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- Correct conversion from mm to cm when passing particle vertex to MC.
[u/mrichter/AliRoot.git] / EVGEN / AliGenPythia.cxx
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4c039060 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$Log$
4451ef92 18Revision 1.21 2000/09/12 14:14:55 morsch
19Call fDecayer->ForceDecay() at the beginning of Generate().
20
00d6ce7d 21Revision 1.20 2000/09/06 14:29:33 morsch
22Use AliPythia for event generation an AliDecayPythia for decays.
23Correct handling of "nodecay" option
24
18edb254 25Revision 1.19 2000/07/11 18:24:56 fca
26Coding convention corrections + few minor bug fixes
27
aee8290b 28Revision 1.18 2000/06/30 12:40:34 morsch
29Pythia takes care of vertex smearing. Correct conversion from Pythia units (mm) to
30Geant units (cm).
31
1512e357 32Revision 1.17 2000/06/09 20:34:07 morsch
33All coding rule violations except RS3 corrected
34
f87cfe57 35Revision 1.16 2000/05/15 15:04:20 morsch
36The full event is written for fNtrack = -1
37Coding rule violations corrected.
38
5ddeb374 39Revision 1.15 2000/04/26 10:14:24 morsch
40Particles array has one entry more than pythia particle list. Upper bound of
41particle loop changed to np-1 (R. Guernane, AM)
42
2a0e6f5b 43Revision 1.14 2000/04/05 08:36:13 morsch
44Check status code of particles in Pythia event
45to avoid double counting as partonic state and final state particle.
46
23211d3e 47Revision 1.13 1999/11/09 07:38:48 fca
48Changes for compatibility with version 2.23 of ROOT
49
084c1b4a 50Revision 1.12 1999/11/03 17:43:20 fca
51New version from G.Martinez & A.Morsch
52
886b6f73 53Revision 1.11 1999/09/29 09:24:14 fca
54Introduction of the Copyright and cvs Log
4c039060 55*/
56
fe4da5cc 57#include "AliGenPythia.h"
18edb254 58#include "AliDecayerPythia.h"
fe4da5cc 59#include "AliRun.h"
60#include "AliPythia.h"
18edb254 61#include "AliPDG.h"
1578254f 62#include <TParticle.h>
18edb254 63#include <TSystem.h>
f87cfe57 64
fe4da5cc 65 ClassImp(AliGenPythia)
66
67AliGenPythia::AliGenPythia()
68 :AliGenerator()
69{
18edb254 70// Default Constructor
71 fDecayer = new AliDecayerPythia();
fe4da5cc 72}
73
74AliGenPythia::AliGenPythia(Int_t npart)
75 :AliGenerator(npart)
76{
77// default charm production at 5. 5 TeV
78// semimuonic decay
79// structure function GRVHO
80//
81 fXsection = 0.;
82 fParentSelect.Set(5);
83 fChildSelect.Set(5);
84 for (Int_t i=0; i<5; i++) fParentSelect[i]=fChildSelect[i]=0;
85 SetProcess();
86 SetStrucFunc();
886b6f73 87 SetForceDecay();
fe4da5cc 88 SetPtHard();
89 SetEnergyCMS();
18edb254 90 fDecayer = new AliDecayerPythia();
fe4da5cc 91}
92
f87cfe57 93AliGenPythia::AliGenPythia(const AliGenPythia & Pythia)
94{
95// copy constructor
96}
97
fe4da5cc 98AliGenPythia::~AliGenPythia()
99{
5ddeb374 100// Destructor
fe4da5cc 101}
102
103void AliGenPythia::Init()
104{
5ddeb374 105// Initialisation
18edb254 106 SetMC(AliPythia::Instance());
fe4da5cc 107 fPythia=(AliPythia*) fgMCEvGen;
108//
109 fParentWeight=1./Float_t(fNpart);
110//
111// Forward Paramters to the AliPythia object
18edb254 112 // gSystem->Exec("ln -s $ALICE_ROOT/data/Decay.table fort.1");
113 // fPythia->Pyupda(2,1);
114 // gSystem->Exec("rm fort.1");
00d6ce7d 115
116 fDecayer->SetForceDecay(fForceDecay);
18edb254 117 fDecayer->Init();
00d6ce7d 118
18edb254 119
fe4da5cc 120 fPythia->SetCKIN(3,fPtHardMin);
121 fPythia->SetCKIN(4,fPtHardMax);
122 fPythia->ProcInit(fProcess,fEnergyCMS,fStrucFunc);
18edb254 123
124 // fPythia->Pylist(0);
125 // fPythia->Pystat(2);
fe4da5cc 126// Parent and Children Selection
127 switch (fProcess)
128 {
129 case charm:
130
131 fParentSelect[0]=411;
132 fParentSelect[1]=421;
133 fParentSelect[2]=431;
134 fParentSelect[3]=4122;
135 break;
136 case charm_unforced:
137
138 fParentSelect[0]=411;
139 fParentSelect[1]=421;
140 fParentSelect[2]=431;
141 fParentSelect[3]=4122;
142 break;
143 case beauty:
144 fParentSelect[0]=511;
145 fParentSelect[1]=521;
146 fParentSelect[2]=531;
147 fParentSelect[3]=5122;
148 break;
149 case beauty_unforced:
150 fParentSelect[0]=511;
151 fParentSelect[1]=521;
152 fParentSelect[2]=531;
153 fParentSelect[3]=5122;
154 break;
155 case jpsi_chi:
156 case jpsi:
157 fParentSelect[0]=443;
158 break;
5be1fe76 159 case mb:
160 break;
fe4da5cc 161 }
162
163 switch (fForceDecay)
164 {
165 case semielectronic:
166 case dielectron:
167 case b_jpsi_dielectron:
168 case b_psip_dielectron:
18edb254 169 fChildSelect[0]=kElectron;
fe4da5cc 170 break;
171 case semimuonic:
172 case dimuon:
173 case b_jpsi_dimuon:
174 case b_psip_dimuon:
5be1fe76 175 case pitomu:
176 case katomu:
18edb254 177 fChildSelect[0]=kMuonMinus;
fe4da5cc 178 break;
18edb254 179 case hadronicD:
180 fChildSelect[0]=kPiPlus;
181 fChildSelect[1]=kKPlus;
182 break;
886b6f73 183 case all:
184 case nodecay:
18edb254 185 break;
fe4da5cc 186 }
187}
188
189void AliGenPythia::Generate()
190{
5ddeb374 191// Generate one event
00d6ce7d 192 fDecayer->ForceDecay();
fe4da5cc 193
5be1fe76 194 Float_t polar[3] = {0,0,0};
195 Float_t origin[3]= {0,0,0};
5ddeb374 196 Float_t originP[3]= {0,0,0};
5be1fe76 197 Float_t origin0[3]= {0,0,0};
1512e357 198 Float_t p[3], pP[4];
199// Float_t random[6];
09fd3ea2 200 static TClonesArray *particles;
5be1fe76 201// converts from mm/c to s
202 const Float_t kconv=0.001/2.999792458e8;
fe4da5cc 203
204
205//
fe4da5cc 206 Int_t nt=0;
5ddeb374 207 Int_t ntP=0;
fe4da5cc 208 Int_t jev=0;
7921755b 209 Int_t j, kf;
09fd3ea2 210
211 if(!particles) particles=new TClonesArray("TParticle",1000);
fe4da5cc 212
213 fTrials=0;
214 for (j=0;j<3;j++) origin0[j]=fOrigin[j];
aee8290b 215 if(fVertexSmear==kPerEvent) {
1512e357 216 fPythia->SetMSTP(151,1);
fe4da5cc 217 for (j=0;j<3;j++) {
1512e357 218 fPythia->SetPARP(151+j, fOsigma[j]/10.);
fe4da5cc 219 }
aee8290b 220 } else if (fVertexSmear==kPerTrack) {
fe4da5cc 221 fPythia->SetMSTP(151,0);
fe4da5cc 222 }
1512e357 223
fe4da5cc 224 while(1)
225 {
084c1b4a 226 fPythia->Pyevnt();
18edb254 227// fPythia->Pylist(1);
fe4da5cc 228 fTrials++;
f1092809 229 fPythia->ImportParticles(particles,"All");
fe4da5cc 230 Int_t np = particles->GetEntriesFast();
231 printf("\n **************************************************%d\n",np);
232 Int_t nc=0;
233 if (np == 0 ) continue;
5be1fe76 234 if (fProcess != mb) {
2a0e6f5b 235 for (Int_t i = 0; i<np-1; i++) {
1578254f 236 TParticle * iparticle = (TParticle *) particles->At(i);
23211d3e 237 Int_t ks = iparticle->GetStatusCode();
a8228d85 238 kf = CheckPDGCode(iparticle->GetPdgCode());
2a0e6f5b 239 if (ks==21) continue;
240
18edb254 241 fChildWeight=(fDecayer->GetPartialBranchingRatio(kf))*fParentWeight;
fe4da5cc 242//
243// Parent
5be1fe76 244 if (ParentSelected(TMath::Abs(kf))) {
245 if (KinematicSelection(iparticle)) {
246 if (nc==0) {
247//
248// Store information concerning the hard scattering process
249//
5ddeb374 250 Float_t massP = fPythia->GetPARI(13);
251 Float_t ptP = fPythia->GetPARI(17);
252 Float_t yP = fPythia->GetPARI(37);
253 Float_t xmtP = sqrt(ptP*ptP+massP*massP);
254 Float_t ty = Float_t(TMath::TanH(yP));
255 pP[0] = ptP;
256 pP[1] = 0;
257 pP[2] = xmtP*ty/sqrt(1.-ty*ty);
258 pP[3] = massP;
5be1fe76 259 gAlice->SetTrack(0,-1,-1,
5ddeb374 260 pP,originP,polar,
261 0,"Hard Scat.",ntP,fParentWeight);
262 gAlice->KeepTrack(ntP);
5be1fe76 263 }
264 nc++;
fe4da5cc 265//
266// store parent track information
1578254f 267 p[0]=iparticle->Px();
268 p[1]=iparticle->Py();
269 p[2]=iparticle->Pz();
1512e357 270 origin[0]=origin0[0]+iparticle->Vx()*10.;
271 origin[1]=origin0[1]+iparticle->Vy()*10.;
272 origin[2]=origin0[2]+iparticle->Vz()*10.;
fe4da5cc 273
1578254f 274 Int_t ifch=iparticle->GetFirstDaughter();
275 Int_t ilch=iparticle->GetLastDaughter();
18edb254 276
277 if ((ifch !=0 && ilch !=0) || fForceDecay == nodecay) {
278 Int_t trackit=0;
279 if (fForceDecay == nodecay) trackit = 1;
280 gAlice->SetTrack(trackit,ntP,kf,
5be1fe76 281 p,origin,polar,
282 0,"Primary",nt,fParentWeight);
283 gAlice->KeepTrack(nt);
284 Int_t iparent = nt;
fe4da5cc 285//
286// Children
18edb254 287 if (fForceDecay != nodecay) {
288 for (j=ifch; j<=ilch; j++)
289 {
290 TParticle * ichild =
1578254f 291 (TParticle *) particles->At(j-1);
18edb254 292 kf = CheckPDGCode(ichild->GetPdgCode());
fe4da5cc 293//
294//
18edb254 295 if (ChildSelected(TMath::Abs(kf))) {
4451ef92 296 origin[0]=origin0[0]+ichild->Vx()/10.;
297 origin[1]=origin0[1]+ichild->Vy()/10.;
298 origin[2]=origin0[2]+ichild->Vz()/10.;
1578254f 299 p[0]=ichild->Px();
300 p[1]=ichild->Py();
301 p[2]=ichild->Pz();
302 Float_t tof=kconv*ichild->T();
303 gAlice->SetTrack(fTrackIt, iparent, kf,
5be1fe76 304 p,origin,polar,
305 tof,"Decay",nt,fChildWeight);
306 gAlice->KeepTrack(nt);
18edb254 307 } // select child
308 } // child loop
309 }
5be1fe76 310 }
311 } // kinematic selection
312 } // select particle
313 } // particle loop
314 } else {
2a0e6f5b 315 for (Int_t i = 0; i<np-1; i++) {
1578254f 316 TParticle * iparticle = (TParticle *) particles->At(i);
a8228d85 317 kf = CheckPDGCode(iparticle->GetPdgCode());
1578254f 318 Int_t ks = iparticle->GetStatusCode();
2a0e6f5b 319
1578254f 320 if (ks==1 && kf!=0 && KinematicSelection(iparticle)) {
5be1fe76 321 nc++;
322//
323// store track information
1578254f 324 p[0]=iparticle->Px();
325 p[1]=iparticle->Py();
326 p[2]=iparticle->Pz();
4451ef92 327 origin[0]=origin0[0]+iparticle->Vx()/10.;
328 origin[1]=origin0[1]+iparticle->Vy()/10.;
329 origin[2]=origin0[2]+iparticle->Vz()/10.;
1578254f 330 Float_t tof=kconv*iparticle->T();
331 gAlice->SetTrack(fTrackIt,-1,kf,p,origin,polar,
5be1fe76 332 tof,"Primary",nt);
333 gAlice->KeepTrack(nt);
334 } // select particle
335 } // particle loop
336 printf("\n I've put %i particles on the stack \n",nc);
337 } // mb ?
fe4da5cc 338 if (nc > 0) {
5be1fe76 339 jev+=nc;
5ddeb374 340 if (jev >= fNpart || fNpart == -1) {
fe4da5cc 341 fKineBias=Float_t(fNpart)/Float_t(fTrials);
23211d3e 342 printf("\n Trials: %i %i %i\n",fTrials, fNpart, jev);
fe4da5cc 343 break;
344 }
345 }
346 } // event loop
347// adjust weight due to kinematic selection
348 AdjustWeights();
349// get cross-section
350 fXsection=fPythia->GetPARI(1);
351}
352
353Bool_t AliGenPythia::ParentSelected(Int_t ip)
354{
5ddeb374 355// True if particle is in list of parent particles to be selected
fe4da5cc 356 for (Int_t i=0; i<5; i++)
357 {
358 if (fParentSelect[i]==ip) return kTRUE;
359 }
360 return kFALSE;
361}
362
363Bool_t AliGenPythia::ChildSelected(Int_t ip)
364{
5ddeb374 365// True if particle is in list of decay products to be selected
4451ef92 366 if (fForceDecay == all) return kTRUE;
367
fe4da5cc 368 for (Int_t i=0; i<5; i++)
369 {
370 if (fChildSelect[i]==ip) return kTRUE;
371 }
372 return kFALSE;
373}
374
1578254f 375Bool_t AliGenPythia::KinematicSelection(TParticle *particle)
fe4da5cc 376{
5ddeb374 377// Perform kinematic selection
1578254f 378 Float_t px=particle->Px();
379 Float_t py=particle->Py();
380 Float_t pz=particle->Pz();
381 Float_t e=particle->Energy();
fe4da5cc 382
383//
384// transverse momentum cut
385 Float_t pt=TMath::Sqrt(px*px+py*py);
386 if (pt > fPtMax || pt < fPtMin)
387 {
388// printf("\n failed pt cut %f %f %f \n",pt,fPtMin,fPtMax);
389 return kFALSE;
390 }
391//
392// momentum cut
393 Float_t p=TMath::Sqrt(px*px+py*py+pz*pz);
394 if (p > fPMax || p < fPMin)
395 {
396// printf("\n failed p cut %f %f %f \n",p,fPMin,fPMax);
397 return kFALSE;
398 }
399
400//
401// theta cut
5be1fe76 402 Float_t theta = Float_t(TMath::ATan2(Double_t(pt),Double_t(pz)));
fe4da5cc 403 if (theta > fThetaMax || theta < fThetaMin)
404 {
405// printf("\n failed theta cut %f %f %f \n",theta,fThetaMin,fThetaMax);
406 return kFALSE;
407 }
408
409//
410// rapidity cut
411 Float_t y = 0.5*TMath::Log((e+pz)/(e-pz));
412 if (y > fYMax || y < fYMin)
413 {
414// printf("\n failed y cut %f %f %f \n",y,fYMin,fYMax);
415 return kFALSE;
416 }
417
418//
419// phi cut
f87cfe57 420 Float_t phi=Float_t(TMath::ATan2(Double_t(py),Double_t(px)));
fe4da5cc 421 if (phi > fPhiMax || phi < fPhiMin)
422 {
423// printf("\n failed phi cut %f %f %f \n",phi,fPhiMin,fPhiMax);
424 return kFALSE;
425 }
426
427 return kTRUE;
428}
429void AliGenPythia::AdjustWeights()
430{
5ddeb374 431// Adjust the weights after generation of all events
432//
433 TClonesArray *partArray = gAlice->Particles();
434 TParticle *part;
fe4da5cc 435 Int_t ntrack=gAlice->GetNtrack();
436 for (Int_t i=0; i<ntrack; i++) {
5ddeb374 437 part= (TParticle*) partArray->UncheckedAt(i);
438 part->SetWeight(part->GetWeight()*fKineBias);
fe4da5cc 439 }
440}
441
a8228d85 442Int_t AliGenPythia::CheckPDGCode(Int_t pdgcode)
443{
444//
23211d3e 445// If the particle is in a diffractive state, then take action accordingly
a8228d85 446 switch (pdgcode) {
18edb254 447 case 91:
448 return 92;
a8228d85 449 case 110:
450 //rho_diff0 -- difficult to translate, return rho0
451 return 113;
452 case 210:
453 //pi_diffr+ -- change to pi+
454 return 211;
455 case 220:
456 //omega_di0 -- change to omega0
457 return 223;
458 case 330:
459 //phi_diff0 -- return phi0
460 return 333;
461 case 440:
462 //J/psi_di0 -- return J/psi
463 return 443;
464 case 2110:
465 //n_diffr -- return neutron
466 return 2112;
467 case 2210:
468 //p_diffr+ -- return proton
469 return 2212;
470 }
471 //non diffractive state -- return code unchanged
472 return pdgcode;
473}
474
f87cfe57 475AliGenPythia& AliGenPythia::operator=(const AliGenPythia& rhs)
476{
477// Assignment operator
478 return *this;
479}
fe4da5cc 480
481
18edb254 482void AliGenPythia::Streamer(TBuffer &R__b)
483{
484 // Stream an object of class AliGenPythia.
485
486 if (R__b.IsReading()) {
487 Version_t R__v = R__b.ReadVersion(); if (R__v) { }
488 AliGenerator::Streamer(R__b);
489 R__b >> (Int_t&)fProcess;
490 R__b >> (Int_t&)fStrucFunc;
491 R__b >> (Int_t&)fForceDecay;
492 R__b >> fEnergyCMS;
493 R__b >> fKineBias;
494 R__b >> fTrials;
495 fParentSelect.Streamer(R__b);
496 fChildSelect.Streamer(R__b);
497 R__b >> fXsection;
498// (AliPythia::Instance())->Streamer(R__b);
499 R__b >> fPtHardMin;
500 R__b >> fPtHardMax;
501// if (fDecayer) fDecayer->Streamer(R__b);
502 } else {
503 R__b.WriteVersion(AliGenPythia::IsA());
504 AliGenerator::Streamer(R__b);
505 R__b << (Int_t)fProcess;
506 R__b << (Int_t)fStrucFunc;
507 R__b << (Int_t)fForceDecay;
508 R__b << fEnergyCMS;
509 R__b << fKineBias;
510 R__b << fTrials;
511 fParentSelect.Streamer(R__b);
512 fChildSelect.Streamer(R__b);
513 R__b << fXsection;
514// R__b << fPythia;
515 R__b << fPtHardMin;
516 R__b << fPtHardMax;
517 // fDecayer->Streamer(R__b);
518 }
519}
520
521
522
fe4da5cc 523
5be1fe76 524
525
526
527