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[u/mrichter/AliRoot.git] / EVGEN / AliGenPythia.cxx
CommitLineData
fe4da5cc 1#include "AliGenerator.h"
2#include "AliGenPythia.h"
fe4da5cc 3#include "AliRun.h"
4#include "AliPythia.h"
5#include <TDirectory.h>
6#include <TFile.h>
7#include <TTree.h>
8#include <stdlib.h>
9#include <AliPythia.h>
1578254f 10#include <TParticle.h>
11//#include <GParticle.h>
fe4da5cc 12 ClassImp(AliGenPythia)
13
14AliGenPythia::AliGenPythia()
15 :AliGenerator()
16{
17}
18
19AliGenPythia::AliGenPythia(Int_t npart)
20 :AliGenerator(npart)
21{
22// default charm production at 5. 5 TeV
23// semimuonic decay
24// structure function GRVHO
25//
26 fXsection = 0.;
27 fParentSelect.Set(5);
28 fChildSelect.Set(5);
29 for (Int_t i=0; i<5; i++) fParentSelect[i]=fChildSelect[i]=0;
30 SetProcess();
31 SetStrucFunc();
32 ForceDecay();
33 SetPtHard();
34 SetEnergyCMS();
35}
36
37AliGenPythia::~AliGenPythia()
38{
39}
40
41void AliGenPythia::Init()
42{
43 SetMC(new AliPythia());
44 fPythia=(AliPythia*) fgMCEvGen;
45//
46 fParentWeight=1./Float_t(fNpart);
47//
48// Forward Paramters to the AliPythia object
49 fPythia->DefineParticles();
fe4da5cc 50 fPythia->SetCKIN(3,fPtHardMin);
51 fPythia->SetCKIN(4,fPtHardMax);
52 fPythia->ProcInit(fProcess,fEnergyCMS,fStrucFunc);
5be1fe76 53 fPythia->ForceDecay(fForceDecay);
fe4da5cc 54 fPythia->LuList(0);
55 fPythia->PyStat(2);
56// Parent and Children Selection
57 switch (fProcess)
58 {
59 case charm:
60
61 fParentSelect[0]=411;
62 fParentSelect[1]=421;
63 fParentSelect[2]=431;
64 fParentSelect[3]=4122;
65 break;
66 case charm_unforced:
67
68 fParentSelect[0]=411;
69 fParentSelect[1]=421;
70 fParentSelect[2]=431;
71 fParentSelect[3]=4122;
72 break;
73 case beauty:
74 fParentSelect[0]=511;
75 fParentSelect[1]=521;
76 fParentSelect[2]=531;
77 fParentSelect[3]=5122;
78 break;
79 case beauty_unforced:
80 fParentSelect[0]=511;
81 fParentSelect[1]=521;
82 fParentSelect[2]=531;
83 fParentSelect[3]=5122;
84 break;
85 case jpsi_chi:
86 case jpsi:
87 fParentSelect[0]=443;
88 break;
5be1fe76 89 case mb:
90 break;
fe4da5cc 91 }
92
93 switch (fForceDecay)
94 {
95 case semielectronic:
96 case dielectron:
97 case b_jpsi_dielectron:
98 case b_psip_dielectron:
99 fChildSelect[0]=11;
100 break;
101 case semimuonic:
102 case dimuon:
103 case b_jpsi_dimuon:
104 case b_psip_dimuon:
5be1fe76 105 case pitomu:
106 case katomu:
fe4da5cc 107 fChildSelect[0]=13;
108 break;
109 }
110}
111
112void AliGenPythia::Generate()
113{
fe4da5cc 114
5be1fe76 115 Float_t polar[3] = {0,0,0};
116 Float_t origin[3]= {0,0,0};
117 Float_t origin_p[3]= {0,0,0};
118 Float_t origin0[3]= {0,0,0};
119 Float_t p[3], p_p[4], random[6];
09fd3ea2 120 static TClonesArray *particles;
5be1fe76 121// converts from mm/c to s
122 const Float_t kconv=0.001/2.999792458e8;
fe4da5cc 123
124
125//
fe4da5cc 126 Int_t nt=0;
5be1fe76 127 Int_t nt_p=0;
fe4da5cc 128 Int_t jev=0;
7921755b 129 Int_t j, kf;
09fd3ea2 130
131 if(!particles) particles=new TClonesArray("TParticle",1000);
fe4da5cc 132
133 fTrials=0;
134 for (j=0;j<3;j++) origin0[j]=fOrigin[j];
135 if(fVertexSmear==perEvent) {
cfce8870 136 gMC->Rndm(random,6);
fe4da5cc 137 for (j=0;j<3;j++) {
138 origin0[j]+=fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
139 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
140 fPythia->SetMSTP(151,0);
141 }
142 } else if (fVertexSmear==perTrack) {
143 fPythia->SetMSTP(151,0);
144 for (j=0;j<3;j++) {
145 fPythia->SetPARP(151+j, fOsigma[j]*10.);
146 }
147 }
fe4da5cc 148 while(1)
149 {
150 fPythia->PyEvnt();
151 fTrials++;
f1092809 152 fPythia->ImportParticles(particles,"All");
fe4da5cc 153 Int_t np = particles->GetEntriesFast();
154 printf("\n **************************************************%d\n",np);
155 Int_t nc=0;
156 if (np == 0 ) continue;
5be1fe76 157 if (fProcess != mb) {
158 for (Int_t i = 0; i<np; i++) {
1578254f 159 TParticle * iparticle = (TParticle *) particles->At(i);
7921755b 160 kf = iparticle->GetPdgCode();
5be1fe76 161 fChildWeight=(fPythia->GetBraPart(kf))*fParentWeight;
fe4da5cc 162//
163// Parent
5be1fe76 164 if (ParentSelected(TMath::Abs(kf))) {
165 if (KinematicSelection(iparticle)) {
166 if (nc==0) {
167//
168// Store information concerning the hard scattering process
169//
170 Float_t mass_p = fPythia->GetPARI(13);
171 Float_t pt_p = fPythia->GetPARI(17);
172 Float_t y_p = fPythia->GetPARI(37);
173 Float_t xmt_p = sqrt(pt_p*pt_p+mass_p*mass_p);
174 Float_t ty = Float_t(TMath::TanH(y_p));
175 p_p[0] = pt_p;
176 p_p[1] = 0;
177 p_p[2] = xmt_p*ty/sqrt(1.-ty*ty);
178 p_p[3] = mass_p;
179 gAlice->SetTrack(0,-1,-1,
180 p_p,origin_p,polar,
181 0,"Hard Scat.",nt_p,fParentWeight);
182 gAlice->KeepTrack(nt_p);
183 }
184 nc++;
fe4da5cc 185//
186// store parent track information
1578254f 187 p[0]=iparticle->Px();
188 p[1]=iparticle->Py();
189 p[2]=iparticle->Pz();
190 origin[0]=origin0[0]+iparticle->Vx()/10;
191 origin[1]=origin0[1]+iparticle->Vy()/10;
192 origin[2]=origin0[2]+iparticle->Vz()/10;
fe4da5cc 193
1578254f 194 Int_t ifch=iparticle->GetFirstDaughter();
195 Int_t ilch=iparticle->GetLastDaughter();
5be1fe76 196 if (ifch !=0 && ilch !=0) {
1578254f 197 gAlice->SetTrack(0,nt_p,kf,
5be1fe76 198 p,origin,polar,
199 0,"Primary",nt,fParentWeight);
200 gAlice->KeepTrack(nt);
201 Int_t iparent = nt;
fe4da5cc 202//
203// Children
204
7921755b 205 for (j=ifch; j<=ilch; j++)
5be1fe76 206 {
1578254f 207 TParticle * ichild =
208 (TParticle *) particles->At(j-1);
209 Int_t kf = ichild->GetPdgCode();
fe4da5cc 210//
211//
5be1fe76 212 if (ChildSelected(TMath::Abs(kf))) {
1578254f 213 origin[0]=ichild->Vx();
214 origin[1]=ichild->Vy();
215 origin[2]=ichild->Vz();
216 p[0]=ichild->Px();
217 p[1]=ichild->Py();
218 p[2]=ichild->Pz();
219 Float_t tof=kconv*ichild->T();
220 gAlice->SetTrack(fTrackIt, iparent, kf,
5be1fe76 221 p,origin,polar,
222 tof,"Decay",nt,fChildWeight);
223 gAlice->KeepTrack(nt);
224 } // select child
225 } // child loop
226 }
227 } // kinematic selection
228 } // select particle
229 } // particle loop
230 } else {
231 for (Int_t i = 0; i<np; i++) {
1578254f 232 TParticle * iparticle = (TParticle *) particles->At(i);
233 Int_t kf = iparticle->GetPdgCode();
234 Int_t ks = iparticle->GetStatusCode();
235 if (ks==1 && kf!=0 && KinematicSelection(iparticle)) {
5be1fe76 236 nc++;
237//
238// store track information
1578254f 239 p[0]=iparticle->Px();
240 p[1]=iparticle->Py();
241 p[2]=iparticle->Pz();
242 origin[0]=origin0[0]+iparticle->Vx()/10;
243 origin[1]=origin0[1]+iparticle->Vy()/10;
244 origin[2]=origin0[2]+iparticle->Vz()/10;
245 Float_t tof=kconv*iparticle->T();
246 gAlice->SetTrack(fTrackIt,-1,kf,p,origin,polar,
5be1fe76 247 tof,"Primary",nt);
248 gAlice->KeepTrack(nt);
249 } // select particle
250 } // particle loop
251 printf("\n I've put %i particles on the stack \n",nc);
252 } // mb ?
fe4da5cc 253 if (nc > 0) {
5be1fe76 254 jev+=nc;
fe4da5cc 255 if (jev >= fNpart) {
256 fKineBias=Float_t(fNpart)/Float_t(fTrials);
257 printf("\n Trials: %i\n",fTrials);
258 break;
259 }
260 }
261 } // event loop
262// adjust weight due to kinematic selection
263 AdjustWeights();
264// get cross-section
265 fXsection=fPythia->GetPARI(1);
266}
267
268Bool_t AliGenPythia::ParentSelected(Int_t ip)
269{
270 for (Int_t i=0; i<5; i++)
271 {
272 if (fParentSelect[i]==ip) return kTRUE;
273 }
274 return kFALSE;
275}
276
277Bool_t AliGenPythia::ChildSelected(Int_t ip)
278{
279 for (Int_t i=0; i<5; i++)
280 {
281 if (fChildSelect[i]==ip) return kTRUE;
282 }
283 return kFALSE;
284}
285
1578254f 286Bool_t AliGenPythia::KinematicSelection(TParticle *particle)
fe4da5cc 287{
1578254f 288 Float_t px=particle->Px();
289 Float_t py=particle->Py();
290 Float_t pz=particle->Pz();
291 Float_t e=particle->Energy();
fe4da5cc 292
293//
294// transverse momentum cut
295 Float_t pt=TMath::Sqrt(px*px+py*py);
296 if (pt > fPtMax || pt < fPtMin)
297 {
298// printf("\n failed pt cut %f %f %f \n",pt,fPtMin,fPtMax);
299 return kFALSE;
300 }
301//
302// momentum cut
303 Float_t p=TMath::Sqrt(px*px+py*py+pz*pz);
304 if (p > fPMax || p < fPMin)
305 {
306// printf("\n failed p cut %f %f %f \n",p,fPMin,fPMax);
307 return kFALSE;
308 }
309
310//
311// theta cut
5be1fe76 312 Float_t theta = Float_t(TMath::ATan2(Double_t(pt),Double_t(pz)));
fe4da5cc 313 if (theta > fThetaMax || theta < fThetaMin)
314 {
315// printf("\n failed theta cut %f %f %f \n",theta,fThetaMin,fThetaMax);
316 return kFALSE;
317 }
318
319//
320// rapidity cut
321 Float_t y = 0.5*TMath::Log((e+pz)/(e-pz));
322 if (y > fYMax || y < fYMin)
323 {
324// printf("\n failed y cut %f %f %f \n",y,fYMin,fYMax);
325 return kFALSE;
326 }
327
328//
329// phi cut
330 Float_t phi=Float_t(TMath::ATan2(Double_t(py),Double_t(px)))+TMath::Pi();
331 if (phi > fPhiMax || phi < fPhiMin)
332 {
333// printf("\n failed phi cut %f %f %f \n",phi,fPhiMin,fPhiMax);
334 return kFALSE;
335 }
336
337 return kTRUE;
338}
339void AliGenPythia::AdjustWeights()
340{
341 TClonesArray *PartArray = gAlice->Particles();
1578254f 342 TParticle *Part;
fe4da5cc 343 Int_t ntrack=gAlice->GetNtrack();
344 for (Int_t i=0; i<ntrack; i++) {
1578254f 345 Part= (TParticle*) PartArray->UncheckedAt(i);
346 Part->SetWeight(Part->GetWeight()*fKineBias);
fe4da5cc 347 }
348}
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