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 #if !defined(__CINT__) || defined(__MAKECINT__)
  11   #include <TMath.h>
  12   #include <TError.h>
  13   #include <Riostream.h>
  14   #include <TH1F.h>
  15   #include <TTree.h>
  16   #include <TParticle.h>
  17   #include <TCanvas.h>
  18   #include <TLine.h>
  19   #include <TText.h>
  20   #include <TBenchmark.h>
  21   #include <TStyle.h>
  22   #include <TFile.h>
  23   #include <TROOT.h>
  24
  25   #include "AliStack.h"
  26   #include "AliHeader.h"
  27   #include "AliTrackReference.h"
  28   #include "AliRunLoader.h"
  29   #include "AliRun.h"
  30   #include "AliESDEvent.h"
  31   #include "AliESDcascade.h"
  32 #else
  33   const Int_t kXiMinus    = 3312;
  34   const Int_t kXiPlusBar  = -3312;
  35   const Int_t kOmegaMinus = 3334;
  36   const Int_t kOmegaPlusBar = -3334;
  37 #endif
  38
  39 Int_t GoodCascades(const Char_t *dir=".");
  40
  41 extern AliRun *gAlice;
  42 extern TBenchmark *gBenchmark;
  43 extern TROOT *gROOT;
  44
  45 static Int_t allgood=0;
  46 static Int_t allfound=0;
  47
  48 Int_t AliCascadeComparison(Int_t code=3312, const Char_t *dir=".") {
  49   //code= 3312; //kXiMinus
  50   //code=-3312; //kXiPlusBar
  51   //code= 3334; //kOmegaMinus
  52   //code=-3334; //kOmegaPlusBar
  53    gBenchmark->Start("AliCascadeComparison");
  54
  55    ::Info("AliCascadeComparison.C","Doing comparison...");
  56
  57    const Double_t cascadeWindow=0.05, cascadeWidth=0.015;
  58    Double_t ptncut=0.12, ptpcut=0.33, kine0cut=0.003;
  59    Double_t ptbcut=0.11, kinecut=0.002;
  60    Double_t cascadeMass=1.32131;
  61    switch (code) {
  62    case kXiMinus:
  63         break;
  64    case kXiPlusBar:
  65         ptncut=0.33; ptpcut=0.12;
  66         break;
  67    case kOmegaMinus:
  68         cascadeMass=1.67245;
  69         kine0cut=0.001;
  70         ptbcut=0.22; kinecut=0.006;
  71         break;
  72    case kOmegaPlusBar:
  73         cascadeMass=1.67245;
  74         kine0cut=0.001;
  75         ptncut=0.33; ptpcut=0.12;
  76         ptbcut=0.22; kinecut=0.006;
  77         break;
  78    default: cerr<<"Invalid PDG code !\n"; return 1;
  79    }
  80
  81
  82    TH1F *hp=(TH1F*)gROOT->FindObject("hp");
  83    if (!hp) hp=new TH1F("hp","Angular Resolution",30,-30.,30.);
  84    hp->SetXTitle("(mrad)"); hp->SetFillColor(2);
  85
  86    TH1F *hl=(TH1F*)gROOT->FindObject("hl");
  87    if (!hl) hl=new TH1F("hl","Lambda Resolution",30,-30,30);
  88    hl->SetXTitle("(mrad)"); hl->SetFillColor(1); hl->SetFillStyle(3013);
  89
  90    TH1F *hpt=(TH1F*)gROOT->FindObject("hpt");
  91    if (!hpt) hpt=new TH1F("hpt","Relative Pt Resolution",30,-10.,10.);
  92    hpt->SetXTitle("(%)"); hpt->SetFillColor(2);
  93
  94    TH1F *hx=(TH1F*)gROOT->FindObject("hx");
  95    if (!hx) hx=new TH1F("hx","Position Resolution (X,Y)",30,-3.,3.);
  96    hx->SetXTitle("(mm)"); hx->SetFillColor(6);
  97
  98    TH1F *hy=(TH1F*)gROOT->FindObject("hy");
  99    if (!hy) hy=new TH1F("hy","Position Resolution (Y)",30,-3.,3.);
 100    hy->SetXTitle("(mm)"); hy->SetFillColor(1); hy->SetFillStyle(3013);
 101
 102    TH1F *hz=(TH1F*)gROOT->FindObject("hz");
 103    if (!hz) hz=new TH1F("hz","Position Resolution (Z)",30,-3.,3.);
 104    hz->SetXTitle("(mm)"); hz->SetFillColor(6);
 105
 106
 107    Double_t pmin=0.2, pmax=4.2; Int_t nchan=20;
 108    TH1F *hgood=(TH1F*)gROOT->FindObject("hgood");
 109    if (!hgood) hgood=new TH1F("hgood","Good Cascades",nchan,pmin,pmax);
 110
 111    TH1F *hfound=(TH1F*)gROOT->FindObject("hfound");
 112    if (!hfound) hfound=new TH1F("hfound","Found Cascades",nchan,pmin,pmax);
 113
 114    TH1F *hfake=(TH1F*)gROOT->FindObject("hfake");
 115    if (!hfake) hfake=new TH1F("hfake","Fake Cascades",nchan,pmin,pmax);
 116
 117    TH1F *hg=(TH1F*)gROOT->FindObject("hg");
 118    if (!hg) hg=new TH1F("hg","Efficiency for Good Cascades",nchan,pmin,pmax);
 119    hg->SetLineColor(4); hg->SetLineWidth(2);
 120
 121    TH1F *hf=(TH1F*)gROOT->FindObject("hf");
 122    if (!hf) hf=new TH1F("hf","Probability of Fake Cascades",nchan,pmin,pmax);
 123    hf->SetFillColor(1); hf->SetFillStyle(3013); hf->SetLineWidth(2);
 124
 125
 126    Double_t mmin=cascadeMass-cascadeWindow, mmax=cascadeMass+cascadeWindow;
 127    TH1F *cs=(TH1F*)gROOT->FindObject("cs");
 128    if (!cs) cs=new TH1F("cs","Cascade Effective Mass",40, mmin, mmax);
 129    cs->SetXTitle("(GeV)"); cs->SetLineColor(4); cs->SetLineWidth(4);
 130
 131    TH1F *csf=(TH1F*)gROOT->FindObject("csf");
 132    if (!csf) csf=new TH1F("csf","Fake Cascade Effective Mass",40, mmin, mmax);
 133    csf->SetXTitle("(GeV)"); csf->SetFillColor(6);
 134
 135
 136    Char_t fname[100];
 137    sprintf(fname,"%s/GoodCascades.root",dir);
 138
 139    TFile *refFile=TFile::Open(fname,"old");
 140    if (!refFile || !refFile->IsOpen()) {
 141    ::Info("AliCascadeComparison.C","Marking good cascades (will take a while)...");
 142      if (GoodCascades(dir)) {
 143         ::Error("AliCascadesComparison.C","Can't generate the reference file !");
 144         return 1;
 145      }
 146    }
 147    refFile=TFile::Open(fname,"old");
 148    if (!refFile || !refFile->IsOpen()) {
 149      ::Error("AliCascadeComparison.C","Can't open the reference file !");
 150      return 1;
 151    }
 152
 153    TTree *csTree=(TTree*)refFile->Get("csTree");
 154    if (!csTree) {
 155      ::Error("AliCascadeComparison.C","Can't get the reference tree !");
 156      return 2;
 157    }
 158    TBranch *pbranch=csTree->GetBranch("positive");
 159    if (!pbranch) {
 160      ::Error("AliCascadeComparison.C","Can't get the positive daughter branch !");
 161      return 3;
 162    }
 163    TClonesArray dummy("AliTrackReference",1000), *prefs=&dummy;
 164    pbranch->SetAddress(&prefs);
 165
 166    TBranch *nbranch=csTree->GetBranch("negative");
 167    if (!nbranch) {
 168      ::Error("AliCascadeComparison.C","Can't get the negative daughter branch !");
 169      return 4;
 170    }
 171    TClonesArray dumm("AliTrackReference",1000), *nrefs=&dumm;
 172    nbranch->SetAddress(&nrefs);
 173
 174    TBranch *bbranch=csTree->GetBranch("bachelor");
 175    if (!nbranch) {
 176      ::Error("AliCascadeComparison.C","Can't get the bachelor branch !");
 177      return 4;
 178    }
 179    TClonesArray dum("AliTrackReference",1000), *brefs=&dum;
 180    bbranch->SetAddress(&brefs);
 181
 182
 183
 184    sprintf(fname,"%s/AliESDs.root",dir);
 185    TFile *ef=TFile::Open(fname);
 186    if ((!ef)||(!ef->IsOpen())) {
 187       sprintf(fname,"%s/AliESDcascade.root",dir);
 188       ef=TFile::Open(fname);
 189       if ((!ef)||(!ef->IsOpen())) {
 190          ::Error("AliCascadeComparison.C","Can't open AliESDcascade.root !");
 191          return 5;
 192       }
 193    }
 194    AliESDEvent* event = new AliESDEvent();
 195    TTree* esdTree = (TTree*) ef->Get("esdTree");
 196    if (!esdTree) {
 197       ::Error("AliCascadeComparison.C", "no ESD tree found");
 198       return 6;
 199    }
 200    event->ReadFromTree(esdTree);
 201
 202
 203    //******* Loop over events *********
 204    Int_t e=0;
 205    while (esdTree->GetEvent(e)) {
 206       cout<<endl<<endl<<"********* Processing event number: "<<e<<"*******\n";
 207
 208       Int_t nentr=event->GetNumberOfCascades();
 209       allfound+=nentr;
 210
 211
 212       if (csTree->GetEvent(e++)==0) {
 213          cerr<<"No reconstructable cascades !\n";
 214          continue;
 215       }
 216
 217       Int_t ngood=prefs->GetEntriesFast(),ng=0;
 218
 219       Double_t pxg=0.,pyg=0.,pzg=0.,ptg=0.;
 220       Int_t nlab=-1, plab=-1, blab=-1;
 221       Int_t i;
 222       for (i=0; i<nentr; i++) {
 223           AliESDcascade *cascade=event->GetCascade(i);
 224
 225           Int_t nidx=TMath::Abs(cascade->GetNindex());
 226           Int_t pidx=TMath::Abs(cascade->GetPindex());
 227           Int_t bidx=TMath::Abs(cascade->GetBindex());
 228
 229           AliESDtrack *ntrack=event->GetTrack(nidx);
 230           AliESDtrack *ptrack=event->GetTrack(pidx);
 231           AliESDtrack *btrack=event->GetTrack(bidx);
 232
 233           nlab=TMath::Abs(ntrack->GetLabel());
 234           plab=TMath::Abs(ptrack->GetLabel());
 235           blab=TMath::Abs(btrack->GetLabel());
 236
 237           /** Kinematical cuts **/
 238           Double_t pxn,pyn,pzn; cascade->GetNPxPyPz(pxn,pyn,pzn);
 239           Double_t ptn=TMath::Sqrt(pxn*pxn + pyn*pyn);
 240           if (ptn < ptncut) continue;
 241           Double_t pxp,pyp,pzp; cascade->GetPPxPyPz(pxp,pyp,pzp);
 242           Double_t ptp=TMath::Sqrt(pxp*pxp + pyp*pyp);
 243           if (ptp < ptpcut) continue;
 244           Double_t pxb,pyb,pzb; cascade->GetBPxPyPz(pxb,pyb,pzb);
 245           Double_t ptb=TMath::Sqrt(pxb*pxb + pyb*pyb);
 246           if (ptb < ptbcut) continue;
 247           Double_t kine0;
 248           Double_t kine=cascade->ChangeMassHypothesis(kine0,code);
 249           if (TMath::Abs(kine0)>kine0cut) continue;
 250           //if (TMath::Abs(kine)>kinecut) continue;
 251
 252           Double_t mass=cascade->GetEffMass();
 253           cs->Fill(mass);
 254           csf->Fill(mass);
 255
 256           AliTrackReference *nref=0, *pref=0, *bref=0;
 257           Int_t j;
 258           for (j=0; j<ngood; j++) {
 259               bref=(AliTrackReference*)brefs->UncheckedAt(j);
 260               nref=(AliTrackReference*)nrefs->UncheckedAt(j);
 261               pref=(AliTrackReference*)prefs->UncheckedAt(j);
 262               if (bref->Label() == blab)
 263               if (nref->Label() == nlab)
 264               if (pref->Label() == plab) break;
 265           }
 266
 267           if (TMath::Abs(mass-cascadeMass)>cascadeWidth) continue;
 268
 269           Double_t px,py,pz; cascade->GetPxPyPz(px,py,pz);
 270           Double_t pt=TMath::Sqrt(px*px+py*py);
 271
 272           if (j==ngood) {
 273              hfake->Fill(pt);
 274              cout<<"Fake cascade: ("<<nlab<<","<<plab<<","<<blab<<")\n";
 275              continue;
 276           }
 277           csf->Fill(mass,-1);
 278
 279           pxg=bref->Px()+nref->Px()+pref->Px();
 280           pyg=bref->Px()+nref->Py()+pref->Py();
 281           pzg=nref->Pz()+pref->Pz();
 282           ptg=TMath::Sqrt(pxg*pxg+pyg*pyg);
 283           Double_t phig=TMath::ATan2(pyg,pxg), phi=TMath::ATan2(py,px);
 284           Double_t lamg=TMath::ATan2(pzg,ptg), lam=TMath::ATan2(pz,pt);
 285           hp->Fill((phi - phig)*1000.);
 286           hl->Fill((lam - lamg)*1000.);
 287           hpt->Fill((1/pt - 1/ptg)/(1/ptg)*100.);
 288
 289           Double_t x,y,z; cascade->GetXYZ(x,y,z);
 290           hx->Fill((x-nref->X())*10);
 291           hy->Fill((y-nref->Y())*10);
 292           hz->Fill((z-nref->Z())*10);
 293
 294           hfound->Fill(ptg);
 295           nref->SetLabel(-1);
 296
 297       }
 298       for (i=0; i<ngood; i++) {
 299          AliTrackReference *bref=(AliTrackReference*)brefs->UncheckedAt(i);
 300          AliTrackReference *nref=(AliTrackReference*)nrefs->UncheckedAt(i);
 301          AliTrackReference *pref=(AliTrackReference*)prefs->UncheckedAt(i);
 302          Int_t pdg=(Int_t)nref->GetLength();  //this is the cascade's PDG !
 303          if (code!=pdg) continue;
 304          ng++;
 305          pxg=bref->Px()+nref->Px()+pref->Px();
 306          pyg=bref->Px()+nref->Py()+pref->Py();
 307          ptg=TMath::Sqrt(pxg*pxg+pyg*pyg);
 308          hgood->Fill(ptg);
 309          nlab=nref->Label(); plab=pref->Label(); blab=bref->Label();
 310          if (nlab < 0) continue;
 311          cout<<"Cascade ("<<nlab<<','<<plab<<","<<blab<<") has not been found !\n";
 312       }
 313       allgood+=ng;
 314
 315       cout<<"Number of found cascades : "<<nentr<<endl;
 316       cout<<"Number of \"good\" cascades : "<<ng<<endl;
 317
 318       brefs->Clear();
 319       prefs->Clear();
 320       nrefs->Clear();
 321
 322    } //**** End of the loop over events
 323
 324    delete event;
 325    delete esdTree;
 326    ef->Close();
 327
 328    delete csTree;
 329    refFile->Close();
 330
 331    Stat_t ngg=hgood->GetEntries(), nf=hfound->GetEntries();
 332    if (ngg!=0) cout<<"Integral efficiency is about "<<nf/ngg*100.<<" %\n";
 333    cout<<
 334    "Total number of found cascades: "<<allfound<<" ("<<nf<<" in the peak)\n";
 335    cout<<"Total number of \"good\" cascades: "<<allgood<<endl;
 336
 337
 338    gStyle->SetOptStat(111110);
 339    gStyle->SetOptFit(1);
 340
 341    TCanvas *c1=(TCanvas*)gROOT->FindObject("c1");
 342    if (!c1) {
 343       c1=new TCanvas("c1","",0,0,580,610);
 344       c1->Divide(2,2);
 345    }
 346
 347    Int_t minc=33;
 348
 349    c1->cd(1);
 350    gPad->SetFillColor(42); gPad->SetFrameFillColor(10);
 351    if (hp->GetEntries()<minc) hp->Draw(); else hp->Fit("gaus");
 352    hl->Draw("same"); c1->cd();
 353
 354    c1->cd(2);
 355    gPad->SetFillColor(42); gPad->SetFrameFillColor(10);
 356    if (hpt->GetEntries()<minc) hpt->Draw(); else hpt->Fit("gaus");
 357    c1->cd();
 358
 359    c1->cd(3);
 360    gPad->SetFillColor(42); gPad->SetFrameFillColor(10);
 361    if (hx->GetEntries()<minc) hx->Draw(); else hx->Fit("gaus");
 362    hy->Draw("same"); c1->cd();
 363
 364    c1->cd(4);
 365    gPad->SetFillColor(42); gPad->SetFrameFillColor(10);
 366    if (hz->GetEntries()<minc) hz->Draw(); else hz->Fit("gaus");
 367
 368    c1->Update();
 369
 370    TCanvas *c2=(TCanvas*)gROOT->FindObject("c2");
 371    if (!c2) {
 372       c2=new TCanvas("c2","",600,0,580,610);
 373       c2->Divide(1,2);
 374    }
 375
 376    c2->cd(1);
 377    gPad->SetFillColor(42); gPad->SetFrameFillColor(10);
 378    hfound->Sumw2(); hgood->Sumw2(); hfake->Sumw2();
 379    hg->Divide(hfound,hgood,1,1.,"b");
 380    hf->Divide(hfake,hgood,1,1.,"b");
 381    hg->SetMaximum(1.4);
 382    hg->SetYTitle("Cascade reconstruction efficiency");
 383    hg->SetXTitle("Pt (GeV/c)");
 384    hg->Draw();
 385
 386    TLine *line1 = new TLine(pmin,1.0,pmax,1.0); line1->SetLineStyle(4);
 387    line1->Draw("same");
 388    TLine *line2 = new TLine(pmin,0.9,pmax,0.9); line2->SetLineStyle(4);
 389    line2->Draw("same");
 390
 391    hf->SetFillColor(1);
 392    hf->SetFillStyle(3013);
 393    hf->SetLineColor(2);
 394    hf->SetLineWidth(2);
 395    hf->Draw("histsame");
 396    TText *text = new TText(0.461176,0.248448,"Fake cascades");
 397    text->SetTextSize(0.05);
 398    text->Draw();
 399    text = new TText(0.453919,1.11408,"Good cascades");
 400    text->SetTextSize(0.05);
 401    text->Draw();
 402
 403
 404    c2->cd(2);
 405    gPad->SetFillColor(42); gPad->SetFrameFillColor(10);
 406    if (cs->GetEntries()<minc) cs->Draw();
 407    else cs->Fit("gaus","","",cascadeMass-cascadeWidth,cascadeMass+cascadeWidth);
 408    csf->Draw("same");
 409    Double_t max=cs->GetMaximum();
 410    TLine *line3 =
 411       new TLine(cascadeMass-cascadeWidth,0.,cascadeMass-cascadeWidth,max);
 412    line3->Draw("same");
 413    TLine *line4 =
 414       new TLine(cascadeMass+cascadeWidth,0.,cascadeMass+cascadeWidth,max);
 415    line4->Draw("same");
 416
 417    c2->Update();
 418
 419    TFile fc("AliCascadeComparison.root","RECREATE");
 420    c1->Write();
 421    c2->Write();
 422    fc.Close();
 423
 424    gBenchmark->Stop("AliCascadeComparison");
 425    gBenchmark->Show("AliCascadeComparison");
 426
 427
 428    return 0;
 429 }
 430
 431
 432 Int_t GoodCascades(const Char_t *dir) {
 433    if (gAlice) {
 434       delete gAlice->GetRunLoader();
 435       delete gAlice;
 436       gAlice=0;
 437    }
 438
 439    Char_t fname[100];
 440    sprintf(fname,"%s/galice.root",dir);
 441
 442    AliRunLoader *rl = AliRunLoader::Open(fname,"COMPARISON");
 443    if (!rl) {
 444        ::Error("GoodCascades","Can't start session !");
 445        return 1;
 446    }
 447
 448    rl->LoadgAlice();
 449    rl->LoadHeader();
 450    rl->LoadKinematics();
 451
 452
 453    Int_t nev=rl->GetNumberOfEvents();
 454    ::Info("GoodCascades","Number of events : %d\n",nev);
 455
 456
 457    sprintf(fname,"%s/GoodTracksITS.root",dir);
 458    TFile *itsFile=TFile::Open(fname);
 459    if ((!itsFile)||(!itsFile->IsOpen())) {
 460        ::Error("GoodCAscades","Can't open the GoodTracksITS.root !");
 461        delete rl;
 462        return 5;
 463    }
 464    TClonesArray dm("AliTrackReference",1000), *itsRefs=&dm;
 465    TTree *itsTree=(TTree*)itsFile->Get("itsTree");
 466    if (!itsTree) {
 467        ::Error("GoodCascades","Can't get the ITS reference tree !");
 468        delete rl;
 469        return 6;
 470    }
 471    TBranch *itsBranch=itsTree->GetBranch("ITS");
 472    if (!itsBranch) {
 473       ::Error("GoodCascades","Can't get the ITS reference branch !");
 474       delete rl;
 475       return 7;
 476    }
 477    itsBranch->SetAddress(&itsRefs);
 478
 479
 480    sprintf(fname,"%s/GoodCascades.root",dir);
 481    TFile *csFile=TFile::Open(fname,"recreate");
 482    TClonesArray dummy("AliTrackReference",1000), *nrefs=&dummy;
 483    TClonesArray dumm("AliTrackReference",1000), *prefs=&dumm;
 484    TClonesArray dum("AliTrackReference",1000), *brefs=&dum;
 485    TTree csTree("csTree","Tree with info about the reconstructable cascades");
 486    csTree.Branch("negative",&nrefs);
 487    csTree.Branch("positive",&prefs);
 488    csTree.Branch("bachelor",&brefs);
 489
 490
 491    // *** Get information about the cuts ***
 492    Double_t r2min=0.9*0.9;
 493    Double_t r2max=2.9*2.9;
 494
 495
 496    //********  Loop over generated events
 497    for (Int_t e=0; e<nev; e++) {
 498       rl->GetEvent(e);  csFile->cd();
 499
 500       Int_t np = rl->GetHeader()->GetNtrack();
 501       cout<<"Event "<<e<<" Number of particles: "<<np<<endl;
 502
 503       itsTree->GetEvent(e);
 504       Int_t nk=itsRefs->GetEntriesFast();
 505
 506       AliStack *stack=rl->Stack();
 507
 508       AliTrackReference *nref=0, *pref=0, *bref=0;
 509
 510       Int_t nc=0;
 511       while (np--) {
 512          //cerr<<np<<'\r';
 513          TParticle *cp=stack->Particle(np);
 514
 515          // *** only these cascades are "good" ***
 516          Int_t code=cp->GetPdgCode();
 517          if (code!=kXiMinus)    if (code!=kXiPlusBar)
 518          if (code!=kOmegaMinus) if (code!=kOmegaPlusBar) continue;
 519
 520          // *** daughter tracks must be "good" ***
 521          Int_t v0lab=cp->GetFirstDaughter(), blab=cp->GetLastDaughter();
 522          if (v0lab==blab) continue;
 523          if (v0lab<0) continue;
 524          if (blab<0) continue;
 525
 526          TParticle *p0=stack->Particle(v0lab);
 527          TParticle *bp=stack->Particle(blab);
 528          Int_t i;
 529          if ((p0->GetPdgCode()!=kLambda0) && (p0->GetPdgCode()!=kLambda0Bar)) {
 530             TParticle *p=p0; p0=bp; bp=p;
 531             i=v0lab; v0lab=blab; blab=i;
 532             if ((p0->GetPdgCode()!=kLambda0)&&(p0->GetPdgCode()!=kLambda0Bar))
 533                                                                    continue;
 534          }
 535
 536          // ** is the bachelor "good" ? **
 537          for (i=0; i<nk; i++) {
 538              bref=(AliTrackReference*)itsRefs->UncheckedAt(i);
 539              if (bref->Label()==blab) break;
 540          }
 541          if (i==nk) continue;
 542
 543          // ** is the V0 "good" ? **
 544          Int_t plab=p0->GetFirstDaughter(), nlab=p0->GetLastDaughter();
 545          if (nlab==plab) continue;
 546          if (nlab<0) continue;
 547          if (plab<0) continue;
 548          if (stack->Particle(plab)->GetPDG()->Charge() < 0.) {
 549             i=plab; plab=nlab; nlab=i;
 550          }
 551          for (i=0; i<nk; i++) {
 552              nref=(AliTrackReference*)itsRefs->UncheckedAt(i);
 553              if (nref->Label()==nlab) break;
 554          }
 555          if (i==nk) continue;
 556          for (i=0; i<nk; i++) {
 557              pref=(AliTrackReference*)itsRefs->UncheckedAt(i);
 558              if (pref->Label()==plab) break;
 559          }
 560          if (i==nk) continue;
 561
 562
 563          // *** fiducial volume ***
 564          Double_t x=bp->Vx(), y=bp->Vy(), r2=x*x+y*y; //bachelor
 565          if (r2<r2min) continue;
 566          if (r2>r2max) continue;
 567          TParticle *pp=stack->Particle(plab);
 568          x=pp->Vx(); y=pp->Vy(); r2=x*x+y*y;          //V0
 569          if (r2<r2min) continue;
 570          if (r2>r2max) continue;
 571
 572          Int_t pdg=cp->GetPdgCode();
 573          nref->SetLength(pdg);  //This will the cascade's PDG !
 574
 575          new((*nrefs)[nc]) AliTrackReference(*nref);
 576          new((*prefs)[nc]) AliTrackReference(*pref);
 577          new((*brefs)[nc]) AliTrackReference(*bref);
 578
 579          nc++;
 580       }
 581       itsRefs->Clear();
 582
 583       csTree.Fill();
 584       nrefs->Clear(); prefs->Clear(); brefs->Clear();
 585
 586    } //**** end of the loop over generated events
 587
 588    csTree.Write();
 589    csFile->Close();
 590
 591    delete itsTree;
 592    itsFile->Close();
 593
 594    delete rl;
 595    return 0;
 596 }