Completely Updated (Mario Sitta)
[u/mrichter/AliRoot.git] / 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 }