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 1.30  2001/06/15 07:55:04  morsch
  19 Put only first generation decay products on the stack.
  20
  21 Revision 1.29  2001/03/27 10:58:41  morsch
  22 Initialize decayer before generation. Important if run inside cocktail.
  23
  24 Revision 1.28  2001/03/09 13:01:41  morsch
  25 - enum constants for paramterisation type (particle family) moved to AliGen*lib.h
  26 - use AliGenGSIlib::kUpsilon, AliGenPHOSlib::kEtaPrime to access the constants
  27
  28 Revision 1.27  2001/02/02 15:21:10  morsch
  29 Set high water mark after last particle.
  30 Use Vertex() method for Vertex.
  31
  32 Revision 1.26  2000/12/21 16:24:06  morsch
  33 Coding convention clean-up
  34
  35 Revision 1.25  2000/11/30 07:12:50  alibrary
  36 Introducing new Rndm and QA classes
  37
  38 Revision 1.24  2000/10/18 19:11:27  hristov
  39 Division by zero fixed
  40
  41 Revision 1.23  2000/10/02 21:28:06  fca
  42 Removal of useless dependecies via forward declarations
  43
  44 Revision 1.22  2000/09/12 14:14:55  morsch
  45 Call fDecayer->ForceDecay() at the beginning of Generate().
  46
  47 Revision 1.21  2000/09/08 15:39:01  morsch
  48 Handle the case fForceDecay=all during the generation, i.e. select all secondaries.
  49
  50 Revision 1.20  2000/09/06 14:35:44  morsch
  51 Use AliDecayerPythia for particle decays.
  52
  53 Revision 1.19  2000/07/11 18:24:56  fca
  54 Coding convention corrections + few minor bug fixes
  55
  56 Revision 1.18  2000/06/29 21:08:27  morsch
  57 All paramatrisation libraries derive from the pure virtual base class AliGenLib.
  58 This allows to pass a pointer to a library directly to AliGenParam and avoids the
  59 use of function pointers in Config.C.
  60
  61 Revision 1.17  2000/06/09 20:33:30  morsch
  62 All coding rule violations except RS3 corrected
  63
  64 Revision 1.16  2000/05/02 07:51:31  morsch
  65 - Control precision of pT sampling TF1::SetNpx(..)
  66 - Correct initialisation of child-cuts in all constructors.
  67 - Most coding rule violations corrected.
  68
  69 Revision 1.15  2000/04/03 15:42:12  morsch
  70 Cuts on primary particles are separated from those on the decay products. Methods
  71 SetChildMomentumRange, SetChildPtRange, SetChildPhiRange, SetChildThetaRange added.
  72
  73 Revision 1.14  1999/11/09 07:38:48  fca
  74 Changes for compatibility with version 2.23 of ROOT
  75
  76 Revision 1.13  1999/11/04 11:30:31  fca
  77 Correct the logics for SetForceDecay
  78
  79 Revision 1.12  1999/11/03 17:43:20  fca
  80 New version from G.Martinez & A.Morsch
  81
  82 Revision 1.11  1999/09/29 09:24:14  fca
  83 Introduction of the Copyright and cvs Log
  84
  85 */
  86
  87 #include "AliGenParam.h"
  88 #include "AliDecayerPythia.h"
  89 #include "AliGenMUONlib.h"
  90 #include "AliRun.h"
  91 #include <TParticle.h>
  92 #include <TParticlePDG.h>
  93 #include <TDatabasePDG.h>
  94 #include <TLorentzVector.h>
  95
  96 #include <TF1.h>
  97
  98 ClassImp(AliGenParam)
  99
 100 //------------------------------------------------------------
 101
 102   //Begin_Html
 103   /*
 104     <img src="picts/AliGenParam.gif">
 105   */
 106   //End_Html
 107
 108 //____________________________________________________________
 109 //____________________________________________________________
 110 AliGenParam::AliGenParam()
 111 {
 112 // Deafault constructor
 113     fPtPara = 0;
 114     fYPara  = 0;
 115     fParam  = 0;
 116     fAnalog = kAnalog;
 117     SetDeltaPt();
 118 //
 119 // Set random number generator
 120     sRandom = fRandom;
 121 }
 122
 123 AliGenParam::AliGenParam(Int_t npart, AliGenLib * Library,  Int_t param, char* tname):AliGenMC(npart)
 124 {
 125 // Constructor using number of particles parameterisation id and library
 126
 127     fPtParaFunc = Library->GetPt(param, tname);
 128     fYParaFunc  = Library->GetY (param, tname);
 129     fIpParaFunc = Library->GetIp(param, tname);
 130
 131     fPtPara = 0;
 132     fYPara  = 0;
 133     fParam  = param;
 134     fAnalog = kAnalog;
 135     SetForceDecay();
 136     SetDeltaPt();
 137 //
 138 // Set random number generator
 139     sRandom = fRandom;
 140 }
 141
 142 //____________________________________________________________
 143
 144 AliGenParam::AliGenParam(Int_t npart, Int_t param, char* tname):AliGenMC(npart)
 145 {
 146 // Constructor using parameterisation id and number of particles
 147 //
 148     AliGenLib* pLibrary = new AliGenMUONlib();
 149
 150     fPtParaFunc = pLibrary->GetPt(param, tname);
 151     fYParaFunc  = pLibrary->GetY (param, tname);
 152     fIpParaFunc = pLibrary->GetIp(param, tname);
 153
 154     fPtPara = 0;
 155     fYPara  = 0;
 156     fParam  = param;
 157     fAnalog = kAnalog;
 158     fChildSelect.Set(5);
 159     for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
 160     SetForceDecay();
 161     SetCutOnChild();
 162     SetChildMomentumRange();
 163     SetChildPtRange();
 164     SetChildPhiRange();
 165     SetChildThetaRange();
 166     SetDeltaPt();
 167 }
 168
 169 AliGenParam::AliGenParam(Int_t npart, Int_t param,
 170                          Double_t (*PtPara) (Double_t*, Double_t*),
 171                          Double_t (*YPara ) (Double_t* ,Double_t*),
 172                          Int_t    (*IpPara) (TRandom *))
 173     :AliGenMC(npart)
 174 {
 175 // Constructor
 176 // Gines Martinez 1/10/99
 177     fPtParaFunc = PtPara;
 178     fYParaFunc  = YPara;
 179     fIpParaFunc = IpPara;
 180 //
 181     fPtPara = 0;
 182     fYPara  = 0;
 183     fParam  = param;
 184     fAnalog = kAnalog;
 185     fChildSelect.Set(5);
 186     for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
 187     SetForceDecay();
 188     SetCutOnChild();
 189     SetChildMomentumRange();
 190     SetChildPtRange();
 191     SetChildPhiRange();
 192     SetChildThetaRange();
 193     SetDeltaPt();
 194 }
 195
 196
 197 AliGenParam::AliGenParam(const AliGenParam & Paramd)
 198 {
 199 // copy constructor
 200 }
 201
 202 //____________________________________________________________
 203 AliGenParam::~AliGenParam()
 204 {
 205 // Destructor
 206     delete  fPtPara;
 207     delete  fYPara;
 208 }
 209
 210 //____________________________________________________________
 211 void AliGenParam::Init()
 212 {
 213 // Initialisation
 214
 215     fDecayer = new AliDecayerPythia();
 216   //Begin_Html
 217   /*
 218     <img src="picts/AliGenParam.gif">
 219   */
 220   //End_Html
 221
 222     fPtPara = new TF1("Pt-Parametrization",fPtParaFunc,fPtMin,fPtMax,0);
 223 //  Set representation precision to 10 MeV
 224     Int_t npx= Int_t((fPtMax-fPtMin)/fDeltaPt);
 225
 226     fPtPara->SetNpx(npx);
 227
 228     fYPara  = new TF1("Y -Parametrization",fYParaFunc,fYMin,fYMax,0);
 229     TF1* ptPara = new TF1("Pt-Parametrization",fPtParaFunc,0,15,0);
 230     TF1* yPara  = new TF1("Y -Parametrization",fYParaFunc,-6,6,0);
 231
 232 //
 233 // dN/dy| y=0
 234     Double_t y1=0;
 235     Double_t y2=0;
 236
 237     fdNdy0=fYParaFunc(&y1,&y2);
 238 //
 239 // Integral over generation region
 240     Float_t intYS  = yPara ->Integral(fYMin, fYMax);
 241     Float_t intPt0 = ptPara->Integral(0,15);
 242     Float_t intPtS = ptPara->Integral(fPtMin,fPtMax);
 243     Float_t phiWgt=(fPhiMax-fPhiMin)/2./TMath::Pi();
 244     if (fAnalog == kAnalog) {
 245         fYWgt  = intYS/fdNdy0;
 246         fPtWgt = intPtS/intPt0;
 247         fParentWeight = fYWgt*fPtWgt*phiWgt/fNpart;
 248     } else {
 249         fYWgt = intYS/fdNdy0;
 250         fPtWgt = (fPtMax-fPtMin)/intPt0;
 251         fParentWeight = fYWgt*fPtWgt*phiWgt/fNpart;
 252     }
 253 //
 254 // particle decay related initialization
 255     fDecayer->SetForceDecay(fForceDecay);
 256     fDecayer->Init();
 257
 258 //
 259     AliGenMC::Init();
 260 }
 261
 262 //____________________________________________________________
 263 void AliGenParam::Generate()
 264 {
 265 //
 266 // Generate 'npart' of light and heavy mesons (J/Psi, upsilon or phi, Pion,
 267 // Kaons, Etas, Omegas) and Baryons (proton, antiprotons, neutrons and
 268 // antineutrons in the the desired theta, phi and momentum windows;
 269 // Gaussian smearing on the vertex is done if selected.
 270 // The decay of heavy mesons is done using lujet,
 271 //    and the childern particle are tracked by GEANT
 272 // However, light mesons are directly tracked by GEANT
 273 // setting fForceDecay = nodecay (SetForceDecay(nodecay))
 274 //
 275 //
 276 //  Reinitialize decayer
 277     fDecayer->Init();
 278 //
 279   Float_t polar[3]= {0,0,0};  // Polarisation of the parent particle (for GEANT tracking)
 280   Float_t origin0[3];         // Origin of the generated parent particle (for GEANT tracking)
 281   Float_t pt, pl, ptot;       // Transverse, logitudinal and total momenta of the parent particle
 282   Float_t phi, theta;         // Phi and theta spherical angles of the parent particle momentum
 283   Float_t p[3], pc[3],
 284           och[3];             // Momentum, polarisation and origin of the children particles from lujet
 285   Float_t ty, xmt;
 286   Int_t nt, i, j;
 287   Float_t  wgtp, wgtch;
 288   Double_t dummy;
 289   static TClonesArray *particles;
 290   //
 291   if(!particles) particles = new TClonesArray("TParticle",1000);
 292
 293   static TDatabasePDG *pDataBase = new TDatabasePDG();
 294   if(!pDataBase) pDataBase = new TDatabasePDG();
 295   //
 296   Float_t random[6];
 297
 298 // Calculating vertex position per event
 299   for (j=0;j<3;j++) origin0[j]=fOrigin[j];
 300   if(fVertexSmear==kPerEvent) {
 301       Vertex();
 302       for (j=0;j<3;j++) origin0[j]=fVertex[j];
 303   }
 304
 305   Int_t ipa=0;
 306
 307 // Generating fNpart particles
 308   while (ipa<fNpart) {
 309       while(1) {
 310 //
 311 // particle type
 312           Int_t iPart = fIpParaFunc(fRandom);
 313           fChildWeight=(fDecayer->GetPartialBranchingRatio(iPart))*fParentWeight;
 314           TParticlePDG *particle = pDataBase->GetParticle(iPart);
 315           Float_t am = particle->Mass();
 316
 317           Rndm(random,2);
 318 //
 319 // phi
 320           phi=fPhiMin+random[0]*(fPhiMax-fPhiMin);
 321 //
 322 // y
 323           ty=Float_t(TMath::TanH(fYPara->GetRandom()));
 324 //
 325 // pT
 326           if (fAnalog == kAnalog) {
 327               pt=fPtPara->GetRandom();
 328               wgtp=fParentWeight;
 329               wgtch=fChildWeight;
 330           } else {
 331               pt=fPtMin+random[1]*(fPtMax-fPtMin);
 332               Double_t ptd=pt;
 333               wgtp=fParentWeight*fPtParaFunc(& ptd, &dummy);
 334               wgtch=fChildWeight*fPtParaFunc(& ptd, &dummy);
 335           }
 336           xmt=sqrt(pt*pt+am*am);
 337       if (TMath::Abs(ty)==1) ty=0;
 338           pl=xmt*ty/sqrt(1.-ty*ty);
 339           theta=TMath::ATan2(pt,pl);
 340 // Cut on theta
 341           if(theta<fThetaMin || theta>fThetaMax) continue;
 342           ptot=TMath::Sqrt(pt*pt+pl*pl);
 343 // Cut on momentum
 344           if(ptot<fPMin || ptot>fPMax) continue;
 345 //
 346           p[0]=pt*TMath::Cos(phi);
 347           p[1]=pt*TMath::Sin(phi);
 348           p[2]=pl;
 349           if(fVertexSmear==kPerTrack) {
 350               Rndm(random,6);
 351               for (j=0;j<3;j++) {
 352                   origin0[j]=
 353                       fOrigin[j]+fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
 354                       TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
 355               }
 356           }
 357
 358 // Looking at fForceDecay :
 359 // if fForceDecay != none Primary particle decays using
 360 // AliPythia and children are tracked by GEANT
 361 //
 362 // if fForceDecay == none Primary particle is tracked by GEANT
 363 // (In the latest, make sure that GEANT actually does all the decays you want)
 364 //
 365
 366           if (fForceDecay != kNoDecay) {
 367 // Using lujet to decay particle
 368               Float_t energy=TMath::Sqrt(ptot*ptot+am*am);
 369               TLorentzVector pmom(p[0], p[1], p[2], energy);
 370               fDecayer->Decay(iPart,&pmom);
 371 //
 372 // select decay particles
 373               Int_t np=fDecayer->ImportParticles(particles);
 374               Int_t ncsel=0;
 375               Int_t* pFlag      = new Int_t[np];
 376               Int_t* pParent    = new Int_t[np];
 377               Int_t* pSelected  = new Int_t[np];
 378               Int_t* trackIt    = new Int_t[np];
 379
 380               for (i=0; i<np; i++) {
 381                   pFlag[i]     =  0;
 382                   pSelected[i] =  0;
 383                   pParent[i]   = -1;
 384               }
 385
 386               if (np >1) {
 387                   TParticle* iparticle =  (TParticle *) particles->At(0);
 388                   Int_t ipF, ipL;
 389                   for (i = 1; i<np ; i++) {
 390                       trackIt[i] = 1;
 391                       iparticle = (TParticle *) particles->At(i);
 392                       Int_t kf = iparticle->GetPdgCode();
 393                       Int_t ks = iparticle->GetStatusCode();
 394 // flagged particle
 395
 396                       if (pFlag[i] == 1) {
 397                           printf("\n deselected %d", i);
 398                           ipF = iparticle->GetFirstDaughter();
 399                           ipL = iparticle->GetLastDaughter();
 400                           if (ipF > 0) for (j=ipF-1; j<ipL; j++) pFlag[j]=1;
 401                           continue;
 402                       }
 403
 404 // flag decay products of particles with long life-time (c tau > .3 mum)
 405
 406                       if (ks != 1) {
 407                           TParticlePDG *particle = pDataBase->GetParticle(kf);
 408
 409                           Double_t lifeTime = fDecayer->GetLifetime(kf);
 410                           Double_t mass     = particle->Mass();
 411                           Double_t width    = particle->Width();
 412                           printf("\n lifetime %d %e %e %e ", i, lifeTime, mass, width);
 413                           if (lifeTime > (Double_t) 1.e-15) {
 414                               ipF = iparticle->GetFirstDaughter();
 415                               ipL = iparticle->GetLastDaughter();
 416                               if (ipF > 0) for (j=ipF-1; j<ipL; j++) pFlag[j]=1;
 417                           } else{
 418                               trackIt[i]     = 0;
 419                               pSelected[i]   = 1;
 420                           }
 421                       } // ks==1 ?
 422 //
 423 // children
 424                       if (ChildSelected(TMath::Abs(kf)) || fForceDecay == kAll && trackIt[i])
 425                       {
 426                           if (fCutOnChild) {
 427                               pc[0]=iparticle->Px();
 428                               pc[1]=iparticle->Py();
 429                               pc[2]=iparticle->Pz();
 430                               Bool_t  childok = KinematicSelection(iparticle, 1);
 431                               if(childok) {
 432                                   pSelected[i]  = 1;
 433                                   ncsel++;
 434                               } else {
 435                                   ncsel=-1;
 436                                   break;
 437                               } // child kine cuts
 438                           } else {
 439                               pSelected[i]  = 1;
 440                               ncsel++;
 441                           } // if child selection
 442                       } // select muon
 443                   } // decay particle loop
 444               } // if decay products
 445
 446               Int_t iparent;
 447               if ((fCutOnChild && ncsel >0) || !fCutOnChild){
 448                   ipa++;
 449 //
 450 // Parent
 451                   gAlice->SetTrack(0, -1, iPart, p, origin0, polar, 0, kPPrimary, nt, wgtp);
 452                   pParent[0] = nt;
 453                   gAlice->KeepTrack(nt);
 454 //
 455 // Decay Products
 456 //
 457                   for (i = 1; i < np; i++) {
 458                       if (pSelected[i]) {
 459                           TParticle* iparticle = (TParticle *) particles->At(i);
 460                           Int_t kf  = iparticle->GetPdgCode();
 461                           Int_t ipa = iparticle->GetFirstMother()-1;
 462
 463                           och[0] = origin0[0]+iparticle->Vx()/10;
 464                           och[1] = origin0[1]+iparticle->Vy()/10;
 465                           och[2] = origin0[2]+iparticle->Vz()/10;
 466                           pc[0]  = iparticle->Px();
 467                           pc[1]  = iparticle->Py();
 468                           pc[2]  = iparticle->Pz();
 469
 470                           if (ipa > -1) {
 471                               iparent = pParent[ipa];
 472                           } else {
 473                               iparent = -1;
 474                           }
 475                           printf("\n SetTrack %d %d %d %d", i, kf, iparent, trackIt[i]);
 476                           gAlice->SetTrack(fTrackIt*trackIt[i], iparent, kf,
 477                                            pc, och, polar,
 478                                            0, kPDecay, nt, wgtch);
 479                           pParent[i] = nt;
 480                           gAlice->KeepTrack(nt);
 481                       }
 482                   }
 483               }  // Decays by Lujet
 484
 485               if (pFlag)      delete[] pFlag;
 486               if (pParent)    delete[] pParent;
 487               if (pSelected)  delete[] pSelected;
 488               if (trackIt)    delete[] trackIt;
 489           } // kinematic selection
 490           else  // nodecay option, so parent will be tracked by GEANT (pions, kaons, eta, omegas, baryons)
 491           {
 492             gAlice->
 493                 SetTrack(fTrackIt,-1,iPart,p,origin0,polar,0,kPPrimary,nt,wgtp);
 494             ipa++;
 495           }
 496           break;
 497     } // while
 498   } // event loop
 499   gAlice->SetHighWaterMark(nt);
 500 }
 501
 502 AliGenParam& AliGenParam::operator=(const  AliGenParam& rhs)
 503 {
 504 // Assignment operator
 505     return *this;
 506 }
 507
 508
 509