostream.h>
  15   #include <TH1F.h>
  16   #include <TTree.h>
  17   #include <TParticle.h>
  18   #include <TCanvas.h>
  19   #include <TLine.h>
  20   #include <TText.h>
  21   #include <TBenchmark.h>
  22   #include <TStyle.h>
  23   #include <TFile.h>
  24   #include <TROOT.h>
  25
  26   #include "AliStack.h"
  27   #include "AliHeader.h"
  28   #include "AliTrackReference.h"
  29   #include "AliRunLoader.h"
  30   #include "AliRun.h"
  31   #include "AliESDEvent.h"
  32   #include "AliESDcascade.h"
  33 #endif
  34
  35 Int_t GoodCascades(const Char_t *dir=".");
  36
  37 extern AliRun *gAlice;
  38 extern TBenchmark *gBenchmark;
  39 extern TROOT *gROOT;
  40
  41 static Int_t allgood=0;
  42 static Int_t allfound=0;
  43
  44 Int_t AliCascadeComparison(Int_t code=3312, const Char_t *dir=".") {
  45   //code= 3312; //kXiMinus
  46   //code=-3312; //kXiPlusBar
  47   //code= 3334; //kOmegaMinus
  48   //code=-3334; //kOmegaPlusBar
  49    gBenchmark->Start("AliCascadeComparison");
  50
  51    ::Info("AliCascadeComparison.C","Doing comparison...");
  52
  53    const Double_t cascadeWindow=0.05, cascadeWidth=0.015;
  54    Double_t ptncut=0.12, ptpcut=0.33, kine0cut=0.003;
  55    Double_t ptbcut=0.11, kinecut=0.002;
  56    Double_t cascadeMass=1.32131;
  57    switch (code) {
  58    case kXiMinus:
  59         break;
  60    case kXiPlusBar:
  61         ptncut=0.33; ptpcut=0.12;
  62         break;
  63    case kOmegaMinus:
  64         cascadeMass=1.67245;
  65         kine0cut=0.001;
  66         ptbcut=0.22; kinecut=0.006;
  67         break;
  68    case kOmegaPlusBar:
  69         cascadeMass=1.67245;
  70         kine0cut=0.001;
  71         ptncut=0.33; ptpcut=0.12;
  72         ptbcut=0.22; kinecut=0.006;
  73         break;
  74    default: cerr<<"Invalid PDG code !\n"; return 1;
  75    }
  76
  77
  78    TH1F *hp=(TH1F*)gROOT->FindObject("hp");
  79    if (!hp) hp=new TH1F("hp","Angular Resolution",30,-30.,30.);
  80    hp->SetXTitle("(mrad)"); hp->SetFillColor(2);
  81
  82    TH1F *hl=(TH1F*)gROOT->FindObject("hl");
  83    if (!hl) hl=new TH1F("hl","Lambda Resolution",30,-30,30);
  84    hl->SetXTitle("(mrad)"); hl->SetFillColor(1); hl->SetFillStyle(3013);
  85
  86    TH1F *hpt=(TH1F*)gROOT->FindObject("hpt");
  87    if (!hpt) hpt=new TH1F("hpt","Relative Pt Resolution",30,-10.,10.);
  88    hpt->SetXTitle("(%)"); hpt->SetFillColor(2);
  89
  90    TH1F *hx=(TH1F*)gROOT->FindObject("hx");
  91    if (!hx) hx=new TH1F("hx","Position Resolution (X,Y)",30,-3.,3.);
  92    hx->SetXTitle("(mm)"); hx->SetFillColor(6);
  93
  94    TH1F *hy=(TH1F*)gROOT->FindObject("hy");
  95    if (!hy) hy=new TH1F("hy","Position Resolution (Y)",30,-3.,3.);
  96    hy->SetXTitle("(mm)"); hy->SetFillColor(1); hy->SetFillStyle(3013);
  97
  98    TH1F *hz=(TH1F*)gROOT->FindObject("hz");
  99    if (!hz) hz=new TH1F("hz","Position Resolution (Z)",30,-3.,3.);
 100    hz->SetXTitle("(mm)"); hz->SetFillColor(6);
 101
 102
 103    Double_t pmin=0.2, pmax=4.2; Int_t nchan=20;
 104    TH1F *hgood=(TH1F*)gROOT->FindObject("hgood");
 105    if (!hgood) hgood=new TH1F("hgood","Good Cascades",nchan,pmin,pmax);
 106
 107    TH1F *hfound=(TH1F*)gROOT->FindObject("hfound");
 108    if (!hfound) hfound=new TH1F("hfound","Found Cascades",nchan,pmin,pmax);
 109
 110    TH1F *hfake=(TH1F*)gROOT->FindObject("hfake");
 111    if (!hfake) hfake=new TH1F("hfake","Fake Cascades",nchan,pmin,pmax);
 112
 113    TH1F *hg=(TH1F*)gROOT->FindObject("hg");
 114    if (!hg) hg=new TH1F("hg","Efficiency for Good Cascades",nchan,pmin,pmax);
 115    hg->SetLineColor(4); hg->SetLineWidth(2);
 116
 117    TH1F *hf=(TH1F*)gROOT->FindObject("hf");
 118    if (!hf) hf=new TH1F("hf","Probability of Fake Cascades",nchan,pmin,pmax);
 119    hf->SetFillColor(1); hf->SetFillStyle(3013); hf->SetLineWidth(2);
 120
 121
 122    Double_t mmin=cascadeMass-cascadeWindow, mmax=cascadeMass+cascadeWindow;
 123    TH1F *cs=(TH1F*)gROOT->FindObject("cs");
 124    if (!cs) cs=new TH1F("cs","Cascade Effective Mass",40, mmin, mmax);
 125    cs->SetXTitle("(GeV)"); cs->SetLineColor(4); cs->SetLineWidth(4);
 126
 127    TH1F *csf=(TH1F*)gROOT->FindObject("csf");
 128    if (!csf) csf=new TH1F("csf","Fake Cascade Effective Mass",40, mmin, mmax);
 129    csf->SetXTitle("(GeV)"); csf->SetFillColor(6);
 130
 131
 132    Char_t fname[100];
 133    sprintf(fname,"%s/GoodCascades.root",dir);
 134
 135    TFile *refFile=TFile::Open(fname,"old");
 136    if (!refFile || !refFile->IsOpen()) {
 137    ::Info("AliCascadeComparison.C","Marking good cascades (will take a while)...");
 138      if (GoodCascades(dir)) {
 139         ::Error("AliCascadesComparison.C","Can't generate the reference file !");
 140         return 1;
 141      }
 142    }
 143    refFile=TFile::Open(fname,"old");
 144    if (!refFile || !refFile->IsOpen()) {
 145      ::Error("AliCascadeComparison.C","Can't open the reference file !");
 146      return 1;
 147    }
 148
 149    TTree *csTree=(TTree*)refFile->Get("csTree");
 150    if (!csTree) {
 151      ::Error("AliCascadeComparison.C","Can't get the reference tree !");
 152      return 2;
 153    }
 154    TBranch *pbranch=csTree->GetBranch("positive");
 155    if (!pbranch) {
 156      ::Error("AliCascadeComparison.C","Can't get the positive daughter branch !");
 157      return 3;
 158    }
 159    TClonesArray dummy("AliTrackReference",1000), *prefs=&dummy;
 160    pbranch->SetAddress(&prefs);
 161
 162    TBranch *nbranch=csTree->GetBranch("negative");
 163    if (!nbranch) {
 164      ::Error("AliCascadeComparison.C","Can't get the negative daughter branch !");
 165      return 4;
 166    }
 167    TClonesArray dumm("AliTrackReference",1000), *nrefs=&dumm;
 168    nbranch->SetAddress(&nrefs);
 169
 170    TBranch *bbranch=csTree->GetBranch("bachelor");
 171    if (!nbranch) {
 172      ::Error("AliCascadeComparison.C","Can't get the bachelor branch !");
 173      return 4;
 174    }
 175    TClonesArray dum("AliTrackReference",1000), *brefs=&dum;
 176    bbranch->SetAddress(&brefs);
 177
 178
 179
 180    sprintf(fname,"%s/AliESDs.root",dir);
 181    TFile *ef=TFile::Open(fname);
 182    if ((!ef)||(!ef->IsOpen())) {
 183       sprintf(fname,"%s/AliESDcascade.root",dir);
 184       ef=TFile::Open(fname);
 185       if ((!ef)||(!ef->IsOpen())) {
 186          ::Error("AliCascadeComparison.C","Can't open AliESDcascade.root !");
 187          return 5;
 188       }
 189    }
 190    AliESDEvent* event = new AliESDEvent();
 191    TTree* esdTree = (TTree*) ef->Get("esdTree");
 192    if (!esdTree) {
 193       ::Error("AliCascadeComparison.C", "no ESD tree found");
 194       return 6;
 195    }
 196    event->ReadFromTree(esdTree);
 197
 198
 199    //******* Loop over events *********
 200    Int_t e=0;
 201    while (esdTree->GetEvent(e)) {
 202       cout<<endl<<endl<<"********* Processing event number: "<<e<<"*******\n";
 203
 204       Int_t nentr=event->GetNumberOfCascades();
 205       allfound+=nentr;
 206
 207
 208       if (csTree->GetEvent(e++)==0) {
 209          cerr<<"No reconstructable cascades !\n";
 210          continue;
 211       }
 212
 213       Int_t ngood=prefs->GetEntriesFast(),ng=0;
 214
 215       Double_t pxg=0.,pyg=0.,pzg=0.,ptg=0.;
 216       Int_t nlab=-1, plab=-1, blab=-1;
 217       Int_t i;
 218       for (i=0; i<nentr; i++) {
 219           AliESDcascade *cascade=event->GetCascade(i);
 220
 221           Int_t nidx=TMath::Abs(cascade->GetNindex());
 222           Int_t pidx=TMath::Abs(cascade->GetPindex());
 223           Int_t bidx=TMath::Abs(cascade->GetBindex());
 224
 225           AliESDtrack *ntrack=event->GetTrack(nidx);
 226           AliESDtrack *ptrack=event->GetTrack(pidx);
 227           AliESDtrack *btrack=event->GetTrack(bidx);
 228
 229           nlab=TMath::Abs(ntrack->GetLabel());
 230           plab=TMath::Abs(ptrack->GetLabel());
 231           blab=TMath::Abs(btrack->GetLabel());
 232
 233           /** Kinematical cuts **/
 234           Double_t pxn,pyn,pzn; cascade->GetNPxPyPz(pxn,pyn,pzn);
 235           Double_t ptn=TMath::Sqrt(pxn*pxn + pyn*pyn);
 236           if (ptn < ptncut) continue;
 237           Double_t pxp,pyp,pzp; cascade->GetPPxPyPz(pxp,pyp,pzp);
 238           Double_t ptp=TMath::Sqrt(pxp*pxp + pyp*pyp);
 239           if (ptp < ptpcut) continue;
 240           Double_t pxb,pyb,pzb; cascade->GetBPxPyPz(pxb,pyb,pzb);
 241           Double_t ptb=TMath::Sqrt(pxb*pxb + pyb*pyb);
 242           if (ptb < ptbcut) continue;
 243           Double_t kine0;
 244           Double_t kine=cascade->ChangeMassHypothesis(kine0,code);
 245           if (TMath::Abs(kine0)>kine0cut) continue;
 246           //if (TMath::Abs(kine)>kinecut) continue;
 247
 248           Double_t mass=cascade->GetEffMass();
 249           cs->Fill(mass);
 250           csf->Fill(mass);
 251
 252           AliTrackReference *nref=0, *pref=0, *bref=0;
 253           Int_t j;
 254           for (j=0; j<ngood; j++) {
 255               bref=(AliTrackReference*)brefs->UncheckedAt(j);
 256               nref=(AliTrackReference*)nrefs->UncheckedAt(j);
 257               pref=(AliTrackReference*)prefs->UncheckedAt(j);
 258               if (bref->Label() == blab)
 259               if (nref->Label() == nlab)
 260               if (pref->Label() == plab) break;
 261           }
 262
 263           if (TMath::Abs(mass-cascadeMass)>cascadeWidth) continue;
 264
 265           Double_t px,py,pz; cascade->GetPxPyPz(px,py,pz);
 266           Double_t pt=TMath::Sqrt(px*px+py*py);
 267
 268           if (j==ngood) {
 269              hfake->Fill(pt);
 270              cout<<"Fake cascade: ("<<nlab<<","<<plab<<","<<blab<<")\n";
 271              continue;
 272           }
 273           csf->Fill(mass,-1);
 274
 275           pxg=bref->Px()+nref->Px()+pref->Px();
 276           pyg=bref->Px()+nref->Py()+pref->Py();
 277           pzg=nref->Pz()+pref->Pz();
 278           ptg=TMath::Sqrt(pxg*pxg+pyg*pyg);
 279           Double_t phig=TMath::ATan2(pyg,pxg), phi=TMath::ATan2(py,px);
 280           Double_t lamg=TMath::ATan2(pzg,ptg), lam=TMath::ATan2(pz,pt);
 281           hp->Fill((phi - phig)*1000.);
 282           hl->Fill((lam - lamg)*1000.);
 283           hpt->Fill((1/pt - 1/ptg)/(1/ptg)*100.);
 284
 285           Double_t x,y,z; cascade->GetXYZ(x,y,z);
 286           hx->Fill((x-nref->X())*10);
 287           hy->Fill((y-nref->Y())*10);
 288           hz->Fill((z-nref->Z())*10);
 289
 290           hfound->Fill(ptg);
 291           nref->SetLabel(-1);
 292
 293       }
 294       for (i=0; i<ngood; i++) {
 295          AliTrackReference *bref=(AliTrackReference*)brefs->UncheckedAt(i);
 296          AliTrackReference *nref=(AliTrackReference*)nrefs->UncheckedAt(i);
 297          AliTrackReference *pref=(AliTrackReference*)prefs->UncheckedAt(i);
 298          Int_t pdg=(Int_t)nref->GetLength();  //this is the cascade's PDG !
 299          if (code!=pdg) continue;
 300          ng++;
 301          pxg=bref->Px()+nref->Px()+pref->Px();
 302          pyg=bref->Px()+nref->Py()+pref->Py();
 303          ptg=TMath::Sqrt(pxg*pxg+pyg*pyg);
 304          hgood->Fill(ptg);
 305          nlab=nref->Label(); plab=pref->Label(); blab=bref->Label();
 306          if (nlab < 0) continue;
 307          cout<<"Cascade ("<<nlab<<','<<plab<<","<<blab<<") has not been found !\n";
 308       }
 309       allgood+=ng;
 310
 311       cout<<"Number of found cascades : "<<nentr<<endl;
 312       cout<<"Number of \"good\" cascades : "<<ng<<endl;
 313
 314       brefs->Clear();
 315       prefs->Clear();
 316       nrefs->Clear();
 317
 318    } //**** End of the loop over events
 319
 320    delete event;
 321    delete esdTree;
 322    ef->Close();
 323
 324    delete csTree;
 325    refFile->Close();
 326
 327    Stat_t ngg=hgood->GetEntries(), nf=hfound->GetEntries();
 328    if (ngg!=0) cout<<"Integral efficiency is about "<<nf/ngg*100.<<" %\n";
 329    cout<<
 330    "Total number of found cascades: "<<allfound<<" ("<<nf<<" in the peak)\n";
 331    cout<<"Total number of \"good\" cascades: "<<allgood<<endl;
 332
 333
 334    gStyle->SetOptStat(111110);
 335    gStyle->SetOptFit(1);
 336
 337    TCanvas *c1=(TCanvas*)gROOT->FindObject("c1");
 338    if (!c1) {
 339       c1=new TCanvas("c1","",0,0,580,610);
 340       c1->Divide(2,2);
 341    }
 342
 343    Int_t minc=33;
 344
 345    c1->cd(1);
 346    gPad->SetFillColor(42); gPad->SetFrameFillColor(10);
 347    if (hp->GetEntries()<minc) hp->Draw(); else hp->Fit("gaus");
 348    hl->Draw("same"); c1->cd();
 349
 350    c1->cd(2);
 351    gPad->SetFillColor(42); gPad->SetFrameFillColor(10);
 352    if (hpt->GetEntries()<minc) hpt->Draw(); else hpt->Fit("gaus");
 353    c1->cd();
 354
 355    c1->cd(3);
 356    gPad->SetFillColor(42); gPad->SetFrameFillColor(10);
 357    if (hx->GetEntries()<minc) hx->Draw(); else hx->Fit("gaus");
 358    hy->Draw("same"); c1->cd();
 359
 360    c1->cd(4);
 361    gPad->SetFillColor(42); gPad->SetFrameFillColor(10);
 362    if (hz->GetEntries()<minc) hz->Draw(); else hz->Fit("gaus");
 363
 364    c1->Update();
 365
 366    TCanvas *c2=(TCanvas*)gROOT->FindObject("c2");
 367    if (!c2) {
 368       c2=new TCanvas("c2","",600,0,580,610);
 369       c2->Divide(1,2);
 370    }
 371
 372    c2->cd(1);
 373    gPad->SetFillColor(42); gPad->SetFrameFillColor(10);
 374    hfound->Sumw2(); hgood->Sumw2(); hfake->Sumw2();
 375    hg->Divide(hfound,hgood,1,1.,"b");
 376    hf->Divide(hfake,hgood,1,1.,"b");
 377    hg->SetMaximum(1.4);
 378    hg->SetYTitle("Cascade reconstruction efficiency");
 379    hg->SetXTitle("Pt (GeV/c)");
 380    hg->Draw();
 381
 382    TLine *line1 = new TLine(pmin,1.0,pmax,1.0); line1->SetLineStyle(4);
 383    line1->Draw("same");
 384    TLine *line2 = new TLine(pmin,0.9,pmax,0.9); line2->SetLineStyle(4);
 385    line2->Draw("same");
 386
 387    hf->SetFillColor(1);
 388    hf->SetFillStyle(3013);
 389    hf->SetLineColor(2);
 390    hf->SetLineWidth(2);
 391    hf->Draw("histsame");
 392    TText *text = new TText(0.461176,0.248448,"Fake cascades");
 393    text->SetTextSize(0.05);
 394    text->Draw();
 395    text = new TText(0.453919,1.11408,"Good cascades");
 396    text->SetTextSize(0.05);
 397    text->Draw();
 398
 399
 400    c2->cd(2);
 401    gPad->SetFillColor(42); gPad->SetFrameFillColor(10);
 402    if (cs->GetEntries()<minc) cs->Draw();
 403    else cs->Fit("gaus","","",cascadeMass-cascadeWidth,cascadeMass+cascadeWidth);
 404    csf->Draw("same");
 405    Double_t max=cs->GetMaximum();
 406    TLine *line3 =
 407       new TLine(cascadeMass-cascadeWidth,0.,cascadeMass-cascadeWidth,max);
 408    line3->Draw("same");
 409    TLine *line4 =
 410       new TLine(cascadeMass+cascadeWidth,0.,cascadeMass+cascadeWidth,max);
 411    line4->Draw("same");
 412
 413    c2->Update();
 414
 415    TFile fc("AliCascadeComparison.root","RECREATE");
 416    c1->Write();
 417    c2->Write();
 418    fc.Close();
 419
 420    gBenchmark->Stop("AliCascadeComparison");
 421    gBenchmark->Show("AliCascadeComparison");
 422
 423
 424    return 0;
 425 }
 426
 427
 428 Int_t GoodCascades(const Char_t *dir) {
 429    if (gAlice) {
 430       delete AliRunLoader::Instance();
 431       delete gAlice;
 432       gAlice=0;
 433    }
 434
 435    Char_t fname[100];
 436    sprintf(fname,"%s/galice.root",dir);
 437
 438    AliRunLoader *rl = AliRunLoader::Open(fname,"COMPARISON");
 439    if (!rl) {
 440        ::Error("GoodCascades","Can't start session !");
 441        return 1;
 442    }
 443
 444    rl->LoadgAlice();
 445    rl->LoadHeader();
 446    rl->LoadKinematics();
 447
 448
 449    Int_t nev=rl->GetNumberOfEvents();
 450    ::Info("GoodCascades","Number of events : %d\n",nev);
 451
 452
 453    sprintf(fname,"%s/GoodTracksITS.root",dir);
 454    TFile *itsFile=TFile::Open(fname);
 455    if ((!itsFile)||(!itsFile->IsOpen())) {
 456        ::Error("GoodCAscades","Can't open the GoodTracksITS.root !");
 457        delete rl;
 458        return 5;
 459    }
 460    TClonesArray dm("AliTrackReference",1000), *itsRefs=&dm;
 461    TTree *itsTree=(TTree*)itsFile->Get("itsTree");
 462    if (!itsTree) {
 463        ::Error("GoodCascades","Can't get the ITS reference tree !");
 464        delete rl;
 465        return 6;
 466    }
 467    TBranch *itsBranch=itsTree->GetBranch("ITS");
 468    if (!itsBranch) {
 469       ::Error("GoodCascades","Can't get the ITS reference branch !");
 470       delete rl;
 471       return 7;
 472    }
 473    itsBranch->SetAddress(&itsRefs);
 474
 475
 476    sprintf(fname,"%s/GoodCascades.root",dir);
 477    TFile *csFile=TFile::Open(fname,"recreate");
 478    TClonesArray dummy("AliTrackReference",1000), *nrefs=&dummy;
 479    TClonesArray dumm("AliTrackReference",1000), *prefs=&dumm;
 480    TClonesArray dum("AliTrackReference",1000), *brefs=&dum;
 481    TTree csTree("csTree","Tree with info about the reconstructable cascades");
 482    csTree.Branch("negative",&nrefs);
 483    csTree.Branch("positive",&prefs);
 484    csTree.Branch("bachelor",&brefs);
 485
 486
 487    // *** Get information about the cuts ***
 488    Double_t r2min=0.9*0.9;
 489    Double_t r2max=2.9*2.9;
 490
 491
 492    //********  Loop over generated events
 493    for (Int_t e=0; e<nev; e++) {
 494       rl->GetEvent(e);  csFile->cd();
 495
 496       Int_t np = rl->GetHeader()->GetNtrack();
 497       cout<<"Event "<<e<<" Number of particles: "<<np<<endl;
 498
 499       itsTree->GetEvent(e);
 500       Int_t nk=itsRefs->GetEntriesFast();
 501
 502       AliStack *stack=rl->Stack();
 503
 504       AliTrackReference *nref=0, *pref=0, *bref=0;
 505
 506       Int_t nc=0;
 507       while (np--) {
 508          //cerr<<np<<'\r';
 509          TParticle *cp=stack->Particle(np);
 510
 511          // *** only these cascades are "good" ***
 512          Int_t code=cp->GetPdgCode();
 513          if (code!=kXiMinus)    if (code!=kXiPlusBar)
 514          if (code!=kOmegaMinus) if (code!=kOmegaPlusBar) continue;
 515
 516          // *** daughter tracks must be "good" ***
 517          Int_t v0lab=cp->GetFirstDaughter(), blab=cp->GetLastDaughter();
 518          if (v0lab==blab) continue;
 519          if (v0lab<0) continue;
 520          if (blab<0) continue;
 521
 522          TParticle *p0=stack->Particle(v0lab);
 523          TParticle *bp=stack->Particle(blab);
 524          Int_t i;
 525          if ((p0->GetPdgCode()!=kLambda0) && (p0->GetPdgCode()!=kLambda0Bar)) {
 526             TParticle *p=p0; p0=bp; bp=p;
 527             i=v0lab; v0lab=blab; blab=i;
 528             if ((p0->GetPdgCode()!=kLambda0)&&(p0->GetPdgCode()!=kLambda0Bar))
 529                                                                    continue;
 530          }
 531
 532          // ** is the bachelor "good" ? **
 533          for (i=0; i<nk; i++) {
 534              bref=(AliTrackReference*)itsRefs->UncheckedAt(i);
 535              if (bref->Label()==blab) break;
 536          }
 537          if (i==nk) continue;
 538
 539          // ** is the V0 "good" ? **
 540          Int_t plab=p0->GetFirstDaughter(), nlab=p0->GetLastDaughter();
 541          if (nlab==plab) continue;
 542          if (nlab<0) continue;
 543          if (plab<0) continue;
 544          if (stack->Particle(plab)->GetPDG()->Charge() < 0.) {
 545             i=plab; plab=nlab; nlab=i;
 546          }
 547          for (i=0; i<nk; i++) {
 548              nref=(AliTrackReference*)itsRefs->UncheckedAt(i);
 549              if (nref->Label()==nlab) break;
 550          }
 551          if (i==nk) continue;
 552          for (i=0; i<nk; i++) {
 553              pref=(AliTrackReference*)itsRefs->UncheckedAt(i);
 554              if (pref->Label()==plab) break;
 555          }
 556          if (i==nk) continue;
 557
 558
 559          // *** fiducial volume ***
 560          Double_t x=bp->Vx(), y=bp->Vy(), r2=x*x+y*y; //bachelor
 561          if (r2<r2min) continue;
 562          if (r2>r2max) continue;
 563          TParticle *pp=stack->Particle(plab);
 564          x=pp->Vx(); y=pp->Vy(); r2=x*x+y*y;          //V0
 565          if (r2<r2min) continue;
 566          if (r2>r2max) continue;
 567
 568          Int_t pdg=cp->GetPdgCode();
 569          nref->SetLength(pdg);  //This will the cascade's PDG !
 570
 571          new((*nrefs)[nc]) AliTrackReference(*nref);
 572          new((*prefs)[nc]) AliTrackReference(*pref);
 573          new((*brefs)[nc]) AliTrackReference(*bref);
 574
 575          nc++;
 576       }
 577       itsRefs->Clear();
 578
 579       csTree.Fill();
 580       nrefs->Clear(); prefs->Clear(); brefs->Clear();
 581
 582    } //**** end of the loop over generated events
 583
 584    csTree.Write();
 585    csFile->Close();
 586
 587    delete itsTree;
 588    itsFile->Close();
 589
 590    delete rl;
 591    return 0;
 592 }