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 1.13  1999/11/04 11:30:31  fca
  19 Correct the logics for SetForceDecay
  20
  21 Revision 1.12  1999/11/03 17:43:20  fca
  22 New version from G.Martinez & A.Morsch
  23
  24 Revision 1.11  1999/09/29 09:24:14  fca
  25 Introduction of the Copyright and cvs Log
  26
  27 */
  28
  29 #include "AliGenParam.h"
  30 #include "AliGenMUONlib.h"
  31 #include "AliGenPHOSlib.h"
  32 #include "AliRun.h"
  33 #include "AliPythia.h"
  34 #include <TDirectory.h>
  35 #include <TFile.h>
  36 #include <TTree.h>
  37 #include <stdlib.h>
  38 #include <TParticle.h>
  39
  40 ClassImp(AliGenParam)
  41
  42 //------------------------------------------------------------
  43
  44   //Begin_Html
  45   /*
  46     <img src="picts/AliGenParam.gif">
  47   */
  48   //End_Html
  49
  50 //____________________________________________________________
  51 //____________________________________________________________
  52 AliGenParam::AliGenParam()
  53                  :AliGenerator()
  54 {
  55   fPtPara = 0;
  56   fYPara  = 0;
  57   fParam  = jpsi_p;
  58   fAnalog = analog;
  59   SetCutOnChild();
  60 }
  61
  62 //____________________________________________________________
  63
  64 AliGenParam::AliGenParam(Int_t npart, Param_t param) :AliGenerator(npart)
  65 {
  66   //
  67   //  fName="HMESONpara";
  68   //  fTitle="Heavy Mesons Parametrisation";
  69   fPtParaFunc = AliGenMUONlib::GetPt(param);
  70   fYParaFunc  = AliGenMUONlib::GetY(param);
  71   fIpParaFunc = AliGenMUONlib::GetIp(param);
  72
  73   fPtPara = 0;
  74   fYPara  = 0;
  75   fParam  = param;
  76   fAnalog = analog;
  77   fChildSelect.Set(5);
  78   for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
  79   SetForceDecay();
  80   SetCutOnChild();
  81 }
  82
  83 AliGenParam::AliGenParam(Int_t npart, Param_t param,
  84                          Double_t (*PtPara) (Double_t*, Double_t*),
  85                          Double_t (*YPara ) (Double_t* ,Double_t*),
  86                          Int_t    (*IpPara) ())
  87     :AliGenerator(npart)
  88 {
  89 // Gines Martinez 1/10/99
  90     fPtParaFunc = PtPara;
  91     fYParaFunc  = YPara;
  92     fIpParaFunc = IpPara;
  93 //
  94     fPtPara = 0;
  95     fYPara  = 0;
  96     fParam  = param;
  97     fAnalog = analog;
  98     fChildSelect.Set(5);
  99     for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
 100     SetForceDecay();
 101     SetCutOnChild();
 102 }
 103
 104 //____________________________________________________________
 105 AliGenParam::~AliGenParam()
 106 {
 107     delete  fPtPara;
 108     delete  fYPara;
 109 }
 110
 111 //____________________________________________________________
 112 void AliGenParam::Init()
 113 {
 114     SetMC(new AliPythia());
 115     fPythia= (AliPythia*) fgMCEvGen;
 116
 117 //  End of the test !!!
 118   //Begin_Html
 119   /*
 120     <img src="picts/AliGenParam.gif">
 121   */
 122   //End_Html
 123
 124   fPtPara = new TF1("Pt-Parametrization",fPtParaFunc,fPtMin,fPtMax,0);
 125   fYPara  = new TF1("Y -Parametrization",fYParaFunc,fYMin,fYMax,0);
 126   TF1* PtPara = new TF1("Pt-Parametrization",fPtParaFunc,0,15,0);
 127   TF1* YPara  = new TF1("Y -Parametrization",fYParaFunc,-6,6,0);
 128
 129 //
 130 // dN/dy| y=0
 131   Double_t y1=0;
 132   Double_t y2=0;
 133
 134   fdNdy0=fYParaFunc(&y1,&y2);
 135 //
 136 // Integral over generation region
 137   Float_t IntYS  = YPara ->Integral(fYMin, fYMax);
 138   Float_t IntPt0 = PtPara->Integral(0,15);
 139   Float_t IntPtS = PtPara->Integral(fPtMin,fPtMax);
 140   Float_t PhiWgt=(fPhiMax-fPhiMin)/2./TMath::Pi();
 141   if (fAnalog == analog) {
 142      fYWgt  = IntYS/fdNdy0;
 143      fPtWgt = IntPtS/IntPt0;
 144      fParentWeight = fYWgt*fPtWgt*PhiWgt/fNpart;
 145   } else {
 146       fYWgt = IntYS/fdNdy0;
 147       fPtWgt = (fPtMax-fPtMin)/IntPt0;
 148       fParentWeight = fYWgt*fPtWgt*PhiWgt/fNpart;
 149   }
 150 //
 151 // particle decay related initialization
 152   fPythia->DefineParticles();
 153 // semimuonic decays of charm and beauty
 154   fPythia->ForceDecay(fForceDecay);
 155 //
 156     switch (fForceDecay)
 157     {
 158     case semielectronic:
 159     case dielectron:
 160     case b_jpsi_dielectron:
 161     case b_psip_dielectron:
 162         fChildSelect[0]=11;
 163         break;
 164     case semimuonic:
 165     case dimuon:
 166     case b_jpsi_dimuon:
 167     case b_psip_dimuon:
 168         fChildSelect[0]=13;
 169         break;
 170     case pitomu:
 171         fChildSelect[0]=13;
 172         break;
 173     case katomu:
 174         fChildSelect[0]=13;
 175         break;
 176     case nodecay:
 177         break;
 178     case all:
 179         break;
 180     }
 181 }
 182
 183 //____________________________________________________________
 184 void AliGenParam::Generate()
 185 {
 186 //
 187 // Generate 'npart' of light and heavy mesons (J/Psi, upsilon or phi, Pion,
 188 // Kaons, Etas, Omegas) and Baryons (proton, antiprotons, neutrons and
 189 // antineutrons in the the desired theta, phi and momentum windows;
 190 // Gaussian smearing on the vertex is done if selected.
 191 // The decay of heavy mesons is done using lujet, and the childern particle are tracked by GEANT
 192 // However, light mesons are directly tracked by GEANT setting fForceDecay = nodecay (SetForceDecay(nodecay))
 193 //
 194
 195 // printf("Generate !!!!!!!!!!!!!\n");
 196
 197   Float_t polar[3]= {0,0,0};  // Polarisation of the parent particle (for GEANT tracking)
 198   Float_t origin0[3];         // Origin of the generated parent particle (for GEANT tracking)
 199   Float_t pt, pl, ptot;       // Transverse, logitudinal and total momenta of the parent particle
 200   Float_t phi, theta;         // Phi and theta spherical angles of the parent particle momentum
 201   Float_t p[3], pc[3],
 202           och[3], pch[10][3]; // Momentum, polarisation and origin of the children particles from lujet
 203   Float_t ty, xmt;
 204   Int_t nt, i, j, kfch[10];
 205   Float_t  wgtp, wgtch;
 206   Double_t dummy;
 207   static TClonesArray *particles;
 208   //
 209   if(!particles) particles=new TClonesArray("TParticle",1000);
 210   //
 211   Float_t random[6];
 212
 213 // Calculating vertex position per event
 214   for (j=0;j<3;j++) origin0[j]=fOrigin[j];
 215   if(fVertexSmear==perEvent) {
 216       gMC->Rndm(random,6);
 217       for (j=0;j<3;j++) {
 218           origin0[j]+=fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
 219               TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
 220       }
 221   }
 222   Int_t ipa=0;
 223 // Generating fNpart particles
 224   while (ipa<fNpart) {
 225     while(1) {
 226 //
 227 // particle type
 228           Int_t Ipart = fIpParaFunc();
 229           fChildWeight=(fPythia->GetBraPart(Ipart))*fParentWeight;
 230           Float_t am=fPythia->GetPMAS(fPythia->Lucomp(Ipart),1);
 231           gMC->Rndm(random,2);
 232 //
 233 // phi
 234           phi=fPhiMin+random[0]*(fPhiMax-fPhiMin);
 235 //
 236 // y
 237           ty=Float_t(TMath::TanH(fYPara->GetRandom()));
 238 //
 239 // pT
 240           if (fAnalog == analog) {
 241               pt=fPtPara->GetRandom();
 242               wgtp=fParentWeight;
 243               wgtch=fChildWeight;
 244           } else {
 245               pt=fPtMin+random[1]*(fPtMax-fPtMin);
 246               Double_t ptd=pt;
 247               wgtp=fParentWeight*fPtParaFunc(& ptd, &dummy);
 248               wgtch=fChildWeight*fPtParaFunc(& ptd, &dummy);
 249           }
 250           xmt=sqrt(pt*pt+am*am);
 251           pl=xmt*ty/sqrt(1.-ty*ty);
 252           theta=TMath::ATan2(pt,pl);
 253           if(theta<fThetaMin || theta>fThetaMax) continue;
 254           ptot=TMath::Sqrt(pt*pt+pl*pl);
 255           if(ptot<fPMin || ptot>fPMax) continue;
 256           p[0]=pt*TMath::Cos(phi);
 257           p[1]=pt*TMath::Sin(phi);
 258           p[2]=pl;
 259           if(fVertexSmear==perTrack) {
 260               gMC->Rndm(random,6);
 261               for (j=0;j<3;j++) {
 262                   origin0[j]=
 263                       fOrigin[j]+fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
 264                       TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
 265               }
 266           }
 267
 268 // Looking at fForceDecay :
 269 //                          if fForceDecay != none Primary particle decays using
 270 //                             AliPythia  and children are tracked by GEANT
 271 //
 272 //                          if fForceDecay == none Primary particle is tracked by GEANT
 273 //                          (In the latest, make sure that GEANT actually does all the decays you want)
 274 //
 275           if (fForceDecay != nodecay) {
 276 // Using lujet to decay particle
 277               Float_t energy=TMath::Sqrt(ptot*ptot+am*am);
 278               fPythia->DecayParticle(Ipart,energy,theta,phi);
 279               //          fPythia->LuList(1);
 280               //printf("origin0 %f %f %f\n",origin0[0],origin0[1],origin0[2]);
 281               //printf("fCutOnChild %d \n",fCutOnChild);
 282 //
 283 // select muons
 284               Int_t np=fPythia->ImportParticles(particles,"All");
 285               //printf("np     %d \n",np);
 286               Int_t ncsel=0;
 287               for (i = 1; i<np; i++) {
 288                   TParticle *  iparticle = (TParticle *) particles->At(i);
 289                   Int_t kf = iparticle->GetPdgCode();
 290 //
 291 // children
 292                   if (ChildSelected(TMath::Abs(kf)))
 293                   {
 294                       pc[0]=iparticle->Px();
 295                       pc[1]=iparticle->Py();
 296                       pc[2]=iparticle->Pz();
 297                       och[0]=origin0[0]+iparticle->Vx()/10;
 298                       och[1]=origin0[1]+iparticle->Vy()/10;
 299                       och[2]=origin0[2]+iparticle->Vz()/10;
 300                       if (fCutOnChild) {
 301                           Float_t PtChild=TMath::Sqrt(pc[0]*pc[0]+pc[1]*pc[1]);
 302                           Float_t PChild=TMath::Sqrt(PtChild*PtChild+pc[2]*pc[2]);
 303                           Float_t ThetaChild=TMath::ATan2(PtChild,pc[2]);
 304                           Float_t PhiChild=TMath::ATan2(pc[1],pc[0])+TMath::Pi();
 305                           Bool_t childok =
 306                               ((PtChild   > fPtMin   && PtChild   <fPtMax)      &&
 307                                (PChild    > fPMin    && PChild    <fPMax)       &&
 308                                (ThetaChild>fThetaMin && ThetaChild<fThetaMax)   &&
 309                                (PhiChild  >  fPhiMin && PhiChild  <fPhiMax));
 310                           if(childok)
 311                           {
 312                               pch[ncsel][0]=pc[0];
 313                               pch[ncsel][1]=pc[1];
 314                               pch[ncsel][2]=pc[2];
 315                               kfch[ncsel]=kf;
 316                               ncsel++;
 317                           } else {
 318                               ncsel=-1;
 319                               break;
 320                           } // child kine cuts
 321                       } else {
 322                           pch[ncsel][0]=pc[0];
 323                           pch[ncsel][1]=pc[1];
 324                           pch[ncsel][2]=pc[2];
 325                           kfch[ncsel]=kf;
 326                           ncsel++;
 327                       } // if child selection
 328                   } // select muon
 329               } // decay particle loop
 330               Int_t iparent;
 331               if ((fCutOnChild && ncsel >0) || !fCutOnChild){
 332                   ipa++;
 333 //
 334 // parent
 335                   gAlice->
 336                       SetTrack(0,-1,Ipart,p,origin0,polar,0,"Primary",nt,wgtp);
 337                   iparent=nt;
 338
 339                   for (i=0; i< ncsel; i++) {
 340                       gAlice->SetTrack(fTrackIt,iparent,kfch[i],
 341                                        &pch[i][0],och,polar,
 342                                        0,"Decay",nt,wgtch);
 343                       gAlice->KeepTrack(nt);
 344                   }
 345               }  // Decays by Lujet
 346           } // kinematic selection
 347           else  // nodecay option, so parent will be tracked by GEANT (pions, kaons, eta, omegas, baryons)
 348           {
 349             gAlice->
 350                 SetTrack(fTrackIt,-1,Ipart,p,origin0,polar,0,"Primary",nt,wgtp);
 351             ipa++;
 352           }
 353           break;
 354     } // while
 355   } // event loop
 356 }
 357
 358 Bool_t AliGenParam::ChildSelected(Int_t ip)
 359 {
 360     for (Int_t i=0; i<5; i++)
 361     {
 362         if (fChildSelect[i]==ip) return kTRUE;
 363     }
 364     return kFALSE;
 365 }
 366
 367 Bool_t AliGenParam::KinematicSelection(TParticle *particle)
 368 {
 369     Float_t px=particle->Px();
 370     Float_t py=particle->Py();
 371     Float_t pz=particle->Pz();
 372 //
 373 // momentum cut
 374     Float_t p=TMath::Sqrt(px*px+py*py+pz*pz);
 375     if (p > fPMax || p < fPMin)
 376     {
 377 //      printf("\n failed p cut %f %f %f \n",p,fPMin,fPMax);
 378         return kFALSE;
 379     }
 380     Float_t pt=TMath::Sqrt(px*px+py*py);
 381
 382 //
 383 // theta cut
 384     Float_t  theta = Float_t(TMath::ATan2(Double_t(pt),Double_t(p)));
 385     if (theta > fThetaMax || theta < fThetaMin)
 386     {
 387 //      printf("\n failed theta cut %f %f %f \n",theta,fThetaMin,fThetaMax);
 388         return kFALSE;
 389     }
 390
 391     return kTRUE;
 392 }
 393
 394
 395
 396