EVGEN/AliGenParam.cxx

   1 /**************************************************************************
   2  * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
   3  *                                                                        *
   4  * Author: The ALICE Off-line Project.                                    *
   5  * Contributors are mentioned in the code where appropriate.              *
   6  *                                                                        *
   7  * Permission to use, copy, modify and distribute this software and its   *
   8  * documentation strictly for non-commercial purposes is hereby granted   *
   9  * without fee, provided that the above copyright notice appears in all   *
  10  * copies and that both the copyright notice and this permission notice   *
  11  * appear in the supporting documentation. The authors make no claims     *
  12  * about the suitability of this software for any purpose. It is          *
  13  * provided "as is" without express or implied warranty.                  *
  14  **************************************************************************/
  15
  16 /*
  17 $Log$
  18 Revision 1.12  1999/11/03 17:43:20  fca
  19 New version from G.Martinez & A.Morsch
  20
  21 Revision 1.11  1999/09/29 09:24:14  fca
  22 Introduction of the Copyright and cvs Log
  23
  24 */
  25
  26 #include "AliGenParam.h"
  27 #include "AliGenMUONlib.h"
  28 #include "AliGenPHOSlib.h"
  29 #include "AliRun.h"
  30 #include "AliPythia.h"
  31 #include <TDirectory.h>
  32 #include <TFile.h>
  33 #include <TTree.h>
  34 #include <stdlib.h>
  35 #include <TParticle.h>
  36
  37 ClassImp(AliGenParam)
  38
  39 //------------------------------------------------------------
  40
  41   //Begin_Html
  42   /*
  43     <img src="picts/AliGenParam.gif">
  44   */
  45   //End_Html
  46
  47 //____________________________________________________________
  48 //____________________________________________________________
  49 AliGenParam::AliGenParam()
  50                  :AliGenerator()
  51 {
  52   fPtPara = 0;
  53   fYPara  = 0;
  54   fParam  = jpsi_p;
  55   fAnalog = analog;
  56   SetCutOnChild();
  57 }
  58
  59 //____________________________________________________________
  60
  61 AliGenParam::AliGenParam(Int_t npart, Param_t param) :AliGenerator(npart)
  62 {
  63   //
  64   //  fName="HMESONpara";
  65   //  fTitle="Heavy Mesons Parametrisation";
  66   fPtParaFunc = AliGenMUONlib::GetPt(param);
  67   fYParaFunc  = AliGenMUONlib::GetY(param);
  68   fIpParaFunc = AliGenMUONlib::GetIp(param);
  69
  70   fPtPara = 0;
  71   fYPara  = 0;
  72   fParam  = param;
  73   fAnalog = analog;
  74   fChildSelect.Set(5);
  75   for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
  76   SetForceDecay();
  77   SetCutOnChild();
  78 }
  79
  80 AliGenParam::AliGenParam(Int_t npart, Param_t param,
  81                          Double_t (*PtPara) (Double_t*, Double_t*),
  82                          Double_t (*YPara ) (Double_t* ,Double_t*),
  83                          Int_t    (*IpPara) ())
  84     :AliGenerator(npart)
  85 {
  86 // Gines Martinez 1/10/99
  87     fPtParaFunc = PtPara;
  88     fYParaFunc  = YPara;
  89     fIpParaFunc = IpPara;
  90 //
  91     fPtPara = 0;
  92     fYPara  = 0;
  93     fParam  = param;
  94     fAnalog = analog;
  95     fChildSelect.Set(5);
  96     for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
  97     SetForceDecay();
  98     SetCutOnChild();
  99 }
 100
 101 //____________________________________________________________
 102 AliGenParam::~AliGenParam()
 103 {
 104     delete  fPtPara;
 105     delete  fYPara;
 106 }
 107
 108 //____________________________________________________________
 109 void AliGenParam::Init()
 110 {
 111     SetMC(new AliPythia());
 112     fPythia= (AliPythia*) fgMCEvGen;
 113
 114 //  End of the test !!!
 115   //Begin_Html
 116   /*
 117     <img src="picts/AliGenParam.gif">
 118   */
 119   //End_Html
 120
 121   fPtPara = new TF1("Pt-Parametrization",fPtParaFunc,fPtMin,fPtMax,0);
 122   fYPara  = new TF1("Y -Parametrization",fYParaFunc,fYMin,fYMax,0);
 123   TF1* PtPara = new TF1("Pt-Parametrization",fPtParaFunc,0,15,0);
 124   TF1* YPara  = new TF1("Y -Parametrization",fYParaFunc,-6,6,0);
 125
 126 //
 127 // dN/dy| y=0
 128   Double_t y1=0;
 129   Double_t y2=0;
 130
 131   fdNdy0=fYParaFunc(&y1,&y2);
 132 //
 133 // Integral over generation region
 134   Float_t IntYS  = YPara ->Integral(fYMin, fYMax);
 135   Float_t IntPt0 = PtPara->Integral(0,15);
 136   Float_t IntPtS = PtPara->Integral(fPtMin,fPtMax);
 137   Float_t PhiWgt=(fPhiMax-fPhiMin)/2./TMath::Pi();
 138   if (fAnalog == analog) {
 139      fYWgt  = IntYS/fdNdy0;
 140      fPtWgt = IntPtS/IntPt0;
 141      fParentWeight = fYWgt*fPtWgt*PhiWgt/fNpart;
 142   } else {
 143       fYWgt = IntYS/fdNdy0;
 144       fPtWgt = (fPtMax-fPtMin)/IntPt0;
 145       fParentWeight = fYWgt*fPtWgt*PhiWgt/fNpart;
 146   }
 147 //
 148 // particle decay related initialization
 149   fPythia->DefineParticles();
 150 // semimuonic decays of charm and beauty
 151   fPythia->ForceDecay(fForceDecay);
 152 //
 153     switch (fForceDecay)
 154     {
 155     case semielectronic:
 156     case dielectron:
 157     case b_jpsi_dielectron:
 158     case b_psip_dielectron:
 159         fChildSelect[0]=11;
 160         break;
 161     case semimuonic:
 162     case dimuon:
 163     case b_jpsi_dimuon:
 164     case b_psip_dimuon:
 165         fChildSelect[0]=13;
 166         break;
 167     case pitomu:
 168         fChildSelect[0]=13;
 169         break;
 170     case katomu:
 171         fChildSelect[0]=13;
 172         break;
 173     case nodecay:
 174         break;
 175     case all:
 176         break;
 177     }
 178 }
 179
 180 //____________________________________________________________
 181 void AliGenParam::Generate()
 182 {
 183 //
 184 // Generate 'npart' of light and heavy mesons (J/Psi, upsilon or phi, Pion,
 185 // Kaons, Etas, Omegas) and Baryons (proton, antiprotons, neutrons and
 186 // antineutrons in the the desired theta, phi and momentum windows;
 187 // Gaussian smearing on the vertex is done if selected.
 188 // The decay of heavy mesons is done using lujet, and the childern particle are tracked by GEANT
 189 // However, light mesons are directly tracked by GEANT setting fForceDecay = nodecay (SetForceDecay(nodecay))
 190 //
 191
 192 // printf("Generate !!!!!!!!!!!!!\n");
 193
 194   Float_t polar[3]= {0,0,0};  // Polarisation of the parent particle (for GEANT tracking)
 195   Float_t origin0[3];         // Origin of the generated parent particle (for GEANT tracking)
 196   Float_t pt, pl, ptot;       // Transverse, logitudinal and total momenta of the parent particle
 197   Float_t phi, theta;         // Phi and theta spherical angles of the parent particle momentum
 198   Float_t p[3], pc[3],
 199           och[3], pch[10][3]; // Momentum, polarisation and origin of the children particles from lujet
 200   Float_t ty, xmt;
 201   Int_t nt, i, j, kfch[10];
 202   Float_t  wgtp, wgtch;
 203   Double_t dummy;
 204   static TClonesArray *particles;
 205   //
 206   if(!particles) particles=new TClonesArray("TParticle",1000);
 207   //
 208   Float_t random[6];
 209
 210 // Calculating vertex position per event
 211   for (j=0;j<3;j++) origin0[j]=fOrigin[j];
 212   if(fVertexSmear==perEvent) {
 213       gMC->Rndm(random,6);
 214       for (j=0;j<3;j++) {
 215           origin0[j]+=fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
 216               TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
 217       }
 218   }
 219   Int_t ipa=0;
 220 // Generating fNpart particles
 221   while (ipa<fNpart) {
 222     while(1) {
 223 //
 224 // particle type
 225           Int_t Ipart = fIpParaFunc();
 226           fChildWeight=(fPythia->GetBraPart(Ipart))*fParentWeight;
 227           Float_t am=fPythia->GetPMAS(fPythia->LuComp(Ipart),1);
 228           gMC->Rndm(random,2);
 229 //
 230 // phi
 231           phi=fPhiMin+random[0]*(fPhiMax-fPhiMin);
 232 //
 233 // y
 234           ty=Float_t(TMath::TanH(fYPara->GetRandom()));
 235 //
 236 // pT
 237           if (fAnalog == analog) {
 238               pt=fPtPara->GetRandom();
 239               wgtp=fParentWeight;
 240               wgtch=fChildWeight;
 241           } else {
 242               pt=fPtMin+random[1]*(fPtMax-fPtMin);
 243               Double_t ptd=pt;
 244               wgtp=fParentWeight*fPtParaFunc(& ptd, &dummy);
 245               wgtch=fChildWeight*fPtParaFunc(& ptd, &dummy);
 246           }
 247           xmt=sqrt(pt*pt+am*am);
 248           pl=xmt*ty/sqrt(1.-ty*ty);
 249           theta=TMath::ATan2(pt,pl);
 250           if(theta<fThetaMin || theta>fThetaMax) continue;
 251           ptot=TMath::Sqrt(pt*pt+pl*pl);
 252           if(ptot<fPMin || ptot>fPMax) continue;
 253           p[0]=pt*TMath::Cos(phi);
 254           p[1]=pt*TMath::Sin(phi);
 255           p[2]=pl;
 256           if(fVertexSmear==perTrack) {
 257               gMC->Rndm(random,6);
 258               for (j=0;j<3;j++) {
 259                   origin0[j]=
 260                       fOrigin[j]+fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
 261                       TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
 262               }
 263           }
 264
 265 // Looking at fForceDecay :
 266 //                          if fForceDecay != none Primary particle decays using
 267 //                             AliPythia  and children are tracked by GEANT
 268 //
 269 //                          if fForceDecay == none Primary particle is tracked by GEANT
 270 //                          (In the latest, make sure that GEANT actually does all the decays you want)
 271 //
 272           if (fForceDecay != nodecay) {
 273 // Using lujet to decay particle
 274               Float_t energy=TMath::Sqrt(ptot*ptot+am*am);
 275               fPythia->DecayParticle(Ipart,energy,theta,phi);
 276               //          fPythia->LuList(1);
 277               //printf("origin0 %f %f %f\n",origin0[0],origin0[1],origin0[2]);
 278               //printf("fCutOnChild %d \n",fCutOnChild);
 279 //
 280 // select muons
 281               Int_t np=fPythia->ImportParticles(particles,"All");
 282               //printf("np     %d \n",np);
 283               Int_t ncsel=0;
 284               for (i = 1; i<np; i++) {
 285                   TParticle *  iparticle = (TParticle *) particles->At(i);
 286                   Int_t kf = iparticle->GetPdgCode();
 287 //
 288 // children
 289                   if (ChildSelected(TMath::Abs(kf)))
 290                   {
 291                       pc[0]=iparticle->Px();
 292                       pc[1]=iparticle->Py();
 293                       pc[2]=iparticle->Pz();
 294                       och[0]=origin0[0]+iparticle->Vx()/10;
 295                       och[1]=origin0[1]+iparticle->Vy()/10;
 296                       och[2]=origin0[2]+iparticle->Vz()/10;
 297                       if (fCutOnChild) {
 298                           Float_t PtChild=TMath::Sqrt(pc[0]*pc[0]+pc[1]*pc[1]);
 299                           Float_t PChild=TMath::Sqrt(PtChild*PtChild+pc[2]*pc[2]);
 300                           Float_t ThetaChild=TMath::ATan2(PtChild,pc[2]);
 301                           Float_t PhiChild=TMath::ATan2(pc[1],pc[0])+TMath::Pi();
 302                           Bool_t childok =
 303                               ((PtChild   > fPtMin   && PtChild   <fPtMax)      &&
 304                                (PChild    > fPMin    && PChild    <fPMax)       &&
 305                                (ThetaChild>fThetaMin && ThetaChild<fThetaMax)   &&
 306                                (PhiChild  >  fPhiMin && PhiChild  <fPhiMax));
 307                           if(childok)
 308                           {
 309                               pch[ncsel][0]=pc[0];
 310                               pch[ncsel][1]=pc[1];
 311                               pch[ncsel][2]=pc[2];
 312                               kfch[ncsel]=kf;
 313                               ncsel++;
 314                           } else {
 315                               ncsel=-1;
 316                               break;
 317                           } // child kine cuts
 318                       } else {
 319                           pch[ncsel][0]=pc[0];
 320                           pch[ncsel][1]=pc[1];
 321                           pch[ncsel][2]=pc[2];
 322                           kfch[ncsel]=kf;
 323                           ncsel++;
 324                       } // if child selection
 325                   } // select muon
 326               } // decay particle loop
 327               Int_t iparent;
 328               if ((fCutOnChild && ncsel >0) || !fCutOnChild){
 329                   ipa++;
 330 //
 331 // parent
 332                   gAlice->
 333                       SetTrack(0,-1,Ipart,p,origin0,polar,0,"Primary",nt,wgtp);
 334                   iparent=nt;
 335
 336                   for (i=0; i< ncsel; i++) {
 337                       gAlice->SetTrack(fTrackIt,iparent,kfch[i],
 338                                        &pch[i][0],och,polar,
 339                                        0,"Decay",nt,wgtch);
 340                       gAlice->KeepTrack(nt);
 341                   }
 342               }  // Decays by Lujet
 343           } // kinematic selection
 344           else  // nodecay option, so parent will be tracked by GEANT (pions, kaons, eta, omegas, baryons)
 345           {
 346             gAlice->
 347                 SetTrack(fTrackIt,-1,Ipart,p,origin0,polar,0,"Primary",nt,wgtp);
 348             ipa++;
 349           }
 350           break;
 351     } // while
 352   } // event loop
 353 }
 354
 355 Bool_t AliGenParam::ChildSelected(Int_t ip)
 356 {
 357     for (Int_t i=0; i<5; i++)
 358     {
 359         if (fChildSelect[i]==ip) return kTRUE;
 360     }
 361     return kFALSE;
 362 }
 363
 364 Bool_t AliGenParam::KinematicSelection(TParticle *particle)
 365 {
 366     Float_t px=particle->Px();
 367     Float_t py=particle->Py();
 368     Float_t pz=particle->Pz();
 369 //
 370 // momentum cut
 371     Float_t p=TMath::Sqrt(px*px+py*py+pz*pz);
 372     if (p > fPMax || p < fPMin)
 373     {
 374 //      printf("\n failed p cut %f %f %f \n",p,fPMin,fPMax);
 375         return kFALSE;
 376     }
 377     Float_t pt=TMath::Sqrt(px*px+py*py);
 378
 379 //
 380 // theta cut
 381     Float_t  theta = Float_t(TMath::ATan2(Double_t(pt),Double_t(p)));
 382     if (theta > fThetaMax || theta < fThetaMin)
 383     {
 384 //      printf("\n failed theta cut %f %f %f \n",theta,fThetaMin,fThetaMax);
 385         return kFALSE;
 386     }
 387
 388     return kTRUE;
 389 }
 390
 391
 392
 393