Add method for computing true impact parameter (only for D+ for now)

diff --git a/PWGHF/vertexingHF/AliVertexingHFUtils.cxx b/PWGHF/vertexingHF/AliVertexingHFUtils.cxx
index 71838036fdca0e09c94a6759dadf6a3979b45419..5441ccb331ee5caea74d0f15cfed579d6755fe70 100644 (file)
--- a/PWGHF/vertexingHF/AliVertexingHFUtils.cxx
+++ b/PWGHF/vertexingHF/AliVertexingHFUtils.cxx
@@ -15,8 +15,15 @@
 
 #include <TMath.h>
 #include <TRandom.h>
+#include <TProfile.h>
+#include <TClonesArray.h>
+#include <TH1F.h>
+#include <TH2F.h>
+#include <TF1.h>
 #include "AliAODEvent.h"
+#include "AliAODMCHeader.h"
 #include "AliAODMCParticle.h"
+#include "AliAODRecoDecayHF.h"
 #include "AliVertexingHFUtils.h"
 
 /* $Id$ */
@@ -288,6 +295,92 @@ void AliVertexingHFUtils::AveragePt(Float_t& averagePt, Float_t& errorPt,Float_t
   delete hMptSig;
 
 }
+//____________________________________________________________________________
+Double_t AliVertexingHFUtils::GetTrueImpactParameterDplus(AliAODMCHeader *mcHeader, TClonesArray* arrayMC, AliAODMCParticle *partD) {
+  // true impact parameter calculation for Dplus
+
+  if(!partD || !arrayMC || !mcHeader) return 99999.;
+  Int_t code=partD->GetPdgCode();
+  if(TMath::Abs(code)!=411) return 99999.;
+
+  Double_t vtxTrue[3];
+  mcHeader->GetVertex(vtxTrue);
+  Double_t origD[3];
+  partD->XvYvZv(origD);
+  Short_t charge=partD->Charge();
+  Double_t pXdauTrue[3],pYdauTrue[3],pZdauTrue[3];
+  for(Int_t iDau=0; iDau<3; iDau++){
+    pXdauTrue[iDau]=0.;
+    pYdauTrue[iDau]=0.;
+    pZdauTrue[iDau]=0.;
+  }
+
+  Int_t nDau=partD->GetNDaughters();
+  Int_t labelFirstDau = partD->GetDaughter(0); 
+  if(nDau==3){
+    for(Int_t iDau=0; iDau<3; iDau++){
+      Int_t ind = labelFirstDau+iDau;
+      AliAODMCParticle* part = dynamic_cast<AliAODMCParticle*>(arrayMC->At(ind));
+      if(!part){
+       printf("Daughter particle not found in MC array");
+       return 99999.;
+      } 
+      pXdauTrue[iDau]=part->Px();
+      pYdauTrue[iDau]=part->Py();
+      pZdauTrue[iDau]=part->Pz();
+    }
+  }else if(nDau==2){
+    Int_t theDau=0;
+    for(Int_t iDau=0; iDau<2; iDau++){
+      Int_t ind = labelFirstDau+iDau;
+      AliAODMCParticle* part = dynamic_cast<AliAODMCParticle*>(arrayMC->At(ind));
+      if(!part){
+       printf("Daughter particle not found in MC array");
+       return 99999.;
+      } 
+      Int_t pdgCode=TMath::Abs(part->GetPdgCode());
+      if(pdgCode==211 || pdgCode==321){
+       pXdauTrue[theDau]=part->Px();
+       pYdauTrue[theDau]=part->Py();
+       pZdauTrue[theDau]=part->Pz();
+       ++theDau;
+      }else{
+       Int_t nDauRes=part->GetNDaughters();
+       if(nDauRes==2){
+         Int_t labelFirstDauRes = part->GetDaughter(0);        
+         for(Int_t iDauRes=0; iDauRes<2; iDauRes++){
+           Int_t indDR = labelFirstDauRes+iDauRes;
+           AliAODMCParticle* partDR = dynamic_cast<AliAODMCParticle*>(arrayMC->At(indDR));
+           if(!partDR){
+             printf("Daughter particle not found in MC array");
+             return 99999.;
+           } 
+           
+           Int_t pdgCodeDR=TMath::Abs(partDR->GetPdgCode());
+           if(pdgCodeDR==211 || pdgCodeDR==321){
+             pXdauTrue[theDau]=partDR->Px();
+             pYdauTrue[theDau]=partDR->Py();
+             pZdauTrue[theDau]=partDR->Pz();
+             ++theDau;
+           }
+         }
+       }
+      }
+    }
+    if(theDau!=3){
+      printf("Wrong number of decay prongs");
+      return 99999.;
+    }
+  }
+
+  Double_t d0dummy[3]={0.,0.,0.};
+  AliAODRecoDecayHF aodDvsMC(vtxTrue,origD,3,charge,pXdauTrue,pYdauTrue,pZdauTrue,d0dummy);
+  return aodDvsMC.ImpParXY();
+
+}
+
+
+
 //____________________________________________________________________________
 Double_t AliVertexingHFUtils::GetCorrectedNtracklets(TProfile* estimatorAvg, Double_t uncorrectedNacc, Double_t vtxZ, Double_t refMult) {
   //

diff --git a/PWGHF/vertexingHF/AliVertexingHFUtils.h b/PWGHF/vertexingHF/AliVertexingHFUtils.h
index 53b2f6993bfa7962ded77acfd16666f10f55358e..808e449754575792577afe155551190153748d9b 100644 (file)
--- a/PWGHF/vertexingHF/AliVertexingHFUtils.h
+++ b/PWGHF/vertexingHF/AliVertexingHFUtils.h
@@ -15,10 +15,14 @@
 ///////////////////////////////////////////////////////////////////
 
 #include "TObject.h"
-#include "TProfile.h"
-#include "TH1F.h"
-#include "TH2F.h"
-#include "TF1.h"
+
+class AliAODMCParticle;
+class AliAODMCHeader;
+class TProfile;
+class TClonesArray;
+class TH1F;
+class TH2F;
+class TF1;
 
 class AliVertexingHFUtils : public TObject{
  public:
@@ -73,6 +77,9 @@ class AliVertexingHFUtils : public TObject{
   // Functions for computing average pt 
   static void AveragePt(Float_t& averagePt, Float_t& errorPt, Float_t ptmin, Float_t ptmax, TH2F* hMassD, Float_t massFromFit, Float_t sigmaFromFit, TF1* funcB2, Float_t sigmaRangeForSig=2.5, Float_t sigmaRangeForBkg=4.5, Int_t rebin=4);
 
+  // Functions for computing true impact parameter of D meson
+  static Double_t GetTrueImpactParameterDplus(AliAODMCHeader *mcHeader, TClonesArray* arrayMC, AliAODMCParticle *partDp);
+
   static Double_t GetCorrectedNtracklets(TProfile* estimatorAvg, Double_t uncorrectedNacc, Double_t vtxZ, Double_t refMult);
 
  private: