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