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