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