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[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$Log$
819f84ad 18Revision 1.22 2000/09/14 14:02:22 morsch
19- Correct conversion from mm to cm when passing particle vertex to MC.
20- Correct handling of fForceDecay == all.
21
4451ef92 22Revision 1.21 2000/09/12 14:14:55 morsch
23Call fDecayer->ForceDecay() at the beginning of Generate().
24
00d6ce7d 25Revision 1.20 2000/09/06 14:29:33 morsch
26Use AliPythia for event generation an AliDecayPythia for decays.
27Correct handling of "nodecay" option
28
18edb254 29Revision 1.19 2000/07/11 18:24:56 fca
30Coding convention corrections + few minor bug fixes
31
aee8290b 32Revision 1.18 2000/06/30 12:40:34 morsch
33Pythia takes care of vertex smearing. Correct conversion from Pythia units (mm) to
34Geant units (cm).
35
1512e357 36Revision 1.17 2000/06/09 20:34:07 morsch
37All coding rule violations except RS3 corrected
38
f87cfe57 39Revision 1.16 2000/05/15 15:04:20 morsch
40The full event is written for fNtrack = -1
41Coding rule violations corrected.
42
5ddeb374 43Revision 1.15 2000/04/26 10:14:24 morsch
44Particles array has one entry more than pythia particle list. Upper bound of
45particle loop changed to np-1 (R. Guernane, AM)
46
2a0e6f5b 47Revision 1.14 2000/04/05 08:36:13 morsch
48Check status code of particles in Pythia event
49to avoid double counting as partonic state and final state particle.
50
23211d3e 51Revision 1.13 1999/11/09 07:38:48 fca
52Changes for compatibility with version 2.23 of ROOT
53
084c1b4a 54Revision 1.12 1999/11/03 17:43:20 fca
55New version from G.Martinez & A.Morsch
56
886b6f73 57Revision 1.11 1999/09/29 09:24:14 fca
58Introduction of the Copyright and cvs Log
4c039060 59*/
60
fe4da5cc 61#include "AliGenPythia.h"
18edb254 62#include "AliDecayerPythia.h"
fe4da5cc 63#include "AliRun.h"
64#include "AliPythia.h"
18edb254 65#include "AliPDG.h"
1578254f 66#include <TParticle.h>
18edb254 67#include <TSystem.h>
f87cfe57 68
fe4da5cc 69 ClassImp(AliGenPythia)
70
71AliGenPythia::AliGenPythia()
72 :AliGenerator()
73{
18edb254 74// Default Constructor
75 fDecayer = new AliDecayerPythia();
fe4da5cc 76}
77
78AliGenPythia::AliGenPythia(Int_t npart)
79 :AliGenerator(npart)
80{
81// default charm production at 5. 5 TeV
82// semimuonic decay
83// structure function GRVHO
84//
85 fXsection = 0.;
86 fParentSelect.Set(5);
87 fChildSelect.Set(5);
88 for (Int_t i=0; i<5; i++) fParentSelect[i]=fChildSelect[i]=0;
89 SetProcess();
90 SetStrucFunc();
886b6f73 91 SetForceDecay();
fe4da5cc 92 SetPtHard();
93 SetEnergyCMS();
18edb254 94 fDecayer = new AliDecayerPythia();
fe4da5cc 95}
96
f87cfe57 97AliGenPythia::AliGenPythia(const AliGenPythia & Pythia)
98{
99// copy constructor
100}
101
fe4da5cc 102AliGenPythia::~AliGenPythia()
103{
5ddeb374 104// Destructor
fe4da5cc 105}
106
107void AliGenPythia::Init()
108{
5ddeb374 109// Initialisation
18edb254 110 SetMC(AliPythia::Instance());
fe4da5cc 111 fPythia=(AliPythia*) fgMCEvGen;
112//
113 fParentWeight=1./Float_t(fNpart);
114//
115// Forward Paramters to the AliPythia object
18edb254 116 // gSystem->Exec("ln -s $ALICE_ROOT/data/Decay.table fort.1");
117 // fPythia->Pyupda(2,1);
118 // gSystem->Exec("rm fort.1");
00d6ce7d 119
120 fDecayer->SetForceDecay(fForceDecay);
18edb254 121 fDecayer->Init();
00d6ce7d 122
18edb254 123
fe4da5cc 124 fPythia->SetCKIN(3,fPtHardMin);
125 fPythia->SetCKIN(4,fPtHardMax);
126 fPythia->ProcInit(fProcess,fEnergyCMS,fStrucFunc);
18edb254 127
128 // fPythia->Pylist(0);
129 // fPythia->Pystat(2);
fe4da5cc 130// Parent and Children Selection
131 switch (fProcess)
132 {
133 case charm:
134
135 fParentSelect[0]=411;
136 fParentSelect[1]=421;
137 fParentSelect[2]=431;
138 fParentSelect[3]=4122;
139 break;
140 case charm_unforced:
141
142 fParentSelect[0]=411;
143 fParentSelect[1]=421;
144 fParentSelect[2]=431;
145 fParentSelect[3]=4122;
146 break;
147 case beauty:
148 fParentSelect[0]=511;
149 fParentSelect[1]=521;
150 fParentSelect[2]=531;
151 fParentSelect[3]=5122;
152 break;
153 case beauty_unforced:
154 fParentSelect[0]=511;
155 fParentSelect[1]=521;
156 fParentSelect[2]=531;
157 fParentSelect[3]=5122;
158 break;
159 case jpsi_chi:
160 case jpsi:
161 fParentSelect[0]=443;
162 break;
5be1fe76 163 case mb:
164 break;
fe4da5cc 165 }
166
167 switch (fForceDecay)
168 {
169 case semielectronic:
170 case dielectron:
171 case b_jpsi_dielectron:
172 case b_psip_dielectron:
18edb254 173 fChildSelect[0]=kElectron;
fe4da5cc 174 break;
175 case semimuonic:
176 case dimuon:
177 case b_jpsi_dimuon:
178 case b_psip_dimuon:
5be1fe76 179 case pitomu:
180 case katomu:
18edb254 181 fChildSelect[0]=kMuonMinus;
fe4da5cc 182 break;
18edb254 183 case hadronicD:
184 fChildSelect[0]=kPiPlus;
185 fChildSelect[1]=kKPlus;
186 break;
886b6f73 187 case all:
188 case nodecay:
18edb254 189 break;
fe4da5cc 190 }
191}
192
193void AliGenPythia::Generate()
194{
5ddeb374 195// Generate one event
00d6ce7d 196 fDecayer->ForceDecay();
fe4da5cc 197
5be1fe76 198 Float_t polar[3] = {0,0,0};
199 Float_t origin[3]= {0,0,0};
5ddeb374 200 Float_t originP[3]= {0,0,0};
5be1fe76 201 Float_t origin0[3]= {0,0,0};
1512e357 202 Float_t p[3], pP[4];
203// Float_t random[6];
09fd3ea2 204 static TClonesArray *particles;
5be1fe76 205// converts from mm/c to s
206 const Float_t kconv=0.001/2.999792458e8;
fe4da5cc 207
208
209//
fe4da5cc 210 Int_t nt=0;
5ddeb374 211 Int_t ntP=0;
fe4da5cc 212 Int_t jev=0;
7921755b 213 Int_t j, kf;
09fd3ea2 214
215 if(!particles) particles=new TClonesArray("TParticle",1000);
fe4da5cc 216
217 fTrials=0;
218 for (j=0;j<3;j++) origin0[j]=fOrigin[j];
aee8290b 219 if(fVertexSmear==kPerEvent) {
1512e357 220 fPythia->SetMSTP(151,1);
fe4da5cc 221 for (j=0;j<3;j++) {
1512e357 222 fPythia->SetPARP(151+j, fOsigma[j]/10.);
fe4da5cc 223 }
aee8290b 224 } else if (fVertexSmear==kPerTrack) {
fe4da5cc 225 fPythia->SetMSTP(151,0);
fe4da5cc 226 }
1512e357 227
fe4da5cc 228 while(1)
229 {
084c1b4a 230 fPythia->Pyevnt();
18edb254 231// fPythia->Pylist(1);
fe4da5cc 232 fTrials++;
f1092809 233 fPythia->ImportParticles(particles,"All");
fe4da5cc 234 Int_t np = particles->GetEntriesFast();
235 printf("\n **************************************************%d\n",np);
236 Int_t nc=0;
237 if (np == 0 ) continue;
5be1fe76 238 if (fProcess != mb) {
2a0e6f5b 239 for (Int_t i = 0; i<np-1; i++) {
1578254f 240 TParticle * iparticle = (TParticle *) particles->At(i);
23211d3e 241 Int_t ks = iparticle->GetStatusCode();
a8228d85 242 kf = CheckPDGCode(iparticle->GetPdgCode());
2a0e6f5b 243 if (ks==21) continue;
244
18edb254 245 fChildWeight=(fDecayer->GetPartialBranchingRatio(kf))*fParentWeight;
fe4da5cc 246//
247// Parent
5be1fe76 248 if (ParentSelected(TMath::Abs(kf))) {
249 if (KinematicSelection(iparticle)) {
250 if (nc==0) {
251//
252// Store information concerning the hard scattering process
253//
5ddeb374 254 Float_t massP = fPythia->GetPARI(13);
255 Float_t ptP = fPythia->GetPARI(17);
256 Float_t yP = fPythia->GetPARI(37);
257 Float_t xmtP = sqrt(ptP*ptP+massP*massP);
258 Float_t ty = Float_t(TMath::TanH(yP));
259 pP[0] = ptP;
260 pP[1] = 0;
261 pP[2] = xmtP*ty/sqrt(1.-ty*ty);
262 pP[3] = massP;
5be1fe76 263 gAlice->SetTrack(0,-1,-1,
5ddeb374 264 pP,originP,polar,
265 0,"Hard Scat.",ntP,fParentWeight);
266 gAlice->KeepTrack(ntP);
5be1fe76 267 }
268 nc++;
fe4da5cc 269//
270// store parent track information
1578254f 271 p[0]=iparticle->Px();
272 p[1]=iparticle->Py();
273 p[2]=iparticle->Pz();
819f84ad 274 origin[0]=origin0[0]+iparticle->Vx()/10.;
275 origin[1]=origin0[1]+iparticle->Vy()/10.;
276 origin[2]=origin0[2]+iparticle->Vz()/10.;
fe4da5cc 277
1578254f 278 Int_t ifch=iparticle->GetFirstDaughter();
279 Int_t ilch=iparticle->GetLastDaughter();
18edb254 280
281 if ((ifch !=0 && ilch !=0) || fForceDecay == nodecay) {
282 Int_t trackit=0;
283 if (fForceDecay == nodecay) trackit = 1;
284 gAlice->SetTrack(trackit,ntP,kf,
5be1fe76 285 p,origin,polar,
286 0,"Primary",nt,fParentWeight);
287 gAlice->KeepTrack(nt);
288 Int_t iparent = nt;
fe4da5cc 289//
290// Children
18edb254 291 if (fForceDecay != nodecay) {
292 for (j=ifch; j<=ilch; j++)
293 {
294 TParticle * ichild =
1578254f 295 (TParticle *) particles->At(j-1);
18edb254 296 kf = CheckPDGCode(ichild->GetPdgCode());
fe4da5cc 297//
298//
18edb254 299 if (ChildSelected(TMath::Abs(kf))) {
4451ef92 300 origin[0]=origin0[0]+ichild->Vx()/10.;
301 origin[1]=origin0[1]+ichild->Vy()/10.;
302 origin[2]=origin0[2]+ichild->Vz()/10.;
1578254f 303 p[0]=ichild->Px();
304 p[1]=ichild->Py();
305 p[2]=ichild->Pz();
306 Float_t tof=kconv*ichild->T();
307 gAlice->SetTrack(fTrackIt, iparent, kf,
5be1fe76 308 p,origin,polar,
309 tof,"Decay",nt,fChildWeight);
310 gAlice->KeepTrack(nt);
18edb254 311 } // select child
312 } // child loop
313 }
5be1fe76 314 }
315 } // kinematic selection
316 } // select particle
317 } // particle loop
318 } else {
2a0e6f5b 319 for (Int_t i = 0; i<np-1; i++) {
1578254f 320 TParticle * iparticle = (TParticle *) particles->At(i);
a8228d85 321 kf = CheckPDGCode(iparticle->GetPdgCode());
1578254f 322 Int_t ks = iparticle->GetStatusCode();
2a0e6f5b 323
1578254f 324 if (ks==1 && kf!=0 && KinematicSelection(iparticle)) {
5be1fe76 325 nc++;
326//
327// store track information
1578254f 328 p[0]=iparticle->Px();
329 p[1]=iparticle->Py();
330 p[2]=iparticle->Pz();
4451ef92 331 origin[0]=origin0[0]+iparticle->Vx()/10.;
332 origin[1]=origin0[1]+iparticle->Vy()/10.;
333 origin[2]=origin0[2]+iparticle->Vz()/10.;
1578254f 334 Float_t tof=kconv*iparticle->T();
335 gAlice->SetTrack(fTrackIt,-1,kf,p,origin,polar,
5be1fe76 336 tof,"Primary",nt);
337 gAlice->KeepTrack(nt);
338 } // select particle
339 } // particle loop
340 printf("\n I've put %i particles on the stack \n",nc);
341 } // mb ?
fe4da5cc 342 if (nc > 0) {
5be1fe76 343 jev+=nc;
5ddeb374 344 if (jev >= fNpart || fNpart == -1) {
fe4da5cc 345 fKineBias=Float_t(fNpart)/Float_t(fTrials);
23211d3e 346 printf("\n Trials: %i %i %i\n",fTrials, fNpart, jev);
fe4da5cc 347 break;
348 }
349 }
350 } // event loop
351// adjust weight due to kinematic selection
352 AdjustWeights();
353// get cross-section
354 fXsection=fPythia->GetPARI(1);
355}
356
357Bool_t AliGenPythia::ParentSelected(Int_t ip)
358{
5ddeb374 359// True if particle is in list of parent particles to be selected
fe4da5cc 360 for (Int_t i=0; i<5; i++)
361 {
362 if (fParentSelect[i]==ip) return kTRUE;
363 }
364 return kFALSE;
365}
366
367Bool_t AliGenPythia::ChildSelected(Int_t ip)
368{
5ddeb374 369// True if particle is in list of decay products to be selected
4451ef92 370 if (fForceDecay == all) return kTRUE;
371
fe4da5cc 372 for (Int_t i=0; i<5; i++)
373 {
374 if (fChildSelect[i]==ip) return kTRUE;
375 }
376 return kFALSE;
377}
378
1578254f 379Bool_t AliGenPythia::KinematicSelection(TParticle *particle)
fe4da5cc 380{
5ddeb374 381// Perform kinematic selection
1578254f 382 Float_t px=particle->Px();
383 Float_t py=particle->Py();
384 Float_t pz=particle->Pz();
385 Float_t e=particle->Energy();
fe4da5cc 386
387//
388// transverse momentum cut
389 Float_t pt=TMath::Sqrt(px*px+py*py);
390 if (pt > fPtMax || pt < fPtMin)
391 {
392// printf("\n failed pt cut %f %f %f \n",pt,fPtMin,fPtMax);
393 return kFALSE;
394 }
395//
396// momentum cut
397 Float_t p=TMath::Sqrt(px*px+py*py+pz*pz);
398 if (p > fPMax || p < fPMin)
399 {
400// printf("\n failed p cut %f %f %f \n",p,fPMin,fPMax);
401 return kFALSE;
402 }
403
404//
405// theta cut
5be1fe76 406 Float_t theta = Float_t(TMath::ATan2(Double_t(pt),Double_t(pz)));
fe4da5cc 407 if (theta > fThetaMax || theta < fThetaMin)
408 {
409// printf("\n failed theta cut %f %f %f \n",theta,fThetaMin,fThetaMax);
410 return kFALSE;
411 }
412
413//
414// rapidity cut
415 Float_t y = 0.5*TMath::Log((e+pz)/(e-pz));
416 if (y > fYMax || y < fYMin)
417 {
418// printf("\n failed y cut %f %f %f \n",y,fYMin,fYMax);
419 return kFALSE;
420 }
421
422//
423// phi cut
f87cfe57 424 Float_t phi=Float_t(TMath::ATan2(Double_t(py),Double_t(px)));
fe4da5cc 425 if (phi > fPhiMax || phi < fPhiMin)
426 {
427// printf("\n failed phi cut %f %f %f \n",phi,fPhiMin,fPhiMax);
428 return kFALSE;
429 }
430
431 return kTRUE;
432}
433void AliGenPythia::AdjustWeights()
434{
5ddeb374 435// Adjust the weights after generation of all events
436//
437 TClonesArray *partArray = gAlice->Particles();
438 TParticle *part;
fe4da5cc 439 Int_t ntrack=gAlice->GetNtrack();
440 for (Int_t i=0; i<ntrack; i++) {
5ddeb374 441 part= (TParticle*) partArray->UncheckedAt(i);
442 part->SetWeight(part->GetWeight()*fKineBias);
fe4da5cc 443 }
444}
445
a8228d85 446Int_t AliGenPythia::CheckPDGCode(Int_t pdgcode)
447{
448//
23211d3e 449// If the particle is in a diffractive state, then take action accordingly
a8228d85 450 switch (pdgcode) {
18edb254 451 case 91:
452 return 92;
a8228d85 453 case 110:
454 //rho_diff0 -- difficult to translate, return rho0
455 return 113;
456 case 210:
457 //pi_diffr+ -- change to pi+
458 return 211;
459 case 220:
460 //omega_di0 -- change to omega0
461 return 223;
462 case 330:
463 //phi_diff0 -- return phi0
464 return 333;
465 case 440:
466 //J/psi_di0 -- return J/psi
467 return 443;
468 case 2110:
469 //n_diffr -- return neutron
470 return 2112;
471 case 2210:
472 //p_diffr+ -- return proton
473 return 2212;
474 }
475 //non diffractive state -- return code unchanged
476 return pdgcode;
477}
478
f87cfe57 479AliGenPythia& AliGenPythia::operator=(const AliGenPythia& rhs)
480{
481// Assignment operator
482 return *this;
483}
fe4da5cc 484
485
18edb254 486void AliGenPythia::Streamer(TBuffer &R__b)
487{
488 // Stream an object of class AliGenPythia.
489
490 if (R__b.IsReading()) {
491 Version_t R__v = R__b.ReadVersion(); if (R__v) { }
492 AliGenerator::Streamer(R__b);
493 R__b >> (Int_t&)fProcess;
494 R__b >> (Int_t&)fStrucFunc;
495 R__b >> (Int_t&)fForceDecay;
496 R__b >> fEnergyCMS;
497 R__b >> fKineBias;
498 R__b >> fTrials;
499 fParentSelect.Streamer(R__b);
500 fChildSelect.Streamer(R__b);
501 R__b >> fXsection;
502// (AliPythia::Instance())->Streamer(R__b);
503 R__b >> fPtHardMin;
504 R__b >> fPtHardMax;
505// if (fDecayer) fDecayer->Streamer(R__b);
506 } else {
507 R__b.WriteVersion(AliGenPythia::IsA());
508 AliGenerator::Streamer(R__b);
509 R__b << (Int_t)fProcess;
510 R__b << (Int_t)fStrucFunc;
511 R__b << (Int_t)fForceDecay;
512 R__b << fEnergyCMS;
513 R__b << fKineBias;
514 R__b << fTrials;
515 fParentSelect.Streamer(R__b);
516 fChildSelect.Streamer(R__b);
517 R__b << fXsection;
518// R__b << fPythia;
519 R__b << fPtHardMin;
520 R__b << fPtHardMax;
521 // fDecayer->Streamer(R__b);
522 }
523}
524
525
526
fe4da5cc 527
5be1fe76 528
529
530
531