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[u/mrichter/AliRoot.git] / EVGEN / AliGenMC.cxx
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e36044d6 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
88cb7938 16/* $Id$ */
e36044d6 17
62d0ae06 18// Base class for generators using external MC generators.
19// For example AliGenPythia using Pythia.
20// Provides basic functionality: setting of kinematic cuts on
21// decay products and particle selection.
22// andreas.morsch@cern.ch
23
ac3faee4 24#include <TClonesArray.h>
65de9f86 25#include <TMath.h>
116cbefd 26#include <TPDGCode.h>
e36044d6 27#include <TParticle.h>
7eb751fe 28#include <TLorentzVector.h>
29#include <TVector3.h>
e36044d6 30
116cbefd 31#include "AliGenMC.h"
e052713d 32#include "AliGenEventHeader.h"
d97fb2bb 33#include "AliRun.h"
ac3faee4 34#include "AliGeometry.h"
4a33c50d 35#include "AliDecayer.h"
116cbefd 36
198bb1c7 37ClassImp(AliGenMC)
e36044d6 38
39AliGenMC::AliGenMC()
1c56e311 40 :AliGenerator(),
969a210b 41 fParticles("TParticle", 1000),
1c56e311 42 fParentSelect(8),
43 fChildSelect(8),
44 fCutOnChild(0),
45 fChildPtMin(0.),
46 fChildPtMax(1.e10),
47 fChildPMin(0.),
48 fChildPMax(1.e10),
49 fChildPhiMin(0.),
50 fChildPhiMax(2. * TMath::Pi()),
51 fChildThetaMin(0.),
52 fChildThetaMax(TMath::Pi()),
53 fChildYMin(-12.),
54 fChildYMax(12.),
55 fXingAngleX(0.),
56 fXingAngleY(0.),
57 fForceDecay(kAll),
58 fMaxLifeTime(1.e-15),
1c56e311 59 fDyBoost(0.),
60 fGeometryAcceptance(0),
61 fPdgCodeParticleforAcceptanceCut(0),
d97fb2bb 62 fNumberOfAcceptedParticles(0),
e7c989e4 63 fNprimaries(0)
e36044d6 64{
65// Default Constructor
e7c989e4 66 fAProjectile = 1;
67 fZProjectile = 1;
68 fATarget = 1;
69 fZTarget = 1;
70 fProjectile = "P";
71 fTarget = "P";
e36044d6 72}
73
74AliGenMC::AliGenMC(Int_t npart)
1c56e311 75 :AliGenerator(npart),
ea24f998 76 fParticles("TParticle", 1000),
1c56e311 77 fParentSelect(8),
78 fChildSelect(8),
79 fCutOnChild(0),
80 fChildPtMin(0.),
81 fChildPtMax(1.e10),
82 fChildPMin(0.),
83 fChildPMax(1.e10),
84 fChildPhiMin(0.),
85 fChildPhiMax(2. * TMath::Pi()),
86 fChildThetaMin(0.),
87 fChildThetaMax(TMath::Pi()),
88 fChildYMin(-12.),
89 fChildYMax(12.),
90 fXingAngleX(0.),
91 fXingAngleY(0.),
92 fForceDecay(kAll),
93 fMaxLifeTime(1.e-15),
1c56e311 94 fDyBoost(0.),
95 fGeometryAcceptance(0),
96 fPdgCodeParticleforAcceptanceCut(0),
d97fb2bb 97 fNumberOfAcceptedParticles(0),
e7c989e4 98 fNprimaries(0)
e36044d6 99{
100// Constructor
e36044d6 101//
e7c989e4 102 fAProjectile = 1;
103 fZProjectile = 1;
104 fATarget = 1;
105 fZTarget = 1;
106 fProjectile = "P";
107 fTarget = "P";
108 for (Int_t i=0; i<8; i++) fParentSelect[i]=fChildSelect[i]=0;
e36044d6 109}
110
e36044d6 111AliGenMC::~AliGenMC()
112{
113// Destructor
114}
115
116void AliGenMC::Init()
117{
118//
119// Initialization
120 switch (fForceDecay) {
e345c619 121 case kBSemiElectronic:
e36044d6 122 case kSemiElectronic:
123 case kDiElectron:
124 case kBJpsiDiElectron:
125 case kBPsiPrimeDiElectron:
e40b9538 126 case kElectronEM:
127 case kDiElectronEM:
47fc6bd5 128 fChildSelect[0] = kElectron;
e36044d6 129 break;
2dcb5874 130 case kHardMuons:
e345c619 131 case kBSemiMuonic:
62e445df 132 case kDSemiMuonic:
e36044d6 133 case kSemiMuonic:
134 case kDiMuon:
38a19176 135 case kJpsiDiMuon:
e36044d6 136 case kBJpsiDiMuon:
137 case kBPsiPrimeDiMuon:
138 case kPiToMu:
139 case kKaToMu:
cd159249 140 case kWToMuon:
141 case kWToCharmToMuon:
2f299526 142 case kZDiMuon:
f5b581a1 143 case kZDiElectron:
e36044d6 144 fChildSelect[0]=kMuonMinus;
145 break;
cd159249 146 case kWToCharm:
147 break;
e36044d6 148 case kHadronicD:
af33df34 149 case kHadronicDWithout4Bodies:
e36044d6 150 fChildSelect[0]=kPiPlus;
151 fChildSelect[1]=kKPlus;
152 break;
00cb2f27 153 case kPhiKK:
027677ae 154 fChildSelect[0]=kKPlus;
56d47239 155 break;
156 case kBJpsi:
f2f8bbb9 157 case kBJpsiUndecayed:
00935af2 158 fChildSelect[0]= 443;
56d47239 159 break;
00935af2 160 case kChiToJpsiGammaToMuonMuon:
161 fChildSelect[0]= 22;
162 fChildSelect[1]= 13;
163 break;
164 case kChiToJpsiGammaToElectronElectron:
165 fChildSelect[0]= 22;
166 fChildSelect[1]= 11;
167 break;
d3553100 168 case kLambda:
199786f7 169 fChildSelect[0]= kProton;
170 fChildSelect[1]= 211;
171 break;
9610308a 172 case kPsiPrimeJpsiDiElectron:
e40b9538 173 fChildSelect[0]= 211;
174 fChildSelect[1]= 11;
175 break;
176 case kGammaEM:
177 fChildSelect[0] = kGamma;
178 break;
199786f7 179 case kOmega:
e36044d6 180 case kAll:
2b1f8257 181 case kAllMuonic:
e36044d6 182 case kNoDecay:
d5f86442 183 case kNoDecayHeavy:
1fefb2d4 184 case kNoDecayBeauty:
847af604 185 case kNeutralPion:
482c0e0c 186 case kBeautyUpgrade:
e36044d6 187 break;
188 }
36d770d9 189
190 if (fZTarget != 0 && fAProjectile != 0)
191 {
192 fDyBoost = - 0.5 * TMath::Log(Double_t(fZProjectile) * Double_t(fATarget) /
193 (Double_t(fZTarget) * Double_t(fAProjectile)));
194 }
e36044d6 195}
196
197
62d0ae06 198Bool_t AliGenMC::ParentSelected(Int_t ip) const
e36044d6 199{
200// True if particle is in list of parent particles to be selected
201 for (Int_t i=0; i<8; i++)
202 {
62d0ae06 203 if (fParentSelect.At(i) == ip) return kTRUE;
e36044d6 204 }
205 return kFALSE;
206}
207
62d0ae06 208Bool_t AliGenMC::ChildSelected(Int_t ip) const
e36044d6 209{
210// True if particle is in list of decay products to be selected
211 for (Int_t i=0; i<5; i++)
212 {
62d0ae06 213 if (fChildSelect.At(i) == ip) return kTRUE;
e36044d6 214 }
215 return kFALSE;
216}
217
4a33c50d 218Bool_t AliGenMC::KinematicSelection(const TParticle *particle, Int_t flag) const
e36044d6 219{
220// Perform kinematic selection
43a333ec 221 Double_t pz = particle->Pz();
43a333ec 222 Double_t pt = particle->Pt();
223 Double_t p = particle->P();
224 Double_t theta = particle->Theta();
225 Double_t mass = particle->GetCalcMass();
226 Double_t mt2 = pt * pt + mass * mass;
227 Double_t phi = particle->Phi();
d643e262 228 Double_t e = particle->Energy();
229
230 if (e == 0.)
231 e = TMath::Sqrt(p * p + mass * mass);
232
95450c6d 233
95450c6d 234 Double_t y, y0;
235
fef61e14 236 if (TMath::Abs(pz) < e) {
95450c6d 237 y = 0.5*TMath::Log((e+pz)/(e-pz));
238 } else {
239 y = 1.e10;
240 }
e36044d6 241
95450c6d 242 if (mt2) {
243 y0 = 0.5*TMath::Log((e+TMath::Abs(pz))*(e+TMath::Abs(pz))/mt2);
e36044d6 244 } else {
95450c6d 245 if (TMath::Abs(y) < 1.e10) {
246 y0 = y;
247 } else {
248 y0 = 1.e10;
249 }
e36044d6 250 }
95450c6d 251
252 y = (pz < 0) ? -y0 : y0;
e36044d6 253
254 if (flag == 0) {
255//
256// Primary particle cuts
257//
258// transverse momentum cut
259 if (pt > fPtMax || pt < fPtMin) {
260// printf("\n failed pt cut %f %f %f \n",pt,fPtMin,fPtMax);
261 return kFALSE;
262 }
263//
264// momentum cut
265 if (p > fPMax || p < fPMin) {
266// printf("\n failed p cut %f %f %f \n",p,fPMin,fPMax);
267 return kFALSE;
268 }
269//
270// theta cut
271 if (theta > fThetaMax || theta < fThetaMin) {
272// printf("\n failed theta cut %f %f %f \n",theta,fThetaMin,fThetaMax);
273 return kFALSE;
274 }
275//
276// rapidity cut
277 if (y > fYMax || y < fYMin) {
278// printf("\n failed y cut %f %f %f \n",y,fYMin,fYMax);
279 return kFALSE;
280 }
281//
282// phi cut
283 if (phi > fPhiMax || phi < fPhiMin) {
284// printf("\n failed phi cut %f %f %f \n",phi,fPhiMin,fPhiMax);
285 return kFALSE;
286 }
287 } else {
288//
289// Decay product cuts
290//
291// transverse momentum cut
292 if (pt > fChildPtMax || pt < fChildPtMin) {
293// printf("\n failed pt cut %f %f %f \n",pt,fChildPtMin,fChildPtMax);
294 return kFALSE;
295 }
296//
297// momentum cut
298 if (p > fChildPMax || p < fChildPMin) {
299// printf("\n failed p cut %f %f %f \n",p,fChildPMin,fChildPMax);
300 return kFALSE;
301 }
302//
303// theta cut
304 if (theta > fChildThetaMax || theta < fChildThetaMin) {
305// printf("\n failed theta cut %f %f %f \n",theta,fChildThetaMin,fChildThetaMax);
306 return kFALSE;
307 }
308//
309// rapidity cut
310 if (y > fChildYMax || y < fChildYMin) {
311// printf("\n failed y cut %f %f %f \n",y,fChildYMin,fChildYMax);
312 return kFALSE;
313 }
314//
315// phi cut
316 if (phi > fChildPhiMax || phi < fChildPhiMin) {
317// printf("\n failed phi cut %f %f %f \n",phi,fChildPhiMin,fChildPhiMax);
318 return kFALSE;
319 }
320 }
321
e36044d6 322 return kTRUE;
323}
324
65de9f86 325Bool_t AliGenMC::CheckAcceptanceGeometry(Int_t np, TClonesArray* particles)
326{
e033748b 327// Check the geometrical acceptance for particle.
328
329 Bool_t check ;
330 Int_t numberOfPdgCodeParticleforAcceptanceCut = 0;
331 Int_t numberOfAcceptedPdgCodeParticleforAcceptanceCut = 0;
65de9f86 332 TParticle * particle;
333 Int_t i;
e033748b 334 for (i = 0; i < np; i++) {
65de9f86 335 particle = (TParticle *) particles->At(i);
336 if( TMath::Abs( particle->GetPdgCode() ) == TMath::Abs( fPdgCodeParticleforAcceptanceCut ) ) {
e033748b 337 numberOfPdgCodeParticleforAcceptanceCut++;
338 if (fGeometryAcceptance->Impact(particle)) numberOfAcceptedPdgCodeParticleforAcceptanceCut++;
65de9f86 339 }
340 }
e033748b 341 if ( numberOfAcceptedPdgCodeParticleforAcceptanceCut > (fNumberOfAcceptedParticles-1) )
342 check = kTRUE;
65de9f86 343 else
e033748b 344 check = kFALSE;
65de9f86 345
e033748b 346 return check;
65de9f86 347}
348
62d0ae06 349Int_t AliGenMC::CheckPDGCode(Int_t pdgcode) const
e36044d6 350{
351//
352// If the particle is in a diffractive state, then take action accordingly
353 switch (pdgcode) {
354 case 91:
355 return 92;
356 case 110:
357 //rho_diff0 -- difficult to translate, return rho0
358 return 113;
359 case 210:
360 //pi_diffr+ -- change to pi+
361 return 211;
362 case 220:
363 //omega_di0 -- change to omega0
364 return 223;
365 case 330:
366 //phi_diff0 -- return phi0
367 return 333;
368 case 440:
369 //J/psi_di0 -- return J/psi
370 return 443;
371 case 2110:
372 //n_diffr -- return neutron
373 return 2112;
374 case 2210:
375 //p_diffr+ -- return proton
376 return 2212;
377 }
378 //non diffractive state -- return code unchanged
379 return pdgcode;
380}
3b945a60 381
36d770d9 382void AliGenMC::Boost()
3b945a60 383{
384//
385// Boost cms into LHC lab frame
386//
387
36d770d9 388 Double_t beta = TMath::TanH(fDyBoost);
60e55aee 389 Double_t gamma = 1./TMath::Sqrt((1.-beta)*(1.+beta));
3b945a60 390 Double_t gb = gamma * beta;
391
cda4be86 392 // printf("\n Boosting particles to lab frame %f %f %f", fDyBoost, beta, gamma);
3b945a60 393
394 Int_t i;
ea24f998 395 Int_t np = fParticles.GetEntriesFast();
3b945a60 396 for (i = 0; i < np; i++)
397 {
ea24f998 398 TParticle* iparticle = (TParticle*) fParticles.At(i);
3b945a60 399
400 Double_t e = iparticle->Energy();
401 Double_t px = iparticle->Px();
402 Double_t py = iparticle->Py();
403 Double_t pz = iparticle->Pz();
404
405 Double_t eb = gamma * e - gb * pz;
406 Double_t pzb = -gb * e + gamma * pz;
407
408 iparticle->SetMomentum(px, py, pzb, eb);
409 }
410}
d97fb2bb 411
7eb751fe 412void AliGenMC::BeamCrossAngle()
413{
414 // Applies a boost in the y-direction in order to take into account the
415 // beam crossing angle
416
89c6e78b 417 Double_t thetaPr0, pyPr2, pzPr2;
7eb751fe 418 TVector3 beta;
419
420 thetaPr0 = fXingAngleY / 2.;
7eb751fe 421
422 // Momentum of the CMS system
423 pyPr2 = TMath::Sqrt(fEnergyCMS * fEnergyCMS/ 4 - 0.938 * 0.938) * TMath::Sin(thetaPr0);
424 pzPr2 = TMath::Sqrt(fEnergyCMS * fEnergyCMS/ 4 - 0.938 * 0.938) * TMath::Cos(thetaPr0);
425
426 TLorentzVector proj1Vect, proj2Vect, projVect;
427 proj1Vect.SetPxPyPzE(0., pyPr2, pzPr2, fEnergyCMS/2);
428 proj2Vect.SetPxPyPzE(0., pyPr2,-pzPr2, fEnergyCMS/2);
429 projVect = proj1Vect + proj2Vect;
430 beta=(1. / projVect.E()) * (projVect.Vect());
431
432 Int_t i;
433 Int_t np = fParticles.GetEntriesFast();
434 for (i = 0; i < np; i++)
435 {
436 TParticle* iparticle = (TParticle*) fParticles.At(i);
437
438 Double_t e = iparticle->Energy();
439 Double_t px = iparticle->Px();
440 Double_t py = iparticle->Py();
441 Double_t pz = iparticle->Pz();
442
443 TLorentzVector partIn;
444 partIn.SetPxPyPzE(px,py,pz,e);
445 partIn.Boost(beta);
446 iparticle->SetMomentum(partIn.Px(),partIn.Py(),partIn.Pz(),partIn.E());
447 }
448}
449
450
d97fb2bb 451void AliGenMC::AddHeader(AliGenEventHeader* header)
452{
453 // Passes header either to the container or to gAlice
454 if (fContainer) {
e052713d 455 header->SetName(fName);
d97fb2bb 456 fContainer->AddHeader(header);
457 } else {
458 gAlice->SetGenEventHeader(header);
459 }
460}