EVGEN/AliDimuCombinator.cxx

   1 //
   2 //
   3 //
   4 //
   5 #include "AliDimuCombinator.h"
   6 #include "AliRun.h"
   7 #include "TRandom.h"
   8 //
   9 ClassImp(AliDimuCombinator)
  10 //
  11 //                       Iterators
  12 //
  13  TParticle* AliDimuCombinator::FirstMuon()
  14      {
  15          fimuon1=fimin1;
  16          fmuon1 = (TParticle*) fPartArray->UncheckedAt(fimuon1);
  17          while(Type(fmuon1)!=5 && Type(fmuon1)!=6) {
  18              fimuon1++;
  19              if (fimuon1 >= fimax1) {fmuon1=0; break;}
  20              fmuon1 = (TParticle*) fPartArray->UncheckedAt(fimuon1);
  21          }
  22          return fmuon1;
  23      }
  24
  25  TParticle* AliDimuCombinator::FirstMuonSelected()
  26      {
  27          TParticle * muon=FirstMuon();
  28          while(muon!=0 && !Selected(muon)) {muon=NextMuon();}
  29          return muon;
  30      }
  31
  32
  33  TParticle* AliDimuCombinator::NextMuon()
  34      {
  35          fimuon1++;
  36          if (fimuon1>=fNParticle) {fmuon1 = 0; return fmuon1;}
  37
  38          fmuon1 = (TParticle*) fPartArray->UncheckedAt(fimuon1);
  39          while(Type(fmuon1)!=5 && Type(fmuon1)!=6) {
  40              fimuon1++;
  41              if (fimuon1>=fimax1) {fmuon1 = 0; break;}
  42              fmuon1 = (TParticle*) fPartArray->UncheckedAt(fimuon1);
  43          }
  44          return fmuon1;
  45      }
  46
  47 TParticle* AliDimuCombinator::NextMuonSelected()
  48      {
  49          TParticle * muon=NextMuon();
  50          while(muon !=0 && !Selected(muon)) {muon=NextMuon();}
  51          return muon;
  52      }
  53
  54
  55  void AliDimuCombinator::FirstPartner()
  56      {
  57          if (fimin1==fimin2) {
  58              fimuon2=fimuon1+1;
  59          } else {
  60              fimuon2=fimin2;
  61          }
  62          if (fimuon2 >= fimax2) {fmuon2=0; return;}
  63          fmuon2 = (TParticle*) fPartArray->UncheckedAt(fimuon2);
  64          while(Type(fmuon2)!=5 && Type(fmuon2)!=6) {
  65              fimuon2++;
  66              if (fimuon2 >= fimax2) {fmuon2=0; break;}
  67              fmuon2 = (TParticle*) fPartArray->UncheckedAt(fimuon2);
  68          }
  69      }
  70 void AliDimuCombinator::FirstPartnerSelected()
  71 {
  72          FirstPartner();
  73          while(fmuon2 !=0 && !Selected(fmuon2)) {NextPartner();}
  74 }
  75
  76
  77  void AliDimuCombinator::NextPartner()
  78      {
  79          fimuon2++;
  80          if (fimuon2>=fimax2) {fmuon2 = 0; return;}
  81
  82
  83          fmuon2 = (TParticle*) fPartArray->UncheckedAt(fimuon2);
  84
  85          while(Type(fmuon2)!=5 && Type(fmuon2)!=6) {
  86              fimuon2++;
  87              if (fimuon2>=fimax2) {fmuon2 = 0; break;}
  88              fmuon2 = (TParticle*) fPartArray->UncheckedAt(fimuon2);
  89          }
  90
  91      }
  92
  93 void AliDimuCombinator::NextPartnerSelected()
  94 {
  95          NextPartner();
  96          while(fmuon2 !=0 && !Selected(fmuon2)) {NextPartner();}
  97 }
  98
  99
 100  TParticle*  AliDimuCombinator::Partner()
 101      {
 102          return fmuon2;
 103      }
 104
 105 void AliDimuCombinator::FirstMuonPair(TParticle* & muon1, TParticle* & muon2)
 106      {
 107          FirstMuon();
 108          FirstPartner();
 109          muon1=fmuon1;
 110          muon2=fmuon2;
 111      }
 112 void AliDimuCombinator::NextMuonPair(TParticle* & muon1, TParticle* & muon2)
 113      {
 114          NextPartner();
 115          if (!Partner()) {
 116              NextMuon();
 117              FirstPartner();
 118          }
 119          muon1=fmuon1;
 120          muon2=fmuon2;
 121      }
 122 void AliDimuCombinator::FirstMuonPairSelected(TParticle* & muon1, TParticle* & muon2)
 123      {
 124          FirstMuonSelected();
 125          FirstPartnerSelected();
 126          muon1=fmuon1;
 127          muon2=fmuon2;
 128      }
 129 void AliDimuCombinator::NextMuonPairSelected(TParticle* & muon1, TParticle* & muon2)
 130      {
 131          NextPartnerSelected();
 132          if (!Partner()) {
 133              NextMuonSelected();
 134              FirstPartnerSelected();
 135          }
 136          muon1=fmuon1;
 137          muon2=fmuon2;
 138      }
 139 void AliDimuCombinator::ResetRange()
 140 {
 141     fimin1=fimin2=0;
 142     fimax1=fimax2=fNParticle;
 143 }
 144
 145 void AliDimuCombinator::SetFirstRange(Int_t from, Int_t to)
 146 {
 147     fimin1=from;
 148     fimax1=to;
 149     if (fimax1 > fNParticle) fimax1=fNParticle;
 150 }
 151
 152 void AliDimuCombinator::SetSecondRange(Int_t from, Int_t to)
 153 {
 154     fimin2=from;
 155     fimax2=to;
 156     if (fimax2 > fNParticle) fimax2=fNParticle;
 157 }
 158 //
 159 //                       Selection
 160 //
 161
 162 Bool_t AliDimuCombinator::Selected(TParticle* part)
 163 {
 164 //
 165 //
 166     if (part==0) {return 0;}
 167
 168     if (part->Pt() > fPtMin && part->Eta()>fEtaMin && part->Eta()<fEtaMax) {
 169         return 1;
 170     } else {
 171         return 0;
 172     }
 173
 174
 175 }
 176
 177 Bool_t AliDimuCombinator::Selected(TParticle* part1, TParticle* part2)
 178 {
 179      return Selected(part1)*Selected(part2);
 180 }
 181 //
 182 //                       Kinematics
 183 //
 184 Float_t AliDimuCombinator::Mass(TParticle* part1, TParticle* part2)
 185 {
 186     Float_t px,py,pz,e;
 187     px=part1->Px()+part2->Px();
 188     py=part1->Py()+part2->Py();
 189     pz=part1->Pz()+part2->Pz();
 190     e =part1->Energy()+part2->Energy();
 191     Float_t p=px*px+py*py+pz*pz;
 192     if (e*e < p) {
 193         return -1;
 194     } else {
 195         return TMath::Sqrt(e*e-p);
 196     }
 197 }
 198
 199 Float_t AliDimuCombinator::PT(TParticle* part1, TParticle* part2)
 200 {
 201     Float_t px,py;
 202     px=part1->Px()+part2->Px();
 203     py=part1->Py()+part2->Py();
 204     return TMath::Sqrt(px*px+py*py);
 205 }
 206
 207 Float_t AliDimuCombinator::Pz(TParticle* part1, TParticle* part2)
 208 {
 209     return part1->Pz()+part2->Pz();
 210 }
 211
 212 Float_t AliDimuCombinator::Y(TParticle* part1, TParticle* part2)
 213 {
 214     Float_t pz,e;
 215     pz=part1->Pz()+part2->Pz();
 216     e =part1->Energy()+part2->Energy();
 217     return 0.5*TMath::Log((e+pz)/(e-pz));
 218 }
 219 //                  Response
 220 //
 221 void AliDimuCombinator::SmearGauss(Float_t width, Float_t & value)
 222 {
 223     value+=gRandom->Gaus(0, width);
 224 }
 225 //              Weighting
 226 //
 227
 228 Float_t AliDimuCombinator::Decay_Prob(TParticle* part)
 229 {
 230     Float_t d, h, theta, CTau;
 231     TParticle* parent = Parent(part);
 232     Int_t ipar=Type(parent);
 233     if (ipar==8 || ipar==9) {
 234         CTau=780.4;
 235     } else if (ipar==11 || ipar==12) {
 236         CTau=370.9;
 237     } else {
 238         CTau=0;
 239     }
 240
 241
 242     Float_t GammaBeta=(parent->P())/(parent->GetMass());
 243 //
 244 // this part is still very ALICE muon-arm specific
 245 //
 246     theta=parent->Theta();
 247     h=90*TMath::Tan(theta);
 248
 249     if (h<4) {
 250         d=4/TMath::Sin(theta);
 251     } else {
 252         d=90/TMath::Cos(theta);
 253     }
 254
 255     if (CTau > 0) {
 256         return 1-TMath::Exp(-d/CTau/GammaBeta);
 257     } else {
 258         return 1;
 259     }
 260 }
 261
 262 Float_t AliDimuCombinator::Weight(TParticle* part1, TParticle* part2)
 263 {
 264     Float_t wgt=(part1->GetWeight())*(part2->GetWeight());
 265
 266     if (Correlated(part1, part2)) {
 267         return wgt/(Parent(part1)->GetWeight())*fRate1;
 268     } else {
 269         return wgt*fRate1*fRate2;
 270     }
 271 }
 272
 273
 274 Float_t AliDimuCombinator::Weight(TParticle* part)
 275 {
 276     return (part->GetWeight())*(Parent(part)->GetWeight())*fRate1;
 277 }
 278 Bool_t  AliDimuCombinator::Correlated(TParticle* part1, TParticle* part2)
 279 {
 280     if (Origin(part1) == Origin(part2)) {
 281         return kTRUE;
 282     } else {
 283         return kFALSE;
 284     }
 285 }
 286
 287 TParticle* AliDimuCombinator::Parent(TParticle* part)
 288 {
 289     return (TParticle*) (fPartArray->UncheckedAt(part->GetFirstMother()));
 290 }
 291
 292 Int_t AliDimuCombinator::Origin(TParticle* part)
 293 {
 294     Int_t iparent= part->GetFirstMother();
 295     if (iparent < 0) return iparent;
 296     Int_t ip;
 297     while(1) {
 298         ip=((TParticle*) fPartArray->UncheckedAt(iparent))->GetFirstMother();
 299         if (ip < 0) {
 300             break;
 301         } else {
 302             iparent=ip;
 303         }
 304     }
 305     return iparent;
 306 }
 307