Minor corrections thanks to I.Hrivnacova
[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$Log$
886b6f73 18Revision 1.11 1999/09/29 09:24:14 fca
19Introduction of the Copyright and cvs Log
4c039060 20*/
21
fe4da5cc 22#include "AliGenerator.h"
23#include "AliGenPythia.h"
fe4da5cc 24#include "AliRun.h"
25#include "AliPythia.h"
26#include <TDirectory.h>
27#include <TFile.h>
28#include <TTree.h>
29#include <stdlib.h>
30#include <AliPythia.h>
1578254f 31#include <TParticle.h>
32//#include <GParticle.h>
fe4da5cc 33 ClassImp(AliGenPythia)
34
35AliGenPythia::AliGenPythia()
36 :AliGenerator()
37{
38}
39
40AliGenPythia::AliGenPythia(Int_t npart)
41 :AliGenerator(npart)
42{
43// default charm production at 5. 5 TeV
44// semimuonic decay
45// structure function GRVHO
46//
47 fXsection = 0.;
48 fParentSelect.Set(5);
49 fChildSelect.Set(5);
50 for (Int_t i=0; i<5; i++) fParentSelect[i]=fChildSelect[i]=0;
51 SetProcess();
52 SetStrucFunc();
886b6f73 53 SetForceDecay();
fe4da5cc 54 SetPtHard();
55 SetEnergyCMS();
56}
57
58AliGenPythia::~AliGenPythia()
59{
60}
61
62void AliGenPythia::Init()
63{
64 SetMC(new AliPythia());
65 fPythia=(AliPythia*) fgMCEvGen;
66//
67 fParentWeight=1./Float_t(fNpart);
68//
69// Forward Paramters to the AliPythia object
70 fPythia->DefineParticles();
fe4da5cc 71 fPythia->SetCKIN(3,fPtHardMin);
72 fPythia->SetCKIN(4,fPtHardMax);
73 fPythia->ProcInit(fProcess,fEnergyCMS,fStrucFunc);
5be1fe76 74 fPythia->ForceDecay(fForceDecay);
fe4da5cc 75 fPythia->LuList(0);
76 fPythia->PyStat(2);
77// Parent and Children Selection
78 switch (fProcess)
79 {
80 case charm:
81
82 fParentSelect[0]=411;
83 fParentSelect[1]=421;
84 fParentSelect[2]=431;
85 fParentSelect[3]=4122;
86 break;
87 case charm_unforced:
88
89 fParentSelect[0]=411;
90 fParentSelect[1]=421;
91 fParentSelect[2]=431;
92 fParentSelect[3]=4122;
93 break;
94 case beauty:
95 fParentSelect[0]=511;
96 fParentSelect[1]=521;
97 fParentSelect[2]=531;
98 fParentSelect[3]=5122;
99 break;
100 case beauty_unforced:
101 fParentSelect[0]=511;
102 fParentSelect[1]=521;
103 fParentSelect[2]=531;
104 fParentSelect[3]=5122;
105 break;
106 case jpsi_chi:
107 case jpsi:
108 fParentSelect[0]=443;
109 break;
5be1fe76 110 case mb:
111 break;
fe4da5cc 112 }
113
114 switch (fForceDecay)
115 {
116 case semielectronic:
117 case dielectron:
118 case b_jpsi_dielectron:
119 case b_psip_dielectron:
120 fChildSelect[0]=11;
121 break;
122 case semimuonic:
123 case dimuon:
124 case b_jpsi_dimuon:
125 case b_psip_dimuon:
5be1fe76 126 case pitomu:
127 case katomu:
fe4da5cc 128 fChildSelect[0]=13;
129 break;
886b6f73 130 case all:
131 case nodecay:
132 break;
fe4da5cc 133 }
134}
135
136void AliGenPythia::Generate()
137{
fe4da5cc 138
5be1fe76 139 Float_t polar[3] = {0,0,0};
140 Float_t origin[3]= {0,0,0};
141 Float_t origin_p[3]= {0,0,0};
142 Float_t origin0[3]= {0,0,0};
143 Float_t p[3], p_p[4], random[6];
09fd3ea2 144 static TClonesArray *particles;
5be1fe76 145// converts from mm/c to s
146 const Float_t kconv=0.001/2.999792458e8;
fe4da5cc 147
148
149//
fe4da5cc 150 Int_t nt=0;
5be1fe76 151 Int_t nt_p=0;
fe4da5cc 152 Int_t jev=0;
7921755b 153 Int_t j, kf;
09fd3ea2 154
155 if(!particles) particles=new TClonesArray("TParticle",1000);
fe4da5cc 156
157 fTrials=0;
158 for (j=0;j<3;j++) origin0[j]=fOrigin[j];
159 if(fVertexSmear==perEvent) {
cfce8870 160 gMC->Rndm(random,6);
fe4da5cc 161 for (j=0;j<3;j++) {
162 origin0[j]+=fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
163 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
164 fPythia->SetMSTP(151,0);
165 }
166 } else if (fVertexSmear==perTrack) {
167 fPythia->SetMSTP(151,0);
168 for (j=0;j<3;j++) {
169 fPythia->SetPARP(151+j, fOsigma[j]*10.);
170 }
171 }
fe4da5cc 172 while(1)
173 {
174 fPythia->PyEvnt();
175 fTrials++;
f1092809 176 fPythia->ImportParticles(particles,"All");
fe4da5cc 177 Int_t np = particles->GetEntriesFast();
178 printf("\n **************************************************%d\n",np);
179 Int_t nc=0;
180 if (np == 0 ) continue;
5be1fe76 181 if (fProcess != mb) {
182 for (Int_t i = 0; i<np; i++) {
1578254f 183 TParticle * iparticle = (TParticle *) particles->At(i);
a8228d85 184 kf = CheckPDGCode(iparticle->GetPdgCode());
5be1fe76 185 fChildWeight=(fPythia->GetBraPart(kf))*fParentWeight;
fe4da5cc 186//
187// Parent
5be1fe76 188 if (ParentSelected(TMath::Abs(kf))) {
189 if (KinematicSelection(iparticle)) {
190 if (nc==0) {
191//
192// Store information concerning the hard scattering process
193//
194 Float_t mass_p = fPythia->GetPARI(13);
195 Float_t pt_p = fPythia->GetPARI(17);
196 Float_t y_p = fPythia->GetPARI(37);
197 Float_t xmt_p = sqrt(pt_p*pt_p+mass_p*mass_p);
198 Float_t ty = Float_t(TMath::TanH(y_p));
199 p_p[0] = pt_p;
200 p_p[1] = 0;
201 p_p[2] = xmt_p*ty/sqrt(1.-ty*ty);
202 p_p[3] = mass_p;
203 gAlice->SetTrack(0,-1,-1,
204 p_p,origin_p,polar,
205 0,"Hard Scat.",nt_p,fParentWeight);
206 gAlice->KeepTrack(nt_p);
207 }
208 nc++;
fe4da5cc 209//
210// store parent track information
1578254f 211 p[0]=iparticle->Px();
212 p[1]=iparticle->Py();
213 p[2]=iparticle->Pz();
214 origin[0]=origin0[0]+iparticle->Vx()/10;
215 origin[1]=origin0[1]+iparticle->Vy()/10;
216 origin[2]=origin0[2]+iparticle->Vz()/10;
fe4da5cc 217
1578254f 218 Int_t ifch=iparticle->GetFirstDaughter();
219 Int_t ilch=iparticle->GetLastDaughter();
5be1fe76 220 if (ifch !=0 && ilch !=0) {
1578254f 221 gAlice->SetTrack(0,nt_p,kf,
5be1fe76 222 p,origin,polar,
223 0,"Primary",nt,fParentWeight);
224 gAlice->KeepTrack(nt);
225 Int_t iparent = nt;
fe4da5cc 226//
227// Children
228
7921755b 229 for (j=ifch; j<=ilch; j++)
5be1fe76 230 {
1578254f 231 TParticle * ichild =
232 (TParticle *) particles->At(j-1);
a8228d85 233 kf = CheckPDGCode(ichild->GetPdgCode());
fe4da5cc 234//
235//
5be1fe76 236 if (ChildSelected(TMath::Abs(kf))) {
1578254f 237 origin[0]=ichild->Vx();
238 origin[1]=ichild->Vy();
239 origin[2]=ichild->Vz();
240 p[0]=ichild->Px();
241 p[1]=ichild->Py();
242 p[2]=ichild->Pz();
243 Float_t tof=kconv*ichild->T();
244 gAlice->SetTrack(fTrackIt, iparent, kf,
5be1fe76 245 p,origin,polar,
246 tof,"Decay",nt,fChildWeight);
247 gAlice->KeepTrack(nt);
248 } // select child
249 } // child loop
250 }
251 } // kinematic selection
252 } // select particle
253 } // particle loop
254 } else {
255 for (Int_t i = 0; i<np; i++) {
1578254f 256 TParticle * iparticle = (TParticle *) particles->At(i);
a8228d85 257 kf = CheckPDGCode(iparticle->GetPdgCode());
1578254f 258 Int_t ks = iparticle->GetStatusCode();
259 if (ks==1 && kf!=0 && KinematicSelection(iparticle)) {
5be1fe76 260 nc++;
261//
262// store track information
1578254f 263 p[0]=iparticle->Px();
264 p[1]=iparticle->Py();
265 p[2]=iparticle->Pz();
266 origin[0]=origin0[0]+iparticle->Vx()/10;
267 origin[1]=origin0[1]+iparticle->Vy()/10;
268 origin[2]=origin0[2]+iparticle->Vz()/10;
269 Float_t tof=kconv*iparticle->T();
270 gAlice->SetTrack(fTrackIt,-1,kf,p,origin,polar,
5be1fe76 271 tof,"Primary",nt);
272 gAlice->KeepTrack(nt);
273 } // select particle
274 } // particle loop
275 printf("\n I've put %i particles on the stack \n",nc);
276 } // mb ?
fe4da5cc 277 if (nc > 0) {
5be1fe76 278 jev+=nc;
fe4da5cc 279 if (jev >= fNpart) {
280 fKineBias=Float_t(fNpart)/Float_t(fTrials);
281 printf("\n Trials: %i\n",fTrials);
282 break;
283 }
284 }
285 } // event loop
286// adjust weight due to kinematic selection
287 AdjustWeights();
288// get cross-section
289 fXsection=fPythia->GetPARI(1);
290}
291
292Bool_t AliGenPythia::ParentSelected(Int_t ip)
293{
294 for (Int_t i=0; i<5; i++)
295 {
296 if (fParentSelect[i]==ip) return kTRUE;
297 }
298 return kFALSE;
299}
300
301Bool_t AliGenPythia::ChildSelected(Int_t ip)
302{
303 for (Int_t i=0; i<5; i++)
304 {
305 if (fChildSelect[i]==ip) return kTRUE;
306 }
307 return kFALSE;
308}
309
1578254f 310Bool_t AliGenPythia::KinematicSelection(TParticle *particle)
fe4da5cc 311{
1578254f 312 Float_t px=particle->Px();
313 Float_t py=particle->Py();
314 Float_t pz=particle->Pz();
315 Float_t e=particle->Energy();
fe4da5cc 316
317//
318// transverse momentum cut
319 Float_t pt=TMath::Sqrt(px*px+py*py);
320 if (pt > fPtMax || pt < fPtMin)
321 {
322// printf("\n failed pt cut %f %f %f \n",pt,fPtMin,fPtMax);
323 return kFALSE;
324 }
325//
326// momentum cut
327 Float_t p=TMath::Sqrt(px*px+py*py+pz*pz);
328 if (p > fPMax || p < fPMin)
329 {
330// printf("\n failed p cut %f %f %f \n",p,fPMin,fPMax);
331 return kFALSE;
332 }
333
334//
335// theta cut
5be1fe76 336 Float_t theta = Float_t(TMath::ATan2(Double_t(pt),Double_t(pz)));
fe4da5cc 337 if (theta > fThetaMax || theta < fThetaMin)
338 {
339// printf("\n failed theta cut %f %f %f \n",theta,fThetaMin,fThetaMax);
340 return kFALSE;
341 }
342
343//
344// rapidity cut
345 Float_t y = 0.5*TMath::Log((e+pz)/(e-pz));
346 if (y > fYMax || y < fYMin)
347 {
348// printf("\n failed y cut %f %f %f \n",y,fYMin,fYMax);
349 return kFALSE;
350 }
351
352//
353// phi cut
354 Float_t phi=Float_t(TMath::ATan2(Double_t(py),Double_t(px)))+TMath::Pi();
355 if (phi > fPhiMax || phi < fPhiMin)
356 {
357// printf("\n failed phi cut %f %f %f \n",phi,fPhiMin,fPhiMax);
358 return kFALSE;
359 }
360
361 return kTRUE;
362}
363void AliGenPythia::AdjustWeights()
364{
365 TClonesArray *PartArray = gAlice->Particles();
1578254f 366 TParticle *Part;
fe4da5cc 367 Int_t ntrack=gAlice->GetNtrack();
368 for (Int_t i=0; i<ntrack; i++) {
1578254f 369 Part= (TParticle*) PartArray->UncheckedAt(i);
370 Part->SetWeight(Part->GetWeight()*fKineBias);
fe4da5cc 371 }
372}
373
a8228d85 374Int_t AliGenPythia::CheckPDGCode(Int_t pdgcode)
375{
376//
377// If the particle is in a diffractive state, then take action accordigly
378 switch (pdgcode) {
379 case 110:
380 //rho_diff0 -- difficult to translate, return rho0
381 return 113;
382 case 210:
383 //pi_diffr+ -- change to pi+
384 return 211;
385 case 220:
386 //omega_di0 -- change to omega0
387 return 223;
388 case 330:
389 //phi_diff0 -- return phi0
390 return 333;
391 case 440:
392 //J/psi_di0 -- return J/psi
393 return 443;
394 case 2110:
395 //n_diffr -- return neutron
396 return 2112;
397 case 2210:
398 //p_diffr+ -- return proton
399 return 2212;
400 }
401 //non diffractive state -- return code unchanged
402 return pdgcode;
403}
404
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