1 #include "AliGenParam.h"
2 #include "AliGenMUONlib.h"
6 #include <TDirectory.h>
10 #include <TMCParticle.h>
14 //------------------------------------------------------------
18 <img src="gif/AliGenParam.gif">
22 //____________________________________________________________
23 //____________________________________________________________
24 AliGenParam::AliGenParam()
33 //____________________________________________________________
34 AliGenParam::AliGenParam(Int_t npart, Int_t Ipart)
35 // Double_t (*PtPara)(Double_t*, Double_t*),
36 // Double_t (*YPara) (Double_t* ,Double_t*))
40 // fName="HMESONpara";
41 // fTitle="Heavy Mesons Parametrisation";
42 fPtParaFunc = AliGenMUONlib::GetPt(Ipart);
43 fYParaFunc = AliGenMUONlib::GetY(Ipart);
44 fIpParaFunc = AliGenMUONlib::GetIp(Ipart);
51 for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
55 //____________________________________________________________
56 AliGenParam::~AliGenParam()
62 //____________________________________________________________
63 void AliGenParam::Init()
65 SetMC(new AliPythia());
66 fPythia= (AliPythia*) fgMCEvGen;
68 // End of the test !!!
71 <img src="gif/AliGenParam.gif">
75 fPtPara = new TF1("Pt-Parametrization",fPtParaFunc,0,15,0);
76 fYPara = new TF1("Y -Parametrization",fYParaFunc,-6,6,0);
82 fdNdy0=fYParaFunc(&y1,&y2);
84 // Integral over generation region
85 Float_t IntYS = fYPara ->Integral(fYMin, fYMax);
86 Float_t IntPt0 = fPtPara->Integral(0,15);
87 Float_t IntPtS = fPtPara->Integral(fPtMin,fPtMax);
88 Float_t PhiWgt=(fPhiMax-fPhiMin)/2./TMath::Pi();
91 fPtWgt = IntPtS/IntPt0;
92 fParentWeight = fYWgt*fPtWgt*PhiWgt/fNpart;
95 fPtWgt = (fPtMax-fPtMin)/IntPt0;
96 fParentWeight = fYWgt*fPtWgt*PhiWgt/fNpart;
99 // particle decay related initialization
100 fPythia->DefineParticles();
101 // semimuonic decays of charm and beauty
102 fPythia->ForceDecay(fForceDecay);
108 case b_jpsi_dielectron:
109 case b_psip_dielectron:
122 //____________________________________________________________
123 void AliGenParam::Generate()
125 // Generate 'npart' of heavy mesons (J/Psi, upsilon or phi) in the
126 // the desired theta, phi and momentum windows; Gaussian smearing
127 // on the vertex is done if selected
129 AliMC* pMC = AliMC::GetMC();
131 Float_t polar[3]= {0,0,0};
133 Float_t origin[3], origin0[3];
134 Float_t pt, pl, ptot;
144 for (j=0;j<3;j++) origin0[j]=fOrigin[j];
145 if(fVertexSmear==perEvent) {
148 origin0[j]+=fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
149 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
152 for(i=0;i<fNpart;i++) {
156 Int_t Ipart = fIpParaFunc();
157 fChildWeight=(fPythia->GetBraPart(Ipart))*fParentWeight;
158 Float_t am=fPythia->GetPMAS(fPythia->LuComp(Ipart),1);
162 phi=fPhiMin+random[0]*(fPhiMax-fPhiMin);
165 ty=Float_t(TMath::TanH(fYPara->GetRandom()));
169 pt=fPtPara->GetRandom();
173 pt=fPtMin+random[1]*(fPtMax-fPtMin);
175 wgtp=fParentWeight*fPtParaFunc(& ptd, &dummy);
176 wgtch=fChildWeight*fPtParaFunc(& ptd, &dummy);
178 xmt=sqrt(pt*pt+am*am);
179 pl=xmt*ty/sqrt(1.-ty*ty);
180 theta=TMath::ATan2(pt,pl);
181 if(theta<fThetaMin || theta>fThetaMax) continue;
182 ptot=TMath::Sqrt(pt*pt+pl*pl);
183 if(ptot<fPMin || ptot>fPMax) continue;
184 p[0]=pt*TMath::Cos(phi);
185 p[1]=pt*TMath::Sin(phi);
187 if(fVertexSmear==perTrack) {
191 fOrigin[j]+fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
192 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
196 Int_t kg=fPythia->GetGeantCode(Ipart);
201 SetTrack(0,-1,kg,p,origin,polar,0,"Primary",nt,wgtp);
204 // use lujet to decay particle
206 Float_t energy=TMath::Sqrt(ptot*ptot+am*am);
207 fPythia->DecayParticle(Ipart,energy,theta,phi);
210 TObjArray* particles = fPythia->GetPrimaries() ;
211 Int_t np = particles->GetEntriesFast();
212 for (Int_t i = 0; i<np; i++) {
213 TMCParticle * iparticle = (TMCParticle *) particles->At(i);
214 Int_t kf = iparticle->GetKF();
217 if (ChildSelected(TMath::Abs(kf)))
219 p[0]=iparticle->GetPx();
220 p[1]=iparticle->GetPy();
221 p[2]=iparticle->GetPz();
222 origin[0]=origin0[0]+iparticle->GetVx()/10;
223 origin[1]=origin0[1]+iparticle->GetVy()/10;
224 origin[2]=origin0[2]+iparticle->GetVz()/10;
225 gAlice->SetTrack(1,iparent,fPythia->GetGeantCode(kf),
228 gAlice->KeepTrack(nt);
230 } // decay particle loop
232 } // kinematic selection
236 Bool_t AliGenParam::ChildSelected(Int_t ip)
238 for (Int_t i=0; i<5; i++)
240 if (fChildSelect[i]==ip) return kTRUE;
245 Bool_t AliGenParam::KinematicSelection(TMCParticle *particle)
247 Float_t px=particle->GetPx();
248 Float_t py=particle->GetPy();
249 Float_t pz=particle->GetPz();
252 Float_t p=TMath::Sqrt(px*px+py*py+pz*pz);
253 if (p > fPMax || p < fPMin)
255 // printf("\n failed p cut %f %f %f \n",p,fPMin,fPMax);
258 Float_t pt=TMath::Sqrt(px*px+py*py);
262 Float_t theta = Float_t(TMath::ATan2(Double_t(pt),Double_t(p)));
263 if (theta > fThetaMax || theta < fThetaMin)
265 // printf("\n failed theta cut %f %f %f \n",theta,fThetaMin,fThetaMax);