1 #include "AliGenerator.h"
2 #include "AliGenPythia.h"
6 #include <TDirectory.h>
10 #include <AliPythia.h>
11 #include <TParticle.h>
12 //#include <GParticle.h>
13 ClassImp(AliGenPythia)
15 AliGenPythia::AliGenPythia()
20 AliGenPythia::AliGenPythia(Int_t npart)
23 // default charm production at 5. 5 TeV
25 // structure function GRVHO
30 for (Int_t i=0; i<5; i++) fParentSelect[i]=fChildSelect[i]=0;
38 AliGenPythia::~AliGenPythia()
42 void AliGenPythia::Init()
44 SetMC(new AliPythia());
45 fPythia=(AliPythia*) fgMCEvGen;
47 fParentWeight=1./Float_t(fNpart);
49 // Forward Paramters to the AliPythia object
50 fPythia->DefineParticles();
51 fPythia->SetCKIN(3,fPtHardMin);
52 fPythia->SetCKIN(4,fPtHardMax);
53 fPythia->ProcInit(fProcess,fEnergyCMS,fStrucFunc);
54 fPythia->ForceDecay(fForceDecay);
57 // Parent and Children Selection
65 fParentSelect[3]=4122;
72 fParentSelect[3]=4122;
78 fParentSelect[3]=5122;
84 fParentSelect[3]=5122;
98 case b_jpsi_dielectron:
99 case b_psip_dielectron:
113 void AliGenPythia::Generate()
115 AliMC* pMC = AliMC::GetMC();
117 Float_t polar[3] = {0,0,0};
118 Float_t origin[3]= {0,0,0};
119 Float_t origin_p[3]= {0,0,0};
120 Float_t origin0[3]= {0,0,0};
121 Float_t p[3], p_p[4], random[6];
122 // converts from mm/c to s
123 const Float_t kconv=0.001/2.999792458e8;
133 for (j=0;j<3;j++) origin0[j]=fOrigin[j];
134 if(fVertexSmear==perEvent) {
137 origin0[j]+=fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
138 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
139 fPythia->SetMSTP(151,0);
141 } else if (fVertexSmear==perTrack) {
142 fPythia->SetMSTP(151,0);
144 fPythia->SetPARP(151+j, fOsigma[j]*10.);
151 TObjArray* particles = fPythia->ImportParticles();
152 Int_t np = particles->GetEntriesFast();
153 printf("\n **************************************************%d\n",np);
155 if (np == 0 ) continue;
156 if (fProcess != mb) {
157 for (Int_t i = 0; i<np; i++) {
158 TParticle * iparticle = (TParticle *) particles->At(i);
159 Int_t kf = iparticle->GetPdgCode();
160 fChildWeight=(fPythia->GetBraPart(kf))*fParentWeight;
163 if (ParentSelected(TMath::Abs(kf))) {
164 if (KinematicSelection(iparticle)) {
167 // Store information concerning the hard scattering process
169 Float_t mass_p = fPythia->GetPARI(13);
170 Float_t pt_p = fPythia->GetPARI(17);
171 Float_t y_p = fPythia->GetPARI(37);
172 Float_t xmt_p = sqrt(pt_p*pt_p+mass_p*mass_p);
173 Float_t ty = Float_t(TMath::TanH(y_p));
176 p_p[2] = xmt_p*ty/sqrt(1.-ty*ty);
178 gAlice->SetTrack(0,-1,-1,
180 0,"Hard Scat.",nt_p,fParentWeight);
181 gAlice->KeepTrack(nt_p);
185 // store parent track information
186 p[0]=iparticle->Px();
187 p[1]=iparticle->Py();
188 p[2]=iparticle->Pz();
189 origin[0]=origin0[0]+iparticle->Vx()/10;
190 origin[1]=origin0[1]+iparticle->Vy()/10;
191 origin[2]=origin0[2]+iparticle->Vz()/10;
193 Int_t ifch=iparticle->GetFirstDaughter();
194 Int_t ilch=iparticle->GetLastDaughter();
195 if (ifch !=0 && ilch !=0) {
196 gAlice->SetTrack(0,nt_p,kf,
198 0,"Primary",nt,fParentWeight);
199 gAlice->KeepTrack(nt);
204 for (Int_t j=ifch; j<=ilch; j++)
207 (TParticle *) particles->At(j-1);
208 Int_t kf = ichild->GetPdgCode();
211 if (ChildSelected(TMath::Abs(kf))) {
212 origin[0]=ichild->Vx();
213 origin[1]=ichild->Vy();
214 origin[2]=ichild->Vz();
218 Float_t tof=kconv*ichild->T();
219 gAlice->SetTrack(fTrackIt, iparent, kf,
221 tof,"Decay",nt,fChildWeight);
222 gAlice->KeepTrack(nt);
226 } // kinematic selection
230 for (Int_t i = 0; i<np; i++) {
231 TParticle * iparticle = (TParticle *) particles->At(i);
232 Int_t kf = iparticle->GetPdgCode();
233 Int_t ks = iparticle->GetStatusCode();
234 if (ks==1 && kf!=0 && KinematicSelection(iparticle)) {
237 // store track information
238 p[0]=iparticle->Px();
239 p[1]=iparticle->Py();
240 p[2]=iparticle->Pz();
241 origin[0]=origin0[0]+iparticle->Vx()/10;
242 origin[1]=origin0[1]+iparticle->Vy()/10;
243 origin[2]=origin0[2]+iparticle->Vz()/10;
244 Float_t tof=kconv*iparticle->T();
245 gAlice->SetTrack(fTrackIt,-1,kf,p,origin,polar,
247 gAlice->KeepTrack(nt);
250 printf("\n I've put %i particles on the stack \n",nc);
255 fKineBias=Float_t(fNpart)/Float_t(fTrials);
256 printf("\n Trials: %i\n",fTrials);
261 // adjust weight due to kinematic selection
264 fXsection=fPythia->GetPARI(1);
267 Bool_t AliGenPythia::ParentSelected(Int_t ip)
269 for (Int_t i=0; i<5; i++)
271 if (fParentSelect[i]==ip) return kTRUE;
276 Bool_t AliGenPythia::ChildSelected(Int_t ip)
278 for (Int_t i=0; i<5; i++)
280 if (fChildSelect[i]==ip) return kTRUE;
285 Bool_t AliGenPythia::KinematicSelection(TParticle *particle)
287 Float_t px=particle->Px();
288 Float_t py=particle->Py();
289 Float_t pz=particle->Pz();
290 Float_t e=particle->Energy();
293 // transverse momentum cut
294 Float_t pt=TMath::Sqrt(px*px+py*py);
295 if (pt > fPtMax || pt < fPtMin)
297 // printf("\n failed pt cut %f %f %f \n",pt,fPtMin,fPtMax);
302 Float_t p=TMath::Sqrt(px*px+py*py+pz*pz);
303 if (p > fPMax || p < fPMin)
305 // printf("\n failed p cut %f %f %f \n",p,fPMin,fPMax);
311 Float_t theta = Float_t(TMath::ATan2(Double_t(pt),Double_t(pz)));
312 if (theta > fThetaMax || theta < fThetaMin)
314 // printf("\n failed theta cut %f %f %f \n",theta,fThetaMin,fThetaMax);
320 Float_t y = 0.5*TMath::Log((e+pz)/(e-pz));
321 if (y > fYMax || y < fYMin)
323 // printf("\n failed y cut %f %f %f \n",y,fYMin,fYMax);
329 Float_t phi=Float_t(TMath::ATan2(Double_t(py),Double_t(px)))+TMath::Pi();
330 if (phi > fPhiMax || phi < fPhiMin)
332 // printf("\n failed phi cut %f %f %f \n",phi,fPhiMin,fPhiMax);
338 void AliGenPythia::AdjustWeights()
340 TClonesArray *PartArray = gAlice->Particles();
342 Int_t ntrack=gAlice->GetNtrack();
343 for (Int_t i=0; i<ntrack; i++) {
344 Part= (TParticle*) PartArray->UncheckedAt(i);
345 Part->SetWeight(Part->GetWeight()*fKineBias);