]> git.uio.no Git - u/mrichter/AliRoot.git/blobdiff - EVGEN/AliGenHIJINGpara.cxx
New class used for primary vertex finding (AliITSVertexerTracks)
[u/mrichter/AliRoot.git] / EVGEN / AliGenHIJINGpara.cxx
index 9d5cb519d9aed061b1e34a336eb580cf1a2c04e0..17fae20c87a23625da0f2e929e0f270a4420ee1b 100644 (file)
 
 /*
 $Log$
+Revision 1.19  2003/01/14 10:50:18  alibrary
+Cleanup of STEER coding conventions
+
+Revision 1.18  2002/12/11 11:58:11  morsch
+Bug in formula for pi0 energy for decay corrected.
+
+Revision 1.17  2002/12/10 17:44:57  morsch
+Correct mother child relation for pi0.
+
+Revision 1.16  2002/11/28 11:46:15  morsch
+Don't track pi0 if already decayed.
+
+Revision 1.15  2002/11/28 11:38:53  morsch
+Typo corrected.
+
+Revision 1.14  2002/11/26 17:12:36  morsch
+Decay pi0 if requested.
+
+Revision 1.13  2002/10/14 14:55:35  hristov
+Merging the VirtualMC branch to the main development branch (HEAD)
+
+Revision 1.11.4.1  2002/07/24 08:56:28  alibrary
+Updating EVGEN on TVirtulaMC
+
+Revision 1.12  2002/06/19 06:56:34  hristov
+Memory leak corrected
+
+Revision 1.11  2002/03/20 10:21:13  hristov
+Set fPtMax to 15 GeV in order to avoid some numerical problems
+
+Revision 1.10  2001/10/15 16:44:46  morsch
+- Possibility for vertex distribution truncation.
+- Write mc header with vertex position.
+
+Revision 1.9  2001/07/27 17:09:36  morsch
+Use local SetTrack, KeepTrack and SetHighWaterMark methods
+to delegate either to local stack or to stack owned by AliRun.
+(Piotr Skowronski, A.M.)
+
+Revision 1.8  2001/07/20 11:03:58  morsch
+Issue warning message if used outside allowed eta range (-8 to 8).
+
+Revision 1.7  2001/07/17 12:41:01  morsch
+- Calculation of fraction of event corresponding to selected pt-range corrected
+(R. Turrisi)
+- Parent weight corrected.
+
+Revision 1.6  2001/05/16 14:57:10  alibrary
+New files for folders and Stack
+
+Revision 1.5  2000/12/21 16:24:06  morsch
+Coding convention clean-up
+
 Revision 1.4  2000/11/30 07:12:50  alibrary
 Introducing new Rndm and QA classes
 
@@ -52,11 +105,19 @@ All coding rule violations except RS3 corrected (AM)
 //                                                               //
 ///////////////////////////////////////////////////////////////////
 
+#include <TArrayF.h>
+#include <TClonesArray.h>
+#include <TDatabasePDG.h>
+#include <TF1.h>
+#include <TParticle.h>
+#include <TPDGCode.h>
+
+#include "AliConst.h"
+#include "AliDecayer.h"
+#include "AliDecayerPythia.h"
+#include "AliGenEventHeader.h"
 #include "AliGenHIJINGpara.h"
-#include "TF1.h"
 #include "AliRun.h"
-#include "AliConst.h"
-#include "AliPDG.h"
 
 ClassImp(AliGenHIJINGpara)
 
@@ -168,10 +229,15 @@ AliGenHIJINGpara::AliGenHIJINGpara()
     //
     // Default constructor
     //
-    fPtpi = 0;
-    fPtka = 0;
-    fETApic = 0;
-    fETAkac = 0;
+    fPtpi    =  0;
+    fPtka    =  0;
+    fETApic  =  0;
+    fETAkac  =  0;
+    fDecayer =  0;
+    fNt      = -1;
+    SetCutVertexZ();
+    SetPtRange();
+    SetPi0Decays();
 }
 
 //_____________________________________________________________________________
@@ -181,12 +247,17 @@ AliGenHIJINGpara::AliGenHIJINGpara(Int_t npart)
   // 
   // Standard constructor
   //
-    fName="HIGINGpara";
+    fName="HIJINGpara";
     fTitle="HIJING Parametrisation Particle Generator";
-    fPtpi = 0;
-    fPtka = 0;
-    fETApic = 0;
-    fETAkac = 0;
+    fPtpi    =  0;
+    fPtka    =  0;
+    fETApic  =  0;
+    fETAkac  =  0;
+    fDecayer =  0;
+    fNt      = -1;
+    SetCutVertexZ();
+    SetPtRange();
+    SetPi0Decays();
 }
 
 //_____________________________________________________________________________
@@ -211,33 +282,54 @@ void AliGenHIJINGpara::Init()
        TMath::Min((Double_t)fThetaMax/2,TMath::Pi()/2-1.e-10)));
     Float_t etaMax = -TMath::Log(TMath::Tan(
        TMath::Max((Double_t)fThetaMin/2,1.e-10)));
-    fPtpi = new TF1("ptpi",&ptpi,0,20,0);
-    fPtka = new TF1("ptka",&ptka,0,20,0);
+    fPtpi   = new TF1("ptpi",&ptpi,0,20,0);
+    fPtka   = new TF1("ptka",&ptka,0,20,0);
     fETApic = new TF1("etapic",&etapic,etaMin,etaMax,0);
     fETAkac = new TF1("etakac",&etakac,etaMin,etaMax,0);
-    TF1 *etaPic0 = new TF1("etapic",&etapic,-7,7,0);
-    TF1 *etaKac0 = new TF1("etakac",&etakac,-7,7,0);
-    Float_t intETApi  = etaPic0->Integral(-0.5, 0.5);
-    Float_t intETAka  = etaKac0->Integral(-0.5, 0.5);
-    Float_t scalePi=7316/(intETApi/1.5);
-    Float_t scaleKa= 684/(intETAka/2.0);
-    
-    Float_t intPt  = (0.877*etaPic0->Integral(0, 15)+
-                     0.123*etaKac0->Integral(0, 15));
-    Float_t intPtSel = (0.877*etaPic0->Integral(fPtMin, fPtMax)+
-                       0.123*etaKac0->Integral(fPtMin, fPtMax));
-    Float_t ptFrac = intPtSel/intPt;
-    
-    
-    Float_t intETASel  = (scalePi*etaPic0->Integral(etaMin, etaMax)+
-                         scaleKa*etaKac0->Integral(etaMin, etaMax));
-    Float_t phiFrac = (fPhiMax-fPhiMin)/2/TMath::Pi();
-    fParentWeight = Float_t(fNpart)/intETASel*ptFrac*phiFrac;
-    
-    printf("\n The number of particles in the selected kinematic region corresponds to %f percent of a full event\n ", 100.*fParentWeight);
+
+    TF1 etaPic0("etapic",&etapic,-7,7,0);
+    TF1 etaKac0("etakac",&etakac,-7,7,0);
+
+    TF1 ptPic0("ptpi",&ptpi,0.,15.,0);
+    TF1 ptKac0("ptka",&ptka,0.,15.,0);
+
+    Float_t intETApi  = etaPic0.Integral(-0.5, 0.5);
+    Float_t intETAka  = etaKac0.Integral(-0.5, 0.5);
+    Float_t scalePi   = 7316/(intETApi/1.5);
+    Float_t scaleKa   =  684/(intETAka/2.0);
+
+//  Fraction of events corresponding to the selected pt-range    
+    Float_t intPt    = (0.877*ptPic0.Integral(0, 15)+
+                       0.123*ptKac0.Integral(0, 15));
+    Float_t intPtSel = (0.877*ptPic0.Integral(fPtMin, fPtMax)+
+                       0.123*ptKac0.Integral(fPtMin, fPtMax));
+    Float_t ptFrac   = intPtSel/intPt;
+
+//  Fraction of events corresponding to the selected eta-range    
+    Float_t intETASel  = (scalePi*etaPic0.Integral(etaMin, etaMax)+
+                         scaleKa*etaKac0.Integral(etaMin, etaMax));
+//  Fraction of events corresponding to the selected phi-range    
+    Float_t phiFrac    = (fPhiMax-fPhiMin)/2/TMath::Pi();
+
+    fParentWeight = Float_t(fNpart)/(intETASel*ptFrac*phiFrac);
     
+    printf("%s: The number of particles in the selected kinematic region corresponds to %f percent of a full event\n ", 
+          ClassName(),100.*fParentWeight);
+
+// Issue warning message if etaMin or etaMax are outside the alowed range 
+// of the parametrization
+    if (etaMin < -8.001 || etaMax > 8.001) {
+       printf("\n \n WARNING FROM AliGenHIJINGPara !");
+       printf("\n YOU ARE USING THE PARAMETERISATION OUTSIDE ");       
+       printf("\n THE ALLOWED PSEUDORAPIDITY RANGE (-8. - 8.)");           
+       printf("\n YOUR LIMITS: %f %f \n \n ", etaMin, etaMax);
+    }
+//
+//
+    if (fPi0Decays) fDecayer = new AliDecayerPythia();
 }
 
+
 //_____________________________________________________________________________
 void AliGenHIJINGpara::Generate()
 {
@@ -257,7 +349,7 @@ void AliGenHIJINGpara::Generate()
     Float_t pt, pl, ptot;
     Float_t phi, theta;
     Float_t p[3];
-    Int_t i, part, nt, j;
+    Int_t i, part, j;
     //
     TF1 *ptf;
     TF1 *etaf;
@@ -265,20 +357,32 @@ void AliGenHIJINGpara::Generate()
     Float_t random[6];
     //
     for (j=0;j<3;j++) origin[j]=fOrigin[j];
-    if(fVertexSmear==kPerEvent) {
-       Rndm(random,6);
-       for (j=0;j<3;j++) {
-           origin[j]+=fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
-               TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
+
+    if(fVertexSmear == kPerEvent) {
+       Float_t dv[3];
+       dv[2] = 1.e10;
+       while(TMath::Abs(dv[2]) > fCutVertexZ*fOsigma[2]) {
+           Rndm(random,6);
+           for (j=0; j < 3; j++) {
+               dv[j] = fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
+                   TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
+           }
        }
-    }
+       for (j=0; j < 3; j++) origin[j] += dv[j];
+    } // if kPerEvent
+    TArrayF eventVertex;
+    eventVertex.Set(3);
+    eventVertex[0] = origin[0];
+    eventVertex[1] = origin[1];
+    eventVertex[2] = origin[2];
+
     for(i=0;i<fNpart;i++) {
        while(1) {
            Rndm(random,3);
            if(random[0]<kBorne) {
                part=kPions[Int_t (random[1]*3)];
                ptf=fPtpi;
-             etaf=fETApic;
+               etaf=fETApic;
            } else {
                part=kKaons[Int_t (random[1]*4)];
                ptf=fPtka;
@@ -301,10 +405,28 @@ void AliGenHIJINGpara::Generate()
                        TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
                }
            }
-           gAlice->SetTrack(fTrackIt,-1,part,p,origin,polar,0,kPPrimary,nt,fParentWeight);
+           if (part == kPi0 && fPi0Decays){
+//
+//          Decay pi0 if requested
+               SetTrack(0,-1,part,p,origin,polar,0,kPPrimary,fNt,fParentWeight);
+               KeepTrack(fNt);
+               DecayPi0(origin, p);
+           } else {
+               SetTrack(fTrackIt,-1,part,p,origin,polar,0,kPPrimary,fNt,fParentWeight);
+               KeepTrack(fNt);
+           }
+
            break;
        }
+       SetHighWaterMark(fNt);
     }
+//
+
+// Header
+    AliGenEventHeader* header = new AliGenEventHeader("HIJINGparam");
+// Event Vertex
+    header->SetPrimaryVertex(eventVertex);
+    gAlice->SetGenEventHeader(header); 
 }
 
 AliGenHIJINGpara& AliGenHIJINGpara::operator=(const  AliGenHIJINGpara& rhs)
@@ -313,4 +435,42 @@ AliGenHIJINGpara& AliGenHIJINGpara::operator=(const  AliGenHIJINGpara& rhs)
     return *this;
 }
 
+void AliGenHIJINGpara::SetPtRange(Float_t ptmin, Float_t ptmax) {
+    AliGenerator::SetPtRange(ptmin, ptmax);
+}
 
+void AliGenHIJINGpara::DecayPi0(Float_t* orig, Float_t * p) 
+{
+//
+//    Decay the pi0
+//    and put decay products on the stack
+//
+    static TClonesArray *particles;
+    if(!particles) particles = new TClonesArray("TParticle",1000);
+//    
+    const Float_t kMass = TDatabasePDG::Instance()->GetParticle(kPi0)->Mass();
+    Float_t       e     = TMath::Sqrt(p[0] * p[0] + p[1] * p[1] + p[2] * p[2]+ kMass * kMass);
+//
+//  Decay the pi0    
+    TLorentzVector pmom(p[0], p[1], p[2], e);
+    fDecayer->Decay(kPi0, &pmom);
+    
+//
+// Put decay particles on the stack
+//
+    Float_t polar[3] = {0., 0., 0.};
+    Int_t np = fDecayer->ImportParticles(particles);
+    Int_t nt;    
+    for (Int_t i = 1; i < np; i++)
+    {
+       TParticle* iParticle =  (TParticle *) particles->At(i);
+       p[0] = iParticle->Px();
+       p[1] = iParticle->Py();
+       p[2] = iParticle->Pz();
+       Int_t part = iParticle->GetPdgCode();
+
+       SetTrack(fTrackIt, fNt, part, p, orig, polar, 0, kPDecay, nt, fParentWeight);
+       KeepTrack(nt);
+    }
+    fNt = nt;
+}