1 #include "AliGenerator.h"
2 #include "AliGenPythia.h"
6 #include <TDirectory.h>
10 #include <AliPythia.h>
11 #include <TMCParticle.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->GetPrimaries() ;
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 TMCParticle * iparticle = (TMCParticle *) particles->At(i);
159 Int_t kf = iparticle->GetKF();
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->GetPx();
187 p[1]=iparticle->GetPy();
188 p[2]=iparticle->GetPz();
189 origin[0]=origin0[0]+iparticle->GetVx()/10;
190 origin[1]=origin0[1]+iparticle->GetVy()/10;
191 origin[2]=origin0[2]+iparticle->GetVz()/10;
193 Int_t ifch=iparticle->GetFirstChild();
194 Int_t ilch=iparticle->GetLastChild();
195 if (ifch !=0 && ilch !=0) {
196 gAlice->SetTrack(0,nt_p,fPythia->GetGeantCode(kf),
198 0,"Primary",nt,fParentWeight);
199 gAlice->KeepTrack(nt);
204 for (Int_t j=ifch; j<=ilch; j++)
206 TMCParticle * ichild =
207 (TMCParticle *) particles->At(j-1);
208 Int_t kf = ichild->GetKF();
211 if (ChildSelected(TMath::Abs(kf))) {
212 Int_t kg=fPythia->GetGeantCode(kf);
213 origin[0]=ichild->GetVx();
214 origin[1]=ichild->GetVy();
215 origin[2]=ichild->GetVz();
216 p[0]=ichild->GetPx();
217 p[1]=ichild->GetPy();
218 p[2]=ichild->GetPz();
219 Float_t tof=kconv*ichild->GetTime();
220 gAlice->SetTrack(fTrackIt, iparent, kg,
222 tof,"Decay",nt,fChildWeight);
223 gAlice->KeepTrack(nt);
227 } // kinematic selection
231 for (Int_t i = 0; i<np; i++) {
232 TMCParticle * iparticle = (TMCParticle *) particles->At(i);
233 Int_t kf = iparticle->GetKF();
234 Int_t ks = iparticle->GetKS();
235 Int_t gc = fPythia->GetGeantCode(kf);
236 if (ks==1 && gc!=0 && KinematicSelection(iparticle)) {
239 // store track information
240 p[0]=iparticle->GetPx();
241 p[1]=iparticle->GetPy();
242 p[2]=iparticle->GetPz();
243 origin[0]=origin0[0]+iparticle->GetVx()/10;
244 origin[1]=origin0[1]+iparticle->GetVy()/10;
245 origin[2]=origin0[2]+iparticle->GetVz()/10;
246 Float_t tof=kconv*iparticle->GetTime();
247 gAlice->SetTrack(fTrackIt,-1,gc,p,origin,polar,
249 gAlice->KeepTrack(nt);
252 printf("\n I've put %i particles on the stack \n",nc);
257 fKineBias=Float_t(fNpart)/Float_t(fTrials);
258 printf("\n Trials: %i\n",fTrials);
263 // adjust weight due to kinematic selection
266 fXsection=fPythia->GetPARI(1);
269 Bool_t AliGenPythia::ParentSelected(Int_t ip)
271 for (Int_t i=0; i<5; i++)
273 if (fParentSelect[i]==ip) return kTRUE;
278 Bool_t AliGenPythia::ChildSelected(Int_t ip)
280 for (Int_t i=0; i<5; i++)
282 if (fChildSelect[i]==ip) return kTRUE;
287 Bool_t AliGenPythia::KinematicSelection(TMCParticle *particle)
289 Float_t px=particle->GetPx();
290 Float_t py=particle->GetPy();
291 Float_t pz=particle->GetPz();
292 Float_t e=particle->GetEnergy();
295 // transverse momentum cut
296 Float_t pt=TMath::Sqrt(px*px+py*py);
297 if (pt > fPtMax || pt < fPtMin)
299 // printf("\n failed pt cut %f %f %f \n",pt,fPtMin,fPtMax);
304 Float_t p=TMath::Sqrt(px*px+py*py+pz*pz);
305 if (p > fPMax || p < fPMin)
307 // printf("\n failed p cut %f %f %f \n",p,fPMin,fPMax);
313 Float_t theta = Float_t(TMath::ATan2(Double_t(pt),Double_t(pz)));
314 if (theta > fThetaMax || theta < fThetaMin)
316 // printf("\n failed theta cut %f %f %f \n",theta,fThetaMin,fThetaMax);
322 Float_t y = 0.5*TMath::Log((e+pz)/(e-pz));
323 if (y > fYMax || y < fYMin)
325 // printf("\n failed y cut %f %f %f \n",y,fYMin,fYMax);
331 Float_t phi=Float_t(TMath::ATan2(Double_t(py),Double_t(px)))+TMath::Pi();
332 if (phi > fPhiMax || phi < fPhiMin)
334 // printf("\n failed phi cut %f %f %f \n",phi,fPhiMin,fPhiMax);
340 void AliGenPythia::AdjustWeights()
342 TClonesArray *PartArray = gAlice->Particles();
344 Int_t ntrack=gAlice->GetNtrack();
345 for (Int_t i=0; i<ntrack; i++) {
346 Part= (GParticle*) PartArray->UncheckedAt(i);
347 Part->SetWgt(Part->GetWgt()*fKineBias);